From 7563dc64585324f443f5ac107eb6d89ee813a2d2 Mon Sep 17 00:00:00 2001 From: Tony Breeds Date: Tue, 2 Sep 2008 16:50:38 +1000 Subject: powerpc: Work around gcc's -fno-omit-frame-pointer bug This bug is causing random crashes (http://bugzilla.kernel.org/show_bug.cgi?id=11414). -fno-omit-frame-pointer is only needed on powerpc when -pg is also supplied, and there is a gcc bug that causes incorrect code generation on 32-bit powerpc when -fno-omit-frame-pointer is used---it uses stack locations below the stack pointer, which is not allowed by the ABI because those locations can and sometimes do get corrupted by an interrupt. This ensures that CONFIG_FRAME_POINTER is only selected by ftrace. When CONFIG_FTRACE is enabled we also pass -mno-sched-epilog to work around the gcc codegen bug. Patch based on work by: Andreas Schwab Segher Boessenkool Signed-off-by: Tony Breeds Signed-off-by: Paul Mackerras --- arch/powerpc/Makefile | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'arch/powerpc/Makefile') diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile index 9155c9312c1..c6be19e9cea 100644 --- a/arch/powerpc/Makefile +++ b/arch/powerpc/Makefile @@ -116,6 +116,11 @@ ifeq ($(CONFIG_6xx),y) KBUILD_CFLAGS += -mcpu=powerpc endif +# Work around a gcc code-gen bug with -fno-omit-frame-pointer. +ifeq ($(CONFIG_FTRACE),y) +KBUILD_CFLAGS += -mno-sched-epilog +endif + cpu-as-$(CONFIG_4xx) += -Wa,-m405 cpu-as-$(CONFIG_6xx) += -Wa,-maltivec cpu-as-$(CONFIG_POWER4) += -Wa,-maltivec -- cgit v1.2.3