2024-06-15 21:02:09 +02:00
# SPDX-License-Identifier: GPL-2.0
# Unified Makefile for i386 and x86_64
# select defconfig based on actual architecture
i f e q ( $( ARCH ) , x 8 6 )
ifeq ( $( shell uname -m) ,x86_64)
KBUILD_DEFCONFIG := x86_64_defconfig
else
KBUILD_DEFCONFIG := i386_defconfig
endif
e l s e
KBUILD_DEFCONFIG := $( ARCH) _defconfig
e n d i f
# For gcc stack alignment is specified with -mpreferred-stack-boundary,
# clang has the option -mstack-alignment for that purpose.
i f n e q ( $( call cc -option , -mpreferred -stack -boundary =4) , )
cc_stack_align4 := -mpreferred-stack-boundary= 2
cc_stack_align8 := -mpreferred-stack-boundary= 3
e l s e i f n e q ( $( call cc -option , -mstack -alignment =16) , )
cc_stack_align4 := -mstack-alignment= 4
cc_stack_align8 := -mstack-alignment= 8
e n d i f
# How to compile the 16-bit code. Note we always compile for -march=i386;
# that way we can complain to the user if the CPU is insufficient.
#
# The -m16 option is supported by GCC >= 4.9 and clang >= 3.5. For
# older versions of GCC, include an *assembly* header to make sure that
# gcc doesn't play any games behind our back.
CODE16GCC_CFLAGS := -m32 -Wa,$( srctree) /arch/x86/boot/code16gcc.h
M16_CFLAGS := $( call cc-option, -m16, $( CODE16GCC_CFLAGS) )
REALMODE_CFLAGS := $( M16_CFLAGS) -g -Os -DDISABLE_BRANCH_PROFILING -D__DISABLE_EXPORTS \
-Wall -Wstrict-prototypes -march= i386 -mregparm= 3 \
-fno-strict-aliasing -fomit-frame-pointer -fno-pic \
-mno-mmx -mno-sse $( call cc-option,-fcf-protection= none)
REALMODE_CFLAGS += -ffreestanding
REALMODE_CFLAGS += -fno-stack-protector
REALMODE_CFLAGS += $( call __cc-option, $( CC) , $( REALMODE_CFLAGS) , -Wno-address-of-packed-member)
REALMODE_CFLAGS += $( call __cc-option, $( CC) , $( REALMODE_CFLAGS) , $( cc_stack_align4) )
REALMODE_CFLAGS += $( CLANG_FLAGS)
export REALMODE_CFLAGS
# BITS is used as extension for files which are available in a 32 bit
# and a 64 bit version to simplify shared Makefiles.
# e.g.: obj-y += foo_$(BITS).o
export BITS
#
# Prevent GCC from generating any FP code by mistake.
#
# This must happen before we try the -mpreferred-stack-boundary, see:
#
# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53383
#
KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow
KBUILD_CFLAGS += $( call cc-option,-mno-avx,)
# Intel CET isn't enabled in the kernel
KBUILD_CFLAGS += $( call cc-option,-fcf-protection= none)
i f e q ( $( CONFIG_X 86_ 32) , y )
BITS := 32
UTS_MACHINE := i386
CHECKFLAGS += -D__i386__
biarch := $( call cc-option,-m32)
KBUILD_AFLAGS += $( biarch)
KBUILD_CFLAGS += $( biarch)
KBUILD_CFLAGS += -msoft-float -mregparm= 3 -freg-struct-return
# Never want PIC in a 32-bit kernel, prevent breakage with GCC built
# with nonstandard options
KBUILD_CFLAGS += -fno-pic
# Align the stack to the register width instead of using the default
# alignment of 16 bytes. This reduces stack usage and the number of
# alignment instructions.
KBUILD_CFLAGS += $( call cc-option,$( cc_stack_align4) )
# CPU-specific tuning. Anything which can be shared with UML should go here.
include arch/x86/Makefile_32.cpu
KBUILD_CFLAGS += $( cflags-y)
# temporary until string.h is fixed
KBUILD_CFLAGS += -ffreestanding
x86/stackprotector/32: Make the canary into a regular percpu variable
[ Upstream commit 3fb0fdb3bbe7aed495109b3296b06c2409734023 ]
On 32-bit kernels, the stackprotector canary is quite nasty -- it is
stored at %gs:(20), which is nasty because 32-bit kernels use %fs for
percpu storage. It's even nastier because it means that whether %gs
contains userspace state or kernel state while running kernel code
depends on whether stackprotector is enabled (this is
CONFIG_X86_32_LAZY_GS), and this setting radically changes the way
that segment selectors work. Supporting both variants is a
maintenance and testing mess.
Merely rearranging so that percpu and the stack canary
share the same segment would be messy as the 32-bit percpu address
layout isn't currently compatible with putting a variable at a fixed
offset.
Fortunately, GCC 8.1 added options that allow the stack canary to be
accessed as %fs:__stack_chk_guard, effectively turning it into an ordinary
percpu variable. This lets us get rid of all of the code to manage the
stack canary GDT descriptor and the CONFIG_X86_32_LAZY_GS mess.
(That name is special. We could use any symbol we want for the
%fs-relative mode, but for CONFIG_SMP=n, gcc refuses to let us use any
name other than __stack_chk_guard.)
Forcibly disable stackprotector on older compilers that don't support
the new options and turn the stack canary into a percpu variable. The
"lazy GS" approach is now used for all 32-bit configurations.
Also makes load_gs_index() work on 32-bit kernels. On 64-bit kernels,
it loads the GS selector and updates the user GSBASE accordingly. (This
is unchanged.) On 32-bit kernels, it loads the GS selector and updates
GSBASE, which is now always the user base. This means that the overall
effect is the same on 32-bit and 64-bit, which avoids some ifdeffery.
[ bp: Massage commit message. ]
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/c0ff7dba14041c7e5d1cae5d4df052f03759bef3.1613243844.git.luto@kernel.org
Stable-dep-of: e3f269ed0acc ("x86/pm: Work around false positive kmemleak report in msr_build_context()")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-02-13 20:19:44 +01:00
ifeq ( $( CONFIG_STACKPROTECTOR) ,y)
ifeq ( $( CONFIG_SMP) ,y)
KBUILD_CFLAGS += -mstack-protector-guard-reg= fs -mstack-protector-guard-symbol= __stack_chk_guard
else
KBUILD_CFLAGS += -mstack-protector-guard= global
endif
endif
2024-06-15 21:02:09 +02:00
e l s e
BITS := 64
UTS_MACHINE := x86_64
CHECKFLAGS += -D__x86_64__
biarch := -m64
KBUILD_AFLAGS += -m64
KBUILD_CFLAGS += -m64
# Align jump targets to 1 byte, not the default 16 bytes:
KBUILD_CFLAGS += $( call cc-option,-falign-jumps= 1)
# Pack loops tightly as well:
KBUILD_CFLAGS += $( call cc-option,-falign-loops= 1)
# Don't autogenerate traditional x87 instructions
KBUILD_CFLAGS += $( call cc-option,-mno-80387)
KBUILD_CFLAGS += $( call cc-option,-mno-fp-ret-in-387)
# By default gcc and clang use a stack alignment of 16 bytes for x86.
# However the standard kernel entry on x86-64 leaves the stack on an
# 8-byte boundary. If the compiler isn't informed about the actual
# alignment it will generate extra alignment instructions for the
# default alignment which keep the stack *mis*aligned.
# Furthermore an alignment to the register width reduces stack usage
# and the number of alignment instructions.
KBUILD_CFLAGS += $( call cc-option,$( cc_stack_align8) )
# Use -mskip-rax-setup if supported.
KBUILD_CFLAGS += $( call cc-option,-mskip-rax-setup)
# FIXME - should be integrated in Makefile.cpu (Makefile_32.cpu)
cflags-$( CONFIG_MK8) += $( call cc-option,-march= k8)
cflags-$( CONFIG_MPSC) += $( call cc-option,-march= nocona)
cflags-$( CONFIG_MCORE2) += \
$( call cc-option,-march= core2,$( call cc-option,-mtune= generic) )
cflags-$( CONFIG_MATOM) += $( call cc-option,-march= atom) \
$( call cc-option,-mtune= atom,$( call cc-option,-mtune= generic) )
cflags-$( CONFIG_GENERIC_CPU) += $( call cc-option,-mtune= generic)
KBUILD_CFLAGS += $( cflags-y)
KBUILD_CFLAGS += -mno-red-zone
KBUILD_CFLAGS += -mcmodel= kernel
e n d i f
i f d e f C O N F I G _ X 8 6 _ X 3 2
x32_ld_ok := $( call try-run,\
/bin/echo -e '1: .quad 1b' | \
$( CC) $( KBUILD_AFLAGS) -c -x assembler -o " $$ TMP " - && \
$( OBJCOPY) -O elf32-x86-64 " $$ TMP " " $$ TMPO " && \
$( LD) -m elf32_x86_64 " $$ TMPO " -o " $$ TMP " ,y,n)
ifeq ( $( x32_ld_ok) ,y)
CONFIG_X86_X32_ABI := y
KBUILD_AFLAGS += -DCONFIG_X86_X32_ABI
KBUILD_CFLAGS += -DCONFIG_X86_X32_ABI
else
$( warning CONFIG_X86_X32 enabled but no binutils support)
endif
e n d i f
export CONFIG_X86_X32_ABI
#
# If the function graph tracer is used with mcount instead of fentry,
# '-maccumulate-outgoing-args' is needed to prevent a GCC bug
# (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42109)
#
i f d e f C O N F I G _ F U N C T I O N _ G R A P H _ T R A C E R
ifndef CONFIG_HAVE_FENTRY
ACCUMULATE_OUTGOING_ARGS := 1
else
ifeq ( $( call cc-option-yn, -mfentry) , n)
ACCUMULATE_OUTGOING_ARGS := 1
# GCC ignores '-maccumulate-outgoing-args' when used with '-Os'.
# If '-Os' is enabled, disable it and print a warning.
ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE
undefine CONFIG_CC_OPTIMIZE_FOR_SIZE
$( warning Disabling CONFIG_CC_OPTIMIZE_FOR_SIZE. Your compiler does not have -mfentry so you cannot optimize for size with CONFIG_FUNCTION_GRAPH_TRACER.)
endif
endif
endif
e n d i f
i f e q ( $( ACCUMULATE_OUTGOING_ARGS ) , 1 )
# This compiler flag is not supported by Clang:
KBUILD_CFLAGS += $( call cc-option,-maccumulate-outgoing-args,)
e n d i f
# Workaround for a gcc prelease that unfortunately was shipped in a suse release
KBUILD_CFLAGS += -Wno-sign-compare
#
KBUILD_CFLAGS += -fno-asynchronous-unwind-tables
# Avoid indirect branches in kernel to deal with Spectre
i f d e f C O N F I G _ R E T P O L I N E
KBUILD_CFLAGS += $( RETPOLINE_CFLAGS)
# Additionally, avoid generating expensive indirect jumps which
# are subject to retpolines for small number of switch cases.
# clang turns off jump table generation by default when under
# retpoline builds, however, gcc does not for x86. This has
# only been fixed starting from gcc stable version 8.4.0 and
# onwards, but not for older ones. See gcc bug #86952.
ifndef CONFIG_CC_IS_CLANG
KBUILD_CFLAGS += $( call cc-option,-fno-jump-tables)
endif
e n d i f
i f d e f C O N F I G _ S L S
KBUILD_CFLAGS += -mharden-sls= all
e n d i f
KBUILD_LDFLAGS += -m elf_$( UTS_MACHINE)
i f d e f C O N F I G _ L T O _ C L A N G
i f e q ( $( shell test $ ( CONFIG_LLD_VERSION ) -lt 130000; echo $ $ ?) , 0 )
KBUILD_LDFLAGS += -plugin-opt= -stack-alignment= $( if $( CONFIG_X86_32) ,4,8)
e n d i f
e n d i f
i f d e f C O N F I G _ X 8 6 _ N E E D _ R E L O C S
LDFLAGS_vmlinux := --emit-relocs --discard-none
e l s e
LDFLAGS_vmlinux :=
e n d i f
#
# The 64-bit kernel must be aligned to 2MB. Pass -z max-page-size=0x200000 to
# the linker to force 2MB page size regardless of the default page size used
# by the linker.
#
i f d e f C O N F I G _ X 8 6 _ 6 4
LDFLAGS_vmlinux += -z max-page-size= 0x200000
e n d i f
archscripts : scripts_basic
$( Q) $( MAKE) $( build) = arch/x86/tools relocs
###
# Syscall table generation
archheaders :
$( Q) $( MAKE) $( build) = arch/x86/entry/syscalls all
###
# Kernel objects
head-y := arch/x86/kernel/head_$( BITS) .o
head-y += arch/x86/kernel/head$( BITS) .o
head-y += arch/x86/kernel/ebda.o
head-y += arch/x86/kernel/platform-quirks.o
libs-y += arch/x86/lib/
# See arch/x86/Kbuild for content of core part of the kernel
core-y += arch/x86/
# drivers-y are linked after core-y
drivers-$(CONFIG_MATH_EMULATION) += arch/x86/math-emu/
drivers-$(CONFIG_PCI) += arch/x86/pci/
# must be linked after kernel/
drivers-$(CONFIG_OPROFILE) += arch/x86/oprofile/
# suspend and hibernation support
drivers-$(CONFIG_PM) += arch/x86/power/
drivers-$(CONFIG_FB) += arch/x86/video/
####
# boot loader support. Several targets are kept for legacy purposes
boot := arch/x86/boot
BOOT_TARGETS = bzdisk fdimage fdimage144 fdimage288 isoimage
PHONY += bzImage $( BOOT_TARGETS)
# Don't compile Image in mixed build with "all" target
i f n d e f K B U I L D _ M I X E D _ T R E E
# Default kernel to build
all : bzImage
e n d i f
# KBUILD_IMAGE specify target image being built
KBUILD_IMAGE := $( boot) /bzImage
bzImage : vmlinux
i f e q ( $( CONFIG_X 86_DECODER_SELFTEST ) , y )
$( Q) $( MAKE) $( build) = arch/x86/tools posttest
e n d i f
$( Q) $( MAKE) $( build) = $( boot) $( KBUILD_IMAGE)
$( Q) mkdir -p $( objtree) /arch/$( UTS_MACHINE) /boot
$( Q) ln -fsn ../../x86/boot/bzImage $( objtree) /arch/$( UTS_MACHINE) /boot/$@
$(BOOT_TARGETS) : vmlinux
$( Q) $( MAKE) $( build) = $( boot) $@
PHONY += install bzlilo
install bzlilo :
$( Q) $( MAKE) $( build) = $( boot) $@
PHONY += vdso_install
vdso_install :
$( Q) $( MAKE) $( build) = arch/x86/entry/vdso $@
archprepare : checkbin
checkbin :
i f n d e f C O N F I G _ C C _ H A S _ A S M _ G O T O
@echo Compiler lacks asm-goto support.
@exit 1
e n d i f
i f d e f C O N F I G _ R E T P O L I N E
i f e q ( $( RETPOLINE_CFLAGS ) , )
@echo "You are building kernel with non-retpoline compiler." >& 2
@echo "Please update your compiler." >& 2
@false
e n d i f
e n d i f
archclean :
$( Q) rm -rf $( objtree) /arch/i386
$( Q) rm -rf $( objtree) /arch/x86_64
$( Q) $( MAKE) $( clean) = $( boot)
$( Q) $( MAKE) $( clean) = arch/x86/tools
d e f i n e a r c h h e l p
echo '* bzImage - Compressed kernel image (arch/x86/boot/bzImage)'
echo ' install - Install kernel using'
echo ' (your) ~/bin/$(INSTALLKERNEL) or'
echo ' (distribution) /sbin/$(INSTALLKERNEL) or'
echo ' install to $$(INSTALL_PATH) and run lilo'
echo ' fdimage - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)'
echo ' fdimage144 - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)'
echo ' fdimage288 - Create 2.8MB boot floppy image (arch/x86/boot/fdimage)'
echo ' isoimage - Create a boot CD-ROM image (arch/x86/boot/image.iso)'
echo ' bzdisk/fdimage*/isoimage also accept:'
echo ' FDARGS="..." arguments for the booted kernel'
echo ' FDINITRD=file initrd for the booted kernel'
e n d e f
