From: Masami Hiramatsu (Google) <[email protected]>

Change the fprobe exit handler to use ftrace_regs structure instead of
pt_regs. This also introduce HAVE_FTRACE_REGS_HAVING_PT_REGS which
means the ftrace_regs is including the pt_regs so that ftrace_regs
can provide pt_regs without memory allocation.
Fprobe introduces a new dependency with that.

Signed-off-by: Masami Hiramatsu (Google) <[email protected]>
Acked-by: Heiko Carstens <[email protected]> # s390
Cc: Huacai Chen <[email protected]>
Cc: WANG Xuerui <[email protected]>
Cc: Vasily Gorbik <[email protected]>
Cc: Alexander Gordeev <[email protected]>
Cc: Christian Borntraeger <[email protected]>
Cc: Sven Schnelle <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: [email protected]
Cc: "H. Peter Anvin" <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Mathieu Desnoyers <[email protected]>
Cc: Song Liu <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: KP Singh <[email protected]>
Cc: Matt Bobrowski <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: Daniel Borkmann <[email protected]>
Cc: Andrii Nakryiko <[email protected]>
Cc: Martin KaFai Lau <[email protected]>
Cc: Eduard Zingerman <[email protected]>
Cc: Yonghong Song <[email protected]>
Cc: John Fastabend <[email protected]>
Cc: Stanislav Fomichev <[email protected]>
Cc: Hao Luo <[email protected]>
Cc: Andrew Morton <[email protected]>

---
  Changes in v16:
   - Rename HAVE_PT_REGS_TO_FTRACE_REGS_CAST to
     HAVE_FTRACE_REGS_HAVING_PT_REGS.
  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          |    6 ++++++
 kernel/trace/Kconfig            |    7 +++++++
 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 49f5bfc00e5a..6396615ec035 100644
--- a/arch/loongarch/Kconfig
+++ b/arch/loongarch/Kconfig
@@ -128,6 +128,7 @@ config LOONGARCH
        select HAVE_DMA_CONTIGUOUS
        select HAVE_DYNAMIC_FTRACE
        select HAVE_DYNAMIC_FTRACE_WITH_ARGS
+       select HAVE_FTRACE_REGS_HAVING_PT_REGS
        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 102029e56cf0..d8eee56c10b6 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -183,6 +183,7 @@ config S390
        select HAVE_DMA_CONTIGUOUS
        select HAVE_DYNAMIC_FTRACE
        select HAVE_DYNAMIC_FTRACE_WITH_ARGS
+       select HAVE_FTRACE_REGS_HAVING_PT_REGS
        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 ff0d7e07c611..6cb420783ef3 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -225,6 +225,7 @@ config X86
        select HAVE_DYNAMIC_FTRACE
        select HAVE_DYNAMIC_FTRACE_WITH_REGS
        select HAVE_DYNAMIC_FTRACE_WITH_ARGS    if X86_64
+       select HAVE_FTRACE_REGS_HAVING_PT_REGS  if X86_64
        select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
        select HAVE_SAMPLE_FTRACE_DIRECT        if X86_64
        select HAVE_SAMPLE_FTRACE_DIRECT_MULTI  if X86_64
diff --git a/include/linux/fprobe.h b/include/linux/fprobe.h
index ca64ee5e45d2..ef609bcca0f9 100644
--- a/include/linux/fprobe.h
+++ b/include/linux/fprobe.h
@@ -14,7 +14,7 @@ typedef int (*fprobe_entry_cb)(struct fprobe *fp, unsigned 
long entry_ip,
                               void *entry_data);
 
 typedef void (*fprobe_exit_cb)(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);
 
 /**
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 9a1e768e47da..bf8bb6c10553 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -176,6 +176,12 @@ static inline struct pt_regs *arch_ftrace_get_regs(struct 
ftrace_regs *fregs)
 #define ftrace_regs_set_instruction_pointer(fregs, ip) do { } while (0)
 #endif /* CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS */
 
+#ifdef CONFIG_HAVE_FTRACE_REGS_HAVING_PT_REGS
+
+static_assert(sizeof(struct pt_regs) == ftrace_regs_size());
+
+#endif /* CONFIG_HAVE_FTRACE_REGS_HAVING_PT_REGS */
+
 static __always_inline struct pt_regs *ftrace_get_regs(struct ftrace_regs 
*fregs)
 {
        if (!fregs)
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index f10ca86fbfad..7f8165f2049a 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -57,6 +57,12 @@ config HAVE_DYNAMIC_FTRACE_WITH_ARGS
         This allows for use of ftrace_regs_get_argument() and
         ftrace_regs_get_stack_pointer().
 
+config HAVE_FTRACE_REGS_HAVING_PT_REGS
+       bool
+       help
+        If this is set, ftrace_regs has pt_regs, thus it can convert to
+        pt_regs without allocating memory.
+
 config HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
        bool
        help
@@ -298,6 +304,7 @@ config FPROBE
        bool "Kernel Function Probe (fprobe)"
        depends on FUNCTION_TRACER
        depends on DYNAMIC_FTRACE_WITH_REGS || DYNAMIC_FTRACE_WITH_ARGS
+       depends on HAVE_FTRACE_REGS_HAVING_PT_REGS || 
!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 7bb2e6ecd31f..e469fcbed210 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -2830,10 +2830,14 @@ kprobe_multi_link_handler(struct fprobe *fp, unsigned 
long fentry_ip,
 
 static void
 kprobe_multi_link_exit_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;
 
        link = container_of(fp, struct bpf_kprobe_multi_link, fp);
        kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), regs, true, 
data);
diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c
index 3d3789283873..90a3c8e2bbdf 100644
--- a/kernel/trace/fprobe.c
+++ b/kernel/trace/fprobe.c
@@ -124,6 +124,7 @@ static void fprobe_exit_handler(struct rethook_node *rh, 
void *data,
 {
        struct fprobe *fp = (struct fprobe *)data;
        struct fprobe_rethook_node *fpr;
+       struct ftrace_regs *fregs = (struct ftrace_regs *)regs;
        int bit;
 
        if (!fp || fprobe_disabled(fp))
@@ -141,7 +142,7 @@ static void fprobe_exit_handler(struct rethook_node *rh, 
void *data,
                return;
        }
 
-       fp->exit_handler(fp, fpr->entry_ip, ret_ip, regs,
+       fp->exit_handler(fp, fpr->entry_ip, ret_ip, fregs,
                         fp->entry_data_size ? (void *)fpr->data : NULL);
        ftrace_test_recursion_unlock(bit);
 }
diff --git a/kernel/trace/trace_fprobe.c b/kernel/trace/trace_fprobe.c
index 0f254685e26a..ed49d21269cf 100644
--- a/kernel/trace/trace_fprobe.c
+++ b/kernel/trace/trace_fprobe.c
@@ -361,10 +361,14 @@ static int fentry_dispatcher(struct fprobe *fp, unsigned 
long entry_ip,
 NOKPROBE_SYMBOL(fentry_dispatcher);
 
 static void fexit_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 = container_of(fp, struct trace_fprobe, fp);
+       struct pt_regs *regs = ftrace_get_regs(fregs);
+
+       if (!regs)
+               return;
 
        if (trace_probe_test_flag(&tf->tp, TP_FLAG_TRACE))
                fexit_trace_func(tf, entry_ip, ret_ip, regs, entry_data);
diff --git a/lib/test_fprobe.c b/lib/test_fprobe.c
index ff607babba18..271ce0caeec0 100644
--- a/lib/test_fprobe.c
+++ b/lib/test_fprobe.c
@@ -59,9 +59,9 @@ static notrace int fp_entry_handler(struct fprobe *fp, 
unsigned long ip,
 
 static notrace void fp_exit_handler(struct fprobe *fp, unsigned long ip,
                                    unsigned long ret_ip,
-                                   struct pt_regs *regs, void *data)
+                                   struct ftrace_regs *fregs, void *data)
 {
-       unsigned long ret = regs_return_value(regs);
+       unsigned long ret = ftrace_regs_get_return_value(fregs);
 
        KUNIT_EXPECT_FALSE(current_test, preemptible());
        if (ip != target_ip) {
@@ -89,7 +89,7 @@ static notrace int nest_entry_handler(struct fprobe *fp, 
unsigned long ip,
 
 static notrace void nest_exit_handler(struct fprobe *fp, unsigned long ip,
                                      unsigned long ret_ip,
-                                     struct pt_regs *regs, void *data)
+                                     struct ftrace_regs *fregs, void *data)
 {
        KUNIT_EXPECT_FALSE(current_test, preemptible());
        KUNIT_EXPECT_EQ(current_test, ip, target_nest_ip);
diff --git a/samples/fprobe/fprobe_example.c b/samples/fprobe/fprobe_example.c
index c234afae52d6..bfe98ce826f3 100644
--- a/samples/fprobe/fprobe_example.c
+++ b/samples/fprobe/fprobe_example.c
@@ -67,7 +67,7 @@ static int sample_entry_handler(struct fprobe *fp, unsigned 
long ip,
 }
 
 static void sample_exit_handler(struct fprobe *fp, unsigned long ip,
-                               unsigned long ret_ip, struct pt_regs *regs,
+                               unsigned long ret_ip, struct ftrace_regs *regs,
                                void *data)
 {
        unsigned long rip = ret_ip;


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