[RFC PATCH] rpmsg: glink: Add bounds check on tx path
Add bounds check on values read from shared memory in the tx path. In
cases where the VM is misbehaving, the transport should exit and print a
warning when bogus values may cause out of bounds to be read.
Link:
https://git.codelinaro.org/clo/la/kernel/msm-5.10/-/commit/32d9c3a2f2b6a4d1fc48d6871194f3faf3184e8b
Suggested-by: Chris Lew
Suggested-by: Sarannya S
Signed-off-by: Michal Koutný
---
drivers/rpmsg/qcom_glink_smem.c | 9 +
1 file changed, 9 insertions(+)
Why RFC? The patch is adopted from the link above. It would be good to
asses whether such conditions can also happen with rpmsg glink.
(And if so, whether the zeroed values are the best correction.)
diff --git a/drivers/rpmsg/qcom_glink_smem.c b/drivers/rpmsg/qcom_glink_smem.c
index 7a982c60a8dd..3e786e590c03 100644
--- a/drivers/rpmsg/qcom_glink_smem.c
+++ b/drivers/rpmsg/qcom_glink_smem.c
@@ -146,6 +146,11 @@ static size_t glink_smem_tx_avail(struct qcom_glink_pipe
*np)
else
avail -= FIFO_FULL_RESERVE + TX_BLOCKED_CMD_RESERVE;
+ if (avail > pipe->native.length) {
+ pr_warn_once("%s: avail clamped\n", __func__);
+ avail = 0;
+ }
+
return avail;
}
@@ -177,6 +182,10 @@ static void glink_smem_tx_write(struct qcom_glink_pipe
*glink_pipe,
unsigned int head;
head = le32_to_cpu(*pipe->head);
+ if (head > pipe->native.length) {
+ pr_warn_once("%s: head overflow\n", __func__);
+ return;
+ }
head = glink_smem_tx_write_one(pipe, head, hdr, hlen);
head = glink_smem_tx_write_one(pipe, head, data, dlen);
--
2.43.0
Re: [GIT PULL] NVDIMM/NFIT changes for 6.8
The pull request you sent on Wed, 10 Jan 2024 23:26:32 -0800: > git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm.git > tags/libnvdimm-for-6.8 has been merged into torvalds/linux.git: https://git.kernel.org/torvalds/c/a3cc31e75185f9b1ad8dc45eac77f8de788dc410 Thank you! -- Deet-doot-dot, I am a bot. https://korg.docs.kernel.org/prtracker.html
[RFC PATCH v1] vsock/test: add '--peer-port' input argument
Implement port for given CID as input argument instead of using
hardcoded value '1234'. This allows to run different test instances
on a single CID. Port argument is not required parameter and if it is
not set, then default value will be '1234' - thus we preserve previous
behaviour.
Signed-off-by: Arseniy Krasnov
---
tools/testing/vsock/util.c| 17 +++-
tools/testing/vsock/util.h| 4 +
tools/testing/vsock/vsock_diag_test.c | 18 -
tools/testing/vsock/vsock_test.c | 96 +--
tools/testing/vsock/vsock_test_zerocopy.c | 12 +--
tools/testing/vsock/vsock_uring_test.c| 16 +++-
6 files changed, 107 insertions(+), 56 deletions(-)
diff --git a/tools/testing/vsock/util.c b/tools/testing/vsock/util.c
index ae2b33c21c45..554b290fefdc 100644
--- a/tools/testing/vsock/util.c
+++ b/tools/testing/vsock/util.c
@@ -33,8 +33,7 @@ void init_signals(void)
signal(SIGPIPE, SIG_IGN);
}
-/* Parse a CID in string representation */
-unsigned int parse_cid(const char *str)
+static unsigned int parse_uint(const char *str, const char *err_str)
{
char *endptr = NULL;
unsigned long n;
@@ -42,12 +41,24 @@ unsigned int parse_cid(const char *str)
errno = 0;
n = strtoul(str, , 10);
if (errno || *endptr != '\0') {
- fprintf(stderr, "malformed CID \"%s\"\n", str);
+ fprintf(stderr, "malformed %s \"%s\"\n", err_str, str);
exit(EXIT_FAILURE);
}
return n;
}
+/* Parse a CID in string representation */
+unsigned int parse_cid(const char *str)
+{
+ return parse_uint(str, "CID");
+}
+
+/* Parse a port in string representation */
+unsigned int parse_port(const char *str)
+{
+ return parse_uint(str, "port");
+}
+
/* Wait for the remote to close the connection */
void vsock_wait_remote_close(int fd)
{
diff --git a/tools/testing/vsock/util.h b/tools/testing/vsock/util.h
index 03c88d0cb861..e95e62485959 100644
--- a/tools/testing/vsock/util.h
+++ b/tools/testing/vsock/util.h
@@ -12,10 +12,13 @@ enum test_mode {
TEST_MODE_SERVER
};
+#define DEFAULT_PEER_PORT 1234
+
/* Test runner options */
struct test_opts {
enum test_mode mode;
unsigned int peer_cid;
+ unsigned int peer_port;
};
/* A test case definition. Test functions must print failures to stderr and
@@ -35,6 +38,7 @@ struct test_case {
void init_signals(void);
unsigned int parse_cid(const char *str);
+unsigned int parse_port(const char *str);
int vsock_stream_connect(unsigned int cid, unsigned int port);
int vsock_bind_connect(unsigned int cid, unsigned int port,
unsigned int bind_port, int type);
diff --git a/tools/testing/vsock/vsock_diag_test.c
b/tools/testing/vsock/vsock_diag_test.c
index fa927ad16f8a..5e6049226b77 100644
--- a/tools/testing/vsock/vsock_diag_test.c
+++ b/tools/testing/vsock/vsock_diag_test.c
@@ -342,7 +342,7 @@ static void test_listen_socket_server(const struct
test_opts *opts)
} addr = {
.svm = {
.svm_family = AF_VSOCK,
- .svm_port = 1234,
+ .svm_port = opts->peer_port,
.svm_cid = VMADDR_CID_ANY,
},
};
@@ -378,7 +378,7 @@ static void test_connect_client(const struct test_opts
*opts)
LIST_HEAD(sockets);
struct vsock_stat *st;
- fd = vsock_stream_connect(opts->peer_cid, 1234);
+ fd = vsock_stream_connect(opts->peer_cid, opts->peer_port);
if (fd < 0) {
perror("connect");
exit(EXIT_FAILURE);
@@ -403,7 +403,7 @@ static void test_connect_server(const struct test_opts
*opts)
LIST_HEAD(sockets);
int client_fd;
- client_fd = vsock_stream_accept(VMADDR_CID_ANY, 1234, NULL);
+ client_fd = vsock_stream_accept(VMADDR_CID_ANY, opts->peer_port, NULL);
if (client_fd < 0) {
perror("accept");
exit(EXIT_FAILURE);
@@ -461,6 +461,11 @@ static const struct option longopts[] = {
.has_arg = required_argument,
.val = 'p',
},
+ {
+ .name = "peer-port",
+ .has_arg = required_argument,
+ .val = 'q',
+ },
{
.name = "list",
.has_arg = no_argument,
@@ -481,7 +486,7 @@ static const struct option longopts[] = {
static void usage(void)
{
- fprintf(stderr, "Usage: vsock_diag_test [--help]
[--control-host=] --control-port= --mode=client|server
--peer-cid= [--list] [--skip=]\n"
+ fprintf(stderr, "Usage: vsock_diag_test [--help]
[--control-host=] --control-port= --mode=client|server
--peer-cid= [--peer-port=] [--list] [--skip=]\n"
"\n"
" Server: vsock_diag_test --control-port=1234 --mode=server
--peer-cid=3\n"
" Client: vsock_diag_test
Re: [PATCH v6 09/12] x86/sgx: Restructure top-level EPC reclaim function
On Sun, 17 Dec 2023 19:44:56 -0600, Huang, Kai wrote: > > The point is, with or w/o this patch, you can only reclaim 16 EPC pages > in one > function call (as you have said you are going to remove > SGX_NR_TO_SCAN_MAX, > which is a cipher to both of us). The only difference I can see is, > with this > patch, you can have multiple calls of "isolate" and then call the > "do_reclaim" > once. > > But what's the good of having the "isolate" if the "do_reclaim" can only > reclaim > 16 pages anyway? > > Back to my last reply, are you afraid of any LRU has less than 16 pages > to > "isolate", therefore you need to loop LRUs of descendants to get 16? > Cause I > really cannot think of any other reason why you are doing this. > > I think I see your point. By capping pages reclaimed per cycle to 16, there is not much difference even if those 16 pages are spread in separate LRUs . The difference is only significant when we ever raise that cap. To preserve the current behavior of ewb loops independent on number of LRUs to loop through for each reclaiming cycle, regardless of the exact value of the page cap, I would still think current approach in the patch is reasonable choice. What do you think? To me I won't bother to do that. Having less than 16 pages in one LRU is *extremely rare* that should never happen in practice. It's pointless to make such code adjustment at this stage. Let's focus on enabling functionality first. When you have some real performance issue that is related to this, we can come back then. I have done some rethinking about this and realize this does save quite some significant work: without breaking out isolation part from sgx_reclaim_pages(), I can remove the changes to use a list for isolated pages, and no need to introduce "state" such as RECLAIM_IN_PROGRESS. About 1/3 of changes for per-cgroup reclamation will be gone. So I think I'll go this route now. The only downside may be performance if a enclave spreads its pages in different cgroups and even that is minimum impact as we limit reclamation to 16 pages a time. Let me know if someone feel strongly we need dealt with that and see some other potential issues I may have missed. Thanks Haitao
Re: [PATCH v11 2/5] ring-buffer: Introducing ring-buffer mapping functions
On Fri, 12 Jan 2024 10:06:41 -0500
Steven Rostedt wrote:
> I'm thinking both may be good, as the number of dropped events are not
> added if there's no room to put it at the end of the ring buffer. When
> there's no room, it just sets a flag that there was missed events but
> doesn't give how many events were missed.
>
> If anything, it should be in both locations. In the sub-buffer header, to
> be consistent with the read/splice version, and in the meta page were if
> there's no room to add the count, it can be accessed in the meta page.
I think the meta data page should look like this:
struct trace_buffer_meta {
__u32 meta_page_size;
__u32 meta_struct_len;
__u32 subbuf_size;
__u32 nr_subbufs;
struct {
__u64 lost_events;
__u32 id;
__u32 read;
} reader;
__u64 entries;
__u64 overrun;
__u64 read;
};
1) meta_page_size
The size of this meta page. It's the first thing the application
needs to know how much to mmap.
2) meta_struct_len
The actual length of the structure. It's the second thing the
application will look at to know what version it is dealing with.
3) subbuf_size
4) nr_subbufs
The next two is the next thing the application should do. That is to
memory map in all the sub-buffers. With 1) and this, it knows how to
do that.
The first four are needed for setup, and never changes once mapped. The
rest gets updated during the trace.
5) reader
5a) lost_events
5b) id
5c) read
This is actively needed during tracing. It is what is used to know
where and how to read the reader sub-buffer.
6) entries
7) overrun
8) read
These are useful statistics, but probably seldom really looked at.
They should be at the end.
Also notice that I converted all "unsigned long" to __u64. This is because
it is possible to have a 32 bit userspace running this on top of a 64 bit
kernel. If we were to use "long" it would be inconsistent and buggy.
Now if you need subbufs_touched and subbufs_lost. When that gets opened, it
would update the meta_struct_len accordingly, and the structure would look
like:
struct trace_buffer_meta {
__u32 meta_page_size;
__u32 meta_struct_len;
__u32 subbuf_size;
__u32 nr_subbufs;
struct {
__u64 lost_events;
__u32 id;
__u32 read;
} reader;
__u64 entries;
__u64 overrun;
__u64 read;
__u64 subbufs_touched;
__u64 subbufs_lost;
};
Make sense?
-- Steve
Re: [PATCH net-next 16/24] net: netkit, veth, tun, virt*: Use nested-BH locking for XDP redirect.
On 2023-12-18 09:52:05 [+0100], Daniel Borkmann wrote: > Hi Sebastian, Hi Daniel, > Please exclude netkit from this set given it does not support XDP, but > instead only accepts tc BPF typed programs. okay, thank you. > Thanks, > Daniel Sebastian
Re: [PATCH v11 2/5] ring-buffer: Introducing ring-buffer mapping functions
On Fri, 12 Jan 2024 09:13:02 +
Vincent Donnefort wrote:
> > > +
> > > + unsigned long subbufs_touched;
> > > + unsigned long subbufs_lost;
> > > + unsigned long subbufs_read;
> >
> > Now I'm thinking we may not want this exported, as I'm not sure it's
> > useful.
>
> touched and lost are not useful now, but it'll be for my support of the
> hypervisor tracing, that's why I added them already.
>
> subbufs_read could probably go away though as even in that case I can track
> that
> in the reader.
Yeah, but I think we can leave it off for now.
This is something we could extend the structure with. In fact, it can be
different for different buffers!
That is, since they are pretty meaningless for the normal ring buffer, I
don't think we need to export it. But if it's useful for your hypervisor
buffer, it can export it. It would be a good test to know if the extension
works. Of course, that means if the normal ring buffer needs more info, it
must also include this as well, as it will already be part of the extended
structure.
>
> >
> > Vincent, talking with Mathieu, he was suggesting that we only export what
> > we really need, and I don't think we need the above. Especially since they
> > are not exposed in the stats file.
> >
> >
> > > +
> > > + struct {
> > > + unsigned long lost_events;
> > > + __u32 id;
> > > + __u32 read;
> > > + } reader;
> >
> > The above is definitely needed, as all of it is used to read the
> > reader-page of the sub-buffer.
> >
> > lost_events is the number of lost events that happened before this
> > sub-buffer was swapped out.
> >
> > Hmm, Vincent, I just notice that you update the lost_events as:
> >
> > > +static void rb_update_meta_page(struct ring_buffer_per_cpu *cpu_buffer)
> > > +{
> > > + struct trace_buffer_meta *meta = cpu_buffer->meta_page;
> > > +
> > > + WRITE_ONCE(meta->entries, local_read(_buffer->entries));
> > > + WRITE_ONCE(meta->overrun, local_read(_buffer->overrun));
> > > + WRITE_ONCE(meta->read, cpu_buffer->read);
> > > +
> > > + WRITE_ONCE(meta->subbufs_touched,
> > > local_read(_buffer->pages_touched));
> > > + WRITE_ONCE(meta->subbufs_lost, local_read(_buffer->pages_lost));
> > > + WRITE_ONCE(meta->subbufs_read, local_read(_buffer->pages_read));
> > > +
> > > + WRITE_ONCE(meta->reader.read, cpu_buffer->reader_page->read);
> > > + WRITE_ONCE(meta->reader.id, cpu_buffer->reader_page->id);
> > > + WRITE_ONCE(meta->reader.lost_events, cpu_buffer->lost_events);
> > > +}
> >
> > The lost_events may need to be handled differently, as it doesn't always
> > get cleared. So it may be stale data.
>
> My idea was to check this value after the ioctl(). If > 0 then events were
> lost
> between the that ioctl() and the previous swap.
>
> But now if with "[PATCH] ring-buffer: Have mmapped ring buffer keep track of
> missed events" we put this information in the page itself, we can get rid of
> this field.
>
I'm thinking both may be good, as the number of dropped events are not
added if there's no room to put it at the end of the ring buffer. When
there's no room, it just sets a flag that there was missed events but
doesn't give how many events were missed.
If anything, it should be in both locations. In the sub-buffer header, to
be consistent with the read/splice version, and in the meta page were if
there's no room to add the count, it can be accessed in the meta page.
-- Steve
Re: [PATCH] tracefs/eventfs: Use root and instance inodes as default ownership
On Fri, 12 Jan 2024 08:53:44 -0500
Steven Rostedt wrote:
> > // We managed to open the directory so we have permission to list
> > // directory entries in "xfs".
> > fd = open("/sys/kernel/tracing/events/xfs");
> >
> > // Remove ownership so we can't open the directory anymore
> > chown("/sys/kernel/tracing/events/xfs", 0, 0);
> >
> > // Or just remove exec bit for the group and restrict to owner
> > chmod("/sys/kernel/tracing/events/xfs", 700);
> >
> > // Drop caches to force an eventfs_root_lookup() on everything
> > write("/proc/sys/vm/drop_caches", "3", 1);
>
> This requires opening the directory, then having it's permissions
> change, and then immediately dropping the caches.
>
> >
> > // Returns 0 even though directory has a lot of entries and we should be
> > // able to list them
> > getdents64(fd, ...);
>
> And do we care?
Hmm, maybe the issue you have is with the inconsistency of the action?
For this to fail, it would require the admin to do both change the
permission and to flush caches. If you don't flush the caches then the
task with the dir open can still read it regardless. If the dentries
were already created.
In that case I'm fine if we change the creation of the dentries to not
check the permission.
But for now, it's just a weird side effect that I don't really see how
it would affect any user's workflow.
-- Steve
Re: [PATCH] tracefs/eventfs: Use root and instance inodes as default ownership
On Fri, 12 Jan 2024 09:27:24 +0100
Christian Brauner wrote:
> On Thu, Jan 11, 2024 at 04:53:19PM -0500, Steven Rostedt wrote:
> > On Thu, 11 Jan 2024 22:01:32 +0100
> > Christian Brauner wrote:
> >
> > > What I'm pointing out in the current logic is that the caller is
> > > taxed twice:
> > >
> > > (1) Once when the VFS has done inode_permission(MAY_EXEC, "xfs")
> > > (2) And again when you call lookup_one_len() in eventfs_start_creating()
> > > _because_ the permission check in lookup_one_len() is the exact
> > > same permission check again that the vfs has done
> > > inode_permission(MAY_EXEC, "xfs").
> >
> > As I described in:
> > https://lore.kernel.org/all/20240110133154.6e18f...@gandalf.local.home/
> >
> > The eventfs files below "events" doesn't need the .permissions callback at
> > all. It's only there because the "events" inode uses it.
> >
> > The .permissions call for eventfs has:
>
> It doesn't matter whether there's a ->permission handler. If you don't
> add one explicitly the VFS will simply call generic_permission():
>
> inode_permission()
> -> do_inode_permission()
>{
> if (unlikely(!(inode->i_opflags & IOP_FASTPERM))) {
> if (likely(inode->i_op->permission))
> return inode->i_op->permission(idmap, inode, mask);
>
> /* This gets set once for the inode lifetime */
> spin_lock(>i_lock);
> inode->i_opflags |= IOP_FASTPERM;
> spin_unlock(>i_lock);
> }
> return generic_permission(idmap, inode, mask);
>}
Yes I know that, because that's where I knew what to call in the non
"events" dir case.
>
> > Anyway, the issue is with "events" directory and remounting, because like
> > the tracefs system, the inode and dentry for "evnets" is created at boot
> > up, before the mount happens. The VFS layer is going to check the
> > permissions of its inode and dentry, which will be incorrect if the mount
> > was mounted with a "gid" option.
>
> The gid option has nothing to do with this and it is just handled fine
> if you remove the second permission checking in (2).
I guess I'm confused to what you are having an issue with. Is it just
that the permission check gets called twice?
>
> You need to remove the inode_permission() code from
> eventfs_start_creating(). It is just an internal lookup and the fact
> that you have it in there allows userspace to break readdir on the
> eventfs portions of tracefs as I've shown in the parts of the mail that
> you cut off.
That's because I didn't see how it was related to the way I fixed the
mount=gid issue. Are you only concerned because of the check in
eventfs_start_creating()?
Yes, you posted code that would make things act funny for some code
that I see no real world use case for. Yeah, it may not act "properly"
but I'm not sure that's bad.
Here, I'll paste it back:
> // We managed to open the directory so we have permission to list
> // directory entries in "xfs".
> fd = open("/sys/kernel/tracing/events/xfs");
>
> // Remove ownership so we can't open the directory anymore
> chown("/sys/kernel/tracing/events/xfs", 0, 0);
>
> // Or just remove exec bit for the group and restrict to owner
> chmod("/sys/kernel/tracing/events/xfs", 700);
>
> // Drop caches to force an eventfs_root_lookup() on everything
> write("/proc/sys/vm/drop_caches", "3", 1);
This requires opening the directory, then having it's permissions
change, and then immediately dropping the caches.
>
> // Returns 0 even though directory has a lot of entries and we should be
> // able to list them
> getdents64(fd, ...);
And do we care?
Since tracing exposes internal kernel information, perhaps this is a
feature and not a bug. If someone who had access to the tracing system
and you wanted to stop them, if they had a directory open that they no
longer have access to, you don't want them to see what's left in the
directory.
In other words, I like the idea that the getends64(fd, ...) will fail!
If there's a file underneath that wasn't change, and the admin thought
that just keeping the top directory permissions off is good enough,
then that attacker having that directory open before the directory had
it's file permissions change is a way to still have access to the files
below it.
>
> And the failure is in the inode_permission(MAY_EXEC, "xfs") call in
> lookup_one_len() in eventfs_start_creating() which now fails.
And I think is a good thing!
Again, tracefs is special. It gives you access and possibly control to
the kernel behavior. I like the fact that as soon as someone loses
permission to a directory, they immediately lose it.
-- Steve
Re: [PATCH v2 0/5] PM: domains: Add helpers for multi PM domains to avoid open-coding
On Mon, 8 Jan 2024 at 09:44, Daniel Baluta wrote: > > On Fri, Jan 5, 2024 at 6:02 PM Ulf Hansson wrote: > > > > Updates in v2: > > - Ccing Daniel Baluta and Iuliana Prodan the NXP remoteproc patches > > to > > requests help with testing. > > - Fixed NULL pointer bug in patch1, pointed out by Nikunj. > > - Added some tested/reviewed-by tags. > > Thanks for doing this Ulf. I remember that I've tried introducing the > helpers some time ago > but got side tracked by other tasks. > > https://lore.kernel.org/linux-pm/20200624103247.7115-1-daniel.bal...@oss.nxp.com/t/ Thanks for the pointer, yes I recall that too! I should have added your suggested-by tag to patch1 in this series, let me update that if/when I submit a new version! > > Will review the series and test the remoteproc part this week. Thanks a lot, looking forward to your feedback! Kind regards Uffe
[PATCH v6 36/36] Documentation: probes: Update fprobe on function-graph tracer
From: Masami Hiramatsu (Google) Update fprobe documentation for the new fprobe on function-graph tracer. This includes some bahvior changes and pt_regs to ftrace_regs interface change. Signed-off-by: Masami Hiramatsu (Google) --- Changes in v2: - Update @fregs parameter explanation. --- Documentation/trace/fprobe.rst | 42 ++-- 1 file changed, 27 insertions(+), 15 deletions(-) diff --git a/Documentation/trace/fprobe.rst b/Documentation/trace/fprobe.rst index 196f52386aaa..f58bdc64504f 100644 --- a/Documentation/trace/fprobe.rst +++ b/Documentation/trace/fprobe.rst @@ -9,9 +9,10 @@ Fprobe - Function entry/exit probe Introduction -Fprobe is a function entry/exit probe mechanism based on ftrace. -Instead of using ftrace full feature, if you only want to attach callbacks -on function entry and exit, similar to the kprobes and kretprobes, you can +Fprobe is a function entry/exit probe mechanism based on the function-graph +tracer. +Instead of tracing all functions, if you want to attach callbacks on specific +function entry and exit, similar to the kprobes and kretprobes, you can use fprobe. Compared with kprobes and kretprobes, fprobe gives faster instrumentation for multiple functions with single handler. This document describes how to use fprobe. @@ -91,12 +92,14 @@ The prototype of the entry/exit callback function are as follows: .. code-block:: c - int entry_callback(struct fprobe *fp, unsigned long entry_ip, unsigned long ret_ip, struct pt_regs *regs, void *entry_data); + int entry_callback(struct fprobe *fp, unsigned long entry_ip, unsigned long ret_ip, struct ftrace_regs *fregs, void *entry_data); - void exit_callback(struct fprobe *fp, unsigned long entry_ip, unsigned long ret_ip, struct pt_regs *regs, void *entry_data); + void exit_callback(struct fprobe *fp, unsigned long entry_ip, unsigned long ret_ip, struct ftrace_regs *fregs, void *entry_data); -Note that the @entry_ip is saved at function entry and passed to exit handler. -If the entry callback function returns !0, the corresponding exit callback will be cancelled. +Note that the @entry_ip is saved at function entry and passed to exit +handler. +If the entry callback function returns !0, the corresponding exit callback +will be cancelled. @fp This is the address of `fprobe` data structure related to this handler. @@ -112,12 +115,10 @@ If the entry callback function returns !0, the corresponding exit callback will This is the return address that the traced function will return to, somewhere in the caller. This can be used at both entry and exit. -@regs -This is the `pt_regs` data structure at the entry and exit. Note that -the instruction pointer of @regs may be different from the @entry_ip -in the entry_handler. If you need traced instruction pointer, you need -to use @entry_ip. On the other hand, in the exit_handler, the instruction -pointer of @regs is set to the current return address. +@fregs +This is the `ftrace_regs` data structure at the entry and exit. This +includes the function parameters, or the return values. So user can +access thos values via appropriate `ftrace_regs_*` APIs. @entry_data This is a local storage to share the data between entry and exit handlers. @@ -125,6 +126,17 @@ If the entry callback function returns !0, the corresponding exit callback will and `entry_data_size` field when registering the fprobe, the storage is allocated and passed to both `entry_handler` and `exit_handler`. +Entry data size and exit handlers on the same function +== + +Since the entry data is passed via per-task stack and it is has limited size, +the entry data size per probe is limited to `15 * sizeof(long)`. You also need +to take care that the different fprobes are probing on the same function, this +limit becomes smaller. The entry data size is aligned to `sizeof(long)` and +each fprobe which has exit handler uses a `sizeof(long)` space on the stack, +you should keep the number of fprobes on the same function as small as +possible. + Share the callbacks with kprobes @@ -165,8 +177,8 @@ This counter counts up when; - fprobe fails to take ftrace_recursion lock. This usually means that a function which is traced by other ftrace users is called from the entry_handler. - - fprobe fails to setup the function exit because of the shortage of rethook - (the shadow stack for hooking the function return.) + - fprobe fails to setup the function exit because of failing to allocate the + data buffer from the per-task shadow stack. The `fprobe::nmissed` field counts up in both cases. Therefore, the former skips both of entry and exit callback and the latter skips the exit
[PATCH v6 35/36] selftests/ftrace: Add a test case for repeating register/unregister fprobe
From: Masami Hiramatsu (Google) This test case repeats define and undefine the fprobe dynamic event to ensure that the fprobe does not cause any issue with such operations. Signed-off-by: Masami Hiramatsu (Google) --- .../test.d/dynevent/add_remove_fprobe_repeat.tc| 19 +++ 1 file changed, 19 insertions(+) create mode 100644 tools/testing/selftests/ftrace/test.d/dynevent/add_remove_fprobe_repeat.tc diff --git a/tools/testing/selftests/ftrace/test.d/dynevent/add_remove_fprobe_repeat.tc b/tools/testing/selftests/ftrace/test.d/dynevent/add_remove_fprobe_repeat.tc new file mode 100644 index ..b4ad09237e2a --- /dev/null +++ b/tools/testing/selftests/ftrace/test.d/dynevent/add_remove_fprobe_repeat.tc @@ -0,0 +1,19 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0 +# description: Generic dynamic event - Repeating add/remove fprobe events +# requires: dynamic_events "f[:[/][]] [%return] []":README + +echo 0 > events/enable +echo > dynamic_events + +PLACE=$FUNCTION_FORK +REPEAT_TIMES=64 + +for i in `seq 1 $REPEAT_TIMES`; do + echo "f:myevent $PLACE" >> dynamic_events + grep -q myevent dynamic_events + test -d events/fprobes/myevent + echo > dynamic_events +done + +clear_trace
[PATCH v6 34/36] selftests: ftrace: Remove obsolate maxactive syntax check
From: Masami Hiramatsu (Google) Since the fprobe event does not support maxactive anymore, stop testing the maxactive syntax error checking. Signed-off-by: Masami Hiramatsu (Google) --- .../ftrace/test.d/dynevent/fprobe_syntax_errors.tc |4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/tools/testing/selftests/ftrace/test.d/dynevent/fprobe_syntax_errors.tc b/tools/testing/selftests/ftrace/test.d/dynevent/fprobe_syntax_errors.tc index 20e42c030095..66516073ff27 100644 --- a/tools/testing/selftests/ftrace/test.d/dynevent/fprobe_syntax_errors.tc +++ b/tools/testing/selftests/ftrace/test.d/dynevent/fprobe_syntax_errors.tc @@ -16,9 +16,7 @@ aarch64) REG=%r0 ;; esac -check_error 'f^100 vfs_read' # MAXACT_NO_KPROBE -check_error 'f^1a111 vfs_read' # BAD_MAXACT -check_error 'f^10 vfs_read'# MAXACT_TOO_BIG +check_error 'f^100 vfs_read' # BAD_MAXACT check_error 'f ^non_exist_func'# BAD_PROBE_ADDR (enoent) check_error 'f ^vfs_read+10' # BAD_PROBE_ADDR
[PATCH v6 33/36] tracing/fprobe: Remove nr_maxactive from fprobe
From: Masami Hiramatsu (Google)
Remove depercated fprobe::nr_maxactive. This involves fprobe events to
rejects the maxactive number.
Signed-off-by: Masami Hiramatsu (Google)
---
Changes in v2:
- Newly added.
---
include/linux/fprobe.h |2 --
kernel/trace/trace_fprobe.c | 44 ++-
2 files changed, 6 insertions(+), 40 deletions(-)
diff --git a/include/linux/fprobe.h b/include/linux/fprobe.h
index 08b37b0d1d05..c28d06ddfb8e 100644
--- a/include/linux/fprobe.h
+++ b/include/linux/fprobe.h
@@ -47,7 +47,6 @@ struct fprobe_hlist {
* @nmissed: The counter for missing events.
* @flags: The status flag.
* @entry_data_size: The private data storage size.
- * @nr_maxactive: The max number of active functions. (*deprecated)
* @entry_handler: The callback function for function entry.
* @exit_handler: The callback function for function exit.
* @hlist_array: The fprobe_hlist for fprobe search from IP hash table.
@@ -56,7 +55,6 @@ struct fprobe {
unsigned long nmissed;
unsigned intflags;
size_t entry_data_size;
- int nr_maxactive;
int (*entry_handler)(struct fprobe *fp, unsigned long entry_ip,
unsigned long ret_ip, struct ftrace_regs *regs,
diff --git a/kernel/trace/trace_fprobe.c b/kernel/trace/trace_fprobe.c
index 7d2a66135f83..d96de0dbc0cb 100644
--- a/kernel/trace/trace_fprobe.c
+++ b/kernel/trace/trace_fprobe.c
@@ -375,7 +375,6 @@ static struct trace_fprobe *alloc_trace_fprobe(const char
*group,
const char *event,
const char *symbol,
struct tracepoint *tpoint,
- int maxactive,
int nargs, bool is_return)
{
struct trace_fprobe *tf;
@@ -395,7 +394,6 @@ static struct trace_fprobe *alloc_trace_fprobe(const char
*group,
tf->fp.entry_handler = fentry_dispatcher;
tf->tpoint = tpoint;
- tf->fp.nr_maxactive = maxactive;
ret = trace_probe_init(>tp, event, group, false);
if (ret < 0)
@@ -974,12 +972,11 @@ static int __trace_fprobe_create(int argc, const char
*argv[])
* FETCHARG:TYPE : use TYPE instead of unsigned long.
*/
struct trace_fprobe *tf = NULL;
- int i, len, new_argc = 0, ret = 0;
+ int i, new_argc = 0, ret = 0;
bool is_return = false;
char *symbol = NULL;
const char *event = NULL, *group = FPROBE_EVENT_SYSTEM;
const char **new_argv = NULL;
- int maxactive = 0;
char buf[MAX_EVENT_NAME_LEN];
char gbuf[MAX_EVENT_NAME_LEN];
char sbuf[KSYM_NAME_LEN];
@@ -1000,33 +997,13 @@ static int __trace_fprobe_create(int argc, const char
*argv[])
trace_probe_log_init("trace_fprobe", argc, argv);
- event = strchr([0][1], ':');
- if (event)
- event++;
-
- if (isdigit(argv[0][1])) {
- if (event)
- len = event - [0][1] - 1;
- else
- len = strlen([0][1]);
- if (len > MAX_EVENT_NAME_LEN - 1) {
- trace_probe_log_err(1, BAD_MAXACT);
- goto parse_error;
- }
- memcpy(buf, [0][1], len);
- buf[len] = '\0';
- ret = kstrtouint(buf, 0, );
- if (ret || !maxactive) {
+ if (argv[0][1] != '\0') {
+ if (argv[0][1] != ':') {
+ trace_probe_log_set_index(0);
trace_probe_log_err(1, BAD_MAXACT);
goto parse_error;
}
- /* fprobe rethook instances are iterated over via a list. The
-* maximum should stay reasonable.
-*/
- if (maxactive > RETHOOK_MAXACTIVE_MAX) {
- trace_probe_log_err(1, MAXACT_TOO_BIG);
- goto parse_error;
- }
+ event = [0][2];
}
trace_probe_log_set_index(1);
@@ -1036,12 +1013,6 @@ static int __trace_fprobe_create(int argc, const char
*argv[])
if (ret < 0)
goto parse_error;
- if (!is_return && maxactive) {
- trace_probe_log_set_index(0);
- trace_probe_log_err(1, BAD_MAXACT_TYPE);
- goto parse_error;
- }
-
trace_probe_log_set_index(0);
if (event) {
ret = traceprobe_parse_event_name(, , gbuf,
@@ -1095,8 +1066,7 @@ static int __trace_fprobe_create(int argc, const char
*argv[])
}
/* setup a probe */
- tf = alloc_trace_fprobe(group, event, symbol, tpoint, maxactive,
- argc, is_return);
+ tf =
[PATCH v6 32/36] fprobe: Rewrite fprobe on function-graph tracer
From: Masami Hiramatsu (Google)
Rewrite fprobe implementation on function-graph tracer.
Major API changes are:
- 'nr_maxactive' field is deprecated.
- This depends on CONFIG_DYNAMIC_FTRACE_WITH_ARGS or
!CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS, and
CONFIG_HAVE_FUNCTION_GRAPH_FREGS. So currently works only
on x86_64.
- Currently the entry size is limited in 15 * sizeof(long).
- If there is too many fprobe exit handler set on the same
function, it will fail to probe.
Signed-off-by: Masami Hiramatsu (Google)
---
Changes in v3:
- Update for new reserve_data/retrieve_data API.
- Fix internal push/pop on fgraph data logic so that it can
correctly save/restore the returning fprobes.
Changes in v2:
- Add more lockdep_assert_held(fprobe_mutex)
- Use READ_ONCE() and WRITE_ONCE() for fprobe_hlist_node::fp.
- Add NOKPROBE_SYMBOL() for the functions which is called from
entry/exit callback.
---
include/linux/fprobe.h | 54 +++-
kernel/trace/Kconfig |8 -
kernel/trace/fprobe.c | 633 ++--
lib/test_fprobe.c | 45 ---
4 files changed, 494 insertions(+), 246 deletions(-)
diff --git a/include/linux/fprobe.h b/include/linux/fprobe.h
index 879a30956009..08b37b0d1d05 100644
--- a/include/linux/fprobe.h
+++ b/include/linux/fprobe.h
@@ -5,32 +5,56 @@
#include
#include
-#include
+#include
+#include
+#include
+
+struct fprobe;
+
+/**
+ * strcut fprobe_hlist_node - address based hash list node for fprobe.
+ *
+ * @hlist: The hlist node for address search hash table.
+ * @addr: The address represented by this.
+ * @fp: The fprobe which owns this.
+ */
+struct fprobe_hlist_node {
+ struct hlist_node hlist;
+ unsigned long addr;
+ struct fprobe *fp;
+};
+
+/**
+ * struct fprobe_hlist - hash list nodes for fprobe.
+ *
+ * @hlist: The hlist node for existence checking hash table.
+ * @rcu: rcu_head for RCU deferred release.
+ * @fp: The fprobe which owns this fprobe_hlist.
+ * @size: The size of @array.
+ * @array: The fprobe_hlist_node for each address to probe.
+ */
+struct fprobe_hlist {
+ struct hlist_node hlist;
+ struct rcu_head rcu;
+ struct fprobe *fp;
+ int size;
+ struct fprobe_hlist_nodearray[];
+};
/**
* struct fprobe - ftrace based probe.
- * @ops: The ftrace_ops.
+ *
* @nmissed: The counter for missing events.
* @flags: The status flag.
- * @rethook: The rethook data structure. (internal data)
* @entry_data_size: The private data storage size.
- * @nr_maxactive: The max number of active functions.
+ * @nr_maxactive: The max number of active functions. (*deprecated)
* @entry_handler: The callback function for function entry.
* @exit_handler: The callback function for function exit.
+ * @hlist_array: The fprobe_hlist for fprobe search from IP hash table.
*/
struct fprobe {
-#ifdef CONFIG_FUNCTION_TRACER
- /*
-* If CONFIG_FUNCTION_TRACER is not set, CONFIG_FPROBE is disabled too.
-* But user of fprobe may keep embedding the struct fprobe on their own
-* code. To avoid build error, this will keep the fprobe data structure
-* defined here, but remove ftrace_ops data structure.
-*/
- struct ftrace_ops ops;
-#endif
unsigned long nmissed;
unsigned intflags;
- struct rethook *rethook;
size_t entry_data_size;
int nr_maxactive;
@@ -40,6 +64,8 @@ struct fprobe {
void (*exit_handler)(struct fprobe *fp, unsigned long entry_ip,
unsigned long ret_ip, struct ftrace_regs *fregs,
void *entry_data);
+
+ struct fprobe_hlist *hlist_array;
};
/* This fprobe is soft-disabled. */
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index 8b15adde1d8f..169588021d90 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -296,11 +296,9 @@ config DYNAMIC_FTRACE_WITH_ARGS
config FPROBE
bool "Kernel Function Probe (fprobe)"
- depends on FUNCTION_TRACER
- depends on DYNAMIC_FTRACE_WITH_REGS || DYNAMIC_FTRACE_WITH_ARGS
- depends on HAVE_PT_REGS_TO_FTRACE_REGS_CAST ||
!HAVE_DYNAMIC_FTRACE_WITH_ARGS
- depends on HAVE_RETHOOK
- select RETHOOK
+ depends on FUNCTION_GRAPH_TRACER
+ depends on HAVE_FUNCTION_GRAPH_FREGS
+ depends on DYNAMIC_FTRACE_WITH_ARGS || !HAVE_DYNAMIC_FTRACE_WITH_ARGS
default n
help
This option enables kernel function probe (fprobe) based on ftrace.
diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c
index 31210423efc3..53e681c2458b 100644
--- a/kernel/trace/fprobe.c
+++ b/kernel/trace/fprobe.c
@@ -8,98 +8,193 @@
#include
#include
#include
-#include
+#include
+#include
#include
#include
[PATCH v6 31/36] bpf: Enable kprobe_multi feature if CONFIG_FPROBE is enabled
From: Masami Hiramatsu (Google)
Enable kprobe_multi feature if CONFIG_FPROBE is enabled. The pt_regs is
converted from ftrace_regs by ftrace_partial_regs(), thus some registers
may always returns 0. But it should be enough for function entry (access
arguments) and exit (access return value).
Signed-off-by: Masami Hiramatsu (Google)
Acked-by: Florent Revest
---
Changes from previous series: NOTHING, Update against the new series.
---
kernel/trace/bpf_trace.c | 22 +-
1 file changed, 9 insertions(+), 13 deletions(-)
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index efb792f8f2ea..24ee4e960f1d 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -2503,7 +2503,7 @@ static int __init bpf_event_init(void)
fs_initcall(bpf_event_init);
#endif /* CONFIG_MODULES */
-#if defined(CONFIG_FPROBE) && defined(CONFIG_DYNAMIC_FTRACE_WITH_REGS)
+#ifdef CONFIG_FPROBE
struct bpf_kprobe_multi_link {
struct bpf_link link;
struct fprobe fp;
@@ -2526,6 +2526,8 @@ struct user_syms {
char *buf;
};
+static DEFINE_PER_CPU(struct pt_regs, bpf_kprobe_multi_pt_regs);
+
static int copy_user_syms(struct user_syms *us, unsigned long __user *usyms,
u32 cnt)
{
unsigned long __user usymbol;
@@ -2703,13 +2705,14 @@ static u64 bpf_kprobe_multi_entry_ip(struct bpf_run_ctx
*ctx)
static int
kprobe_multi_link_prog_run(struct bpf_kprobe_multi_link *link,
- unsigned long entry_ip, struct pt_regs *regs)
+ unsigned long entry_ip, struct ftrace_regs *fregs)
{
struct bpf_kprobe_multi_run_ctx run_ctx = {
.link = link,
.entry_ip = entry_ip,
};
struct bpf_run_ctx *old_run_ctx;
+ struct pt_regs *regs;
int err;
if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) {
@@ -2720,6 +2723,7 @@ kprobe_multi_link_prog_run(struct bpf_kprobe_multi_link
*link,
migrate_disable();
rcu_read_lock();
+ regs = ftrace_partial_regs(fregs,
this_cpu_ptr(_kprobe_multi_pt_regs));
old_run_ctx = bpf_set_run_ctx(_ctx.run_ctx);
err = bpf_prog_run(link->link.prog, regs);
bpf_reset_run_ctx(old_run_ctx);
@@ -2737,13 +2741,9 @@ kprobe_multi_link_handler(struct fprobe *fp, unsigned
long fentry_ip,
void *data)
{
struct bpf_kprobe_multi_link *link;
- struct pt_regs *regs = ftrace_get_regs(fregs);
-
- if (!regs)
- return 0;
link = container_of(fp, struct bpf_kprobe_multi_link, fp);
- kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), regs);
+ kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), fregs);
return 0;
}
@@ -2753,13 +2753,9 @@ kprobe_multi_link_exit_handler(struct fprobe *fp,
unsigned long fentry_ip,
void *data)
{
struct bpf_kprobe_multi_link *link;
- struct pt_regs *regs = ftrace_get_regs(fregs);
-
- if (!regs)
- return;
link = container_of(fp, struct bpf_kprobe_multi_link, fp);
- kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), regs);
+ kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), fregs);
}
static int symbols_cmp_r(const void *a, const void *b, const void *priv)
@@ -3016,7 +3012,7 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr
*attr, struct bpf_prog *pr
kvfree(cookies);
return err;
}
-#else /* !CONFIG_FPROBE || !CONFIG_DYNAMIC_FTRACE_WITH_REGS */
+#else /* !CONFIG_FPROBE */
int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog
*prog)
{
return -EOPNOTSUPP;
[PATCH v6 30/36] tracing/fprobe: Enable fprobe events with CONFIG_DYNAMIC_FTRACE_WITH_ARGS
From: Masami Hiramatsu (Google)
Allow fprobe events to be enabled with CONFIG_DYNAMIC_FTRACE_WITH_ARGS.
With this change, fprobe events mostly use ftrace_regs instead of pt_regs.
Note that if the arch doesn't enable HAVE_PT_REGS_COMPAT_FTRACE_REGS,
fprobe events will not be able to be used from perf.
Signed-off-by: Masami Hiramatsu (Google)
---
Chagnes in v3:
- Use ftrace_regs_get_return_value().
Changes in v2:
- Define ftrace_regs_get_kernel_stack_nth() for
!CONFIG_HAVE_REGS_AND_STACK_ACCESS_API.
Changes from previous series: Update against the new series.
---
include/linux/ftrace.h | 17 +
kernel/trace/Kconfig|1 -
kernel/trace/trace_fprobe.c | 74 ---
kernel/trace/trace_probe_tmpl.h |2 +
4 files changed, 55 insertions(+), 39 deletions(-)
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 8150edcf8496..ad28daa507f7 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -250,6 +250,23 @@ static __always_inline bool ftrace_regs_has_args(struct
ftrace_regs *fregs)
regs_query_register_offset(name)
#endif
+#ifdef CONFIG_HAVE_REGS_AND_STACK_ACCESS_API
+static __always_inline unsigned long
+ftrace_regs_get_kernel_stack_nth(struct ftrace_regs *fregs, unsigned int nth)
+{
+ unsigned long *stackp;
+
+ stackp = (unsigned long *)ftrace_regs_get_stack_pointer(fregs);
+ if (((unsigned long)(stackp + nth) & ~(THREAD_SIZE - 1)) ==
+ ((unsigned long)stackp & ~(THREAD_SIZE - 1)))
+ return *(stackp + nth);
+
+ return 0;
+}
+#else /* !CONFIG_HAVE_REGS_AND_STACK_ACCESS_API */
+#define ftrace_regs_get_kernel_stack_nth(fregs, nth) (0L)
+#endif /* CONFIG_HAVE_REGS_AND_STACK_ACCESS_API */
+
typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *op, struct ftrace_regs *fregs);
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index 1a2544712690..8b15adde1d8f 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -683,7 +683,6 @@ config FPROBE_EVENTS
select TRACING
select PROBE_EVENTS
select DYNAMIC_EVENTS
- depends on DYNAMIC_FTRACE_WITH_REGS
default y
help
This allows user to add tracing events on the function entry and
diff --git a/kernel/trace/trace_fprobe.c b/kernel/trace/trace_fprobe.c
index 3982626c82e6..7d2a66135f83 100644
--- a/kernel/trace/trace_fprobe.c
+++ b/kernel/trace/trace_fprobe.c
@@ -132,7 +132,7 @@ static int
process_fetch_insn(struct fetch_insn *code, void *rec, void *dest,
void *base)
{
- struct pt_regs *regs = rec;
+ struct ftrace_regs *fregs = rec;
unsigned long val;
int ret;
@@ -140,17 +140,17 @@ process_fetch_insn(struct fetch_insn *code, void *rec,
void *dest,
/* 1st stage: get value from context */
switch (code->op) {
case FETCH_OP_STACK:
- val = regs_get_kernel_stack_nth(regs, code->param);
+ val = ftrace_regs_get_kernel_stack_nth(fregs, code->param);
break;
case FETCH_OP_STACKP:
- val = kernel_stack_pointer(regs);
+ val = ftrace_regs_get_stack_pointer(fregs);
break;
case FETCH_OP_RETVAL:
- val = regs_return_value(regs);
+ val = ftrace_regs_get_return_value(fregs);
break;
#ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
case FETCH_OP_ARG:
- val = regs_get_kernel_argument(regs, code->param);
+ val = ftrace_regs_get_argument(fregs, code->param);
break;
#endif
case FETCH_NOP_SYMBOL: /* Ignore a place holder */
@@ -170,7 +170,7 @@ NOKPROBE_SYMBOL(process_fetch_insn)
/* function entry handler */
static nokprobe_inline void
__fentry_trace_func(struct trace_fprobe *tf, unsigned long entry_ip,
- struct pt_regs *regs,
+ struct ftrace_regs *fregs,
struct trace_event_file *trace_file)
{
struct fentry_trace_entry_head *entry;
@@ -184,36 +184,36 @@ __fentry_trace_func(struct trace_fprobe *tf, unsigned
long entry_ip,
if (trace_trigger_soft_disabled(trace_file))
return;
- dsize = __get_data_size(>tp, regs);
+ dsize = __get_data_size(>tp, fregs);
entry = trace_event_buffer_reserve(, trace_file,
sizeof(*entry) + tf->tp.size +
dsize);
if (!entry)
return;
- fbuffer.regs = regs;
+ fbuffer.regs = ftrace_get_regs(fregs);
entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event);
entry->ip = entry_ip;
- store_trace_args([1], >tp, regs, sizeof(*entry), dsize);
+ store_trace_args([1], >tp, fregs, sizeof(*entry), dsize);
trace_event_buffer_commit();
}
static void
[PATCH v6 29/36] tracing: Add ftrace_fill_perf_regs() for perf event
From: Masami Hiramatsu (Google)
Add ftrace_fill_perf_regs() which should be compatible with the
perf_fetch_caller_regs(). In other words, the pt_regs returned from the
ftrace_fill_perf_regs() must satisfy 'user_mode(regs) == false' and can be
used for stack tracing.
Signed-off-by: Masami Hiramatsu (Google)
---
Changes from previous series: NOTHING, just forward ported.
---
arch/arm64/include/asm/ftrace.h |7 +++
arch/powerpc/include/asm/ftrace.h |7 +++
arch/s390/include/asm/ftrace.h|5 +
arch/x86/include/asm/ftrace.h |7 +++
include/linux/ftrace.h| 31 +++
5 files changed, 57 insertions(+)
diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h
index 31051fa2b4d9..c1921bdf760b 100644
--- a/arch/arm64/include/asm/ftrace.h
+++ b/arch/arm64/include/asm/ftrace.h
@@ -154,6 +154,13 @@ ftrace_partial_regs(const struct ftrace_regs *fregs,
struct pt_regs *regs)
return regs;
}
+#define arch_ftrace_fill_perf_regs(fregs, _regs) do { \
+ (_regs)->pc = (fregs)->pc; \
+ (_regs)->regs[29] = (fregs)->fp;\
+ (_regs)->sp = (fregs)->sp; \
+ (_regs)->pstate = PSR_MODE_EL1h;\
+ } while (0)
+
int ftrace_regs_query_register_offset(const char *name);
int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec);
diff --git a/arch/powerpc/include/asm/ftrace.h
b/arch/powerpc/include/asm/ftrace.h
index 7e138e0e3baf..8737a794c764 100644
--- a/arch/powerpc/include/asm/ftrace.h
+++ b/arch/powerpc/include/asm/ftrace.h
@@ -52,6 +52,13 @@ static __always_inline struct pt_regs
*arch_ftrace_get_regs(struct ftrace_regs *
return fregs->regs.msr ? >regs : NULL;
}
+#define arch_ftrace_fill_perf_regs(fregs, _regs) do { \
+ (_regs)->result = 0;\
+ (_regs)->nip = (fregs)->regs.nip; \
+ (_regs)->gpr[1] = (fregs)->regs.gpr[1]; \
+ asm volatile("mfmsr %0" : "=r" ((_regs)->msr)); \
+ } while (0)
+
static __always_inline void
ftrace_regs_set_instruction_pointer(struct ftrace_regs *fregs,
unsigned long ip)
diff --git a/arch/s390/include/asm/ftrace.h b/arch/s390/include/asm/ftrace.h
index 01e775c98425..c2a269c1617c 100644
--- a/arch/s390/include/asm/ftrace.h
+++ b/arch/s390/include/asm/ftrace.h
@@ -97,6 +97,11 @@ ftrace_regs_set_instruction_pointer(struct ftrace_regs
*fregs,
#define ftrace_regs_query_register_offset(name) \
regs_query_register_offset(name)
+#define arch_ftrace_fill_perf_regs(fregs, _regs)do { \
+ (_regs)->psw.addr = (fregs)->regs.psw.addr; \
+ (_regs)->gprs[15] = (fregs)->regs.gprs[15]; \
+ } while (0)
+
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
/*
* When an ftrace registered caller is tracing a function that is
diff --git a/arch/x86/include/asm/ftrace.h b/arch/x86/include/asm/ftrace.h
index a061f8832b20..2e3de45e9746 100644
--- a/arch/x86/include/asm/ftrace.h
+++ b/arch/x86/include/asm/ftrace.h
@@ -54,6 +54,13 @@ arch_ftrace_get_regs(struct ftrace_regs *fregs)
return >regs;
}
+#define arch_ftrace_fill_perf_regs(fregs, _regs) do { \
+ (_regs)->ip = (fregs)->regs.ip; \
+ (_regs)->sp = (fregs)->regs.sp; \
+ (_regs)->cs = __KERNEL_CS; \
+ (_regs)->flags = 0; \
+ } while (0)
+
#define ftrace_regs_set_instruction_pointer(fregs, _ip)\
do { (fregs)->regs.ip = (_ip); } while (0)
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 515ec804d605..8150edcf8496 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -190,6 +190,37 @@ ftrace_partial_regs(struct ftrace_regs *fregs, struct
pt_regs *regs)
#endif /* !CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS ||
CONFIG_HAVE_PT_REGS_TO_FTRACE_REGS_CAST */
+#ifdef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS
+
+/*
+ * Please define arch dependent pt_regs which compatible to the
+ * perf_arch_fetch_caller_regs() but based on ftrace_regs.
+ * This requires
+ * - user_mode(_regs) returns false (always kernel mode).
+ * - able to use the _regs for stack trace.
+ */
+#ifndef arch_ftrace_fill_perf_regs
+/* As same as perf_arch_fetch_caller_regs(), do nothing by default */
+#define arch_ftrace_fill_perf_regs(fregs, _regs) do {} while (0)
+#endif
+
+static __always_inline struct pt_regs *
+ftrace_fill_perf_regs(struct ftrace_regs *fregs, struct pt_regs *regs)
+{
+ arch_ftrace_fill_perf_regs(fregs, regs);
+ return regs;
+}
+
+#else /* !CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS */
+
+static __always_inline struct pt_regs *
+ftrace_fill_perf_regs(struct ftrace_regs *fregs, struct pt_regs *regs)
+{
+
[PATCH v6 28/36] tracing: Add ftrace_partial_regs() for converting ftrace_regs to pt_regs
From: Masami Hiramatsu (Google)
Add ftrace_partial_regs() which converts the ftrace_regs to pt_regs.
If the architecture defines its own ftrace_regs, this copies partial
registers to pt_regs and returns it. If not, ftrace_regs is the same as
pt_regs and ftrace_partial_regs() will return ftrace_regs::regs.
Signed-off-by: Masami Hiramatsu (Google)
Acked-by: Florent Revest
---
Changes from previous series: NOTHING, just forward ported.
---
arch/arm64/include/asm/ftrace.h | 11 +++
include/linux/ftrace.h | 17 +
2 files changed, 28 insertions(+)
diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h
index efd5dbf74dd6..31051fa2b4d9 100644
--- a/arch/arm64/include/asm/ftrace.h
+++ b/arch/arm64/include/asm/ftrace.h
@@ -143,6 +143,17 @@ ftrace_override_function_with_return(struct ftrace_regs
*fregs)
fregs->pc = fregs->lr;
}
+static __always_inline struct pt_regs *
+ftrace_partial_regs(const struct ftrace_regs *fregs, struct pt_regs *regs)
+{
+ memcpy(regs->regs, fregs->regs, sizeof(u64) * 9);
+ regs->sp = fregs->sp;
+ regs->pc = fregs->pc;
+ regs->regs[29] = fregs->fp;
+ regs->regs[30] = fregs->lr;
+ return regs;
+}
+
int ftrace_regs_query_register_offset(const char *name);
int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec);
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index a72a2eaec576..515ec804d605 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -173,6 +173,23 @@ static __always_inline struct pt_regs
*ftrace_get_regs(struct ftrace_regs *fregs
return arch_ftrace_get_regs(fregs);
}
+#if !defined(CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS) || \
+ defined(CONFIG_HAVE_PT_REGS_TO_FTRACE_REGS_CAST)
+
+static __always_inline struct pt_regs *
+ftrace_partial_regs(struct ftrace_regs *fregs, struct pt_regs *regs)
+{
+ /*
+* If CONFIG_HAVE_PT_REGS_TO_FTRACE_REGS_CAST=y, ftrace_regs memory
+* layout is the same as pt_regs. So always returns that address.
+* Since arch_ftrace_get_regs() will check some members and may return
+* NULL, we can not use it.
+*/
+ return >regs;
+}
+
+#endif /* !CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS ||
CONFIG_HAVE_PT_REGS_TO_FTRACE_REGS_CAST */
+
/*
* When true, the ftrace_regs_{get,set}_*() functions may be used on fregs.
* Note: this can be true even when ftrace_get_regs() cannot provide a pt_regs.
[PATCH v6 27/36] fprobe: Use ftrace_regs in fprobe exit handler
From: Masami Hiramatsu (Google)
Change the fprobe exit handler to use ftrace_regs structure instead of
pt_regs. This also introduce HAVE_PT_REGS_TO_FTRACE_REGS_CAST which means
the ftrace_regs's memory layout is equal to the pt_regs so that those are
able to cast. Fprobe introduces a new dependency with that.
Signed-off-by: Masami Hiramatsu (Google)
---
Changes in v3:
- Use ftrace_regs_get_return_value()
Changes from previous series: NOTHING, just forward ported.
---
arch/loongarch/Kconfig |1 +
arch/s390/Kconfig |1 +
arch/x86/Kconfig|1 +
include/linux/fprobe.h |2 +-
include/linux/ftrace.h |5 +
kernel/trace/Kconfig|8
kernel/trace/bpf_trace.c|6 +-
kernel/trace/fprobe.c |3 ++-
kernel/trace/trace_fprobe.c |6 +-
lib/test_fprobe.c |6 +++---
samples/fprobe/fprobe_example.c |2 +-
11 files changed, 33 insertions(+), 8 deletions(-)
diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
index ee123820a476..b0bd252aefe8 100644
--- a/arch/loongarch/Kconfig
+++ b/arch/loongarch/Kconfig
@@ -108,6 +108,7 @@ config LOONGARCH
select HAVE_DMA_CONTIGUOUS
select HAVE_DYNAMIC_FTRACE
select HAVE_DYNAMIC_FTRACE_WITH_ARGS
+ select HAVE_PT_REGS_TO_FTRACE_REGS_CAST
select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
select HAVE_DYNAMIC_FTRACE_WITH_REGS
select HAVE_EBPF_JIT
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index d5d8f99d1f25..5736c1970f49 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -168,6 +168,7 @@ config S390
select HAVE_DMA_CONTIGUOUS
select HAVE_DYNAMIC_FTRACE
select HAVE_DYNAMIC_FTRACE_WITH_ARGS
+ select HAVE_PT_REGS_TO_FTRACE_REGS_CAST
select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
select HAVE_DYNAMIC_FTRACE_WITH_REGS
select HAVE_EBPF_JIT if HAVE_MARCH_Z196_FEATURES
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 375ad280ee75..1a8b5d447e85 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -209,6 +209,7 @@ config X86
select HAVE_DYNAMIC_FTRACE
select HAVE_DYNAMIC_FTRACE_WITH_REGS
select HAVE_DYNAMIC_FTRACE_WITH_ARGSif X86_64
+ select HAVE_PT_REGS_TO_FTRACE_REGS_CAST if X86_64
select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
select HAVE_SAMPLE_FTRACE_DIRECTif X86_64
select HAVE_SAMPLE_FTRACE_DIRECT_MULTI if X86_64
diff --git a/include/linux/fprobe.h b/include/linux/fprobe.h
index 36c0595f7b93..879a30956009 100644
--- a/include/linux/fprobe.h
+++ b/include/linux/fprobe.h
@@ -38,7 +38,7 @@ struct fprobe {
unsigned long ret_ip, struct ftrace_regs *regs,
void *entry_data);
void (*exit_handler)(struct fprobe *fp, unsigned long entry_ip,
-unsigned long ret_ip, struct pt_regs *regs,
+unsigned long ret_ip, struct ftrace_regs *fregs,
void *entry_data);
};
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index da2a23f5a9ed..a72a2eaec576 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -159,6 +159,11 @@ struct ftrace_regs {
#define ftrace_regs_set_instruction_pointer(fregs, ip) do { } while (0)
#endif /* CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS */
+#ifdef CONFIG_HAVE_PT_REGS_TO_FTRACE_REGS_CAST
+
+static_assert(sizeof(struct pt_regs) == sizeof(struct ftrace_regs));
+
+#endif /* CONFIG_HAVE_PT_REGS_TO_FTRACE_REGS_CAST */
static __always_inline struct pt_regs *ftrace_get_regs(struct ftrace_regs
*fregs)
{
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index 805d72ab77c6..1a2544712690 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -60,6 +60,13 @@ config HAVE_DYNAMIC_FTRACE_WITH_ARGS
This allows for use of ftrace_regs_get_argument() and
ftrace_regs_get_stack_pointer().
+config HAVE_PT_REGS_TO_FTRACE_REGS_CAST
+ bool
+ help
+If this is set, the memory layout of the ftrace_regs data structure
+is the same as the pt_regs. So the pt_regs is possible to be casted
+to ftrace_regs.
+
config HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
bool
help
@@ -291,6 +298,7 @@ config FPROBE
bool "Kernel Function Probe (fprobe)"
depends on FUNCTION_TRACER
depends on DYNAMIC_FTRACE_WITH_REGS || DYNAMIC_FTRACE_WITH_ARGS
+ depends on HAVE_PT_REGS_TO_FTRACE_REGS_CAST ||
!HAVE_DYNAMIC_FTRACE_WITH_ARGS
depends on HAVE_RETHOOK
select RETHOOK
default n
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index d3f8745d8ead..efb792f8f2ea 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -2749,10 +2749,14 @@ kprobe_multi_link_handler(struct fprobe *fp, unsigned
long fentry_ip,
static void
[PATCH v6 26/36] fprobe: Use ftrace_regs in fprobe entry handler
From: Masami Hiramatsu (Google)
This allows fprobes to be available with CONFIG_DYNAMIC_FTRACE_WITH_ARGS
instead of CONFIG_DYNAMIC_FTRACE_WITH_REGS, then we can enable fprobe
on arm64.
Signed-off-by: Masami Hiramatsu (Google)
Acked-by: Florent Revest
---
Changes in v6:
- Keep using SAVE_REGS flag to avoid breaking bpf kprobe-multi test.
---
include/linux/fprobe.h |2 +-
kernel/trace/Kconfig|3 ++-
kernel/trace/bpf_trace.c| 10 +++---
kernel/trace/fprobe.c |3 ++-
kernel/trace/trace_fprobe.c |6 +-
lib/test_fprobe.c |4 ++--
samples/fprobe/fprobe_example.c |2 +-
7 files changed, 20 insertions(+), 10 deletions(-)
diff --git a/include/linux/fprobe.h b/include/linux/fprobe.h
index 3e03758151f4..36c0595f7b93 100644
--- a/include/linux/fprobe.h
+++ b/include/linux/fprobe.h
@@ -35,7 +35,7 @@ struct fprobe {
int nr_maxactive;
int (*entry_handler)(struct fprobe *fp, unsigned long entry_ip,
-unsigned long ret_ip, struct pt_regs *regs,
+unsigned long ret_ip, struct ftrace_regs *regs,
void *entry_data);
void (*exit_handler)(struct fprobe *fp, unsigned long entry_ip,
unsigned long ret_ip, struct pt_regs *regs,
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index 308b3bec01b1..805d72ab77c6 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -290,7 +290,7 @@ config DYNAMIC_FTRACE_WITH_ARGS
config FPROBE
bool "Kernel Function Probe (fprobe)"
depends on FUNCTION_TRACER
- depends on DYNAMIC_FTRACE_WITH_REGS
+ depends on DYNAMIC_FTRACE_WITH_REGS || DYNAMIC_FTRACE_WITH_ARGS
depends on HAVE_RETHOOK
select RETHOOK
default n
@@ -675,6 +675,7 @@ config FPROBE_EVENTS
select TRACING
select PROBE_EVENTS
select DYNAMIC_EVENTS
+ depends on DYNAMIC_FTRACE_WITH_REGS
default y
help
This allows user to add tracing events on the function entry and
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 84e8a0f6e4e0..d3f8745d8ead 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -2503,7 +2503,7 @@ static int __init bpf_event_init(void)
fs_initcall(bpf_event_init);
#endif /* CONFIG_MODULES */
-#ifdef CONFIG_FPROBE
+#if defined(CONFIG_FPROBE) && defined(CONFIG_DYNAMIC_FTRACE_WITH_REGS)
struct bpf_kprobe_multi_link {
struct bpf_link link;
struct fprobe fp;
@@ -2733,10 +2733,14 @@ kprobe_multi_link_prog_run(struct bpf_kprobe_multi_link
*link,
static int
kprobe_multi_link_handler(struct fprobe *fp, unsigned long fentry_ip,
- unsigned long ret_ip, struct pt_regs *regs,
+ unsigned long ret_ip, struct ftrace_regs *fregs,
void *data)
{
struct bpf_kprobe_multi_link *link;
+ struct pt_regs *regs = ftrace_get_regs(fregs);
+
+ if (!regs)
+ return 0;
link = container_of(fp, struct bpf_kprobe_multi_link, fp);
kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), regs);
@@ -3008,7 +3012,7 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr
*attr, struct bpf_prog *pr
kvfree(cookies);
return err;
}
-#else /* !CONFIG_FPROBE */
+#else /* !CONFIG_FPROBE || !CONFIG_DYNAMIC_FTRACE_WITH_REGS */
int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog
*prog)
{
return -EOPNOTSUPP;
diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c
index 6cd2a4e3afb8..a932c3a79e8f 100644
--- a/kernel/trace/fprobe.c
+++ b/kernel/trace/fprobe.c
@@ -46,7 +46,7 @@ static inline void __fprobe_handler(unsigned long ip,
unsigned long parent_ip,
}
if (fp->entry_handler)
- ret = fp->entry_handler(fp, ip, parent_ip,
ftrace_get_regs(fregs), entry_data);
+ ret = fp->entry_handler(fp, ip, parent_ip, fregs, entry_data);
/* If entry_handler returns !0, nmissed is not counted. */
if (rh) {
@@ -182,6 +182,7 @@ static void fprobe_init(struct fprobe *fp)
fp->ops.func = fprobe_kprobe_handler;
else
fp->ops.func = fprobe_handler;
+
fp->ops.flags |= FTRACE_OPS_FL_SAVE_REGS;
}
diff --git a/kernel/trace/trace_fprobe.c b/kernel/trace/trace_fprobe.c
index 7d2ddbcfa377..ef6b36fd05ae 100644
--- a/kernel/trace/trace_fprobe.c
+++ b/kernel/trace/trace_fprobe.c
@@ -320,12 +320,16 @@ NOKPROBE_SYMBOL(fexit_perf_func);
#endif /* CONFIG_PERF_EVENTS */
static int fentry_dispatcher(struct fprobe *fp, unsigned long entry_ip,
-unsigned long ret_ip, struct pt_regs *regs,
+unsigned long ret_ip, struct ftrace_regs *fregs,
void *entry_data)
{
struct trace_fprobe *tf =
[PATCH v6 25/36] arm64: ftrace: Enable HAVE_FUNCTION_GRAPH_FREGS
From: Masami Hiramatsu (Google)
Enable CONFIG_HAVE_FUNCTION_GRAPH_FREGS on arm64. Note that this
depends on HAVE_DYNAMIC_FTRACE_WITH_ARGS which is enabled if the
compiler supports "-fpatchable-function-entry=2". If not, it
continue to use ftrace_ret_regs.
Signed-off-by: Masami Hiramatsu (Google)
---
Changes in v3:
- Newly added.
---
arch/arm64/Kconfig |2 ++
arch/arm64/include/asm/ftrace.h |6 ++
arch/arm64/kernel/entry-ftrace.S | 28
3 files changed, 36 insertions(+)
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 7b071a00425d..beebc724dcae 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -192,6 +192,8 @@ config ARM64
select HAVE_DYNAMIC_FTRACE
select HAVE_DYNAMIC_FTRACE_WITH_ARGS \
if $(cc-option,-fpatchable-function-entry=2)
+ select HAVE_FUNCTION_GRAPH_FREGS \
+ if HAVE_DYNAMIC_FTRACE_WITH_ARGS
select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS \
if DYNAMIC_FTRACE_WITH_ARGS && DYNAMIC_FTRACE_WITH_CALL_OPS
select HAVE_DYNAMIC_FTRACE_WITH_CALL_OPS \
diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h
index ab158196480c..efd5dbf74dd6 100644
--- a/arch/arm64/include/asm/ftrace.h
+++ b/arch/arm64/include/asm/ftrace.h
@@ -131,6 +131,12 @@ ftrace_regs_set_return_value(struct ftrace_regs *fregs,
fregs->regs[0] = ret;
}
+static __always_inline unsigned long
+ftrace_regs_get_frame_pointer(struct ftrace_regs *fregs)
+{
+ return fregs->fp;
+}
+
static __always_inline void
ftrace_override_function_with_return(struct ftrace_regs *fregs)
{
diff --git a/arch/arm64/kernel/entry-ftrace.S b/arch/arm64/kernel/entry-ftrace.S
index f0c16640ef21..d87ccdb9e678 100644
--- a/arch/arm64/kernel/entry-ftrace.S
+++ b/arch/arm64/kernel/entry-ftrace.S
@@ -328,6 +328,33 @@ SYM_FUNC_END(ftrace_stub_graph)
* Run ftrace_return_to_handler() before going back to parent.
* @fp is checked against the value passed by ftrace_graph_caller().
*/
+#ifdef CONFIG_HAVE_FUNCTION_GRAPH_FREGS
+SYM_CODE_START(return_to_handler)
+ /* save ftrace_regs except for PC */
+ sub sp, sp, #FREGS_SIZE
+ stp x0, x1, [sp, #FREGS_X0]
+ stp x2, x3, [sp, #FREGS_X2]
+ stp x4, x5, [sp, #FREGS_X4]
+ stp x6, x7, [sp, #FREGS_X6]
+ str x8, [sp, #FREGS_X8]
+ str x29, [sp, #FREGS_FP]
+ str x9, [sp, #FREGS_LR]
+ str x10, [sp, #FREGS_SP]
+
+ mov x0, sp
+ bl ftrace_return_to_handler// addr =
ftrace_return_to_hander(fregs);
+ mov x30, x0 // restore the original return
address
+
+ /* restore return value regs */
+ ldp x0, x1, [sp, #FREGS_X0]
+ ldp x2, x3, [sp, #FREGS_X2]
+ ldp x4, x5, [sp, #FREGS_X4]
+ ldp x6, x7, [sp, #FREGS_X6]
+ add sp, sp, #FREGS_SIZE
+
+ ret
+SYM_CODE_END(return_to_handler)
+#else /* !CONFIG_HAVE_FUNCTION_GRAPH_FREGS */
SYM_CODE_START(return_to_handler)
/* save return value regs */
sub sp, sp, #FGRET_REGS_SIZE
@@ -350,4 +377,5 @@ SYM_CODE_START(return_to_handler)
ret
SYM_CODE_END(return_to_handler)
+#endif /* CONFIG_HAVE_FUNCTION_GRAPH_FREGS */
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
[PATCH v6 24/36] x86/ftrace: Enable HAVE_FUNCTION_GRAPH_FREGS
From: Masami Hiramatsu (Google) Support HAVE_FUNCTION_GRAPH_FREGS on x86-64, which saves ftrace_regs on the stack in ftrace_graph return trampoline so that the callbacks can access registers via ftrace_regs APIs. Note that this only recovers 'rax' and 'rdx' registers because other registers are not used anymore and recovered by caller. 'rax' and 'rdx' will be used for passing the return value. Signed-off-by: Masami Hiramatsu (Google) --- Changes in v3: - Add a comment about rip. Changes in v2: - Save rsp register and drop clearing orig_ax. --- arch/x86/Kconfig|3 ++- arch/x86/kernel/ftrace_64.S | 37 + 2 files changed, 31 insertions(+), 9 deletions(-) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 1566748f16c4..375ad280ee75 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -219,7 +219,8 @@ config X86 select HAVE_FAST_GUP select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE select HAVE_FTRACE_MCOUNT_RECORD - select HAVE_FUNCTION_GRAPH_RETVAL if HAVE_FUNCTION_GRAPH_TRACER + select HAVE_FUNCTION_GRAPH_FREGSif HAVE_DYNAMIC_FTRACE_WITH_ARGS + select HAVE_FUNCTION_GRAPH_RETVAL if !HAVE_DYNAMIC_FTRACE_WITH_ARGS select HAVE_FUNCTION_GRAPH_TRACER if X86_32 || (X86_64 && DYNAMIC_FTRACE) select HAVE_FUNCTION_TRACER select HAVE_GCC_PLUGINS diff --git a/arch/x86/kernel/ftrace_64.S b/arch/x86/kernel/ftrace_64.S index 214f30e9f0c0..8a16f774604e 100644 --- a/arch/x86/kernel/ftrace_64.S +++ b/arch/x86/kernel/ftrace_64.S @@ -348,21 +348,42 @@ STACK_FRAME_NON_STANDARD_FP(__fentry__) SYM_CODE_START(return_to_handler) UNWIND_HINT_UNDEFINED ANNOTATE_NOENDBR - subq $24, %rsp + /* +* Save the registers requires for ftrace_regs; +* rax, rcx, rdx, rdi, rsi, r8, r9 and rbp +*/ + subq $(FRAME_SIZE), %rsp + movq %rax, RAX(%rsp) + movq %rcx, RCX(%rsp) + movq %rdx, RDX(%rsp) + movq %rsi, RSI(%rsp) + movq %rdi, RDI(%rsp) + movq %r8, R8(%rsp) + movq %r9, R9(%rsp) + movq %rbp, RBP(%rsp) + /* +* orig_ax is not cleared because it is used for indicating the direct +* trampoline in the fentry. And rip is not set because we don't know +* the correct return address here. +*/ + + leaq FRAME_SIZE(%rsp), %rcx + movq %rcx, RSP(%rsp) - /* Save the return values */ - movq %rax, (%rsp) - movq %rdx, 8(%rsp) - movq %rbp, 16(%rsp) movq %rsp, %rdi call ftrace_return_to_handler movq %rax, %rdi - movq 8(%rsp), %rdx - movq (%rsp), %rax - addq $24, %rsp + /* +* Restore only rax and rdx because other registers are not used +* for return value nor callee saved. Caller will reuse/recover it. +*/ + movq RDX(%rsp), %rdx + movq RAX(%rsp), %rax + + addq $(FRAME_SIZE), %rsp /* * Jump back to the old return address. This cannot be JMP_NOSPEC rdi * since IBT would demand that contain ENDBR, which simply isn't so for
[PATCH v6 23/36] function_graph: Add a new exit handler with parent_ip and ftrace_regs
From: Masami Hiramatsu (Google)
Add a new return handler to fgraph_ops as 'retregfunc' which takes
parent_ip and ftrace_regs instead of ftrace_graph_ret. This handler
is available only if the arch support CONFIG_HAVE_FUNCTION_GRAPH_FREGS.
Note that the 'retfunc' and 'reregfunc' are mutual exclusive.
You can set only one of them.
Signed-off-by: Masami Hiramatsu (Google)
---
Changes in v6:
- update to use ftrace_regs_get_return_value() because of reordering
patches.
Changes in v3:
- Update for new multiple fgraph.
- Save the return address to instruction pointer in ftrace_regs.
---
arch/x86/include/asm/ftrace.h |2 +
include/linux/ftrace.h| 10 +-
kernel/trace/Kconfig |5 ++-
kernel/trace/fgraph.c | 70 -
4 files changed, 63 insertions(+), 24 deletions(-)
diff --git a/arch/x86/include/asm/ftrace.h b/arch/x86/include/asm/ftrace.h
index c88bf47f46da..a061f8832b20 100644
--- a/arch/x86/include/asm/ftrace.h
+++ b/arch/x86/include/asm/ftrace.h
@@ -72,6 +72,8 @@ arch_ftrace_get_regs(struct ftrace_regs *fregs)
override_function_with_return(&(fregs)->regs)
#define ftrace_regs_query_register_offset(name) \
regs_query_register_offset(name)
+#define ftrace_regs_get_frame_pointer(fregs) \
+ frame_pointer(&(fregs)->regs)
struct ftrace_ops;
#define ftrace_graph_func ftrace_graph_func
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 65d4d4b68768..da2a23f5a9ed 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -43,7 +43,9 @@ struct dyn_ftrace;
char *arch_ftrace_match_adjust(char *str, const char *search);
-#ifdef CONFIG_HAVE_FUNCTION_GRAPH_RETVAL
+#ifdef CONFIG_HAVE_FUNCTION_GRAPH_FREGS
+unsigned long ftrace_return_to_handler(struct ftrace_regs *fregs);
+#elif defined(CONFIG_HAVE_FUNCTION_GRAPH_RETVAL)
struct fgraph_ret_regs;
unsigned long ftrace_return_to_handler(struct fgraph_ret_regs *ret_regs);
#else
@@ -157,6 +159,7 @@ struct ftrace_regs {
#define ftrace_regs_set_instruction_pointer(fregs, ip) do { } while (0)
#endif /* CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS */
+
static __always_inline struct pt_regs *ftrace_get_regs(struct ftrace_regs
*fregs)
{
if (!fregs)
@@ -1067,6 +1070,10 @@ typedef int (*trace_func_graph_regs_ent_t)(unsigned long
func,
unsigned long parent_ip,
struct ftrace_regs *fregs,
struct fgraph_ops *); /* entry w/
regs */
+typedef void (*trace_func_graph_regs_ret_t)(unsigned long func,
+ unsigned long parent_ip,
+ struct ftrace_regs *,
+ struct fgraph_ops *); /* return w/
regs */
extern int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace, struct
fgraph_ops *gops);
@@ -1076,6 +1083,7 @@ struct fgraph_ops {
trace_func_graph_ent_t entryfunc;
trace_func_graph_ret_t retfunc;
trace_func_graph_regs_ent_t entryregfunc;
+ trace_func_graph_regs_ret_t retregfunc;
struct ftrace_ops ops; /* for the hash lists */
void*private;
int idx;
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index 61c541c36596..308b3bec01b1 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -34,6 +34,9 @@ config HAVE_FUNCTION_GRAPH_TRACER
config HAVE_FUNCTION_GRAPH_RETVAL
bool
+config HAVE_FUNCTION_GRAPH_FREGS
+ bool
+
config HAVE_DYNAMIC_FTRACE
bool
help
@@ -232,7 +235,7 @@ config FUNCTION_GRAPH_TRACER
config FUNCTION_GRAPH_RETVAL
bool "Kernel Function Graph Return Value"
- depends on HAVE_FUNCTION_GRAPH_RETVAL
+ depends on HAVE_FUNCTION_GRAPH_RETVAL || HAVE_FUNCTION_GRAPH_FREGS
depends on FUNCTION_GRAPH_TRACER
default n
help
diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c
index 0cb02de2db70..0f11f80bdd6c 100644
--- a/kernel/trace/fgraph.c
+++ b/kernel/trace/fgraph.c
@@ -742,8 +742,8 @@ int function_graph_enter_ops(unsigned long ret, unsigned
long func,
/* Retrieve a function return address to the trace stack on thread info.*/
static struct ftrace_ret_stack *
-ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret,
- unsigned long frame_pointer, int *index)
+ftrace_pop_return_trace(unsigned long *ret, unsigned long frame_pointer,
+ int *index)
{
struct ftrace_ret_stack *ret_stack;
@@ -788,10 +788,6 @@ ftrace_pop_return_trace(struct ftrace_graph_ret *trace,
unsigned long *ret,
*index += FGRAPH_RET_INDEX;
*ret = ret_stack->ret;
- trace->func = ret_stack->func;
- trace->calltime = ret_stack->calltime;
- trace->overrun =
[PATCH v6 22/36] function_graph: Add a new entry handler with parent_ip and ftrace_regs
From: Masami Hiramatsu (Google)
Add a new entry handler to fgraph_ops as 'entryregfunc' which takes
parent_ip and ftrace_regs. Note that the 'entryfunc' and 'entryregfunc'
are mutual exclusive. You can set only one of them.
Signed-off-by: Masami Hiramatsu (Google)
---
Changes in v3:
- Update for new multiple fgraph.
---
arch/arm64/kernel/ftrace.c |2 +
arch/loongarch/kernel/ftrace_dyn.c |6
arch/powerpc/kernel/trace/ftrace.c |2 +
arch/powerpc/kernel/trace/ftrace_64_pg.c | 10 ---
arch/x86/kernel/ftrace.c | 42 --
include/linux/ftrace.h | 19 +++---
kernel/trace/fgraph.c| 30 +
7 files changed, 76 insertions(+), 35 deletions(-)
diff --git a/arch/arm64/kernel/ftrace.c b/arch/arm64/kernel/ftrace.c
index b96740829798..779b975f03f5 100644
--- a/arch/arm64/kernel/ftrace.c
+++ b/arch/arm64/kernel/ftrace.c
@@ -497,7 +497,7 @@ void ftrace_graph_func(unsigned long ip, unsigned long
parent_ip,
return;
if (!function_graph_enter_ops(*parent, ip, frame_pointer,
- (void *)frame_pointer, gops))
+ (void *)frame_pointer, fregs, gops))
*parent = (unsigned long)_to_handler;
ftrace_test_recursion_unlock(bit);
diff --git a/arch/loongarch/kernel/ftrace_dyn.c
b/arch/loongarch/kernel/ftrace_dyn.c
index 73858c9029cc..39b3f09a5e0c 100644
--- a/arch/loongarch/kernel/ftrace_dyn.c
+++ b/arch/loongarch/kernel/ftrace_dyn.c
@@ -244,7 +244,11 @@ void ftrace_graph_func(unsigned long ip, unsigned long
parent_ip,
struct pt_regs *regs = >regs;
unsigned long *parent = (unsigned long *)>regs[1];
- prepare_ftrace_return(ip, (unsigned long *)parent);
+ if (unlikely(atomic_read(>tracing_graph_pause)))
+ return;
+
+ if (!function_graph_enter_regs(regs->regs[1], ip, 0, parent, fregs))
+ regs->regs[1] = (unsigned long)_to_handler;
}
#else
static int ftrace_modify_graph_caller(bool enable)
diff --git a/arch/powerpc/kernel/trace/ftrace.c
b/arch/powerpc/kernel/trace/ftrace.c
index 82010629cf88..9bf1b6912116 100644
--- a/arch/powerpc/kernel/trace/ftrace.c
+++ b/arch/powerpc/kernel/trace/ftrace.c
@@ -422,7 +422,7 @@ void ftrace_graph_func(unsigned long ip, unsigned long
parent_ip,
if (bit < 0)
goto out;
- if (!function_graph_enter(parent_ip, ip, 0, (unsigned long *)sp))
+ if (!function_graph_enter_regs(parent_ip, ip, 0, (unsigned long *)sp,
fregs))
parent_ip = ppc_function_entry(return_to_handler);
ftrace_test_recursion_unlock(bit);
diff --git a/arch/powerpc/kernel/trace/ftrace_64_pg.c
b/arch/powerpc/kernel/trace/ftrace_64_pg.c
index 7b85c3b460a3..43f6cfaaf7db 100644
--- a/arch/powerpc/kernel/trace/ftrace_64_pg.c
+++ b/arch/powerpc/kernel/trace/ftrace_64_pg.c
@@ -795,7 +795,8 @@ int ftrace_disable_ftrace_graph_caller(void)
* in current thread info. Return the address we want to divert to.
*/
static unsigned long
-__prepare_ftrace_return(unsigned long parent, unsigned long ip, unsigned long
sp)
+__prepare_ftrace_return(unsigned long parent, unsigned long ip, unsigned long
sp,
+ struct ftrace_regs *fregs)
{
unsigned long return_hooker;
int bit;
@@ -812,7 +813,7 @@ __prepare_ftrace_return(unsigned long parent, unsigned long
ip, unsigned long sp
return_hooker = ppc_function_entry(return_to_handler);
- if (!function_graph_enter(parent, ip, 0, (unsigned long *)sp))
+ if (!function_graph_enter_regs(parent, ip, 0, (unsigned long *)sp,
fregs))
parent = return_hooker;
ftrace_test_recursion_unlock(bit);
@@ -824,13 +825,14 @@ __prepare_ftrace_return(unsigned long parent, unsigned
long ip, unsigned long sp
void ftrace_graph_func(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *op, struct ftrace_regs *fregs)
{
- fregs->regs.link = __prepare_ftrace_return(parent_ip, ip,
fregs->regs.gpr[1]);
+ fregs->regs.link = __prepare_ftrace_return(parent_ip, ip,
+ fregs->regs.gpr[1], fregs);
}
#else
unsigned long prepare_ftrace_return(unsigned long parent, unsigned long ip,
unsigned long sp)
{
- return __prepare_ftrace_return(parent, ip, sp);
+ return __prepare_ftrace_return(parent, ip, sp, NULL);
}
#endif
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index 845e29b4254f..0f757e399a96 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -614,16 +614,8 @@ int ftrace_disable_ftrace_graph_caller(void)
}
#endif /* CONFIG_DYNAMIC_FTRACE && !CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS */
-/*
- * Hook the return address and push it in
[PATCH v6 21/36] function_graph: Add selftest for passing local variables
From: Steven Rostedt (VMware)
Add boot up selftest that passes variables from a function entry to a
function exit, and make sure that they do get passed around.
Signed-off-by: Steven Rostedt (VMware)
Signed-off-by: Masami Hiramatsu (Google)
---
Changes in v2:
- Add reserved size test.
- Use pr_*() instead of printk(KERN_*).
---
kernel/trace/trace_selftest.c | 169 +
1 file changed, 169 insertions(+)
diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c
index f0758afa2f7d..4d86cd4c8c8c 100644
--- a/kernel/trace/trace_selftest.c
+++ b/kernel/trace/trace_selftest.c
@@ -756,6 +756,173 @@ trace_selftest_startup_function(struct tracer *trace,
struct trace_array *tr)
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+#ifdef CONFIG_DYNAMIC_FTRACE
+
+#define BYTE_NUMBER 123
+#define SHORT_NUMBER 12345
+#define WORD_NUMBER 1234567890
+#define LONG_NUMBER 1234567890123456789LL
+
+static int fgraph_store_size __initdata;
+static const char *fgraph_store_type_name __initdata;
+static char *fgraph_error_str __initdata;
+static char fgraph_error_str_buf[128] __initdata;
+
+static __init int store_entry(struct ftrace_graph_ent *trace,
+ struct fgraph_ops *gops)
+{
+ const char *type = fgraph_store_type_name;
+ int size = fgraph_store_size;
+ void *p;
+
+ p = fgraph_reserve_data(gops->idx, size);
+ if (!p) {
+ snprintf(fgraph_error_str_buf, sizeof(fgraph_error_str_buf),
+"Failed to reserve %s\n", type);
+ fgraph_error_str = fgraph_error_str_buf;
+ return 0;
+ }
+
+ switch (fgraph_store_size) {
+ case 1:
+ *(char *)p = BYTE_NUMBER;
+ break;
+ case 2:
+ *(short *)p = SHORT_NUMBER;
+ break;
+ case 4:
+ *(int *)p = WORD_NUMBER;
+ break;
+ case 8:
+ *(long long *)p = LONG_NUMBER;
+ break;
+ }
+
+ return 1;
+}
+
+static __init void store_return(struct ftrace_graph_ret *trace,
+ struct fgraph_ops *gops)
+{
+ const char *type = fgraph_store_type_name;
+ long long expect = 0;
+ long long found = -1;
+ int size;
+ char *p;
+
+ p = fgraph_retrieve_data(gops->idx, );
+ if (!p) {
+ snprintf(fgraph_error_str_buf, sizeof(fgraph_error_str_buf),
+"Failed to retrieve %s\n", type);
+ fgraph_error_str = fgraph_error_str_buf;
+ return;
+ }
+ if (fgraph_store_size > size) {
+ snprintf(fgraph_error_str_buf, sizeof(fgraph_error_str_buf),
+"Retrieved size %d is smaller than expected %d\n",
+size, (int)fgraph_store_size);
+ fgraph_error_str = fgraph_error_str_buf;
+ return;
+ }
+
+ switch (fgraph_store_size) {
+ case 1:
+ expect = BYTE_NUMBER;
+ found = *(char *)p;
+ break;
+ case 2:
+ expect = SHORT_NUMBER;
+ found = *(short *)p;
+ break;
+ case 4:
+ expect = WORD_NUMBER;
+ found = *(int *)p;
+ break;
+ case 8:
+ expect = LONG_NUMBER;
+ found = *(long long *)p;
+ break;
+ }
+
+ if (found != expect) {
+ snprintf(fgraph_error_str_buf, sizeof(fgraph_error_str_buf),
+"%s returned not %lld but %lld\n", type, expect,
found);
+ fgraph_error_str = fgraph_error_str_buf;
+ return;
+ }
+ fgraph_error_str = NULL;
+}
+
+static struct fgraph_ops store_bytes __initdata = {
+ .entryfunc = store_entry,
+ .retfunc= store_return,
+};
+
+static int __init test_graph_storage_type(const char *name, int size)
+{
+ char *func_name;
+ int len;
+ int ret;
+
+ fgraph_store_type_name = name;
+ fgraph_store_size = size;
+
+ snprintf(fgraph_error_str_buf, sizeof(fgraph_error_str_buf),
+"Failed to execute storage %s\n", name);
+ fgraph_error_str = fgraph_error_str_buf;
+
+ pr_cont("PASSED\n");
+ pr_info("Testing fgraph storage of %d byte%s: ", size, size > 1 ? "s" :
"");
+
+ func_name = "*" __stringify(DYN_FTRACE_TEST_NAME);
+ len = strlen(func_name);
+
+ ret = ftrace_set_filter(_bytes.ops, func_name, len, 1);
+ if (ret && ret != -ENODEV) {
+ pr_cont("*Could not set filter* ");
+ return -1;
+ }
+
+ ret = register_ftrace_graph(_bytes);
+ if (ret) {
+ pr_warn("Failed to init store_bytes fgraph tracing\n");
+ return -1;
+ }
+
+ DYN_FTRACE_TEST_NAME();
+
+ unregister_ftrace_graph(_bytes);
[PATCH v6 20/36] function_graph: Improve push operation for several interrupts
From: Masami Hiramatsu (Google)
Improve push and data reserve operation on the shadow stack for
several sequencial interrupts.
To push a ret_stack or data entry on the shadow stack, we need to
prepare an index (offset) entry before updating the stack pointer
(curr_ret_stack) so that unwinder from interrupts can find the
next return address from the shadow stack. Currently we do write index,
update the curr_ret_stack, and rewrite it again. But that is not enough
for the case if two interrupts happens and the first one breaks it.
For example,
1. write reserved index entry at ret_stack[new_index - 1] and ret addr.
2. interrupt comes.
2.1. push new index and ret addr on ret_stack.
2.2. pop it. (corrupt entries on new_index - 1)
3. return from interrupt.
4. update curr_ret_stack = new_index
5. interrupt comes again.
5.1. unwind <-- may not work.
To avoid this issue, this introduces a new rsrv_ret_stack stack
reservation pointer and a new push code (slow path) to commit
previous reserved code forcibly.
0. update rsrv_ret_stack = new_index.
1. write reserved index entry at ret_stack[new_index - 1] and ret addr.
2. interrupt comes.
2.0. if rsrv_ret_stack != curr_ret_stack, add reserved index
entry on ret_stack[rsrv_ret_stack - 1] to point the previous
ret_stack pointed by ret_stack[curr_ret_stack - 1]. and
update curr_ret_stack = rsrv_ret_stack.
2.1. push new index and ret addr on ret_stack.
2.2. pop it. (corrupt entries on new_index - 1)
3. return from interrupt.
4. update curr_ret_stack = new_index
5. interrupt comes again.
5.1. unwind works, because curr_ret_stack points the previously
saved ret_stack.
5.2. this can do push/pop operations too.
6. return from interrupt.
7. rewrite reserved index entry at ret_stack[new_index] again.
This maybe a bit heavier but safer.
Signed-off-by: Masami Hiramatsu (Google)
---
Changes in v6:
- Newly added.
---
include/linux/sched.h |1
kernel/trace/fgraph.c | 135 +++--
2 files changed, 98 insertions(+), 38 deletions(-)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 4dab30f00211..fda551e1aade 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1387,6 +1387,7 @@ struct task_struct {
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
/* Index of current stored address in ret_stack: */
int curr_ret_stack;
+ int rsrv_ret_stack;
int curr_ret_depth;
/* Stack of return addresses for return function tracing: */
diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c
index a0eb7077b853..6a9206ebc6a2 100644
--- a/kernel/trace/fgraph.c
+++ b/kernel/trace/fgraph.c
@@ -298,31 +298,47 @@ void *fgraph_reserve_data(int idx, int size_bytes)
unsigned long val;
void *data;
int curr_ret_stack = current->curr_ret_stack;
+ int rsrv_ret_stack = current->rsrv_ret_stack;
int data_size;
if (size_bytes > FGRAPH_MAX_DATA_SIZE)
return NULL;
+ /*
+* Since this API is used after pushing ret_stack, curr_ret_stack
+* should be synchronized with rsrv_ret_stack.
+*/
+ if (WARN_ON_ONCE(curr_ret_stack != rsrv_ret_stack))
+ return NULL;
+
/* Convert to number of longs + data word */
data_size = DIV_ROUND_UP(size_bytes, sizeof(long));
val = get_fgraph_entry(current, curr_ret_stack - 1);
data = >ret_stack[curr_ret_stack];
- curr_ret_stack += data_size + 1;
- if (unlikely(curr_ret_stack >= SHADOW_STACK_MAX_INDEX))
+ rsrv_ret_stack += data_size + 1;
+ if (unlikely(rsrv_ret_stack >= SHADOW_STACK_MAX_INDEX))
return NULL;
val = make_fgraph_data(idx, data_size, __get_index(val) + data_size +
1);
- /* Set the last word to be reserved */
- current->ret_stack[curr_ret_stack - 1] = val;
-
- /* Make sure interrupts see this */
+ /* Extend the reserved-ret_stack at first */
+ current->rsrv_ret_stack = rsrv_ret_stack;
+ /* And sync with interrupts, to see the new rsrv_ret_stack */
+ barrier();
+ /*
+* The same reason as the push, this entry must be here before updating
+* the curr_ret_stack. But any interrupt comes before updating
+* curr_ret_stack, it may commit it with different reserve entry.
+* Thus we need to write the data entry after update the curr_ret_stack
+* again. And these operations must be ordered.
+*/
+ current->ret_stack[rsrv_ret_stack - 1] = val;
barrier();
- current->curr_ret_stack = curr_ret_stack;
- /* Again sync with interrupts, and reset reserve */
- current->ret_stack[curr_ret_stack - 1] = val;
+ current->curr_ret_stack = rsrv_ret_stack;
+ barrier();
+
[PATCH v6 19/36] function_graph: Implement fgraph_reserve_data() and fgraph_retrieve_data()
From: Steven Rostedt (VMware)
Added functions that can be called by a fgraph_ops entryfunc and retfunc to
store state between the entry of the function being traced to the exit of
the same function. The fgraph_ops entryfunc() may call
fgraph_reserve_data() to store up to 32 words onto the task's shadow
ret_stack and this then can be retrieved by fgraph_retrieve_data() called
by the corresponding retfunc().
Signed-off-by: Steven Rostedt (VMware)
Signed-off-by: Masami Hiramatsu (Google)
---
Changes in v3:
- Store fgraph_array index to the data entry.
- Both function requires fgraph_array index to store/retrieve data.
- Reserve correct size of the data.
- Return correct data area.
Changes in v2:
- Retrieve the reserved size by fgraph_retrieve_data().
- Expand the maximum data size to 32 words.
- Update stack index with __get_index(val) if FGRAPH_TYPE_ARRAY entry.
- fix typos and make description lines shorter than 76 chars.
---
include/linux/ftrace.h |3 +
kernel/trace/fgraph.c | 175 ++--
2 files changed, 170 insertions(+), 8 deletions(-)
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 737f84104577..815e865f46c9 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -1075,6 +1075,9 @@ struct fgraph_ops {
int idx;
};
+void *fgraph_reserve_data(int idx, int size_bytes);
+void *fgraph_retrieve_data(int idx, int *size_bytes);
+
/*
* Stack of return addresses for functions
* of a thread.
diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c
index 4ff5d2864fd2..a0eb7077b853 100644
--- a/kernel/trace/fgraph.c
+++ b/kernel/trace/fgraph.c
@@ -41,17 +41,29 @@
* bits: 10 - 11 Type of storage
* 0 - reserved
* 1 - bitmap of fgraph_array index
+ * 2 - reserved data
*
* For bitmap of fgraph_array index
* bits: 12 - 27 The bitmap of fgraph_ops fgraph_array index
*
+ * For reserved data:
+ * bits: 12 - 17 The size in words that is stored
+ * bits: 18 - 23 The index of fgraph_array, which shows who is stored
+ *
* That is, at the end of function_graph_enter, if the first and forth
* fgraph_ops on the fgraph_array[] (index 0 and 3) needs their retfunc called
- * on the return of the function being traced, this is what will be on the
- * task's shadow ret_stack: (the stack grows upward)
+ * on the return of the function being traced, and the forth fgraph_ops
+ * stored two words of data, this is what will be on the task's shadow
+ * ret_stack: (the stack grows upward)
*
* || <- task->curr_ret_stack
* ++
+ * | data_type(idx:3, size:2, |
+ * | offset:FGRAPH_RET_INDEX+3) | ( Data with size of 2 words)
+ * ++ ( It is 4 words from the
ret_stack)
+ * |STORED DATA WORD 2 |
+ * |STORED DATA WORD 1 |
+ * +--i-+
* | bitmap_type(bitmap:(BIT(3)|BIT(0)),|
* | offset:FGRAPH_RET_INDEX) | <- the offset is from here
* ++
@@ -78,14 +90,23 @@
enum {
FGRAPH_TYPE_RESERVED= 0,
FGRAPH_TYPE_BITMAP = 1,
+ FGRAPH_TYPE_DATA= 2,
};
#define FGRAPH_INDEX_SIZE 16
#define FGRAPH_INDEX_MASK GENMASK(FGRAPH_INDEX_SIZE - 1, 0)
#define FGRAPH_INDEX_SHIFT (FGRAPH_TYPE_SHIFT + FGRAPH_TYPE_SIZE)
-/* Currently the max stack index can't be more than register callers */
-#define FGRAPH_MAX_INDEX (FGRAPH_INDEX_SIZE + FGRAPH_RET_INDEX)
+#define FGRAPH_DATA_SIZE 5
+#define FGRAPH_DATA_MASK ((1 << FGRAPH_DATA_SIZE) - 1)
+#define FGRAPH_DATA_SHIFT (FGRAPH_TYPE_SHIFT + FGRAPH_TYPE_SIZE)
+
+#define FGRAPH_DATA_INDEX_SIZE 4
+#define FGRAPH_DATA_INDEX_MASK ((1 << FGRAPH_DATA_INDEX_SIZE) - 1)
+#define FGRAPH_DATA_INDEX_SHIFT(FGRAPH_DATA_SHIFT + FGRAPH_DATA_SIZE)
+
+#define FGRAPH_MAX_INDEX \
+ ((FGRAPH_INDEX_SIZE << FGRAPH_DATA_SIZE) + FGRAPH_RET_INDEX)
#define FGRAPH_ARRAY_SIZE FGRAPH_INDEX_SIZE
@@ -97,6 +118,8 @@ enum {
#define RET_STACK(t, index) ((struct ftrace_ret_stack
*)(&(t)->ret_stack[index]))
+#define FGRAPH_MAX_DATA_SIZE (sizeof(long) * (1 << FGRAPH_DATA_SIZE))
+
/*
* Each fgraph_ops has a reservered unsigned long at the end (top) of the
* ret_stack to store task specific state.
@@ -145,14 +168,39 @@ static int fgraph_lru_alloc_index(void)
return idx;
}
+static inline int __get_index(unsigned long val)
+{
+ return val & FGRAPH_RET_INDEX_MASK;
+}
+
+static inline int __get_type(unsigned long val)
+{
+ return (val >> FGRAPH_TYPE_SHIFT) & FGRAPH_TYPE_MASK;
+}
+
+static inline int __get_data_index(unsigned long val)
+{
+ return
[PATCH v6 18/36] function_graph: Move graph notrace bit to shadow stack global var
From: Steven Rostedt (VMware)
The use of the task->trace_recursion for the logic used for the function
graph no-trace was a bit of an abuse of that variable. Now that there
exists global vars that are per stack for registered graph traces, use
that instead.
Signed-off-by: Steven Rostedt (VMware)
Signed-off-by: Masami Hiramatsu (Google)
---
Changes in v2:
- Make description lines shorter than 76 chars.
---
include/linux/trace_recursion.h |7 ---
kernel/trace/trace.h |9 +
kernel/trace/trace_functions_graph.c | 10 ++
3 files changed, 15 insertions(+), 11 deletions(-)
diff --git a/include/linux/trace_recursion.h b/include/linux/trace_recursion.h
index 00e792bf148d..cc11b0e9d220 100644
--- a/include/linux/trace_recursion.h
+++ b/include/linux/trace_recursion.h
@@ -44,13 +44,6 @@ enum {
*/
TRACE_IRQ_BIT,
- /*
-* To implement set_graph_notrace, if this bit is set, we ignore
-* function graph tracing of called functions, until the return
-* function is called to clear it.
-*/
- TRACE_GRAPH_NOTRACE_BIT,
-
/* Used to prevent recursion recording from recursing. */
TRACE_RECORD_RECURSION_BIT,
};
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 1a467b5437b3..1dfa031c2812 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -916,8 +916,17 @@ enum {
TRACE_GRAPH_DEPTH_START_BIT,
TRACE_GRAPH_DEPTH_END_BIT,
+
+ /*
+* To implement set_graph_notrace, if this bit is set, we ignore
+* function graph tracing of called functions, until the return
+* function is called to clear it.
+*/
+ TRACE_GRAPH_NOTRACE_BIT,
};
+#define TRACE_GRAPH_NOTRACE(1 << TRACE_GRAPH_NOTRACE_BIT)
+
static inline unsigned long ftrace_graph_depth(unsigned long *task_var)
{
return (*task_var >> TRACE_GRAPH_DEPTH_START_BIT) & 3;
diff --git a/kernel/trace/trace_functions_graph.c
b/kernel/trace/trace_functions_graph.c
index 66cce73e94f8..13d0387ac6a6 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -130,6 +130,7 @@ static inline int ftrace_graph_ignore_irqs(void)
int trace_graph_entry(struct ftrace_graph_ent *trace,
struct fgraph_ops *gops)
{
+ unsigned long *task_var = fgraph_get_task_var(gops);
struct trace_array *tr = gops->private;
struct trace_array_cpu *data;
unsigned long flags;
@@ -138,7 +139,7 @@ int trace_graph_entry(struct ftrace_graph_ent *trace,
int ret;
int cpu;
- if (trace_recursion_test(TRACE_GRAPH_NOTRACE_BIT))
+ if (*task_var & TRACE_GRAPH_NOTRACE)
return 0;
/*
@@ -149,7 +150,7 @@ int trace_graph_entry(struct ftrace_graph_ent *trace,
* returning from the function.
*/
if (ftrace_graph_notrace_addr(trace->func)) {
- trace_recursion_set(TRACE_GRAPH_NOTRACE_BIT);
+ *task_var |= TRACE_GRAPH_NOTRACE_BIT;
/*
* Need to return 1 to have the return called
* that will clear the NOTRACE bit.
@@ -240,6 +241,7 @@ void __trace_graph_return(struct trace_array *tr,
void trace_graph_return(struct ftrace_graph_ret *trace,
struct fgraph_ops *gops)
{
+ unsigned long *task_var = fgraph_get_task_var(gops);
struct trace_array *tr = gops->private;
struct trace_array_cpu *data;
unsigned long flags;
@@ -249,8 +251,8 @@ void trace_graph_return(struct ftrace_graph_ret *trace,
ftrace_graph_addr_finish(gops, trace);
- if (trace_recursion_test(TRACE_GRAPH_NOTRACE_BIT)) {
- trace_recursion_clear(TRACE_GRAPH_NOTRACE_BIT);
+ if (*task_var & TRACE_GRAPH_NOTRACE) {
+ *task_var &= ~TRACE_GRAPH_NOTRACE;
return;
}
[PATCH v6 17/36] function_graph: Move graph depth stored data to shadow stack global var
From: Steven Rostedt (VMware)
The use of the task->trace_recursion for the logic used for the function
graph depth was a bit of an abuse of that variable. Now that there
exists global vars that are per stack for registered graph traces, use that
instead.
Signed-off-by: Steven Rostedt (VMware)
Signed-off-by: Masami Hiramatsu (Google)
---
include/linux/trace_recursion.h | 29 -
kernel/trace/trace.h| 34 --
2 files changed, 32 insertions(+), 31 deletions(-)
diff --git a/include/linux/trace_recursion.h b/include/linux/trace_recursion.h
index 2efd5ec46d7f..00e792bf148d 100644
--- a/include/linux/trace_recursion.h
+++ b/include/linux/trace_recursion.h
@@ -44,25 +44,6 @@ enum {
*/
TRACE_IRQ_BIT,
- /*
-* In the very unlikely case that an interrupt came in
-* at a start of graph tracing, and we want to trace
-* the function in that interrupt, the depth can be greater
-* than zero, because of the preempted start of a previous
-* trace. In an even more unlikely case, depth could be 2
-* if a softirq interrupted the start of graph tracing,
-* followed by an interrupt preempting a start of graph
-* tracing in the softirq, and depth can even be 3
-* if an NMI came in at the start of an interrupt function
-* that preempted a softirq start of a function that
-* preempted normal context Luckily, it can't be
-* greater than 3, so the next two bits are a mask
-* of what the depth is when we set TRACE_GRAPH_FL
-*/
-
- TRACE_GRAPH_DEPTH_START_BIT,
- TRACE_GRAPH_DEPTH_END_BIT,
-
/*
* To implement set_graph_notrace, if this bit is set, we ignore
* function graph tracing of called functions, until the return
@@ -78,16 +59,6 @@ enum {
#define trace_recursion_clear(bit) do { (current)->trace_recursion &=
~(1<<(bit)); } while (0)
#define trace_recursion_test(bit) ((current)->trace_recursion &
(1<<(bit)))
-#define trace_recursion_depth() \
- (((current)->trace_recursion >> TRACE_GRAPH_DEPTH_START_BIT) & 3)
-#define trace_recursion_set_depth(depth) \
- do {\
- current->trace_recursion &= \
- ~(3 << TRACE_GRAPH_DEPTH_START_BIT);\
- current->trace_recursion |= \
- ((depth) & 3) << TRACE_GRAPH_DEPTH_START_BIT; \
- } while (0)
-
#define TRACE_CONTEXT_BITS 4
#define TRACE_FTRACE_START TRACE_FTRACE_BIT
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 883d5c64f43f..1a467b5437b3 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -897,8 +897,38 @@ extern void free_fgraph_ops(struct trace_array *tr);
enum {
TRACE_GRAPH_FL = 1,
+
+ /*
+* In the very unlikely case that an interrupt came in
+* at a start of graph tracing, and we want to trace
+* the function in that interrupt, the depth can be greater
+* than zero, because of the preempted start of a previous
+* trace. In an even more unlikely case, depth could be 2
+* if a softirq interrupted the start of graph tracing,
+* followed by an interrupt preempting a start of graph
+* tracing in the softirq, and depth can even be 3
+* if an NMI came in at the start of an interrupt function
+* that preempted a softirq start of a function that
+* preempted normal context Luckily, it can't be
+* greater than 3, so the next two bits are a mask
+* of what the depth is when we set TRACE_GRAPH_FL
+*/
+
+ TRACE_GRAPH_DEPTH_START_BIT,
+ TRACE_GRAPH_DEPTH_END_BIT,
};
+static inline unsigned long ftrace_graph_depth(unsigned long *task_var)
+{
+ return (*task_var >> TRACE_GRAPH_DEPTH_START_BIT) & 3;
+}
+
+static inline void ftrace_graph_set_depth(unsigned long *task_var, int depth)
+{
+ *task_var &= ~(3 << TRACE_GRAPH_DEPTH_START_BIT);
+ *task_var |= (depth & 3) << TRACE_GRAPH_DEPTH_START_BIT;
+}
+
#ifdef CONFIG_DYNAMIC_FTRACE
extern struct ftrace_hash __rcu *ftrace_graph_hash;
extern struct ftrace_hash __rcu *ftrace_graph_notrace_hash;
@@ -931,7 +961,7 @@ ftrace_graph_addr(unsigned long *task_var, struct
ftrace_graph_ent *trace)
* when the depth is zero.
*/
*task_var |= TRACE_GRAPH_FL;
- trace_recursion_set_depth(trace->depth);
+ ftrace_graph_set_depth(task_var, trace->depth);
/*
* If no irqs are to be traced, but a set_graph_function
@@ -956,7 +986,7 @@ ftrace_graph_addr_finish(struct fgraph_ops *gops, struct
ftrace_graph_ret *trace
unsigned long *task_var = fgraph_get_task_var(gops);
if
[PATCH v6 16/36] function_graph: Move set_graph_function tests to shadow stack global var
From: Steven Rostedt (VMware)
The use of the task->trace_recursion for the logic used for the
set_graph_funnction was a bit of an abuse of that variable. Now that there
exists global vars that are per stack for registered graph traces, use that
instead.
Signed-off-by: Steven Rostedt (VMware)
Signed-off-by: Masami Hiramatsu (Google)
---
include/linux/trace_recursion.h |5 +
kernel/trace/trace.h | 32 +---
kernel/trace/trace_functions_graph.c |6 +++---
kernel/trace/trace_irqsoff.c |4 ++--
kernel/trace/trace_sched_wakeup.c|4 ++--
5 files changed, 29 insertions(+), 22 deletions(-)
diff --git a/include/linux/trace_recursion.h b/include/linux/trace_recursion.h
index d48cd92d2364..2efd5ec46d7f 100644
--- a/include/linux/trace_recursion.h
+++ b/include/linux/trace_recursion.h
@@ -44,9 +44,6 @@ enum {
*/
TRACE_IRQ_BIT,
- /* Set if the function is in the set_graph_function file */
- TRACE_GRAPH_BIT,
-
/*
* In the very unlikely case that an interrupt came in
* at a start of graph tracing, and we want to trace
@@ -60,7 +57,7 @@ enum {
* that preempted a softirq start of a function that
* preempted normal context Luckily, it can't be
* greater than 3, so the next two bits are a mask
-* of what the depth is when we set TRACE_GRAPH_BIT
+* of what the depth is when we set TRACE_GRAPH_FL
*/
TRACE_GRAPH_DEPTH_START_BIT,
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 3176f8dcaf94..883d5c64f43f 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -895,11 +895,16 @@ extern void init_array_fgraph_ops(struct trace_array *tr,
struct ftrace_ops *ops
extern int allocate_fgraph_ops(struct trace_array *tr, struct ftrace_ops *ops);
extern void free_fgraph_ops(struct trace_array *tr);
+enum {
+ TRACE_GRAPH_FL = 1,
+};
+
#ifdef CONFIG_DYNAMIC_FTRACE
extern struct ftrace_hash __rcu *ftrace_graph_hash;
extern struct ftrace_hash __rcu *ftrace_graph_notrace_hash;
-static inline int ftrace_graph_addr(struct ftrace_graph_ent *trace)
+static inline int
+ftrace_graph_addr(unsigned long *task_var, struct ftrace_graph_ent *trace)
{
unsigned long addr = trace->func;
int ret = 0;
@@ -921,12 +926,11 @@ static inline int ftrace_graph_addr(struct
ftrace_graph_ent *trace)
}
if (ftrace_lookup_ip(hash, addr)) {
-
/*
* This needs to be cleared on the return functions
* when the depth is zero.
*/
- trace_recursion_set(TRACE_GRAPH_BIT);
+ *task_var |= TRACE_GRAPH_FL;
trace_recursion_set_depth(trace->depth);
/*
@@ -946,11 +950,14 @@ static inline int ftrace_graph_addr(struct
ftrace_graph_ent *trace)
return ret;
}
-static inline void ftrace_graph_addr_finish(struct ftrace_graph_ret *trace)
+static inline void
+ftrace_graph_addr_finish(struct fgraph_ops *gops, struct ftrace_graph_ret
*trace)
{
- if (trace_recursion_test(TRACE_GRAPH_BIT) &&
+ unsigned long *task_var = fgraph_get_task_var(gops);
+
+ if ((*task_var & TRACE_GRAPH_FL) &&
trace->depth == trace_recursion_depth())
- trace_recursion_clear(TRACE_GRAPH_BIT);
+ *task_var &= ~TRACE_GRAPH_FL;
}
static inline int ftrace_graph_notrace_addr(unsigned long addr)
@@ -977,7 +984,7 @@ static inline int ftrace_graph_notrace_addr(unsigned long
addr)
}
#else
-static inline int ftrace_graph_addr(struct ftrace_graph_ent *trace)
+static inline int ftrace_graph_addr(unsigned long *task_var, struct
ftrace_graph_ent *trace)
{
return 1;
}
@@ -986,17 +993,20 @@ static inline int ftrace_graph_notrace_addr(unsigned long
addr)
{
return 0;
}
-static inline void ftrace_graph_addr_finish(struct ftrace_graph_ret *trace)
+static inline void ftrace_graph_addr_finish(struct fgraph_ops *gops, struct
ftrace_graph_ret *trace)
{ }
#endif /* CONFIG_DYNAMIC_FTRACE */
extern unsigned int fgraph_max_depth;
-static inline bool ftrace_graph_ignore_func(struct ftrace_graph_ent *trace)
+static inline bool
+ftrace_graph_ignore_func(struct fgraph_ops *gops, struct ftrace_graph_ent
*trace)
{
+ unsigned long *task_var = fgraph_get_task_var(gops);
+
/* trace it when it is-nested-in or is a function enabled. */
- return !(trace_recursion_test(TRACE_GRAPH_BIT) ||
-ftrace_graph_addr(trace)) ||
+ return !((*task_var & TRACE_GRAPH_FL) ||
+ftrace_graph_addr(task_var, trace)) ||
(trace->depth < 0) ||
(fgraph_max_depth && trace->depth >= fgraph_max_depth);
}
diff --git a/kernel/trace/trace_functions_graph.c
b/kernel/trace/trace_functions_graph.c
index 7f30652f0e97..66cce73e94f8 100644
--- a/kernel/trace/trace_functions_graph.c
+++
[PATCH v6 15/36] function_graph: Add "task variables" per task for fgraph_ops
From: Steven Rostedt (VMware)
Add a "task variables" array on the tasks shadow ret_stack that is the
size of longs for each possible registered fgraph_ops. That's a total
of 16, taking up 8 * 16 = 128 bytes (out of a page size 4k).
This will allow for fgraph_ops to do specific features on a per task basis
having a way to maintain state for each task.
Signed-off-by: Steven Rostedt (VMware)
Signed-off-by: Masami Hiramatsu (Google)
---
Changes in v3:
- Move fgraph_ops::idx to previous patch in the series.
Changes in v2:
- Make description lines shorter than 76 chars.
---
include/linux/ftrace.h |1 +
kernel/trace/fgraph.c | 70 +++-
2 files changed, 70 insertions(+), 1 deletion(-)
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 3d9e74ea6065..737f84104577 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -1116,6 +1116,7 @@ ftrace_graph_get_ret_stack(struct task_struct *task, int
idx);
unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx,
unsigned long ret, unsigned long *retp);
+unsigned long *fgraph_get_task_var(struct fgraph_ops *gops);
/*
* Sometimes we don't want to trace a function with the function
diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c
index ad4ea196b76e..4ff5d2864fd2 100644
--- a/kernel/trace/fgraph.c
+++ b/kernel/trace/fgraph.c
@@ -92,10 +92,18 @@ enum {
#define SHADOW_STACK_SIZE (PAGE_SIZE)
#define SHADOW_STACK_INDEX (SHADOW_STACK_SIZE / sizeof(long))
/* Leave on a buffer at the end */
-#define SHADOW_STACK_MAX_INDEX (SHADOW_STACK_INDEX - (FGRAPH_RET_INDEX + 1))
+#define SHADOW_STACK_MAX_INDEX \
+ (SHADOW_STACK_INDEX - (FGRAPH_RET_INDEX + 1 + FGRAPH_ARRAY_SIZE))
#define RET_STACK(t, index) ((struct ftrace_ret_stack
*)(&(t)->ret_stack[index]))
+/*
+ * Each fgraph_ops has a reservered unsigned long at the end (top) of the
+ * ret_stack to store task specific state.
+ */
+#define SHADOW_STACK_TASK_VARS(ret_stack) \
+ ((unsigned long *)(&(ret_stack)[SHADOW_STACK_INDEX -
FGRAPH_ARRAY_SIZE]))
+
DEFINE_STATIC_KEY_FALSE(kill_ftrace_graph);
int ftrace_graph_active;
@@ -182,6 +190,44 @@ static void return_run(struct ftrace_graph_ret *trace,
struct fgraph_ops *ops)
{
}
+static void ret_stack_set_task_var(struct task_struct *t, int idx, long val)
+{
+ unsigned long *gvals = SHADOW_STACK_TASK_VARS(t->ret_stack);
+
+ gvals[idx] = val;
+}
+
+static unsigned long *
+ret_stack_get_task_var(struct task_struct *t, int idx)
+{
+ unsigned long *gvals = SHADOW_STACK_TASK_VARS(t->ret_stack);
+
+ return [idx];
+}
+
+static void ret_stack_init_task_vars(unsigned long *ret_stack)
+{
+ unsigned long *gvals = SHADOW_STACK_TASK_VARS(ret_stack);
+
+ memset(gvals, 0, sizeof(*gvals) * FGRAPH_ARRAY_SIZE);
+}
+
+/**
+ * fgraph_get_task_var - retrieve a task specific state variable
+ * @gops: The ftrace_ops that owns the task specific variable
+ *
+ * Every registered fgraph_ops has a task state variable
+ * reserved on the task's ret_stack. This function returns the
+ * address to that variable.
+ *
+ * Returns the address to the fgraph_ops @gops tasks specific
+ * unsigned long variable.
+ */
+unsigned long *fgraph_get_task_var(struct fgraph_ops *gops)
+{
+ return ret_stack_get_task_var(current, gops->idx);
+}
+
/*
* @offset: The index into @t->ret_stack to find the ret_stack entry
* @index: Where to place the index into @t->ret_stack of that entry
@@ -791,6 +837,7 @@ static int alloc_retstack_tasklist(unsigned long
**ret_stack_list)
if (t->ret_stack == NULL) {
atomic_set(>trace_overrun, 0);
+ ret_stack_init_task_vars(ret_stack_list[start]);
t->curr_ret_stack = 0;
t->curr_ret_depth = -1;
/* Make sure the tasks see the 0 first: */
@@ -851,6 +898,7 @@ static void
graph_init_task(struct task_struct *t, unsigned long *ret_stack)
{
atomic_set(>trace_overrun, 0);
+ ret_stack_init_task_vars(ret_stack);
t->ftrace_timestamp = 0;
t->curr_ret_stack = 0;
t->curr_ret_depth = -1;
@@ -949,6 +997,24 @@ static int start_graph_tracing(void)
return ret;
}
+static void init_task_vars(int idx)
+{
+ struct task_struct *g, *t;
+ int cpu;
+
+ for_each_online_cpu(cpu) {
+ if (idle_task(cpu)->ret_stack)
+ ret_stack_set_task_var(idle_task(cpu), idx, 0);
+ }
+
+ read_lock(_lock);
+ for_each_process_thread(g, t) {
+ if (t->ret_stack)
+ ret_stack_set_task_var(t, idx, 0);
+ }
+ read_unlock(_lock);
+}
+
int register_ftrace_graph(struct fgraph_ops *gops)
{
int command = 0;
@@ -998,6 +1064,8 @@ int register_ftrace_graph(struct fgraph_ops *gops)
[PATCH v6 14/36] function_graph: Use a simple LRU for fgraph_array index number
From: Masami Hiramatsu (Google)
Since the fgraph_array index is used for the bitmap on the shadow
stack, it may leave some entries after a function_graph instance is
removed. Thus if another instance reuses the fgraph_array index soon
after releasing it, the fgraph may confuse to call the newer callback
for the entries which are pushed by the older instance.
To avoid reusing the fgraph_array index soon after releasing, introduce
a simple LRU table for managing the index number. This will reduce the
possibility of this confusion.
Signed-off-by: Masami Hiramatsu (Google)
---
Changes in v5:
- Fix the underflow bug in fgraph_lru_release_index() and return 0
if the release is succeded.
Changes in v4:
- Newly added.
---
kernel/trace/fgraph.c | 67 ++---
1 file changed, 47 insertions(+), 20 deletions(-)
diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c
index 5724062846f7..ad4ea196b76e 100644
--- a/kernel/trace/fgraph.c
+++ b/kernel/trace/fgraph.c
@@ -99,10 +99,44 @@ enum {
DEFINE_STATIC_KEY_FALSE(kill_ftrace_graph);
int ftrace_graph_active;
-static int fgraph_array_cnt;
-
static struct fgraph_ops *fgraph_array[FGRAPH_ARRAY_SIZE];
+/* LRU index table for fgraph_array */
+static int fgraph_lru_table[FGRAPH_ARRAY_SIZE];
+static int fgraph_lru_next;
+static int fgraph_lru_last;
+
+static void fgraph_lru_init(void)
+{
+ int i;
+
+ for (i = 0; i < FGRAPH_ARRAY_SIZE; i++)
+ fgraph_lru_table[i] = i;
+}
+
+static int fgraph_lru_release_index(int idx)
+{
+ if (idx < 0 || idx >= FGRAPH_ARRAY_SIZE ||
+ fgraph_lru_table[fgraph_lru_last] != -1)
+ return -1;
+
+ fgraph_lru_table[fgraph_lru_last] = idx;
+ fgraph_lru_last = (fgraph_lru_last + 1) % FGRAPH_ARRAY_SIZE;
+ return 0;
+}
+
+static int fgraph_lru_alloc_index(void)
+{
+ int idx = fgraph_lru_table[fgraph_lru_next];
+
+ if (idx == -1)
+ return -1;
+
+ fgraph_lru_table[fgraph_lru_next] = -1;
+ fgraph_lru_next = (fgraph_lru_next + 1) % FGRAPH_ARRAY_SIZE;
+ return idx;
+}
+
static inline int get_ret_stack_index(struct task_struct *t, int offset)
{
return t->ret_stack[offset] & FGRAPH_RET_INDEX_MASK;
@@ -367,7 +401,7 @@ int function_graph_enter(unsigned long ret, unsigned long
func,
if (index < 0)
goto out;
- for (i = 0; i < fgraph_array_cnt; i++) {
+ for (i = 0; i < FGRAPH_ARRAY_SIZE; i++) {
struct fgraph_ops *gops = fgraph_array[i];
if (gops == _stub)
@@ -935,21 +969,17 @@ int register_ftrace_graph(struct fgraph_ops *gops)
/* The array must always have real data on it */
for (i = 0; i < FGRAPH_ARRAY_SIZE; i++)
fgraph_array[i] = _stub;
+ fgraph_lru_init();
}
- /* Look for an available spot */
- for (i = 0; i < FGRAPH_ARRAY_SIZE; i++) {
- if (fgraph_array[i] == _stub)
- break;
- }
- if (i >= FGRAPH_ARRAY_SIZE) {
+ i = fgraph_lru_alloc_index();
+ if (i < 0 ||
+ WARN_ON_ONCE(fgraph_array[i] != _stub)) {
ret = -EBUSY;
goto out;
}
fgraph_array[i] = gops;
- if (i + 1 > fgraph_array_cnt)
- fgraph_array_cnt = i + 1;
gops->idx = i;
ftrace_graph_active++;
@@ -979,25 +1009,22 @@ int register_ftrace_graph(struct fgraph_ops *gops)
void unregister_ftrace_graph(struct fgraph_ops *gops)
{
int command = 0;
- int i;
mutex_lock(_lock);
if (unlikely(!ftrace_graph_active))
goto out;
- if (unlikely(gops->idx < 0 || gops->idx >= fgraph_array_cnt))
+ if (unlikely(gops->idx < 0 || gops->idx >= FGRAPH_ARRAY_SIZE))
+ goto out;
+
+ if (WARN_ON_ONCE(fgraph_array[gops->idx] != gops))
goto out;
- WARN_ON_ONCE(fgraph_array[gops->idx] != gops);
+ if (fgraph_lru_release_index(gops->idx) < 0)
+ goto out;
fgraph_array[gops->idx] = _stub;
- if (gops->idx + 1 == fgraph_array_cnt) {
- i = gops->idx;
- while (i >= 0 && fgraph_array[i] == _stub)
- i--;
- fgraph_array_cnt = i + 1;
- }
ftrace_graph_active--;
[PATCH v6 13/36] function_graph: Have the instances use their own ftrace_ops for filtering
From: Steven Rostedt (VMware)
Allow for instances to have their own ftrace_ops part of the fgraph_ops
that makes the funtion_graph tracer filter on the set_ftrace_filter file
of the instance and not the top instance.
This also change how the function_graph handles multiple instances on the
shadow stack. Previously we use ARRAY type entries to record which one
is enabled, and this makes it a bitmap of the fgraph_array's indexes.
Previous function_graph_enter() expects calling back from
prepare_ftrace_return() function which is called back only once if it is
enabled. But this introduces different ftrace_ops for each fgraph
instance and those are called from ftrace_graph_func() one by one. Thus
we can not loop on the fgraph_array(), and need to reuse the ret_stack
pushed by the previous instance. Finding the ret_stack is easy because
we can check the ret_stack->func. But that is not enough for the self-
recursive tail-call case. Thus fgraph uses the bitmap entry to find it
is already set (this means that entry is for previous tail call).
Signed-off-by: Steven Rostedt (VMware)
Signed-off-by: Masami Hiramatsu (Google)
---
Changes in v6:
- Fix to check whether the fgraph_ops is already unregistered in
function_graph_enter_ops().
- Fix stack unwinder error on arm64 because of passing wrong value
as retp. Thanks Mark!
Changes in v4:
- Simplify get_ret_stack() sanity check and use WARN_ON_ONCE() for
obviously wrong value.
- Do not check ret == return_to_handler but always read the previous
ret_stack in ftrace_push_return_trace() to check it is reusable.
- Set the bit 0 of the bitmap entry always in function_graph_enter()
because it uses bit 0 to check re-usability.
- Fix to ensure the ret_stack entry is bitmap type when checking the
bitmap.
Changes in v3:
- Pass current fgraph_ops to the new entry handler
(function_graph_enter_ops) if fgraph use ftrace.
- Add fgraph_ops::idx in this patch.
- Replace the array type with the bitmap type so that it can record
which fgraph is called.
- Fix some helper function to use passed task_struct instead of current.
- Reduce the ret-index size to 1024 words.
- Make the ret-index directly points the ret_stack.
- Fix ftrace_graph_ret_addr() to handle tail-call case correctly.
Changes in v2:
- Use ftrace_graph_func and FTRACE_OPS_GRAPH_STUB instead of
ftrace_stub and FTRACE_OPS_FL_STUB for new ftrace based fgraph.
---
arch/arm64/kernel/ftrace.c | 21 ++
arch/x86/kernel/ftrace.c | 19 ++
include/linux/ftrace.h |7 +
kernel/trace/fgraph.c| 372 --
kernel/trace/ftrace.c|6 -
kernel/trace/trace.h | 16 +
kernel/trace/trace_functions.c |2
kernel/trace/trace_functions_graph.c |8 +
8 files changed, 282 insertions(+), 169 deletions(-)
diff --git a/arch/arm64/kernel/ftrace.c b/arch/arm64/kernel/ftrace.c
index a650f5e11fc5..b96740829798 100644
--- a/arch/arm64/kernel/ftrace.c
+++ b/arch/arm64/kernel/ftrace.c
@@ -481,7 +481,26 @@ void prepare_ftrace_return(unsigned long self_addr,
unsigned long *parent,
void ftrace_graph_func(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *op, struct ftrace_regs *fregs)
{
- prepare_ftrace_return(ip, >lr, fregs->fp);
+ struct fgraph_ops *gops = container_of(op, struct fgraph_ops, ops);
+ unsigned long frame_pointer = fregs->fp;
+ unsigned long *parent = >lr;
+ int bit;
+
+ if (unlikely(ftrace_graph_is_dead()))
+ return;
+
+ if (unlikely(atomic_read(>tracing_graph_pause)))
+ return;
+
+ bit = ftrace_test_recursion_trylock(ip, *parent);
+ if (bit < 0)
+ return;
+
+ if (!function_graph_enter_ops(*parent, ip, frame_pointer,
+ (void *)frame_pointer, gops))
+ *parent = (unsigned long)_to_handler;
+
+ ftrace_test_recursion_unlock(bit);
}
#else
/*
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index 12df54ff0e81..845e29b4254f 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -657,9 +657,24 @@ void ftrace_graph_func(unsigned long ip, unsigned long
parent_ip,
struct ftrace_ops *op, struct ftrace_regs *fregs)
{
struct pt_regs *regs = >regs;
- unsigned long *stack = (unsigned long *)kernel_stack_pointer(regs);
+ unsigned long *parent = (unsigned long *)kernel_stack_pointer(regs);
+ struct fgraph_ops *gops = container_of(op, struct fgraph_ops, ops);
+ int bit;
+
+ if (unlikely(ftrace_graph_is_dead()))
+ return;
+
+ if (unlikely(atomic_read(>tracing_graph_pause)))
+ return;
- prepare_ftrace_return(ip, (unsigned long *)stack, 0);
+ bit = ftrace_test_recursion_trylock(ip, *parent);
+ if (bit < 0)
+
[PATCH v6 12/36] ftrace: Allow ftrace startup flags exist without dynamic ftrace
From: Steven Rostedt (VMware)
Some of the flags for ftrace_startup() may be exposed even when
CONFIG_DYNAMIC_FTRACE is not configured in. This is fine as the difference
between dynamic ftrace and static ftrace is done within the internals of
ftrace itself. No need to have use cases fail to compile because dynamic
ftrace is disabled.
This change is needed to move some of the logic of what is passed to
ftrace_startup() out of the parameters of ftrace_startup().
Signed-off-by: Steven Rostedt (VMware)
Signed-off-by: Masami Hiramatsu (Google)
---
include/linux/ftrace.h | 18 +-
1 file changed, 9 insertions(+), 9 deletions(-)
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 4df3f44043b8..c385ded1875f 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -538,6 +538,15 @@ static inline void stack_tracer_disable(void) { }
static inline void stack_tracer_enable(void) { }
#endif
+enum {
+ FTRACE_UPDATE_CALLS = (1 << 0),
+ FTRACE_DISABLE_CALLS= (1 << 1),
+ FTRACE_UPDATE_TRACE_FUNC= (1 << 2),
+ FTRACE_START_FUNC_RET = (1 << 3),
+ FTRACE_STOP_FUNC_RET= (1 << 4),
+ FTRACE_MAY_SLEEP= (1 << 5),
+};
+
#ifdef CONFIG_DYNAMIC_FTRACE
void ftrace_arch_code_modify_prepare(void);
@@ -632,15 +641,6 @@ void ftrace_set_global_notrace(unsigned char *buf, int
len, int reset);
void ftrace_free_filter(struct ftrace_ops *ops);
void ftrace_ops_set_global_filter(struct ftrace_ops *ops);
-enum {
- FTRACE_UPDATE_CALLS = (1 << 0),
- FTRACE_DISABLE_CALLS= (1 << 1),
- FTRACE_UPDATE_TRACE_FUNC= (1 << 2),
- FTRACE_START_FUNC_RET = (1 << 3),
- FTRACE_STOP_FUNC_RET= (1 << 4),
- FTRACE_MAY_SLEEP= (1 << 5),
-};
-
/*
* The FTRACE_UPDATE_* enum is used to pass information back
* from the ftrace_update_record() and ftrace_test_record()
[PATCH v6 11/36] ftrace: Allow function_graph tracer to be enabled in instances
From: Steven Rostedt (VMware)
Now that function graph tracing can handle more than one user, allow it to
be enabled in the ftrace instances. Note, the filtering of the functions is
still joined by the top level set_ftrace_filter and friends, as well as the
graph and nograph files.
Signed-off-by: Steven Rostedt (VMware)
Signed-off-by: Masami Hiramatsu (Google)
---
Changes in v2:
- Fix to remove set_graph_array() completely.
---
include/linux/ftrace.h |1 +
kernel/trace/ftrace.c|1 +
kernel/trace/trace.h | 13 ++-
kernel/trace/trace_functions.c |8
kernel/trace/trace_functions_graph.c | 65 +-
kernel/trace/trace_selftest.c|4 +-
6 files changed, 64 insertions(+), 28 deletions(-)
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index d173270352c3..4df3f44043b8 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -1070,6 +1070,7 @@ extern int ftrace_graph_entry_stub(struct
ftrace_graph_ent *trace, struct fgraph
struct fgraph_ops {
trace_func_graph_ent_t entryfunc;
trace_func_graph_ret_t retfunc;
+ void*private;
};
/*
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index b063ab2d2b1f..a720dd7cf290 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -7323,6 +7323,7 @@ __init void ftrace_init_global_array_ops(struct
trace_array *tr)
tr->ops = _ops;
tr->ops->private = tr;
ftrace_init_trace_array(tr);
+ init_array_fgraph_ops(tr);
}
void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index b04a18af71e4..b11e4cf4f72e 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -395,6 +395,9 @@ struct trace_array {
struct ftrace_ops *ops;
struct trace_pid_list __rcu *function_pids;
struct trace_pid_list __rcu *function_no_pids;
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+ struct fgraph_ops *gops;
+#endif
#ifdef CONFIG_DYNAMIC_FTRACE
/* All of these are protected by the ftrace_lock */
struct list_headfunc_probes;
@@ -678,7 +681,6 @@ void print_trace_header(struct seq_file *m, struct
trace_iterator *iter);
void trace_graph_return(struct ftrace_graph_ret *trace, struct fgraph_ops
*gops);
int trace_graph_entry(struct ftrace_graph_ent *trace, struct fgraph_ops *gops);
-void set_graph_array(struct trace_array *tr);
void tracing_start_cmdline_record(void);
void tracing_stop_cmdline_record(void);
@@ -889,6 +891,9 @@ extern int __trace_graph_entry(struct trace_array *tr,
extern void __trace_graph_return(struct trace_array *tr,
struct ftrace_graph_ret *trace,
unsigned int trace_ctx);
+extern void init_array_fgraph_ops(struct trace_array *tr);
+extern int allocate_fgraph_ops(struct trace_array *tr);
+extern void free_fgraph_ops(struct trace_array *tr);
#ifdef CONFIG_DYNAMIC_FTRACE
extern struct ftrace_hash __rcu *ftrace_graph_hash;
@@ -1001,6 +1006,12 @@ print_graph_function_flags(struct trace_iterator *iter,
u32 flags)
{
return TRACE_TYPE_UNHANDLED;
}
+static inline void init_array_fgraph_ops(struct trace_array *tr) { }
+static inline int allocate_fgraph_ops(struct trace_array *tr)
+{
+ return 0;
+}
+static inline void free_fgraph_ops(struct trace_array *tr) { }
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
extern struct list_head ftrace_pids;
diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c
index 9f1bfbe105e8..8e8da0d0ee52 100644
--- a/kernel/trace/trace_functions.c
+++ b/kernel/trace/trace_functions.c
@@ -80,6 +80,7 @@ void ftrace_free_ftrace_ops(struct trace_array *tr)
int ftrace_create_function_files(struct trace_array *tr,
struct dentry *parent)
{
+ int ret;
/*
* The top level array uses the "global_ops", and the files are
* created on boot up.
@@ -90,6 +91,12 @@ int ftrace_create_function_files(struct trace_array *tr,
if (!tr->ops)
return -EINVAL;
+ ret = allocate_fgraph_ops(tr);
+ if (ret) {
+ kfree(tr->ops);
+ return ret;
+ }
+
ftrace_create_filter_files(tr->ops, parent);
return 0;
@@ -99,6 +106,7 @@ void ftrace_destroy_function_files(struct trace_array *tr)
{
ftrace_destroy_filter_files(tr->ops);
ftrace_free_ftrace_ops(tr);
+ free_fgraph_ops(tr);
}
static ftrace_func_t select_trace_function(u32 flags_val)
diff --git a/kernel/trace/trace_functions_graph.c
b/kernel/trace/trace_functions_graph.c
index b7b142b65299..9ccc904a7703 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -83,8 +83,6 @@ static struct tracer_flags tracer_flags = {
[PATCH v6 10/36] ftrace/function_graph: Pass fgraph_ops to function graph callbacks
From: Steven Rostedt (VMware)
Pass the fgraph_ops structure to the function graph callbacks. This will
allow callbacks to add a descriptor to a fgraph_ops private field that wil
be added in the future and use it for the callbacks. This will be useful
when more than one callback can be registered to the function graph tracer.
Signed-off-by: Steven Rostedt (VMware)
Signed-off-by: Masami Hiramatsu (Google)
---
Changes in v2:
- cleanup to set argument name on function prototype.
---
include/linux/ftrace.h | 10 +++---
kernel/trace/fgraph.c| 16 +---
kernel/trace/ftrace.c|6 --
kernel/trace/trace.h |4 ++--
kernel/trace/trace_functions_graph.c | 11 +++
kernel/trace/trace_irqsoff.c |6 --
kernel/trace/trace_sched_wakeup.c|6 --
kernel/trace/trace_selftest.c|5 +++--
8 files changed, 40 insertions(+), 24 deletions(-)
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 39ac1f3e8041..d173270352c3 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -1055,11 +1055,15 @@ struct ftrace_graph_ret {
unsigned long long rettime;
} __packed;
+struct fgraph_ops;
+
/* Type of the callback handlers for tracing function graph*/
-typedef void (*trace_func_graph_ret_t)(struct ftrace_graph_ret *); /* return */
-typedef int (*trace_func_graph_ent_t)(struct ftrace_graph_ent *); /* entry */
+typedef void (*trace_func_graph_ret_t)(struct ftrace_graph_ret *,
+ struct fgraph_ops *); /* return */
+typedef int (*trace_func_graph_ent_t)(struct ftrace_graph_ent *,
+ struct fgraph_ops *); /* entry */
-extern int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace);
+extern int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace, struct
fgraph_ops *gops);
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c
index 97a9ffb8bb4c..62c35d6d95f9 100644
--- a/kernel/trace/fgraph.c
+++ b/kernel/trace/fgraph.c
@@ -129,13 +129,13 @@ static inline int get_fgraph_array(struct task_struct *t,
int offset)
}
/* ftrace_graph_entry set to this to tell some archs to run function graph */
-static int entry_run(struct ftrace_graph_ent *trace)
+static int entry_run(struct ftrace_graph_ent *trace, struct fgraph_ops *ops)
{
return 0;
}
/* ftrace_graph_return set to this to tell some archs to run function graph */
-static void return_run(struct ftrace_graph_ret *trace)
+static void return_run(struct ftrace_graph_ret *trace, struct fgraph_ops *ops)
{
}
@@ -199,12 +199,14 @@ int __weak ftrace_disable_ftrace_graph_caller(void)
}
#endif
-int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
+int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace,
+ struct fgraph_ops *gops)
{
return 0;
}
-static void ftrace_graph_ret_stub(struct ftrace_graph_ret *trace)
+static void ftrace_graph_ret_stub(struct ftrace_graph_ret *trace,
+ struct fgraph_ops *gops)
{
}
@@ -358,7 +360,7 @@ int function_graph_enter(unsigned long ret, unsigned long
func,
atomic_inc(>trace_overrun);
break;
}
- if (fgraph_array[i]->entryfunc()) {
+ if (fgraph_array[i]->entryfunc(, fgraph_array[i])) {
offset = current->curr_ret_stack;
/* Check the top level stored word */
type = get_fgraph_type(current, offset - 1);
@@ -532,7 +534,7 @@ static unsigned long __ftrace_return_to_handler(struct
fgraph_ret_regs *ret_regs
i = 0;
do {
idx = get_fgraph_array(current, offset - i);
- fgraph_array[idx]->retfunc();
+ fgraph_array[idx]->retfunc(, fgraph_array[idx]);
i++;
} while (i < index);
@@ -674,7 +676,7 @@ void ftrace_graph_sleep_time_control(bool enable)
* Simply points to ftrace_stub, but with the proper protocol.
* Defined by the linker script in linux/vmlinux.lds.h
*/
-extern void ftrace_stub_graph(struct ftrace_graph_ret *);
+void ftrace_stub_graph(struct ftrace_graph_ret *trace, struct fgraph_ops
*gops);
/* The callbacks that hook a function */
trace_func_graph_ret_t ftrace_graph_return = ftrace_stub_graph;
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 11aac697d40f..b063ab2d2b1f 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -815,7 +815,8 @@ void ftrace_graph_graph_time_control(bool enable)
fgraph_graph_time = enable;
}
-static int profile_graph_entry(struct ftrace_graph_ent *trace)
+static int profile_graph_entry(struct ftrace_graph_ent *trace,
+ struct fgraph_ops *gops)
{
struct ftrace_ret_stack *ret_stack;
@@ -832,7 +833,8 @@ static int
[PATCH v6 09/36] function_graph: Remove logic around ftrace_graph_entry and return
From: Steven Rostedt (VMware)
The function pointers ftrace_graph_entry and ftrace_graph_return are no
longer called via the function_graph tracer. Instead, an array structure is
now used that will allow for multiple users of the function_graph
infrastructure. The variables are still used by the architecture code for
non dynamic ftrace configs, where a test is made against them to see if
they point to the default stub function or not. This is how the static
function tracing knows to call into the function graph tracer
infrastructure or not.
Two new stub functions are made. entry_run() and return_run(). The
ftrace_graph_entry and ftrace_graph_return are set to them respectively
when the function graph tracer is enabled, and this will trigger the
architecture specific function graph code to be executed.
This also requires checking the global_ops hash for all calls into the
function_graph tracer.
Signed-off-by: Steven Rostedt (VMware)
Signed-off-by: Masami Hiramatsu (Google)
---
Changes in v2:
- Fix typo and make lines shorter than 76 chars in the description.
- Remove unneeded return from return_run() function.
---
kernel/trace/fgraph.c | 71 +++-
kernel/trace/ftrace.c |2 -
kernel/trace/ftrace_internal.h |2 -
3 files changed, 19 insertions(+), 56 deletions(-)
diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c
index 8aba93be11b2..97a9ffb8bb4c 100644
--- a/kernel/trace/fgraph.c
+++ b/kernel/trace/fgraph.c
@@ -128,6 +128,17 @@ static inline int get_fgraph_array(struct task_struct *t,
int offset)
FGRAPH_ARRAY_MASK;
}
+/* ftrace_graph_entry set to this to tell some archs to run function graph */
+static int entry_run(struct ftrace_graph_ent *trace)
+{
+ return 0;
+}
+
+/* ftrace_graph_return set to this to tell some archs to run function graph */
+static void return_run(struct ftrace_graph_ret *trace)
+{
+}
+
/*
* @offset: The index into @t->ret_stack to find the ret_stack entry
* @index: Where to place the index into @t->ret_stack of that entry
@@ -323,6 +334,10 @@ int function_graph_enter(unsigned long ret, unsigned long
func,
ftrace_find_rec_direct(ret - MCOUNT_INSN_SIZE))
return -EBUSY;
#endif
+
+ if (!ftrace_ops_test(_ops, func, NULL))
+ return -EBUSY;
+
trace.func = func;
trace.depth = ++current->curr_ret_depth;
@@ -664,7 +679,6 @@ extern void ftrace_stub_graph(struct ftrace_graph_ret *);
/* The callbacks that hook a function */
trace_func_graph_ret_t ftrace_graph_return = ftrace_stub_graph;
trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
-static trace_func_graph_ent_t __ftrace_graph_entry = ftrace_graph_entry_stub;
/* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
static int alloc_retstack_tasklist(unsigned long **ret_stack_list)
@@ -747,46 +761,6 @@ ftrace_graph_probe_sched_switch(void *ignore, bool preempt,
}
}
-static int ftrace_graph_entry_test(struct ftrace_graph_ent *trace)
-{
- if (!ftrace_ops_test(_ops, trace->func, NULL))
- return 0;
- return __ftrace_graph_entry(trace);
-}
-
-/*
- * The function graph tracer should only trace the functions defined
- * by set_ftrace_filter and set_ftrace_notrace. If another function
- * tracer ops is registered, the graph tracer requires testing the
- * function against the global ops, and not just trace any function
- * that any ftrace_ops registered.
- */
-void update_function_graph_func(void)
-{
- struct ftrace_ops *op;
- bool do_test = false;
-
- /*
-* The graph and global ops share the same set of functions
-* to test. If any other ops is on the list, then
-* the graph tracing needs to test if its the function
-* it should call.
-*/
- do_for_each_ftrace_op(op, ftrace_ops_list) {
- if (op != _ops && op != _ops &&
- op != _list_end) {
- do_test = true;
- /* in double loop, break out with goto */
- goto out;
- }
- } while_for_each_ftrace_op(op);
- out:
- if (do_test)
- ftrace_graph_entry = ftrace_graph_entry_test;
- else
- ftrace_graph_entry = __ftrace_graph_entry;
-}
-
static DEFINE_PER_CPU(unsigned long *, idle_ret_stack);
static void
@@ -927,18 +901,12 @@ int register_ftrace_graph(struct fgraph_ops *gops)
ftrace_graph_active--;
goto out;
}
-
- ftrace_graph_return = gops->retfunc;
-
/*
-* Update the indirect function to the entryfunc, and the
-* function that gets called to the entry_test first. Then
-* call the update fgraph entry function to determine if
-* the entryfunc should be called directly or not.
+
[PATCH v6 08/36] function_graph: Allow multiple users to attach to function graph
From: Steven Rostedt (VMware)
Allow for multiple users to attach to function graph tracer at the same
time. Only 16 simultaneous users can attach to the tracer. This is because
there's an array that stores the pointers to the attached fgraph_ops. When
a function being traced is entered, each of the ftrace_ops entryfunc is
called and if it returns non zero, its index into the array will be added
to the shadow stack.
On exit of the function being traced, the shadow stack will contain the
indexes of the ftrace_ops on the array that want their retfunc to be
called.
Because a function may sleep for a long time (if a task sleeps itself),
the return of the function may be literally days later. If the ftrace_ops
is removed, its place on the array is replaced with a ftrace_ops that
contains the stub functions and that will be called when the function
finally returns.
If another ftrace_ops is added that happens to get the same index into the
array, its return function may be called. But that's actually the way
things current work with the old function graph tracer. If one tracer is
removed and another is added, the new one will get the return calls of the
function traced by the previous one, thus this is not a regression. This
can be fixed by adding a counter to each time the array item is updated and
save that on the shadow stack as well, such that it won't be called if the
index saved does not match the index on the array.
Note, being able to filter functions when both are called is not completely
handled yet, but that shouldn't be too hard to manage.
Signed-off-by: Steven Rostedt (VMware)
Signed-off-by: Masami Hiramatsu (Google)
---
Changes in v2:
- Check return value of the ftrace_pop_return_trace() instead of 'ret'
since 'ret' is set to the address of panic().
- Fix typo and make lines shorter than 76 chars in description.
---
kernel/trace/fgraph.c | 332 +
1 file changed, 280 insertions(+), 52 deletions(-)
diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c
index 86df3ca6964f..8aba93be11b2 100644
--- a/kernel/trace/fgraph.c
+++ b/kernel/trace/fgraph.c
@@ -27,23 +27,144 @@
#define FGRAPH_RET_SIZE sizeof(struct ftrace_ret_stack)
#define FGRAPH_RET_INDEX (FGRAPH_RET_SIZE / sizeof(long))
+
+/*
+ * On entry to a function (via function_graph_enter()), a new ftrace_ret_stack
+ * is allocated on the task's ret_stack, then each fgraph_ops on the
+ * fgraph_array[]'s entryfunc is called and if that returns non-zero, the
+ * index into the fgraph_array[] for that fgraph_ops is added to the ret_stack.
+ * As the associated ftrace_ret_stack saved for those fgraph_ops needs to
+ * be found, the index to it is also added to the ret_stack along with the
+ * index of the fgraph_array[] to each fgraph_ops that needs their retfunc
+ * called.
+ *
+ * The top of the ret_stack (when not empty) will always have a reference
+ * to the last ftrace_ret_stack saved. All references to the
+ * ftrace_ret_stack has the format of:
+ *
+ * bits: 0 - 13 Index in words from the previous ftrace_ret_stack
+ * bits: 14 - 15 Type of storage
+ * 0 - reserved
+ * 1 - fgraph_array index
+ * For fgraph_array_index:
+ * bits: 16 - 23 The fgraph_ops fgraph_array index
+ *
+ * That is, at the end of function_graph_enter, if the first and forth
+ * fgraph_ops on the fgraph_array[] (index 0 and 3) needs their retfunc called
+ * on the return of the function being traced, this is what will be on the
+ * task's shadow ret_stack: (the stack grows upward)
+ *
+ * | | <- task->curr_ret_stack
+ * +--+
+ * | (3 << FGRAPH_ARRAY_SHIFT)|(2)| ( 3 for index of fourth fgraph_ops)
+ * +--+
+ * | (0 << FGRAPH_ARRAY_SHIFT)|(1)| ( 0 for index of first fgraph_ops)
+ * +--+
+ * | struct ftrace_ret_stack |
+ * | (stores the saved ret pointer) |
+ * +--+
+ * | (X) | (N)| ( N words away from previous ret_stack)
+ * | |
+ *
+ * If a backtrace is required, and the real return pointer needs to be
+ * fetched, then it looks at the task's curr_ret_stack index, if it
+ * is greater than zero, it would subtact one, and then mask the value
+ * on the ret_stack by FGRAPH_RET_INDEX_MASK and subtract FGRAPH_RET_INDEX
+ * from that, to get the index of the ftrace_ret_stack structure stored
+ * on the shadow stack.
+ */
+
+#define FGRAPH_RET_INDEX_SIZE 14
+#define FGRAPH_RET_INDEX_MASK ((1 << FGRAPH_RET_INDEX_SIZE) - 1)
+
+
+#define FGRAPH_TYPE_SIZE 2
+#define FGRAPH_TYPE_MASK ((1 << FGRAPH_TYPE_SIZE) - 1)
+#define FGRAPH_TYPE_SHIFT FGRAPH_RET_INDEX_SIZE
+
+enum {
+ FGRAPH_TYPE_RESERVED= 0,
+ FGRAPH_TYPE_ARRAY = 1,
+};
+
+#define FGRAPH_ARRAY_SIZE 16
+#define
[PATCH v6 07/36] function_graph: Add an array structure that will allow multiple callbacks
From: Steven Rostedt (VMware)
Add an array structure that will eventually allow the function graph tracer
to have up to 16 simultaneous callbacks attached. It's an array of 16
fgraph_ops pointers, that is assigned when one is registered. On entry of a
function the entry of the first item in the array is called, and if it
returns zero, then the callback returns non zero if it wants the return
callback to be called on exit of the function.
The array will simplify the process of having more than one callback
attached to the same function, as its index into the array can be stored on
the shadow stack. We need to only save the index, because this will allow
the fgraph_ops to be freed before the function returns (which may happen if
the function call schedule for a long time).
Signed-off-by: Steven Rostedt (VMware)
Signed-off-by: Masami Hiramatsu (Google)
---
Changes in v2:
- Remove unneeded brace.
---
kernel/trace/fgraph.c | 114 +++--
1 file changed, 81 insertions(+), 33 deletions(-)
diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c
index 837daf929d2a..86df3ca6964f 100644
--- a/kernel/trace/fgraph.c
+++ b/kernel/trace/fgraph.c
@@ -39,6 +39,11 @@
DEFINE_STATIC_KEY_FALSE(kill_ftrace_graph);
int ftrace_graph_active;
+static int fgraph_array_cnt;
+#define FGRAPH_ARRAY_SIZE 16
+
+static struct fgraph_ops *fgraph_array[FGRAPH_ARRAY_SIZE];
+
/* Both enabled by default (can be cleared by function_graph tracer flags */
static bool fgraph_sleep_time = true;
@@ -62,6 +67,20 @@ int __weak ftrace_disable_ftrace_graph_caller(void)
}
#endif
+int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
+{
+ return 0;
+}
+
+static void ftrace_graph_ret_stub(struct ftrace_graph_ret *trace)
+{
+}
+
+static struct fgraph_ops fgraph_stub = {
+ .entryfunc = ftrace_graph_entry_stub,
+ .retfunc = ftrace_graph_ret_stub,
+};
+
/**
* ftrace_graph_stop - set to permanently disable function graph tracing
*
@@ -159,7 +178,7 @@ int function_graph_enter(unsigned long ret, unsigned long
func,
goto out;
/* Only trace if the calling function expects to */
- if (!ftrace_graph_entry())
+ if (!fgraph_array[0]->entryfunc())
goto out_ret;
return 0;
@@ -274,7 +293,7 @@ static unsigned long __ftrace_return_to_handler(struct
fgraph_ret_regs *ret_regs
trace.retval = fgraph_ret_regs_return_value(ret_regs);
#endif
trace.rettime = trace_clock_local();
- ftrace_graph_return();
+ fgraph_array[0]->retfunc();
/*
* The ftrace_graph_return() may still access the current
* ret_stack structure, we need to make sure the update of
@@ -410,11 +429,6 @@ void ftrace_graph_sleep_time_control(bool enable)
fgraph_sleep_time = enable;
}
-int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
-{
- return 0;
-}
-
/*
* Simply points to ftrace_stub, but with the proper protocol.
* Defined by the linker script in linux/vmlinux.lds.h
@@ -652,37 +666,54 @@ static int start_graph_tracing(void)
int register_ftrace_graph(struct fgraph_ops *gops)
{
int ret = 0;
+ int i;
mutex_lock(_lock);
- /* we currently allow only one tracer registered at a time */
- if (ftrace_graph_active) {
+ if (!fgraph_array[0]) {
+ /* The array must always have real data on it */
+ for (i = 0; i < FGRAPH_ARRAY_SIZE; i++)
+ fgraph_array[i] = _stub;
+ }
+
+ /* Look for an available spot */
+ for (i = 0; i < FGRAPH_ARRAY_SIZE; i++) {
+ if (fgraph_array[i] == _stub)
+ break;
+ }
+ if (i >= FGRAPH_ARRAY_SIZE) {
ret = -EBUSY;
goto out;
}
- register_pm_notifier(_suspend_notifier);
+ fgraph_array[i] = gops;
+ if (i + 1 > fgraph_array_cnt)
+ fgraph_array_cnt = i + 1;
ftrace_graph_active++;
- ret = start_graph_tracing();
- if (ret) {
- ftrace_graph_active--;
- goto out;
- }
- ftrace_graph_return = gops->retfunc;
+ if (ftrace_graph_active == 1) {
+ register_pm_notifier(_suspend_notifier);
+ ret = start_graph_tracing();
+ if (ret) {
+ ftrace_graph_active--;
+ goto out;
+ }
+
+ ftrace_graph_return = gops->retfunc;
- /*
-* Update the indirect function to the entryfunc, and the
-* function that gets called to the entry_test first. Then
-* call the update fgraph entry function to determine if
-* the entryfunc should be called directly or not.
-*/
- __ftrace_graph_entry = gops->entryfunc;
- ftrace_graph_entry = ftrace_graph_entry_test;
- update_function_graph_func();
+ /*
+
[PATCH v6 06/36] fgraph: Use BUILD_BUG_ON() to make sure we have structures divisible by long
From: Steven Rostedt (VMware)
Instead of using "ALIGN()", use BUILD_BUG_ON() as the structures should
always be divisible by sizeof(long).
Link:
http://lkml.kernel.org/r/2019052444.gi2...@hirez.programming.kicks-ass.net
Suggested-by: Peter Zijlstra
Signed-off-by: Steven Rostedt (VMware)
Signed-off-by: Masami Hiramatsu (Google)
---
kernel/trace/fgraph.c |9 ++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c
index 30edeb6d4aa9..837daf929d2a 100644
--- a/kernel/trace/fgraph.c
+++ b/kernel/trace/fgraph.c
@@ -26,10 +26,9 @@
#endif
#define FGRAPH_RET_SIZE sizeof(struct ftrace_ret_stack)
-#define FGRAPH_RET_INDEX (ALIGN(FGRAPH_RET_SIZE, sizeof(long)) / sizeof(long))
+#define FGRAPH_RET_INDEX (FGRAPH_RET_SIZE / sizeof(long))
#define SHADOW_STACK_SIZE (PAGE_SIZE)
-#define SHADOW_STACK_INDEX \
- (ALIGN(SHADOW_STACK_SIZE, sizeof(long)) / sizeof(long))
+#define SHADOW_STACK_INDEX (SHADOW_STACK_SIZE / sizeof(long))
/* Leave on a buffer at the end */
#define SHADOW_STACK_MAX_INDEX (SHADOW_STACK_INDEX - FGRAPH_RET_INDEX)
@@ -91,6 +90,8 @@ ftrace_push_return_trace(unsigned long ret, unsigned long
func,
if (!current->ret_stack)
return -EBUSY;
+ BUILD_BUG_ON(SHADOW_STACK_SIZE % sizeof(long));
+
/*
* We must make sure the ret_stack is tested before we read
* anything else.
@@ -325,6 +326,8 @@ ftrace_graph_get_ret_stack(struct task_struct *task, int
idx)
{
int index = task->curr_ret_stack;
+ BUILD_BUG_ON(FGRAPH_RET_SIZE % sizeof(long));
+
index -= FGRAPH_RET_INDEX * (idx + 1);
if (index < 0)
return NULL;
[PATCH v6 05/36] function_graph: Convert ret_stack to a series of longs
From: Steven Rostedt (VMware)
In order to make it possible to have multiple callbacks registered with the
function_graph tracer, the retstack needs to be converted from an array of
ftrace_ret_stack structures to an array of longs. This will allow to store
the list of callbacks on the stack for the return side of the functions.
Signed-off-by: Steven Rostedt (VMware)
Signed-off-by: Masami Hiramatsu (Google)
---
include/linux/sched.h |2 -
kernel/trace/fgraph.c | 124 -
2 files changed, 71 insertions(+), 55 deletions(-)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 292c31697248..4dab30f00211 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1390,7 +1390,7 @@ struct task_struct {
int curr_ret_depth;
/* Stack of return addresses for return function tracing: */
- struct ftrace_ret_stack *ret_stack;
+ unsigned long *ret_stack;
/* Timestamp for last schedule: */
unsigned long long ftrace_timestamp;
diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c
index c83c005e654e..30edeb6d4aa9 100644
--- a/kernel/trace/fgraph.c
+++ b/kernel/trace/fgraph.c
@@ -25,6 +25,18 @@
#define ASSIGN_OPS_HASH(opsname, val)
#endif
+#define FGRAPH_RET_SIZE sizeof(struct ftrace_ret_stack)
+#define FGRAPH_RET_INDEX (ALIGN(FGRAPH_RET_SIZE, sizeof(long)) / sizeof(long))
+#define SHADOW_STACK_SIZE (PAGE_SIZE)
+#define SHADOW_STACK_INDEX \
+ (ALIGN(SHADOW_STACK_SIZE, sizeof(long)) / sizeof(long))
+/* Leave on a buffer at the end */
+#define SHADOW_STACK_MAX_INDEX (SHADOW_STACK_INDEX - FGRAPH_RET_INDEX)
+
+#define RET_STACK(t, index) ((struct ftrace_ret_stack
*)(&(t)->ret_stack[index]))
+#define RET_STACK_INC(c) ({ c += FGRAPH_RET_INDEX; })
+#define RET_STACK_DEC(c) ({ c -= FGRAPH_RET_INDEX; })
+
DEFINE_STATIC_KEY_FALSE(kill_ftrace_graph);
int ftrace_graph_active;
@@ -69,6 +81,7 @@ static int
ftrace_push_return_trace(unsigned long ret, unsigned long func,
unsigned long frame_pointer, unsigned long *retp)
{
+ struct ftrace_ret_stack *ret_stack;
unsigned long long calltime;
int index;
@@ -85,23 +98,25 @@ ftrace_push_return_trace(unsigned long ret, unsigned long
func,
smp_rmb();
/* The return trace stack is full */
- if (current->curr_ret_stack == FTRACE_RETFUNC_DEPTH - 1) {
+ if (current->curr_ret_stack >= SHADOW_STACK_MAX_INDEX) {
atomic_inc(>trace_overrun);
return -EBUSY;
}
calltime = trace_clock_local();
- index = ++current->curr_ret_stack;
+ index = current->curr_ret_stack;
+ RET_STACK_INC(current->curr_ret_stack);
+ ret_stack = RET_STACK(current, index);
barrier();
- current->ret_stack[index].ret = ret;
- current->ret_stack[index].func = func;
- current->ret_stack[index].calltime = calltime;
+ ret_stack->ret = ret;
+ ret_stack->func = func;
+ ret_stack->calltime = calltime;
#ifdef HAVE_FUNCTION_GRAPH_FP_TEST
- current->ret_stack[index].fp = frame_pointer;
+ ret_stack->fp = frame_pointer;
#endif
#ifdef HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
- current->ret_stack[index].retp = retp;
+ ret_stack->retp = retp;
#endif
return 0;
}
@@ -148,7 +163,7 @@ int function_graph_enter(unsigned long ret, unsigned long
func,
return 0;
out_ret:
- current->curr_ret_stack--;
+ RET_STACK_DEC(current->curr_ret_stack);
out:
current->curr_ret_depth--;
return -EBUSY;
@@ -159,11 +174,13 @@ static void
ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret,
unsigned long frame_pointer)
{
+ struct ftrace_ret_stack *ret_stack;
int index;
index = current->curr_ret_stack;
+ RET_STACK_DEC(index);
- if (unlikely(index < 0 || index >= FTRACE_RETFUNC_DEPTH)) {
+ if (unlikely(index < 0 || index > SHADOW_STACK_MAX_INDEX)) {
ftrace_graph_stop();
WARN_ON(1);
/* Might as well panic, otherwise we have no where to go */
@@ -171,6 +188,7 @@ ftrace_pop_return_trace(struct ftrace_graph_ret *trace,
unsigned long *ret,
return;
}
+ ret_stack = RET_STACK(current, index);
#ifdef HAVE_FUNCTION_GRAPH_FP_TEST
/*
* The arch may choose to record the frame pointer used
@@ -186,22 +204,22 @@ ftrace_pop_return_trace(struct ftrace_graph_ret *trace,
unsigned long *ret,
* Note, -mfentry does not use frame pointers, and this test
* is not needed if CC_USING_FENTRY is set.
*/
- if (unlikely(current->ret_stack[index].fp != frame_pointer)) {
+ if (unlikely(ret_stack->fp != frame_pointer)) {
ftrace_graph_stop();
WARN(1, "Bad frame
[PATCH v6 04/36] x86: tracing: Add ftrace_regs definition in the header
From: Masami Hiramatsu (Google)
Add ftrace_regs definition for x86_64 in the ftrace header to
clarify what register will be accessible from ftrace_regs.
Signed-off-by: Masami Hiramatsu (Google)
---
Changes in v3:
- Add rip to be saved.
Changes in v2:
- Newly added.
---
arch/x86/include/asm/ftrace.h |6 ++
1 file changed, 6 insertions(+)
diff --git a/arch/x86/include/asm/ftrace.h b/arch/x86/include/asm/ftrace.h
index cf88cc8cc74d..c88bf47f46da 100644
--- a/arch/x86/include/asm/ftrace.h
+++ b/arch/x86/include/asm/ftrace.h
@@ -36,6 +36,12 @@ static inline unsigned long ftrace_call_adjust(unsigned long
addr)
#ifdef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS
struct ftrace_regs {
+ /*
+* On the x86_64, the ftrace_regs saves;
+* rax, rcx, rdx, rdi, rsi, r8, r9, rbp, rip and rsp.
+* Also orig_ax is used for passing direct trampoline address.
+* x86_32 doesn't support ftrace_regs.
+*/
struct pt_regs regs;
};
[PATCH v6 03/36] tracing: Rename ftrace_regs_return_value to ftrace_regs_get_return_value
From: Masami Hiramatsu (Google) Rename ftrace_regs_return_value to ftrace_regs_get_return_value as same as other ftrace_regs_get/set_* APIs. Signed-off-by: Masami Hiramatsu (Google) Acked-by: Mark Rutland --- Changes in v6: - Moved to top of the series. Changes in v3: - Newly added. --- arch/loongarch/include/asm/ftrace.h |2 +- arch/powerpc/include/asm/ftrace.h |2 +- arch/s390/include/asm/ftrace.h |2 +- arch/x86/include/asm/ftrace.h |2 +- include/linux/ftrace.h |2 +- 5 files changed, 5 insertions(+), 5 deletions(-) diff --git a/arch/loongarch/include/asm/ftrace.h b/arch/loongarch/include/asm/ftrace.h index a11996eb5892..a9c3d0f2f941 100644 --- a/arch/loongarch/include/asm/ftrace.h +++ b/arch/loongarch/include/asm/ftrace.h @@ -70,7 +70,7 @@ ftrace_regs_set_instruction_pointer(struct ftrace_regs *fregs, unsigned long ip) regs_get_kernel_argument(&(fregs)->regs, n) #define ftrace_regs_get_stack_pointer(fregs) \ kernel_stack_pointer(&(fregs)->regs) -#define ftrace_regs_return_value(fregs) \ +#define ftrace_regs_get_return_value(fregs) \ regs_return_value(&(fregs)->regs) #define ftrace_regs_set_return_value(fregs, ret) \ regs_set_return_value(&(fregs)->regs, ret) diff --git a/arch/powerpc/include/asm/ftrace.h b/arch/powerpc/include/asm/ftrace.h index 9e5a39b6a311..7e138e0e3baf 100644 --- a/arch/powerpc/include/asm/ftrace.h +++ b/arch/powerpc/include/asm/ftrace.h @@ -69,7 +69,7 @@ ftrace_regs_get_instruction_pointer(struct ftrace_regs *fregs) regs_get_kernel_argument(&(fregs)->regs, n) #define ftrace_regs_get_stack_pointer(fregs) \ kernel_stack_pointer(&(fregs)->regs) -#define ftrace_regs_return_value(fregs) \ +#define ftrace_regs_get_return_value(fregs) \ regs_return_value(&(fregs)->regs) #define ftrace_regs_set_return_value(fregs, ret) \ regs_set_return_value(&(fregs)->regs, ret) diff --git a/arch/s390/include/asm/ftrace.h b/arch/s390/include/asm/ftrace.h index 5a82b08f03cd..01e775c98425 100644 --- a/arch/s390/include/asm/ftrace.h +++ b/arch/s390/include/asm/ftrace.h @@ -88,7 +88,7 @@ ftrace_regs_set_instruction_pointer(struct ftrace_regs *fregs, regs_get_kernel_argument(&(fregs)->regs, n) #define ftrace_regs_get_stack_pointer(fregs) \ kernel_stack_pointer(&(fregs)->regs) -#define ftrace_regs_return_value(fregs) \ +#define ftrace_regs_get_return_value(fregs) \ regs_return_value(&(fregs)->regs) #define ftrace_regs_set_return_value(fregs, ret) \ regs_set_return_value(&(fregs)->regs, ret) diff --git a/arch/x86/include/asm/ftrace.h b/arch/x86/include/asm/ftrace.h index 897cf02c20b1..cf88cc8cc74d 100644 --- a/arch/x86/include/asm/ftrace.h +++ b/arch/x86/include/asm/ftrace.h @@ -58,7 +58,7 @@ arch_ftrace_get_regs(struct ftrace_regs *fregs) regs_get_kernel_argument(&(fregs)->regs, n) #define ftrace_regs_get_stack_pointer(fregs) \ kernel_stack_pointer(&(fregs)->regs) -#define ftrace_regs_return_value(fregs) \ +#define ftrace_regs_get_return_value(fregs) \ regs_return_value(&(fregs)->regs) #define ftrace_regs_set_return_value(fregs, ret) \ regs_set_return_value(&(fregs)->regs, ret) diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 8b48fc621ea0..39ac1f3e8041 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -184,7 +184,7 @@ static __always_inline bool ftrace_regs_has_args(struct ftrace_regs *fregs) regs_get_kernel_argument(ftrace_get_regs(fregs), n) #define ftrace_regs_get_stack_pointer(fregs) \ kernel_stack_pointer(ftrace_get_regs(fregs)) -#define ftrace_regs_return_value(fregs) \ +#define ftrace_regs_get_return_value(fregs) \ regs_return_value(ftrace_get_regs(fregs)) #define ftrace_regs_set_return_value(fregs, ret) \ regs_set_return_value(ftrace_get_regs(fregs), ret)
[PATCH v6 02/36] tracing: Add a comment about ftrace_regs definition
From: Masami Hiramatsu (Google)
To clarify what will be expected on ftrace_regs, add a comment to the
architecture independent definition of the ftrace_regs.
Signed-off-by: Masami Hiramatsu (Google)
Acked-by: Mark Rutland
---
Changes in v3:
- Add instruction pointer
Changes in v2:
- newly added.
---
include/linux/ftrace.h | 26 ++
1 file changed, 26 insertions(+)
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index e8921871ef9a..8b48fc621ea0 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -118,6 +118,32 @@ extern int ftrace_enabled;
#ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS
+/**
+ * ftrace_regs - ftrace partial/optimal register set
+ *
+ * ftrace_regs represents a group of registers which is used at the
+ * function entry and exit. There are three types of registers.
+ *
+ * - Registers for passing the parameters to callee, including the stack
+ * pointer. (e.g. rcx, rdx, rdi, rsi, r8, r9 and rsp on x86_64)
+ * - Registers for passing the return values to caller.
+ * (e.g. rax and rdx on x86_64)
+ * - Registers for hooking the function call and return including the
+ * frame pointer (the frame pointer is architecture/config dependent)
+ * (e.g. rip, rbp and rsp for x86_64)
+ *
+ * Also, architecture dependent fields can be used for internal process.
+ * (e.g. orig_ax on x86_64)
+ *
+ * On the function entry, those registers will be restored except for
+ * the stack pointer, so that user can change the function parameters
+ * and instruction pointer (e.g. live patching.)
+ * On the function exit, only registers which is used for return values
+ * are restored.
+ *
+ * NOTE: user *must not* access regs directly, only do it via APIs, because
+ * the member can be changed according to the architecture.
+ */
struct ftrace_regs {
struct pt_regs regs;
};
[PATCH v6 01/36] ftrace: Fix DIRECT_CALLS to use SAVE_REGS by default
From: Masami Hiramatsu (Google)
The commit 60c8971899f3 ("ftrace: Make DIRECT_CALLS work WITH_ARGS
and !WITH_REGS") changed DIRECT_CALLS to use SAVE_ARGS when there
are multiple ftrace_ops at the same function, but since the x86 only
support to jump to direct_call from ftrace_regs_caller, when we set
the function tracer on the same target function on x86, ftrace-direct
does not work as below (this actually works on arm64.)
At first, insmod ftrace-direct.ko to put a direct_call on
'wake_up_process()'.
# insmod kernel/samples/ftrace/ftrace-direct.ko
# less trace
..
-0 [006] ..s1. 564.686958: my_direct_func: waking up
rcu_preempt-17
-0 [007] ..s1. 564.687836: my_direct_func: waking up
kcompactd0-63
-0 [006] ..s1. 564.690926: my_direct_func: waking up
rcu_preempt-17
-0 [006] ..s1. 564.696872: my_direct_func: waking up
rcu_preempt-17
-0 [007] ..s1. 565.191982: my_direct_func: waking up
kcompactd0-63
Setup a function filter to the 'wake_up_process' too, and enable it.
# cd /sys/kernel/tracing/
# echo wake_up_process > set_ftrace_filter
# echo function > current_tracer
# less trace
..
-0 [006] ..s3. 686.180972: wake_up_process
<-call_timer_fn
-0 [006] ..s3. 686.186919: wake_up_process
<-call_timer_fn
-0 [002] ..s3. 686.264049: wake_up_process
<-call_timer_fn
-0 [002] d.h6. 686.515216: wake_up_process <-kick_pool
-0 [002] d.h6. 686.691386: wake_up_process <-kick_pool
Then, only function tracer is shown on x86.
But if you enable 'kprobe on ftrace' event (which uses SAVE_REGS flag)
on the same function, it is shown again.
# echo 'p wake_up_process' >> dynamic_events
# echo 1 > events/kprobes/p_wake_up_process_0/enable
# echo > trace
# less trace
..
-0 [006] ..s2. 2710.345919: p_wake_up_process_0:
(wake_up_process+0x4/0x20)
-0 [006] ..s3. 2710.345923: wake_up_process
<-call_timer_fn
-0 [006] ..s1. 2710.345928: my_direct_func: waking up
rcu_preempt-17
-0 [006] ..s2. 2710.349931: p_wake_up_process_0:
(wake_up_process+0x4/0x20)
-0 [006] ..s3. 2710.349934: wake_up_process
<-call_timer_fn
-0 [006] ..s1. 2710.349937: my_direct_func: waking up
rcu_preempt-17
To fix this issue, use SAVE_REGS flag for multiple ftrace_ops flag of
direct_call by default.
Link:
https://lore.kernel.org/all/170484558617.178953.1590516949390270842.stgit@devnote2/
Fixes: 60c8971899f3 ("ftrace: Make DIRECT_CALLS work WITH_ARGS and !WITH_REGS")
Cc: sta...@vger.kernel.org
Signed-off-by: Masami Hiramatsu (Google)
Reviewed-by: Mark Rutland
Tested-by: Mark Rutland [arm64]
Acked-by: Jiri Olsa
---
kernel/trace/ftrace.c | 10 ++
1 file changed, 10 insertions(+)
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index b01ae7d36021..c060d5b47910 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -5325,7 +5325,17 @@ static LIST_HEAD(ftrace_direct_funcs);
static int register_ftrace_function_nolock(struct ftrace_ops *ops);
+/*
+ * If there are multiple ftrace_ops, use SAVE_REGS by default, so that direct
+ * call will be jumped from ftrace_regs_caller. Only if the architecture does
+ * not support ftrace_regs_caller but direct_call, use SAVE_ARGS so that it
+ * jumps from ftrace_caller for multiple ftrace_ops.
+ */
+#ifndef HAVE_DYNAMIC_FTRACE_WITH_REGS
#define MULTI_FLAGS (FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_ARGS)
+#else
+#define MULTI_FLAGS (FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_REGS)
+#endif
static int check_direct_multi(struct ftrace_ops *ops)
{
[PATCH v6 00/36] tracing: fprobe: function_graph: Multi-function graph and fprobe on fgraph
Hi, Here is the 6th version of the series to re-implement the fprobe on function-graph tracer. The previous version is; https://lore.kernel.org/all/170290509018.220107.1347127510564358608.stgit@devnote2/ This version fixes use-after-unregister bug and arm64 stack unwinding bug [13/36], add an improvement for multiple interrupts during push operation[20/36], keep SAVE_REGS until BPF and fprobe_event using ftrace_regs[26/36], also reorder the patches[30/36][31/36] so that new fprobe can switch to SAVE_ARGS[32/36] safely. This series also temporarily adds a DIRECT_CALLS bugfix[1/36], which should be pushed separatedly as a stable bugfix. There are some TODOs: - Add s390x and loongarch support to fprobe (multiple fgraph). - Fix to get the symbol address from ftrace entry address on arm64. (This should be done in BPF trace event) - Cleanup code, rename some terms(offset/index) and FGRAPH_TYPE_BITMAP part should be merged to FGRAPH_TYPE_ARRAY patch. Overview This series does major 2 changes, enable multiple function-graphs on the ftrace (e.g. allow function-graph on sub instances) and rewrite the fprobe on this function-graph. The former changes had been sent from Steven Rostedt 4 years ago (*), which allows users to set different setting function-graph tracer (and other tracers based on function-graph) in each trace-instances at the same time. (*) https://lore.kernel.org/all/20190525031633.811342...@goodmis.org/ The purpose of latter change are; 1) Remove dependency of the rethook from fprobe so that we can reduce the return hook code and shadow stack. 2) Make 'ftrace_regs' the common trace interface for the function boundary. 1) Currently we have 2(or 3) different function return hook codes, the function-graph tracer and rethook (and legacy kretprobe). But since this is redundant and needs double maintenance cost, I would like to unify those. From the user's viewpoint, function- graph tracer is very useful to grasp the execution path. For this purpose, it is hard to use the rethook in the function-graph tracer, but the opposite is possible. (Strictly speaking, kretprobe can not use it because it requires 'pt_regs' for historical reasons.) 2) Now the fprobe provides the 'pt_regs' for its handler, but that is wrong for the function entry and exit. Moreover, depending on the architecture, there is no way to accurately reproduce 'pt_regs' outside of interrupt or exception handlers. This means fprobe should not use 'pt_regs' because it does not use such exceptions. (Conversely, kprobe should use 'pt_regs' because it is an abstract interface of the software breakpoint exception.) This series changes fprobe to use function-graph tracer for tracing function entry and exit, instead of mixture of ftrace and rethook. Unlike the rethook which is a per-task list of system-wide allocated nodes, the function graph's ret_stack is a per-task shadow stack. Thus it does not need to set 'nr_maxactive' (which is the number of pre-allocated nodes). Also the handlers will get the 'ftrace_regs' instead of 'pt_regs'. Since eBPF mulit_kprobe/multi_kretprobe events still use 'pt_regs' as their register interface, this changes it to convert 'ftrace_regs' to 'pt_regs'. Of course this conversion makes an incomplete 'pt_regs', so users must access only registers for function parameters or return value. Design -- Instead of using ftrace's function entry hook directly, the new fprobe is built on top of the function-graph's entry and return callbacks with 'ftrace_regs'. Since the fprobe requires access to 'ftrace_regs', the architecture must support CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS, which enables to call function-graph entry callback with 'ftrace_regs', and also CONFIG_HAVE_FUNCTION_GRAPH_FREGS, which passes the ftrace_regs to return_to_handler. All fprobes share a single function-graph ops (means shares a common ftrace filter) similar to the kprobe-on-ftrace. This needs another layer to find corresponding fprobe in the common function-graph callbacks, but has much better scalability, since the number of registered function-graph ops is limited. In the entry callback, the fprobe runs its entry_handler and saves the address of 'fprobe' on the function-graph's shadow stack as data. The return callback decodes the data to get the 'fprobe' address, and runs the exit_handler. The fprobe introduces two hash-tables, one is for entry callback which searches fprobes related to the given function address passed by entry callback. The other is for a return callback which checks if the given 'fprobe' data structure pointer is still valid. Note that it is possible to unregister fprobe before the return callback runs. Thus the address validation must be done before using it in the return callback. This series can be applied against the v6.7 kernel. This series can also be found below branch.
Re: [PATCH v11 2/5] ring-buffer: Introducing ring-buffer mapping functions
On Thu, Jan 11, 2024 at 06:23:20PM -0500, Steven Rostedt wrote:
> On Thu, 11 Jan 2024 11:34:58 -0500
> Mathieu Desnoyers wrote:
>
>
> > The LTTng kernel tracer has supported mmap'd buffers for nearly 15 years
> > [1],
> > and has a lot of similarities with this patch series.
> >
> > LTTng has the notion of "subbuffer id" to allow atomically exchanging a
> > "reader" extra subbuffer with the subbuffer to be read. It implements
> > "get subbuffer" / "put subbuffer" ioctls to allow the consumer (reader)
> > to move the currently read subbuffer position. [2]
> >
> > It would not hurt to compare your approach to LTTng and highlight
> > similarities/differences, and the rationale for the differences.
> >
> > Especially when it comes to designing kernel ABIs, it's good to make sure
> > that all bases are covered, because those choices will have lasting impacts.
> >
> > Thanks,
> >
> > Mathieu
> >
> > [1]
> > https://git.lttng.org/?p=lttng-modules.git;a=blob;f=src/lib/ringbuffer/ring_buffer_mmap.c
> > [2]
> > https://git.lttng.org/?p=lttng-modules.git;a=blob;f=src/lib/ringbuffer/ring_buffer_vfs.c
> >
>
> Hi Mathieu,
>
> Thanks for sharing!
>
> As we discussed a little bit in the tracing meeting we do somethings
> differently but very similar too ;-)
>
> The similarities as that all the sub-buffers are mapped. You have a
> reader-sub-buffer as well.
>
> The main difference is that you use an ioctl() that returns where to find
> the reader-sub-buffer, where our ioctl() is just "I'm done, get me a new
> reader-sub-buffer". Ours will update the meta page.
>
> Our meta page looks like this:
>
> > +struct trace_buffer_meta {
> > + unsigned long entries;
> > + unsigned long overrun;
> > + unsigned long read;
>
> If start tracing: trace-cmd start -e sched_switch and do:
>
> ~ cat /sys/kernel/tracing/per_cpu/cpu0/stats
> entries: 14
> overrun: 0
> commit overrun: 0
> bytes: 992
> oldest event ts: 84844.825372
> now ts: 84847.102075
> dropped events: 0
> read events: 0
>
> You'll see similar to the above.
>
> entries = entries
> overrun = overrun
> read = read
>
> The above "read" is total number of events read.
>
> Pretty staight forward ;-)
>
>
> > +
> > + unsigned long subbufs_touched;
> > + unsigned long subbufs_lost;
> > + unsigned long subbufs_read;
>
> Now I'm thinking we may not want this exported, as I'm not sure it's useful.
touched and lost are not useful now, but it'll be for my support of the
hypervisor tracing, that's why I added them already.
subbufs_read could probably go away though as even in that case I can track that
in the reader.
>
> Vincent, talking with Mathieu, he was suggesting that we only export what
> we really need, and I don't think we need the above. Especially since they
> are not exposed in the stats file.
>
>
> > +
> > + struct {
> > + unsigned long lost_events;
> > + __u32 id;
> > + __u32 read;
> > + } reader;
>
> The above is definitely needed, as all of it is used to read the
> reader-page of the sub-buffer.
>
> lost_events is the number of lost events that happened before this
> sub-buffer was swapped out.
>
> Hmm, Vincent, I just notice that you update the lost_events as:
>
> > +static void rb_update_meta_page(struct ring_buffer_per_cpu *cpu_buffer)
> > +{
> > + struct trace_buffer_meta *meta = cpu_buffer->meta_page;
> > +
> > + WRITE_ONCE(meta->entries, local_read(_buffer->entries));
> > + WRITE_ONCE(meta->overrun, local_read(_buffer->overrun));
> > + WRITE_ONCE(meta->read, cpu_buffer->read);
> > +
> > + WRITE_ONCE(meta->subbufs_touched,
> > local_read(_buffer->pages_touched));
> > + WRITE_ONCE(meta->subbufs_lost, local_read(_buffer->pages_lost));
> > + WRITE_ONCE(meta->subbufs_read, local_read(_buffer->pages_read));
> > +
> > + WRITE_ONCE(meta->reader.read, cpu_buffer->reader_page->read);
> > + WRITE_ONCE(meta->reader.id, cpu_buffer->reader_page->id);
> > + WRITE_ONCE(meta->reader.lost_events, cpu_buffer->lost_events);
> > +}
>
> The lost_events may need to be handled differently, as it doesn't always
> get cleared. So it may be stale data.
My idea was to check this value after the ioctl(). If > 0 then events were lost
between the that ioctl() and the previous swap.
But now if with "[PATCH] ring-buffer: Have mmapped ring buffer keep track of
missed events" we put this information in the page itself, we can get rid of
this field.
>
>
> > +
> > + __u32 subbuf_size;
> > + __u32 nr_subbufs;
>
> This gets is the information needed to read the mapped ring buffer.
>
> > +
> > + __u32 meta_page_size;
> > + __u32 meta_struct_len;
>
> The ring buffer gets mapped after "meta_page_size" and this structure is
> "meta_struct_len" which will change if we add new data to it.
>
> > +};
>
> -- Steve
Re: [PATCH] tracefs/eventfs: Use root and instance inodes as default ownership
On Thu, Jan 11, 2024 at 04:53:19PM -0500, Steven Rostedt wrote:
> On Thu, 11 Jan 2024 22:01:32 +0100
> Christian Brauner wrote:
>
> > What I'm pointing out in the current logic is that the caller is
> > taxed twice:
> >
> > (1) Once when the VFS has done inode_permission(MAY_EXEC, "xfs")
> > (2) And again when you call lookup_one_len() in eventfs_start_creating()
> > _because_ the permission check in lookup_one_len() is the exact
> > same permission check again that the vfs has done
> > inode_permission(MAY_EXEC, "xfs").
>
> As I described in:
> https://lore.kernel.org/all/20240110133154.6e18f...@gandalf.local.home/
>
> The eventfs files below "events" doesn't need the .permissions callback at
> all. It's only there because the "events" inode uses it.
>
> The .permissions call for eventfs has:
It doesn't matter whether there's a ->permission handler. If you don't
add one explicitly the VFS will simply call generic_permission():
inode_permission()
-> do_inode_permission()
{
if (unlikely(!(inode->i_opflags & IOP_FASTPERM))) {
if (likely(inode->i_op->permission))
return inode->i_op->permission(idmap, inode, mask);
/* This gets set once for the inode lifetime */
spin_lock(>i_lock);
inode->i_opflags |= IOP_FASTPERM;
spin_unlock(>i_lock);
}
return generic_permission(idmap, inode, mask);
}
> Anyway, the issue is with "events" directory and remounting, because like
> the tracefs system, the inode and dentry for "evnets" is created at boot
> up, before the mount happens. The VFS layer is going to check the
> permissions of its inode and dentry, which will be incorrect if the mount
> was mounted with a "gid" option.
The gid option has nothing to do with this and it is just handled fine
if you remove the second permission checking in (2).
You need to remove the inode_permission() code from
eventfs_start_creating(). It is just an internal lookup and the fact
that you have it in there allows userspace to break readdir on the
eventfs portions of tracefs as I've shown in the parts of the mail that
you cut off.
