On 11/28/22 9:24 AM, Bjoern A. Zeeb wrote:
The branch main has been updated by bz:
URL:
https://cgit.FreeBSD.org/src/commit/?id=0fce2dc1573019d0732f33fa7c26cc228655d3e8
commit 0fce2dc1573019d0732f33fa7c26cc228655d3e8
Author: Bjoern A. Zeeb <[email protected]>
AuthorDate: 2022-10-22 18:12:16 +0000
Commit: Bjoern A. Zeeb <[email protected]>
CommitDate: 2022-11-28 17:21:50 +0000
LinuxKPI,lindebugfs: add u8 base type and blob support
Add debugfs_create_u8() based on other already present implementations.
Add a read-only implementation for debugfs_create_blob().
Both are needed for iwlwifi debugfs support.
This passes kernel pointers to copyout because debugfs is kind of broken due to
quirks in how linux file operations are implemented.
Sponsored by: The FreeBSD Foundation
MFC after: 3 days
OKed by: jfree (earlier version)
Differential Revision: https://reviews.freebsd.org/D37090
---
sys/compat/lindebugfs/lindebugfs.c | 66 ++++++++++++++++++++++
sys/compat/linuxkpi/common/include/linux/debugfs.h | 11 +++-
2 files changed, 76 insertions(+), 1 deletion(-)
diff --git a/sys/compat/lindebugfs/lindebugfs.c
b/sys/compat/lindebugfs/lindebugfs.c
index b88caf9c3140..b72ceb5e0be9 100644
--- a/sys/compat/lindebugfs/lindebugfs.c
+++ b/sys/compat/lindebugfs/lindebugfs.c
@@ -394,6 +423,43 @@ debugfs_create_ulong(const char *name, umode_t mode,
struct dentry *parent, unsi
&fops_ulong_ro, &fops_ulong_wo);
}
+
+static ssize_t
+fops_blob_read(struct file *filp, char __user *ubuf, size_t read_size, loff_t
*ppos)
This is not actually a __user pointer. Note that simple_attr_read/write use
plain pointers.
The only invocations of this function are in debugfs_fill:
rc = -ENODEV;
if (uio->uio_rw == UIO_READ && d->dm_fops->read) {
rc = -ENOMEM;
buf = (char *) malloc(sb->s_size, M_DFSINT, M_ZERO | M_NOWAIT);
if (buf != NULL) {
rc = d->dm_fops->read(&lf, buf, sb->s_size, &off);
if (rc > 0)
sbuf_bcpy(sb, buf, strlen(buf));
free(buf, M_DFSINT);
}
} else if (uio->uio_rw == UIO_WRITE && d->dm_fops->write) {
sbuf_finish(sb);
rc = d->dm_fops->write(&lf, sbuf_data(sb), sbuf_len(sb), &off);
}
+{
+ struct debugfs_blob_wrapper *blob;
+
+ blob = filp->private_data;
+ if (blob == NULL)
+ return (-EINVAL);
+ if (blob->size == 0 || blob->data == NULL)
+ return (-EINVAL);
+
+ return (simple_read_from_buffer(ubuf, read_size, ppos, blob->data,
blob->size));
+}
This means you can't use simple_read_from_buffer() here as it is a wrapper
around
copyout. At least some architectures fail copyout calls where the user pointer
is
a kernel pointer (e.g. arm64 and RISC-V). I haven't looked if amd64 has the
misfeature of letting it work. I'll have to fix this for CheriBSD downstream,
but
I'll try to post a review using an inlined version of simple_read_from_buffer
that
just uses memcpy directly.
--
John Baldwin
