3 files changed, 27 insertions, 2 deletions

diff --git a/arch/Kconfig b/arch/Kconfig
index 53d7f619a1b9..8bf0fa652eb6 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -42,6 +42,20 @@ config KPROBES
           for kernel debugging, non-intrusive instrumentation and testing.
           If in doubt, say "N".
 
+config JUMP_LABEL
+       bool "Optimize trace point call sites"
+       depends on HAVE_ARCH_JUMP_LABEL
+       help
+         If it is detected that the compiler has support for "asm goto",
+         the kernel will compile trace point locations with just a
+         nop instruction. When trace points are enabled, the nop will
+         be converted to a jump to the trace function. This technique
+         lowers overhead and stress on the branch prediction of the
+         processor.
+
+         On i386, options added to the compiler flags may increase
+         the size of the kernel slightly.
+
 config OPTPROBES
         def_bool y
         depends on KPROBES && HAVE_OPTPROBES
diff --git a/arch/x86/Makefile_32.cpu b/arch/x86/Makefile_32.cpu
index 1255d953c65d..f2ee1abb1df9 100644
--- a/arch/x86/Makefile_32.cpu
+++ b/arch/x86/Makefile_32.cpu
@@ -51,7 +51,18 @@ cflags-$(CONFIG_X86_GENERIC) 	+= $(call tune,generic,$(call tune,i686))
 # prologue (push %ebp, mov %esp, %ebp) which breaks the function graph
 # tracer assumptions. For i686, generic, core2 this is set by the
 # compiler anyway
-cflags-$(CONFIG_FUNCTION_GRAPH_TRACER) += $(call cc-option,-maccumulate-outgoing-args)
+ifeq ($(CONFIG_FUNCTION_GRAPH_TRACER), y)
+ADD_ACCUMULATE_OUTGOING_ARGS := y
+endif
+
+# Work around to a bug with asm goto with first implementations of it
+# in gcc causing gcc to mess up the push and pop of the stack in some
+# uses of asm goto.
+ifeq ($(CONFIG_JUMP_LABEL), y)
+ADD_ACCUMULATE_OUTGOING_ARGS := y
+endif
+
+cflags-$(ADD_ACCUMULATE_OUTGOING_ARGS) += $(call cc-option,-maccumulate-outgoing-args)
 
 # Bug fix for binutils: this option is required in order to keep
 # binutils from generating NOPL instructions against our will.
diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h
index 1947a1212678..7880f18e4b86 100644
--- a/include/linux/jump_label.h
+++ b/include/linux/jump_label.h
@@ -1,7 +1,7 @@
 #ifndef _LINUX_JUMP_LABEL_H
 #define _LINUX_JUMP_LABEL_H
 
-#if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_HAVE_ARCH_JUMP_LABEL)
+#if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_JUMP_LABEL)
 # include <asm/jump_label.h>
 # define HAVE_JUMP_LABEL
 #endif