[PATCH 6.5 671/739] powerpc/ftrace: Fix dropping weak symbols with older toolchains
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: 2023-09-11 21:59:43
Also in:
linux-patches
6.5-stable review patch. If anyone has any objections, please let me know.
------------------
From: Naveen N Rao <naveen@kernel.org>
commit f6834c8c59a8e977a6f6e4f96c5d28dfa5db8430 upstream.
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>
Reviewed-by: Christophe Leroy <redacted>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/7b265908a9461e38fc756ef9b569703860a80621.1687166935.git.naveen@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/powerpc/include/asm/ftrace.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- 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