e1789d7c75
Andrew Cooper suggested upgrading the orphan section warning to a hard link error. However Nathan Chancellor said outright turning the warning into an error with no escape hatch might be too aggressive, as we have had these warnings triggered by new compiler generated sections, and suggested turning orphan sections into an error only if CONFIG_WERROR is set. Kees Cook echoed and emphasized that the mandate from Linus is that we should avoid breaking builds. It wrecks bisection, it causes problems across compiler versions, etc. Thus upgrade the orphan section warning to a hard link error only if CONFIG_WERROR is set. Suggested-by: Andrew Cooper <andrew.cooper3@citrix.com> Suggested-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Xin Li <xin3.li@intel.com> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Tested-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20221025073023.16137-2-xin3.li@intel.com
93 lines
2.9 KiB
Makefile
93 lines
2.9 KiB
Makefile
# SPDX-License-Identifier: GPL-2.0
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#
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# Building a vDSO image for AArch64.
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#
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# Author: Will Deacon <will.deacon@arm.com>
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# Heavily based on the vDSO Makefiles for other archs.
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#
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# Absolute relocation type $(ARCH_REL_TYPE_ABS) needs to be defined before
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# the inclusion of generic Makefile.
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ARCH_REL_TYPE_ABS := R_AARCH64_JUMP_SLOT|R_AARCH64_GLOB_DAT|R_AARCH64_ABS64
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include $(srctree)/lib/vdso/Makefile
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obj-vdso := vgettimeofday.o note.o sigreturn.o
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# Build rules
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targets := $(obj-vdso) vdso.so vdso.so.dbg
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obj-vdso := $(addprefix $(obj)/, $(obj-vdso))
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btildflags-$(CONFIG_ARM64_BTI_KERNEL) += -z force-bti
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# -Bsymbolic has been added for consistency with arm, the compat vDSO and
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# potential future proofing if we end up with internal calls to the exported
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# routines, as x86 does (see 6f121e548f83 ("x86, vdso: Reimplement vdso.so
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# preparation in build-time C")).
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ldflags-y := -shared -soname=linux-vdso.so.1 --hash-style=sysv \
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-Bsymbolic --build-id=sha1 -n $(btildflags-y)
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ifdef CONFIG_LD_ORPHAN_WARN
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ldflags-y += --orphan-handling=$(CONFIG_LD_ORPHAN_WARN_LEVEL)
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endif
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ldflags-y += -T
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ccflags-y := -fno-common -fno-builtin -fno-stack-protector -ffixed-x18
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ccflags-y += -DDISABLE_BRANCH_PROFILING -DBUILD_VDSO
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# -Wmissing-prototypes and -Wmissing-declarations are removed from
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# the CFLAGS of vgettimeofday.c to make possible to build the
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# kernel with CONFIG_WERROR enabled.
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CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) -Os $(CC_FLAGS_SCS) \
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$(RANDSTRUCT_CFLAGS) $(GCC_PLUGINS_CFLAGS) \
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$(CC_FLAGS_LTO) $(CC_FLAGS_CFI) \
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-Wmissing-prototypes -Wmissing-declarations
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KASAN_SANITIZE := n
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KCSAN_SANITIZE := n
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UBSAN_SANITIZE := n
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OBJECT_FILES_NON_STANDARD := y
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KCOV_INSTRUMENT := n
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CFLAGS_vgettimeofday.o = -O2 -mcmodel=tiny -fasynchronous-unwind-tables
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ifneq ($(c-gettimeofday-y),)
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CFLAGS_vgettimeofday.o += -include $(c-gettimeofday-y)
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endif
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# Disable gcov profiling for VDSO code
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GCOV_PROFILE := n
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targets += vdso.lds
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CPPFLAGS_vdso.lds += -P -C -U$(ARCH)
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# Link rule for the .so file, .lds has to be first
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$(obj)/vdso.so.dbg: $(obj)/vdso.lds $(obj-vdso) FORCE
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$(call if_changed,vdsold_and_vdso_check)
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# Strip rule for the .so file
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$(obj)/%.so: OBJCOPYFLAGS := -S
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$(obj)/%.so: $(obj)/%.so.dbg FORCE
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$(call if_changed,objcopy)
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# Generate VDSO offsets using helper script
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gen-vdsosym := $(srctree)/$(src)/gen_vdso_offsets.sh
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quiet_cmd_vdsosym = VDSOSYM $@
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cmd_vdsosym = $(NM) $< | $(gen-vdsosym) | LC_ALL=C sort > $@
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include/generated/vdso-offsets.h: $(obj)/vdso.so.dbg FORCE
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$(call if_changed,vdsosym)
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# Actual build commands
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quiet_cmd_vdsold_and_vdso_check = LD $@
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cmd_vdsold_and_vdso_check = $(cmd_ld); $(cmd_vdso_check)
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# Install commands for the unstripped file
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quiet_cmd_vdso_install = INSTALL $@
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cmd_vdso_install = cp $(obj)/$@.dbg $(MODLIB)/vdso/$@
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vdso.so: $(obj)/vdso.so.dbg
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@mkdir -p $(MODLIB)/vdso
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$(call cmd,vdso_install)
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vdso_install: vdso.so
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