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[RFC,v4,07/17] powerpc/ftrace: Skip instruction patching if the instructions are the same

Message ID 2aba0401f39fee0726e3342b21160d2b05bfa53b.1720942106.git.naveen@kernel.org (mailing list archive)
State New
Headers show
Series powerpc: Core ftrace rework, support for ftrace direct and bpf trampolines | expand

Commit Message

Naveen N Rao July 14, 2024, 8:27 a.m. UTC 
To simplify upcoming changes to ftrace, add a check to skip actual
instruction patching if the old and new instructions are the same. We
still validate that the instruction is what we expect, but don't
actually patch the same instruction again.

Signed-off-by: Naveen N Rao <naveen@kernel.org>
---
 arch/powerpc/kernel/trace/ftrace.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
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Patch

diff --git a/arch/powerpc/kernel/trace/ftrace.c b/arch/powerpc/kernel/trace/ftrace.c
index fe0546fbac8e..719517265d39 100644
--- a/arch/powerpc/kernel/trace/ftrace.c
+++ b/arch/powerpc/kernel/trace/ftrace.c
@@ -82,7 +82,7 @@  static inline int ftrace_modify_code(unsigned long ip, ppc_inst_t old, ppc_inst_
 {
 	int ret = ftrace_validate_inst(ip, old);
 
-	if (!ret)
+	if (!ret && !ppc_inst_equal(old, new))
 		ret = patch_instruction((u32 *)ip, new);
 
 	return ret;