x86-64: Turn off -pg and turn on -foptimize-sibling-calls for vDSO

The vDSO isn't part of the kernel, so profiling and kernel backtraces don't really matter. Signed-off-by: Andy Lutomirski <[email protected]> Cc: Andi Kleen <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: "David S. Miller" <[email protected]> Cc: Eric Dumazet <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Borislav Petkov <[email protected]> Link: http://lkml.kernel.org/r/%3C23087b738c037342abb53f2f07b9bef89ceaeea3.1306156808.git.luto%40mit.edu%3E Signed-off-by: Thomas Gleixner <[email protected]>
scastillo · May 24, 2011 · 6447fac · 6447fac
1 parent 44259b1
commit 6447fac
Showing 1 changed file with 14 additions and 1 deletion.
diff --git a/arch/x86/vdso/Makefile b/arch/x86/vdso/Makefile
@@ -37,11 +37,24 @@ $(obj)/%.so: OBJCOPYFLAGS := -S
 $(obj)/%.so: $(obj)/%.so.dbg FORCE
 	$(call if_changed,objcopy)
 
+#
+# Don't omit frame pointers for ease of userspace debugging, but do
+# optimize sibling calls.
+#
 CFL := $(PROFILING) -mcmodel=small -fPIC -O2 -fasynchronous-unwind-tables -m64 \
-       $(filter -g%,$(KBUILD_CFLAGS)) $(call cc-option, -fno-stack-protector)
+       $(filter -g%,$(KBUILD_CFLAGS)) $(call cc-option, -fno-stack-protector) \
+       -fno-omit-frame-pointer -foptimize-sibling-calls
 
 $(vobjs): KBUILD_CFLAGS += $(CFL)
 
+#
+# vDSO code runs in userspace and -pg doesn't help with profiling anyway.
+#
+CFLAGS_REMOVE_vdso-note.o = -pg
+CFLAGS_REMOVE_vclock_gettime.o = -pg
+CFLAGS_REMOVE_vgetcpu.o = -pg
+CFLAGS_REMOVE_vvar.o = -pg
+
 targets += vdso-syms.lds
 obj-$(VDSO64-y)			+= vdso-syms.lds