x86, setup: compile with -DDISABLE_BRANCH_PROFILING

Impact: code size reduction (possibly critical)

The x86 boot and decompression code has no use of the branch profiling
constructs, so disable them.  This would bloat the setup code by as
much as 14K, eating up a fairly large chunk of the 32K area we are
guaranteed to have.

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/arch/x86/boot/Makefile b/arch/x86/boot/Makefile
index fb737ce..6633b6e 100644 (file)
--- a/arch/x86/boot/Makefile
+++ b/arch/x86/boot/Makefile
@@ -57,6 +57,7 @@ $(obj)/cpustr.h: $(obj)/mkcpustr FORCE
 # How to compile the 16-bit code.  Note we always compile for -march=i386,
 # that way we can complain to the user if the CPU is insufficient.
 KBUILD_CFLAGS  := $(LINUXINCLUDE) -g -Os -D_SETUP -D__KERNEL__ \
+                  -DDISABLE_BRANCH_PROFILING \
                   -Wall -Wstrict-prototypes \
                   -march=i386 -mregparm=3 \
                   -include $(srctree)/$(src)/code16gcc.h \
@@ -66,7 +67,7 @@ KBUILD_CFLAGS := $(LINUXINCLUDE) -g -Os -D_SETUP -D__KERNEL__ \
                        $(call cc-option, -fno-unit-at-a-time)) \
                   $(call cc-option, -fno-stack-protector) \
                   $(call cc-option, -mpreferred-stack-boundary=2)
-KBUILD_CFLAGS +=   $(call cc-option,-m32)
+KBUILD_CFLAGS  += $(call cc-option, -m32)
 KBUILD_AFLAGS  := $(KBUILD_CFLAGS) -D__ASSEMBLY__
 
 $(obj)/bzImage: asflags-y  := $(SVGA_MODE)

diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
index 3ca4c19..65551c9 100644 (file)
--- a/arch/x86/boot/compressed/Makefile
+++ b/arch/x86/boot/compressed/Makefile
@@ -8,6 +8,7 @@ targets := vmlinux vmlinux.bin vmlinux.bin.gz vmlinux.bin.bz2 vmlinux.bin.lzma h
 
 KBUILD_CFLAGS := -m$(BITS) -D__KERNEL__ $(LINUX_INCLUDE) -O2
 KBUILD_CFLAGS += -fno-strict-aliasing -fPIC
+KBUILD_CFLAGS += -DDISABLE_BRANCH_PROFILING
 cflags-$(CONFIG_X86_64) := -mcmodel=small
 KBUILD_CFLAGS += $(cflags-y)
 KBUILD_CFLAGS += $(call cc-option,-ffreestanding)