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f43b9876e8
Do fine-grained Kconfig for all the various retbleed parts. NOTE: if your compiler doesn't support return thunks this will silently 'upgrade' your mitigation to IBPB, you might not like this. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de>
87 lines
2.7 KiB
Text
87 lines
2.7 KiB
Text
# SPDX-License-Identifier: GPL-2.0-only
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PHONY := __default
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__default: vmlinux.o
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include include/config/auto.conf
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include $(srctree)/scripts/Kbuild.include
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# for objtool
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include $(srctree)/scripts/Makefile.lib
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# Generate a linker script to ensure correct ordering of initcalls for Clang LTO
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# ---------------------------------------------------------------------------
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quiet_cmd_gen_initcalls_lds = GEN $@
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cmd_gen_initcalls_lds = \
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$(PYTHON3) $(srctree)/scripts/jobserver-exec \
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$(PERL) $(real-prereqs) > $@
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.tmp_initcalls.lds: $(srctree)/scripts/generate_initcall_order.pl \
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$(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS) FORCE
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$(call if_changed,gen_initcalls_lds)
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targets := .tmp_initcalls.lds
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ifdef CONFIG_LTO_CLANG
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initcalls-lds := .tmp_initcalls.lds
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endif
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# objtool for vmlinux.o
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# ---------------------------------------------------------------------------
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#
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# For LTO and IBT, objtool doesn't run on individual translation units.
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# Run everything on vmlinux instead.
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objtool-enabled := $(or $(delay-objtool),$(CONFIG_NOINSTR_VALIDATION))
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# Reuse objtool_args defined in scripts/Makefile.lib if LTO or IBT is enabled.
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#
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# Add some more flags as needed.
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# --no-unreachable and --link might be added twice, but it is fine.
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#
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# Expand objtool_args to a simple variable to avoid circular reference.
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objtool_args := \
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$(if $(delay-objtool),$(objtool_args)) \
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$(if $(CONFIG_NOINSTR_VALIDATION), --noinstr $(if $(CONFIG_CPU_UNRET_ENTRY), --unret)) \
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$(if $(CONFIG_GCOV_KERNEL), --no-unreachable) \
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--link
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# Link of vmlinux.o used for section mismatch analysis
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# ---------------------------------------------------------------------------
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quiet_cmd_ld_vmlinux.o = LD $@
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cmd_ld_vmlinux.o = \
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$(LD) ${KBUILD_LDFLAGS} -r -o $@ \
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$(addprefix -T , $(initcalls-lds)) \
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--whole-archive $(KBUILD_VMLINUX_OBJS) --no-whole-archive \
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--start-group $(KBUILD_VMLINUX_LIBS) --end-group \
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$(cmd_objtool)
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define rule_ld_vmlinux.o
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$(call cmd_and_savecmd,ld_vmlinux.o)
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$(call cmd,gen_objtooldep)
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endef
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vmlinux.o: $(initcalls-lds) $(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS) FORCE
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$(call if_changed_rule,ld_vmlinux.o)
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targets += vmlinux.o
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# Add FORCE to the prequisites of a target to force it to be always rebuilt.
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# ---------------------------------------------------------------------------
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PHONY += FORCE
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FORCE:
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# Read all saved command lines and dependencies for the $(targets) we
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# may be building above, using $(if_changed{,_dep}). As an
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# optimization, we don't need to read them if the target does not
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# exist, we will rebuild anyway in that case.
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existing-targets := $(wildcard $(sort $(targets)))
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-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd)
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.PHONY: $(PHONY)
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