efi/libstub: Optimize for size instead of speed

Reclaim the bloat from the addition of printf by optimizing the stub for
size. With gcc 9, the text size of the stub is:

ARCH    before  +printf    -Os
arm      35197    37889  34638
arm64    34883    38159  34479
i386     18571    21657  17025
x86_64   25677    29328  22144

Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20200518190716.751506-6-nivedita@alum.mit.edu
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
index fb34c9d..034d716 100644 (file)
--- a/drivers/firmware/efi/libstub/Makefile
+++ b/drivers/firmware/efi/libstub/Makefile
@@ -7,7 +7,7 @@
 #
 cflags-$(CONFIG_X86_32)                := -march=i386
 cflags-$(CONFIG_X86_64)                := -mcmodel=small
-cflags-$(CONFIG_X86)           += -m$(BITS) -D__KERNEL__ -O2 \
+cflags-$(CONFIG_X86)           += -m$(BITS) -D__KERNEL__ \
                                   -fPIC -fno-strict-aliasing -mno-red-zone \
                                   -mno-mmx -mno-sse -fshort-wchar \
                                   -Wno-pointer-sign \
@@ -25,7 +25,7 @@ cflags-$(CONFIG_ARM)          := $(subst $(CC_FLAGS_FTRACE),,$(KBUILD_CFLAGS)) \
 
 cflags-$(CONFIG_EFI_GENERIC_STUB) += -I$(srctree)/scripts/dtc/libfdt
 
-KBUILD_CFLAGS                  := $(cflags-y) -DDISABLE_BRANCH_PROFILING \
+KBUILD_CFLAGS                  := $(cflags-y) -Os -DDISABLE_BRANCH_PROFILING \
                                   -include $(srctree)/drivers/firmware/efi/libstub/hidden.h \
                                   -D__NO_FORTIFY \
                                   $(call cc-option,-ffreestanding) \