[PATCH] Disable -fconserve-stack on ARM
From: Andi Kleen <hidden>
Date: 2011-05-31 18:01:12
Also in:
lkml
Subsystem:
arm port, kernel build + files below scripts/ (unless maintained elsewhere), the rest · Maintainers:
Russell King, Nathan Chancellor, Nicolas Schier, Linus Torvalds
Didn't work, on the gcc command line we get -fno-conserve-stack followed by -fconserve-stack from the top makefile and it seems that the latter takes priority.
Ah ok need to move it up then too in the top level Makefile. Like this. -Andi --- Disable -fconserve-stack on ARM v2 There are reports that -fconserve-stack misaligns variables on the stack. Disable it for ARM to work around this gcc bug. v2: Move top level flags definition up Signed-off-by: Andi Kleen <redacted>
diff --git a/Makefile b/Makefile
index 529d93f..08d848f 100644
--- a/Makefile
+++ b/Makefile@@ -564,6 +564,10 @@ else KBUILD_CFLAGS += -O2 endif +# conserve stack if available +# do this early so that an architecture can override it. +KBUILD_CFLAGS += $(call cc-option,-fconserve-stack) + include $(srctree)/arch/$(SRCARCH)/Makefile ifneq ($(CONFIG_FRAME_WARN),0)
@@ -629,9 +633,6 @@ KBUILD_CFLAGS += $(call cc-disable-warning, pointer-sign) # disable invalid "can't wrap" optimizations for signed / pointers KBUILD_CFLAGS += $(call cc-option,-fno-strict-overflow) -# conserve stack if available -KBUILD_CFLAGS += $(call cc-option,-fconserve-stack) - # use the deterministic mode of AR if available KBUILD_ARFLAGS := $(call ar-option,D)
diff --git a/arch/arm/Makefile b/arch/arm/Makefile
index f5b2b39..902fec9 100644
--- a/arch/arm/Makefile
+++ b/arch/arm/Makefile@@ -41,6 +41,10 @@ ifeq ($(CONFIG_CC_STACKPROTECTOR),y) KBUILD_CFLAGS +=-fstack-protector endif +# ARM gcc developers unfortunately broke -fconserve-stack. It misaligns +# variables on the stack +KBUILD_CFLAGS += $(call cc-option,-fno-conserve-stack) + ifeq ($(CONFIG_CPU_BIG_ENDIAN),y) KBUILD_CPPFLAGS += -mbig-endian AS += -EB