diff options
| author | Ard Biesheuvel <ardb@kernel.org> | 2022-01-25 11:20:49 +0100 |
|---|---|---|
| committer | Ard Biesheuvel <ardb@kernel.org> | 2022-02-09 09:12:33 +0100 |
| commit | 953f534a7ed6b725d4f101d2949393acc9262880 (patch) | |
| tree | 7df80887659d9b3f7efb288b11bec86b8c7651c7 /arch/arm | |
| parent | ARM: ftrace: avoid unnecessary literal loads (diff) | |
| download | linux-953f534a7ed6b725d4f101d2949393acc9262880.tar.xz linux-953f534a7ed6b725d4f101d2949393acc9262880.zip | |
ARM: ftrace: enable HAVE_FUNCTION_GRAPH_FP_TEST
Fix the frame pointer handling in the function graph tracer entry and
exit code so we can enable HAVE_FUNCTION_GRAPH_FP_TEST. Instead of using
FP directly (which will have different values between the entry and exit
pieces of the function graph tracer), use the value of SP at entry and
exit, as we can derive the former value from the frame pointer.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Diffstat (limited to 'arch/arm')
| -rw-r--r-- | arch/arm/include/asm/ftrace.h | 2 | ||||
| -rw-r--r-- | arch/arm/kernel/entry-ftrace.S | 2 | ||||
| -rw-r--r-- | arch/arm/kernel/ftrace.c | 5 |
3 files changed, 8 insertions, 1 deletions
diff --git a/arch/arm/include/asm/ftrace.h b/arch/arm/include/asm/ftrace.h index a4dbac07e4ef..b4f5fab6b04e 100644 --- a/arch/arm/include/asm/ftrace.h +++ b/arch/arm/include/asm/ftrace.h @@ -2,6 +2,8 @@ #ifndef _ASM_ARM_FTRACE #define _ASM_ARM_FTRACE +#define HAVE_FUNCTION_GRAPH_FP_TEST + #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS #define ARCH_SUPPORTS_FTRACE_OPS 1 #endif diff --git a/arch/arm/kernel/entry-ftrace.S b/arch/arm/kernel/entry-ftrace.S index 99720064a4c5..bbfa0954c385 100644 --- a/arch/arm/kernel/entry-ftrace.S +++ b/arch/arm/kernel/entry-ftrace.S @@ -247,7 +247,7 @@ ENDPROC(ftrace_graph_regs_caller) .globl return_to_handler return_to_handler: stmdb sp!, {r0-r3} - mov r0, fp @ frame pointer + add r0, sp, #16 @ sp at exit of instrumented routine bl ftrace_return_to_handler mov lr, r0 @ r0 has real ret addr ldmia sp!, {r0-r3} diff --git a/arch/arm/kernel/ftrace.c b/arch/arm/kernel/ftrace.c index 74d3913f5590..ea2396900c7d 100644 --- a/arch/arm/kernel/ftrace.c +++ b/arch/arm/kernel/ftrace.c @@ -233,6 +233,11 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr, if (unlikely(atomic_read(¤t->tracing_graph_pause))) return; + if (IS_ENABLED(CONFIG_UNWINDER_FRAME_POINTER)) { + /* FP points one word below parent's top of stack */ + frame_pointer += 4; + } + old = *parent; *parent = return_hooker; |