From mboxrd@z Thu Jan 1 00:00:00 1970 From: takahiro.akashi@linaro.org (AKASHI Takahiro) Date: Thu, 8 Oct 2015 19:01:41 +0900 Subject: [PATCH v3 4/7] arm64: ftrace: allow for tracing leaf functions In-Reply-To: <1444298504-10392-1-git-send-email-takahiro.akashi@linaro.org> References: <1444298504-10392-1-git-send-email-takahiro.akashi@linaro.org> Message-ID: <1444298504-10392-5-git-send-email-takahiro.akashi@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org CONFIG_FRAME_POINTER is always enabled on arm64, adding -fno-omit-frame-pointer, while ftrace, CONFIG_FUNCTION_TRACER, adds -pg to KBUILD_CFLAGS. The combination of these options, however, does not implicitly enables -fno-omit-leaf-frame-pointer option, and no leaf functions are actually traced under ftrace. This patch allows for tracing leaf functions by adding -fno-omit-leaf-frame-pointer option, but does it only when CONFIG_STACK_TRACER is configured because it will increase the kernel size and add extra instructions on runtime. Signed-off-by: AKASHI Takahiro --- arch/arm64/Makefile | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile index f9914d7..71cad91 100644 --- a/arch/arm64/Makefile +++ b/arch/arm64/Makefile @@ -28,6 +28,11 @@ endif KBUILD_CFLAGS += -mgeneral-regs-only $(lseinstr) KBUILD_AFLAGS += $(lseinstr) +ifdef CONFIG_STACK_TRACER +ifdef CONFIG_FRAME_POINTER +KBUILD_CFLAGS += -mno-omit-leaf-frame-pointer +endif +endif ifeq ($(CONFIG_CPU_BIG_ENDIAN), y) KBUILD_CPPFLAGS += -mbig-endian -- 1.7.9.5