diff options
Diffstat (limited to 'arch/x86/Makefile')
| -rw-r--r-- | arch/x86/Makefile | 30 |
1 files changed, 25 insertions, 5 deletions
diff --git a/arch/x86/Makefile b/arch/x86/Makefile index 57d021507120..eeda43abed6e 100644 --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -11,6 +11,28 @@ else KBUILD_DEFCONFIG := $(ARCH)_defconfig endif +# 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. +# +# The -m16 option is supported by GCC >= 4.9 and clang >= 3.5. For +# older versions of GCC, we need to play evil and unreliable tricks to +# attempt to ensure that our asm(".code16gcc") is first in the asm +# output. +CODE16GCC_CFLAGS := -m32 -include $(srctree)/arch/x86/boot/code16gcc.h \ + $(call cc-option, -fno-toplevel-reorder,\ + $(call cc-option, -fno-unit-at-a-time)) +M16_CFLAGS := $(call cc-option, -m16, $(CODE16GCC_CFLAGS)) + +REALMODE_CFLAGS := $(M16_CFLAGS) -g -Os -D__KERNEL__ \ + -DDISABLE_BRANCH_PROFILING \ + -Wall -Wstrict-prototypes -march=i386 -mregparm=3 \ + -fno-strict-aliasing -fomit-frame-pointer -fno-pic \ + -mno-mmx -mno-sse \ + $(call cc-option, -ffreestanding) \ + $(call cc-option, -fno-stack-protector) \ + $(call cc-option, -mpreferred-stack-boundary=2) +export REALMODE_CFLAGS + # BITS is used as extension for files which are available in a 32 bit # and a 64 bit version to simplify shared Makefiles. # e.g.: obj-y += foo_$(BITS).o @@ -89,13 +111,11 @@ else KBUILD_CFLAGS += -maccumulate-outgoing-args endif +# Make sure compiler does not have buggy stack-protector support. ifdef CONFIG_CC_STACKPROTECTOR cc_has_sp := $(srctree)/scripts/gcc-x86_$(BITS)-has-stack-protector.sh - ifeq ($(shell $(CONFIG_SHELL) $(cc_has_sp) $(CC) $(KBUILD_CPPFLAGS) $(biarch)),y) - stackp-y := -fstack-protector - KBUILD_CFLAGS += $(stackp-y) - else - $(warning stack protector enabled but no compiler support) + ifneq ($(shell $(CONFIG_SHELL) $(cc_has_sp) $(CC) $(KBUILD_CPPFLAGS) $(biarch)),y) + $(warning stack-protector enabled but compiler support broken) endif endif |