x86/vdso: Move DISABLE_BRANCH_PROFILING into the vdso makefile (46b57a76) · Commits · 戴 / test

DISABLE_BRANCH_PROFILING turns off branch profiling (i.e. a redefinition of 'if'). Branch profiling depends on a bunch of kernel-internal symbols and generates extra output sections, none of which are useful or functional in the vDSO. It's currently turned off for vclock_gettime.c, but vgetcpu.c also triggers branch profiling, so just turn it off in the makefile. This fixes the build on some configurations: the vdso could contain undefined symbols, and the fake section table overflowed due to ftrace's added sections. Signed-off-by:

Andy Lutomirski <luto@amacapital.net> Link: http://lkml.kernel.org/r/bf1ec29e03b2bbc081f6dcaefa64db1c3a83fb21.1403642755.git.luto@amacapital.net Signed-off-by:

H. Peter Anvin <hpa@linux.intel.com>

arch/x86/vdso/Makefile

+3 −1

Original line number	Diff line number	Diff line
		@@ -66,7 +66,8 @@ $(obj)/vdso-image-%.c: $(obj)/vdso%.so.dbg $(obj)/vdso2c FORCE
		#
		CFL := $(PROFILING) -mcmodel=small -fPIC -O2 -fasynchronous-unwind-tables -m64 \
		$(filter -g%,$(KBUILD_CFLAGS)) $(call cc-option, -fno-stack-protector) \
		-fno-omit-frame-pointer -foptimize-sibling-calls
		-fno-omit-frame-pointer -foptimize-sibling-calls \
		-DDISABLE_BRANCH_PROFILING

		$(vobjs): KBUILD_CFLAGS += $(CFL)

		@@ -149,6 +150,7 @@ KBUILD_CFLAGS_32 += -m32 -msoft-float -mregparm=0 -fpic
		KBUILD_CFLAGS_32 += $(call cc-option, -fno-stack-protector)
		KBUILD_CFLAGS_32 += $(call cc-option, -foptimize-sibling-calls)
		KBUILD_CFLAGS_32 += -fno-omit-frame-pointer
		KBUILD_CFLAGS_32 += -DDISABLE_BRANCH_PROFILING
		$(vdso32-images:%=$(obj)/%.dbg): KBUILD_CFLAGS = $(KBUILD_CFLAGS_32)

		$(vdso32-images:%=$(obj)/%.dbg): $(obj)/vdso32-%.so.dbg: FORCE \

arch/x86/vdso/vclock_gettime.c

+0 −3

Original line number	Diff line number	Diff line
		@@ -11,9 +11,6 @@
		* Check with readelf after changing.
		*/

		/* Disable profiling for userspace code: */
		#define DISABLE_BRANCH_PROFILING

		#include <uapi/linux/time.h>
		#include <asm/vgtod.h>
		#include <asm/hpet.h>

Admin message