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powerpc/ftrace: Fix dropping weak symbols with older toolchains

Message ID 20230615131829.2814538-1-naveen@kernel.org (mailing list archive)
State Superseded
Headers show
Series powerpc/ftrace: Fix dropping weak symbols with older toolchains | expand

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Commit Message

Naveen N Rao June 15, 2023, 1:18 p.m. UTC
The minimum level of gcc supported for building the kernel is v5.1.
v5.x releases of gcc emitted a three instruction sequence for
-mprofile-kernel:
	mflr	r0
	std	r0, 16(r1)
	bl	_mcount

It is only with the v6.x releases that gcc started emitting the two
instruction sequence for -mprofile-kernel, omitting the second store
instruction.

With the older three instruction sequence, the actual ftrace location
can be the 5th instruction into a function. Update the allowed offset
for ftrace location from 12 to 16 to accommodate the same.

Cc: stable@vger.kernel.org
Fixes: 7af82ff90a2b06 ("powerpc/ftrace: Ignore weak functions")
Signed-off-by: Naveen N Rao <naveen@kernel.org>
---
 arch/powerpc/include/asm/ftrace.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)


base-commit: bd517a8442b6c6646a136421cd4c1b95bf4ce32b
diff mbox series

Patch

diff --git a/arch/powerpc/include/asm/ftrace.h b/arch/powerpc/include/asm/ftrace.h
index 91c049d51d0e10..2edc6269b1a357 100644
--- a/arch/powerpc/include/asm/ftrace.h
+++ b/arch/powerpc/include/asm/ftrace.h
@@ -12,7 +12,7 @@ 
 
 /* Ignore unused weak functions which will have larger offsets */
 #ifdef CONFIG_MPROFILE_KERNEL
-#define FTRACE_MCOUNT_MAX_OFFSET	12
+#define FTRACE_MCOUNT_MAX_OFFSET	16
 #elif defined(CONFIG_PPC32)
 #define FTRACE_MCOUNT_MAX_OFFSET	8
 #endif