From: Sumit Garg Date: Mon, 11 Oct 2021 12:50:59 +0000 (+0530) Subject: arm64: ftrace: use function_nocfi for _mcount as well X-Git-Tag: v6.6.17~8859^2~14^2~2 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=de56379f21c70196ff18c48790e8e43865893869;p=platform%2Fkernel%2Flinux-rpi.git arm64: ftrace: use function_nocfi for _mcount as well Commit 800618f955a9 ("arm64: ftrace: use function_nocfi for ftrace_call") only fixed address of ftrace_call but address of _mcount needs to be fixed as well. Use function_nocfi() to get the actual address of _mcount function as with CONFIG_CFI_CLANG, the compiler replaces function pointers with jump table addresses which breaks dynamic ftrace as the address of _mcount is replaced with the address of _mcount.cfi_jt. With mainline, this won't be a problem since by default CONFIG_DYNAMIC_FTRACE_WITH_REGS=y with Clang >= 10 as it supports -fpatchable-function-entry and CFI requires Clang 12 but for consistency we should add function_nocfi() for _mcount as well. Signed-off-by: Sumit Garg Acked-by: Mark Rutland Reviewed-by: Sami Tolvanen Link: https://lore.kernel.org/r/20211011125059.3378646-1-sumit.garg@linaro.org Signed-off-by: Will Deacon --- diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h index 91fa4ba..347b0cc68f 100644 --- a/arch/arm64/include/asm/ftrace.h +++ b/arch/arm64/include/asm/ftrace.h @@ -15,7 +15,7 @@ #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS #define ARCH_SUPPORTS_FTRACE_OPS 1 #else -#define MCOUNT_ADDR ((unsigned long)_mcount) +#define MCOUNT_ADDR ((unsigned long)function_nocfi(_mcount)) #endif /* The BL at the callsite's adjusted rec->ip */