mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-05 18:39:59 +00:00
![Omar Sandoval](/assets/img/avatar_default.png)
Commitsffb1b4a410
("x86/unwind/orc: Add 'signal' field to ORC metadata") andfb799447ae
("x86,objtool: Split UNWIND_HINT_EMPTY in two") changed the ORC format. Although ORC is internal to the kernel, it's the only way for external tools to get reliable kernel stack traces on x86-64. In particular, the drgn debugger [1] uses ORC for stack unwinding, and these format changes broke it [2]. As the drgn maintainer, I don't care how often or how much the kernel changes the ORC format as long as I have a way to detect the change. It suffices to store a version identifier in the vmlinux and kernel module ELF files (to use when parsing ORC sections from ELF), and in kernel memory (to use when parsing ORC from a core dump+symbol table). Rather than hard-coding a version number that needs to be manually bumped, Peterz suggested hashing the definitions from orc_types.h. If there is a format change that isn't caught by this, the hashing script can be updated. This patch adds an .orc_header allocated ELF section containing the 20-byte hash to vmlinux and kernel modules, along with the corresponding __start_orc_header and __stop_orc_header symbols in vmlinux. 1: https://github.com/osandov/drgn 2: https://github.com/osandov/drgn/issues/303 Fixes:ffb1b4a410
("x86/unwind/orc: Add 'signal' field to ORC metadata") Fixes:fb799447ae
("x86,objtool: Split UNWIND_HINT_EMPTY in two") Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> Link: https://lkml.kernel.org/r/aef9c8dc43915b886a8c48509a12ec1b006ca1ca.1686690801.git.osandov@osandov.com
343 lines
11 KiB
Makefile
343 lines
11 KiB
Makefile
# SPDX-License-Identifier: GPL-2.0
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# Unified Makefile for i386 and x86_64
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# select defconfig based on actual architecture
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ifeq ($(ARCH),x86)
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ifeq ($(shell uname -m | sed -e 's/i.86/i386/'),i386)
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KBUILD_DEFCONFIG := i386_defconfig
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else
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KBUILD_DEFCONFIG := x86_64_defconfig
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endif
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else
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KBUILD_DEFCONFIG := $(ARCH)_defconfig
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endif
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ifdef CONFIG_CC_IS_GCC
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RETPOLINE_CFLAGS := $(call cc-option,-mindirect-branch=thunk-extern -mindirect-branch-register)
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RETPOLINE_VDSO_CFLAGS := $(call cc-option,-mindirect-branch=thunk-inline -mindirect-branch-register)
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endif
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ifdef CONFIG_CC_IS_CLANG
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RETPOLINE_CFLAGS := -mretpoline-external-thunk
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RETPOLINE_VDSO_CFLAGS := -mretpoline
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endif
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RETPOLINE_CFLAGS += $(call cc-option,-mindirect-branch-cs-prefix)
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ifdef CONFIG_RETHUNK
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RETHUNK_CFLAGS := -mfunction-return=thunk-extern
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RETPOLINE_CFLAGS += $(RETHUNK_CFLAGS)
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endif
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export RETHUNK_CFLAGS
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export RETPOLINE_CFLAGS
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export RETPOLINE_VDSO_CFLAGS
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# For gcc stack alignment is specified with -mpreferred-stack-boundary,
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# clang has the option -mstack-alignment for that purpose.
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ifneq ($(call cc-option, -mpreferred-stack-boundary=4),)
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cc_stack_align4 := -mpreferred-stack-boundary=2
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cc_stack_align8 := -mpreferred-stack-boundary=3
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else ifneq ($(call cc-option, -mstack-alignment=16),)
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cc_stack_align4 := -mstack-alignment=4
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cc_stack_align8 := -mstack-alignment=8
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endif
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# How to compile the 16-bit code. Note we always compile for -march=i386;
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# that way we can complain to the user if the CPU is insufficient.
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REALMODE_CFLAGS := -m16 -g -Os -DDISABLE_BRANCH_PROFILING -D__DISABLE_EXPORTS \
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-Wall -Wstrict-prototypes -march=i386 -mregparm=3 \
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-fno-strict-aliasing -fomit-frame-pointer -fno-pic \
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-mno-mmx -mno-sse $(call cc-option,-fcf-protection=none)
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REALMODE_CFLAGS += -ffreestanding
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REALMODE_CFLAGS += -fno-stack-protector
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REALMODE_CFLAGS += -Wno-address-of-packed-member
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REALMODE_CFLAGS += $(cc_stack_align4)
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REALMODE_CFLAGS += $(CLANG_FLAGS)
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export REALMODE_CFLAGS
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# BITS is used as extension for files which are available in a 32 bit
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# and a 64 bit version to simplify shared Makefiles.
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# e.g.: obj-y += foo_$(BITS).o
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export BITS
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#
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# Prevent GCC from generating any FP code by mistake.
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#
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# This must happen before we try the -mpreferred-stack-boundary, see:
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#
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# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53383
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#
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KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow -mno-avx
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KBUILD_RUSTFLAGS += -Ctarget-feature=-sse,-sse2,-sse3,-ssse3,-sse4.1,-sse4.2,-avx,-avx2
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ifeq ($(CONFIG_X86_KERNEL_IBT),y)
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#
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# Kernel IBT has S_CET.NOTRACK_EN=0, as such the compilers must not generate
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# NOTRACK prefixes. Current generation compilers unconditionally employ NOTRACK
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# for jump-tables, as such, disable jump-tables for now.
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#
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# (jump-tables are implicitly disabled by RETPOLINE)
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#
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# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104816
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#
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KBUILD_CFLAGS += $(call cc-option,-fcf-protection=branch -fno-jump-tables)
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else
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KBUILD_CFLAGS += $(call cc-option,-fcf-protection=none)
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endif
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ifeq ($(CONFIG_X86_32),y)
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BITS := 32
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UTS_MACHINE := i386
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CHECKFLAGS += -D__i386__
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KBUILD_AFLAGS += -m32
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KBUILD_CFLAGS += -m32
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KBUILD_CFLAGS += -msoft-float -mregparm=3 -freg-struct-return
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# Never want PIC in a 32-bit kernel, prevent breakage with GCC built
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# with nonstandard options
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KBUILD_CFLAGS += -fno-pic
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# Align the stack to the register width instead of using the default
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# alignment of 16 bytes. This reduces stack usage and the number of
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# alignment instructions.
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KBUILD_CFLAGS += $(cc_stack_align4)
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# CPU-specific tuning. Anything which can be shared with UML should go here.
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include $(srctree)/arch/x86/Makefile_32.cpu
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KBUILD_CFLAGS += $(cflags-y)
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# temporary until string.h is fixed
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KBUILD_CFLAGS += -ffreestanding
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ifeq ($(CONFIG_STACKPROTECTOR),y)
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ifeq ($(CONFIG_SMP),y)
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KBUILD_CFLAGS += -mstack-protector-guard-reg=fs -mstack-protector-guard-symbol=__stack_chk_guard
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else
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KBUILD_CFLAGS += -mstack-protector-guard=global
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endif
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endif
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else
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BITS := 64
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UTS_MACHINE := x86_64
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CHECKFLAGS += -D__x86_64__
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KBUILD_AFLAGS += -m64
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KBUILD_CFLAGS += -m64
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# Align jump targets to 1 byte, not the default 16 bytes:
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KBUILD_CFLAGS += $(call cc-option,-falign-jumps=1)
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# Pack loops tightly as well:
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KBUILD_CFLAGS += $(call cc-option,-falign-loops=1)
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# Don't autogenerate traditional x87 instructions
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KBUILD_CFLAGS += -mno-80387
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KBUILD_CFLAGS += $(call cc-option,-mno-fp-ret-in-387)
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# By default gcc and clang use a stack alignment of 16 bytes for x86.
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# However the standard kernel entry on x86-64 leaves the stack on an
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# 8-byte boundary. If the compiler isn't informed about the actual
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# alignment it will generate extra alignment instructions for the
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# default alignment which keep the stack *mis*aligned.
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# Furthermore an alignment to the register width reduces stack usage
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# and the number of alignment instructions.
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KBUILD_CFLAGS += $(cc_stack_align8)
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# Use -mskip-rax-setup if supported.
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KBUILD_CFLAGS += $(call cc-option,-mskip-rax-setup)
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# FIXME - should be integrated in Makefile.cpu (Makefile_32.cpu)
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cflags-$(CONFIG_MK8) += -march=k8
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cflags-$(CONFIG_MPSC) += -march=nocona
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cflags-$(CONFIG_MCORE2) += -march=core2
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cflags-$(CONFIG_MATOM) += -march=atom
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cflags-$(CONFIG_GENERIC_CPU) += -mtune=generic
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KBUILD_CFLAGS += $(cflags-y)
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rustflags-$(CONFIG_MK8) += -Ctarget-cpu=k8
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rustflags-$(CONFIG_MPSC) += -Ctarget-cpu=nocona
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rustflags-$(CONFIG_MCORE2) += -Ctarget-cpu=core2
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rustflags-$(CONFIG_MATOM) += -Ctarget-cpu=atom
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rustflags-$(CONFIG_GENERIC_CPU) += -Ztune-cpu=generic
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KBUILD_RUSTFLAGS += $(rustflags-y)
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KBUILD_CFLAGS += -mno-red-zone
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KBUILD_CFLAGS += -mcmodel=kernel
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KBUILD_RUSTFLAGS += -Cno-redzone=y
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KBUILD_RUSTFLAGS += -Ccode-model=kernel
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endif
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#
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# If the function graph tracer is used with mcount instead of fentry,
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# '-maccumulate-outgoing-args' is needed to prevent a GCC bug
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# (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42109)
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#
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ifdef CONFIG_FUNCTION_GRAPH_TRACER
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ifndef CONFIG_HAVE_FENTRY
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ACCUMULATE_OUTGOING_ARGS := 1
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endif
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endif
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ifeq ($(ACCUMULATE_OUTGOING_ARGS), 1)
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# This compiler flag is not supported by Clang:
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KBUILD_CFLAGS += $(call cc-option,-maccumulate-outgoing-args,)
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endif
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# Workaround for a gcc prelease that unfortunately was shipped in a suse release
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KBUILD_CFLAGS += -Wno-sign-compare
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#
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KBUILD_CFLAGS += -fno-asynchronous-unwind-tables
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# Avoid indirect branches in kernel to deal with Spectre
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ifdef CONFIG_RETPOLINE
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KBUILD_CFLAGS += $(RETPOLINE_CFLAGS)
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# Additionally, avoid generating expensive indirect jumps which
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# are subject to retpolines for small number of switch cases.
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# clang turns off jump table generation by default when under
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# retpoline builds, however, gcc does not for x86. This has
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# only been fixed starting from gcc stable version 8.4.0 and
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# onwards, but not for older ones. See gcc bug #86952.
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ifndef CONFIG_CC_IS_CLANG
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KBUILD_CFLAGS += -fno-jump-tables
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endif
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endif
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ifdef CONFIG_SLS
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KBUILD_CFLAGS += -mharden-sls=all
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endif
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ifdef CONFIG_CALL_PADDING
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PADDING_CFLAGS := -fpatchable-function-entry=$(CONFIG_FUNCTION_PADDING_BYTES),$(CONFIG_FUNCTION_PADDING_BYTES)
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KBUILD_CFLAGS += $(PADDING_CFLAGS)
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export PADDING_CFLAGS
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endif
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KBUILD_LDFLAGS += -m elf_$(UTS_MACHINE)
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ifdef CONFIG_LTO_CLANG
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ifeq ($(call test-lt, $(CONFIG_LLD_VERSION), 130000),y)
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KBUILD_LDFLAGS += -plugin-opt=-stack-alignment=$(if $(CONFIG_X86_32),4,8)
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endif
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endif
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ifdef CONFIG_X86_NEED_RELOCS
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LDFLAGS_vmlinux := --emit-relocs --discard-none
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else
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LDFLAGS_vmlinux :=
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endif
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#
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# The 64-bit kernel must be aligned to 2MB. Pass -z max-page-size=0x200000 to
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# the linker to force 2MB page size regardless of the default page size used
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# by the linker.
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#
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ifdef CONFIG_X86_64
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LDFLAGS_vmlinux += -z max-page-size=0x200000
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endif
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archscripts: scripts_basic
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$(Q)$(MAKE) $(build)=arch/x86/tools relocs
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###
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# Syscall table generation
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archheaders:
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$(Q)$(MAKE) $(build)=arch/x86/entry/syscalls all
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###
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# Kernel objects
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libs-y += arch/x86/lib/
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# drivers-y are linked after core-y
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drivers-$(CONFIG_MATH_EMULATION) += arch/x86/math-emu/
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drivers-$(CONFIG_PCI) += arch/x86/pci/
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# suspend and hibernation support
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drivers-$(CONFIG_PM) += arch/x86/power/
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drivers-$(CONFIG_FB) += arch/x86/video/
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####
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# boot loader support. Several targets are kept for legacy purposes
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boot := arch/x86/boot
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BOOT_TARGETS = bzdisk fdimage fdimage144 fdimage288 hdimage isoimage
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PHONY += bzImage $(BOOT_TARGETS)
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# Default kernel to build
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all: bzImage
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# KBUILD_IMAGE specify target image being built
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KBUILD_IMAGE := $(boot)/bzImage
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bzImage: vmlinux
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ifeq ($(CONFIG_X86_DECODER_SELFTEST),y)
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$(Q)$(MAKE) $(build)=arch/x86/tools posttest
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endif
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$(Q)$(MAKE) $(build)=$(boot) $(KBUILD_IMAGE)
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$(Q)mkdir -p $(objtree)/arch/$(UTS_MACHINE)/boot
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$(Q)ln -fsn ../../x86/boot/bzImage $(objtree)/arch/$(UTS_MACHINE)/boot/$@
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$(BOOT_TARGETS): vmlinux
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$(Q)$(MAKE) $(build)=$(boot) $@
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PHONY += install
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install:
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$(call cmd,install)
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PHONY += vdso_install
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vdso_install:
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$(Q)$(MAKE) $(build)=arch/x86/entry/vdso $@
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archprepare: checkbin
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checkbin:
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ifdef CONFIG_RETPOLINE
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ifeq ($(RETPOLINE_CFLAGS),)
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@echo "You are building kernel with non-retpoline compiler." >&2
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@echo "Please update your compiler." >&2
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@false
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endif
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endif
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ifdef CONFIG_UNWINDER_ORC
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orc_hash_h := arch/$(SRCARCH)/include/generated/asm/orc_hash.h
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orc_hash_sh := $(srctree)/scripts/orc_hash.sh
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targets += $(orc_hash_h)
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quiet_cmd_orc_hash = GEN $@
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cmd_orc_hash = mkdir -p $(dir $@); \
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$(CONFIG_SHELL) $(orc_hash_sh) < $< > $@
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$(orc_hash_h): $(srctree)/arch/x86/include/asm/orc_types.h $(orc_hash_sh) FORCE
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$(call if_changed,orc_hash)
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archprepare: $(orc_hash_h)
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endif
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archclean:
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$(Q)rm -rf $(objtree)/arch/i386
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$(Q)rm -rf $(objtree)/arch/x86_64
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define archhelp
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echo '* bzImage - Compressed kernel image (arch/x86/boot/bzImage)'
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echo ' install - Install kernel using (your) ~/bin/$(INSTALLKERNEL) or'
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echo ' (distribution) /sbin/$(INSTALLKERNEL) or install to '
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echo ' $$(INSTALL_PATH) and run lilo'
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echo ''
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echo ' fdimage - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)'
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echo ' fdimage144 - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)'
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echo ' fdimage288 - Create 2.8MB boot floppy image (arch/x86/boot/fdimage)'
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echo ' hdimage - Create a BIOS/EFI hard disk image (arch/x86/boot/hdimage)'
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echo ' isoimage - Create a boot CD-ROM image (arch/x86/boot/image.iso)'
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echo ' bzdisk/fdimage*/hdimage/isoimage also accept:'
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echo ' FDARGS="..." arguments for the booted kernel'
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echo ' FDINITRD=file initrd for the booted kernel'
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echo ''
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echo ' kvm_guest.config - Enable Kconfig items for running this kernel as a KVM guest'
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echo ' xen.config - Enable Kconfig items for running this kernel as a Xen guest'
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echo ' x86_debug.config - Enable tip tree debugging options for testing'
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endef
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