On Fri, 26 Jun 2020 at 21:00, Masahiro Yamada <masahiroy@xxxxxxxxxx> wrote: > > Some Makefiles already pass -fno-stack-protector unconditionally. > For example, arch/arm64/kernel/vdso/Makefile, arch/x86/xen/Makefile. > No problem report so far about hard-coding this option. So, we can > assume all supported compilers know -fno-stack-protector. > > GCC 4.8 and Clang support this option (https://godbolt.org/z/_HDGzN) > > Get rid of cc-option from -fno-stack-protector. > > Remove CONFIG_CC_HAS_STACKPROTECTOR_NONE, which should always be 'y'. > > Note: > arch/mips/vdso/Makefile adds -fno-stack-protector twice, first > unconditionally, and second conditionally. I removed the second one. > > Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx> Acked-by: Ard Biesheuvel <ardb@xxxxxxxxxx> > --- > > Documentation/kbuild/kconfig-language.rst | 4 ++-- > Makefile | 2 +- > arch/Kconfig | 3 --- > arch/arm/boot/compressed/Makefile | 3 +-- > arch/mips/vdso/Makefile | 3 +-- > arch/powerpc/kernel/Makefile | 2 +- > arch/powerpc/platforms/powermac/Makefile | 2 +- > arch/sparc/vdso/Makefile | 4 ++-- > arch/um/Makefile | 3 +-- > arch/x86/Makefile | 2 +- > arch/x86/boot/compressed/Makefile | 2 +- > arch/x86/entry/vdso/Makefile | 4 ++-- > arch/x86/kernel/cpu/Makefile | 3 +-- > arch/x86/lib/Makefile | 2 +- > arch/x86/mm/Makefile | 7 +++---- > arch/x86/power/Makefile | 3 +-- > arch/x86/purgatory/Makefile | 2 +- > arch/x86/um/vdso/Makefile | 2 +- > arch/x86/xen/Makefile | 5 ++--- > drivers/firmware/efi/libstub/Makefile | 2 +- > drivers/xen/Makefile | 3 +-- > kernel/kcsan/Makefile | 3 +-- > lib/Makefile | 4 ++-- > mm/kasan/Makefile | 2 +- > 24 files changed, 30 insertions(+), 42 deletions(-) > > diff --git a/Documentation/kbuild/kconfig-language.rst b/Documentation/kbuild/kconfig-language.rst > index a1601ec3317b..2538e7cb08e6 100644 > --- a/Documentation/kbuild/kconfig-language.rst > +++ b/Documentation/kbuild/kconfig-language.rst > @@ -540,8 +540,8 @@ followed by a test macro:: > If you need to expose a compiler capability to makefiles and/or C source files, > `CC_HAS_` is the recommended prefix for the config option:: > > - config CC_HAS_STACKPROTECTOR_NONE > - def_bool $(cc-option,-fno-stack-protector) > + config CC_HAS_ASM_GOTO > + def_bool $(success,$(srctree)/scripts/gcc-goto.sh $(CC)) > > Build as module only > ~~~~~~~~~~~~~~~~~~~~ > diff --git a/Makefile b/Makefile > index 5496a32dffa6..73948798ce3f 100644 > --- a/Makefile > +++ b/Makefile > @@ -762,7 +762,7 @@ ifneq ($(CONFIG_FRAME_WARN),0) > KBUILD_CFLAGS += -Wframe-larger-than=$(CONFIG_FRAME_WARN) > endif > > -stackp-flags-$(CONFIG_CC_HAS_STACKPROTECTOR_NONE) := -fno-stack-protector > +stackp-flags-y := -fno-stack-protector > stackp-flags-$(CONFIG_STACKPROTECTOR) := -fstack-protector > stackp-flags-$(CONFIG_STACKPROTECTOR_STRONG) := -fstack-protector-strong > > diff --git a/arch/Kconfig b/arch/Kconfig > index 8cc35dc556c7..1ea61290900a 100644 > --- a/arch/Kconfig > +++ b/arch/Kconfig > @@ -478,9 +478,6 @@ config HAVE_STACKPROTECTOR > An arch should select this symbol if: > - it has implemented a stack canary (e.g. __stack_chk_guard) > > -config CC_HAS_STACKPROTECTOR_NONE > - def_bool $(cc-option,-fno-stack-protector) > - > config STACKPROTECTOR > bool "Stack Protector buffer overflow detection" > depends on HAVE_STACKPROTECTOR > diff --git a/arch/arm/boot/compressed/Makefile b/arch/arm/boot/compressed/Makefile > index 00602a6fba04..cb7a56c6723c 100644 > --- a/arch/arm/boot/compressed/Makefile > +++ b/arch/arm/boot/compressed/Makefile > @@ -84,9 +84,8 @@ endif > > # -fstack-protector-strong triggers protection checks in this code, > # but it is being used too early to link to meaningful stack_chk logic. > -nossp-flags-$(CONFIG_CC_HAS_STACKPROTECTOR_NONE) := -fno-stack-protector > $(foreach o, $(libfdt_objs) atags_to_fdt.o, \ > - $(eval CFLAGS_$(o) := -I $(srctree)/scripts/dtc/libfdt $(nossp-flags-y))) > + $(eval CFLAGS_$(o) := -I $(srctree)/scripts/dtc/libfdt -fno-stack-protector)) > > # These were previously generated C files. When you are building the kernel > # with O=, make sure to remove the stale files in the output tree. Otherwise, > diff --git a/arch/mips/vdso/Makefile b/arch/mips/vdso/Makefile > index 2e64c7600eea..57fe83235281 100644 > --- a/arch/mips/vdso/Makefile > +++ b/arch/mips/vdso/Makefile > @@ -35,8 +35,7 @@ cflags-vdso := $(ccflags-vdso) \ > -O3 -g -fPIC -fno-strict-aliasing -fno-common -fno-builtin -G 0 \ > -mrelax-pic-calls $(call cc-option, -mexplicit-relocs) \ > -fno-stack-protector -fno-jump-tables -DDISABLE_BRANCH_PROFILING \ > - $(call cc-option, -fno-asynchronous-unwind-tables) \ > - $(call cc-option, -fno-stack-protector) > + $(call cc-option, -fno-asynchronous-unwind-tables) > aflags-vdso := $(ccflags-vdso) \ > -D__ASSEMBLY__ -Wa,-gdwarf-2 > > diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile > index 244542ae2a91..3a83f2b876a5 100644 > --- a/arch/powerpc/kernel/Makefile > +++ b/arch/powerpc/kernel/Makefile > @@ -16,7 +16,7 @@ CFLAGS_prom_init.o += $(DISABLE_LATENT_ENTROPY_PLUGIN) > CFLAGS_btext.o += $(DISABLE_LATENT_ENTROPY_PLUGIN) > CFLAGS_prom.o += $(DISABLE_LATENT_ENTROPY_PLUGIN) > > -CFLAGS_prom_init.o += $(call cc-option, -fno-stack-protector) > +CFLAGS_prom_init.o += -fno-stack-protector > CFLAGS_prom_init.o += -DDISABLE_BRANCH_PROFILING > CFLAGS_prom_init.o += -ffreestanding > > diff --git a/arch/powerpc/platforms/powermac/Makefile b/arch/powerpc/platforms/powermac/Makefile > index f4247ade71ca..cf85f0662d0d 100644 > --- a/arch/powerpc/platforms/powermac/Makefile > +++ b/arch/powerpc/platforms/powermac/Makefile > @@ -1,6 +1,6 @@ > # SPDX-License-Identifier: GPL-2.0 > CFLAGS_bootx_init.o += -fPIC > -CFLAGS_bootx_init.o += $(call cc-option, -fno-stack-protector) > +CFLAGS_bootx_init.o += -fno-stack-protector > > KASAN_SANITIZE_bootx_init.o := n > > diff --git a/arch/sparc/vdso/Makefile b/arch/sparc/vdso/Makefile > index 708cb6304c2d..f44355e46f31 100644 > --- a/arch/sparc/vdso/Makefile > +++ b/arch/sparc/vdso/Makefile > @@ -54,7 +54,7 @@ $(obj)/vdso-image-%.c: $(obj)/vdso%.so.dbg $(obj)/vdso%.so $(obj)/vdso2c FORCE > # optimize sibling calls. > # > CFL := $(PROFILING) -mcmodel=medlow -fPIC -O2 -fasynchronous-unwind-tables -m64 \ > - $(filter -g%,$(KBUILD_CFLAGS)) $(call cc-option, -fno-stack-protector) \ > + $(filter -g%,$(KBUILD_CFLAGS)) -fno-stack-protector \ > -fno-omit-frame-pointer -foptimize-sibling-calls \ > -DDISABLE_BRANCH_PROFILING -DBUILD_VDSO > > @@ -93,7 +93,7 @@ KBUILD_CFLAGS_32 := $(filter-out -fno-pic,$(KBUILD_CFLAGS_32)) > KBUILD_CFLAGS_32 := $(filter-out $(GCC_PLUGINS_CFLAGS),$(KBUILD_CFLAGS_32)) > KBUILD_CFLAGS_32 := $(filter-out $(SPARC_REG_CFLAGS),$(KBUILD_CFLAGS_32)) > KBUILD_CFLAGS_32 += -m32 -msoft-float -fpic > -KBUILD_CFLAGS_32 += $(call cc-option, -fno-stack-protector) > +KBUILD_CFLAGS_32 += -fno-stack-protector > KBUILD_CFLAGS_32 += $(call cc-option, -foptimize-sibling-calls) > KBUILD_CFLAGS_32 += -fno-omit-frame-pointer > KBUILD_CFLAGS_32 += -DDISABLE_BRANCH_PROFILING > diff --git a/arch/um/Makefile b/arch/um/Makefile > index 3f27aa3ec0a6..1cea46ff9bb7 100644 > --- a/arch/um/Makefile > +++ b/arch/um/Makefile > @@ -121,8 +121,7 @@ LINK-$(CONFIG_LD_SCRIPT_STATIC) += -static > LINK-$(CONFIG_LD_SCRIPT_DYN) += -Wl,-rpath,/lib $(call cc-option, -no-pie) > > CFLAGS_NO_HARDENING := $(call cc-option, -fno-PIC,) $(call cc-option, -fno-pic,) \ > - $(call cc-option, -fno-stack-protector,) \ > - $(call cc-option, -fno-stack-protector-all,) > + -fno-stack-protector $(call cc-option, -fno-stack-protector-all) > > # Options used by linker script > export LDS_START := $(START) > diff --git a/arch/x86/Makefile b/arch/x86/Makefile > index 00e378de8bc0..89c3cdfba753 100644 > --- a/arch/x86/Makefile > +++ b/arch/x86/Makefile > @@ -37,7 +37,7 @@ REALMODE_CFLAGS := $(M16_CFLAGS) -g -Os -DDISABLE_BRANCH_PROFILING \ > -mno-mmx -mno-sse > > REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), -ffreestanding) > -REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), -fno-stack-protector) > +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), $(cc_stack_align4)) > export REALMODE_CFLAGS > diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile > index 7619742f91c9..c88a31569a5e 100644 > --- a/arch/x86/boot/compressed/Makefile > +++ b/arch/x86/boot/compressed/Makefile > @@ -36,7 +36,7 @@ cflags-$(CONFIG_X86_64) := -mcmodel=small > KBUILD_CFLAGS += $(cflags-y) > KBUILD_CFLAGS += -mno-mmx -mno-sse > KBUILD_CFLAGS += $(call cc-option,-ffreestanding) > -KBUILD_CFLAGS += $(call cc-option,-fno-stack-protector) > +KBUILD_CFLAGS += -fno-stack-protector > KBUILD_CFLAGS += $(call cc-disable-warning, address-of-packed-member) > KBUILD_CFLAGS += $(call cc-disable-warning, gnu) > KBUILD_CFLAGS += -Wno-pointer-sign > diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile > index 04e65f0698f6..215376d975a2 100644 > --- a/arch/x86/entry/vdso/Makefile > +++ b/arch/x86/entry/vdso/Makefile > @@ -82,7 +82,7 @@ $(obj)/vdso-image-%.c: $(obj)/vdso%.so.dbg $(obj)/vdso%.so $(obj)/vdso2c FORCE > # optimize sibling calls. > # > CFL := $(PROFILING) -mcmodel=small -fPIC -O2 -fasynchronous-unwind-tables -m64 \ > - $(filter -g%,$(KBUILD_CFLAGS)) $(call cc-option, -fno-stack-protector) \ > + $(filter -g%,$(KBUILD_CFLAGS)) -fno-stack-protector \ > -fno-omit-frame-pointer -foptimize-sibling-calls \ > -DDISABLE_BRANCH_PROFILING -DBUILD_VDSO > > @@ -151,7 +151,7 @@ KBUILD_CFLAGS_32 := $(filter-out -mfentry,$(KBUILD_CFLAGS_32)) > KBUILD_CFLAGS_32 := $(filter-out $(GCC_PLUGINS_CFLAGS),$(KBUILD_CFLAGS_32)) > KBUILD_CFLAGS_32 := $(filter-out $(RETPOLINE_CFLAGS),$(KBUILD_CFLAGS_32)) > KBUILD_CFLAGS_32 += -m32 -msoft-float -mregparm=0 -fpic > -KBUILD_CFLAGS_32 += $(call cc-option, -fno-stack-protector) > +KBUILD_CFLAGS_32 += -fno-stack-protector > KBUILD_CFLAGS_32 += $(call cc-option, -foptimize-sibling-calls) > KBUILD_CFLAGS_32 += -fno-omit-frame-pointer > KBUILD_CFLAGS_32 += -DDISABLE_BRANCH_PROFILING > diff --git a/arch/x86/kernel/cpu/Makefile b/arch/x86/kernel/cpu/Makefile > index dba6a83bc349..93792b457b81 100644 > --- a/arch/x86/kernel/cpu/Makefile > +++ b/arch/x86/kernel/cpu/Makefile > @@ -17,8 +17,7 @@ KCOV_INSTRUMENT_perf_event.o := n > KCSAN_SANITIZE_common.o := n > > # Make sure load_percpu_segment has no stackprotector > -nostackp := $(call cc-option, -fno-stack-protector) > -CFLAGS_common.o := $(nostackp) > +CFLAGS_common.o := -fno-stack-protector > > obj-y := cacheinfo.o scattered.o topology.o > obj-y += common.o > diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile > index 6110bce7237b..d46fff11f06f 100644 > --- a/arch/x86/lib/Makefile > +++ b/arch/x86/lib/Makefile > @@ -24,7 +24,7 @@ ifdef CONFIG_FUNCTION_TRACER > CFLAGS_REMOVE_cmdline.o = -pg > endif > > -CFLAGS_cmdline.o := $(call cc-option, -fno-stack-protector) > +CFLAGS_cmdline.o := -fno-stack-protector > endif > > inat_tables_script = $(srctree)/arch/x86/tools/gen-insn-attr-x86.awk > diff --git a/arch/x86/mm/Makefile b/arch/x86/mm/Makefile > index f7fd0e868c9c..5864219221ca 100644 > --- a/arch/x86/mm/Makefile > +++ b/arch/x86/mm/Makefile > @@ -22,10 +22,9 @@ obj-y := init.o init_$(BITS).o fault.o ioremap.o extable.o mmap.o \ > obj-y += pat/ > > # Make sure __phys_addr has no stackprotector > -nostackp := $(call cc-option, -fno-stack-protector) > -CFLAGS_physaddr.o := $(nostackp) > -CFLAGS_setup_nx.o := $(nostackp) > -CFLAGS_mem_encrypt_identity.o := $(nostackp) > +CFLAGS_physaddr.o := -fno-stack-protector > +CFLAGS_setup_nx.o := -fno-stack-protector > +CFLAGS_mem_encrypt_identity.o := -fno-stack-protector > > CFLAGS_fault.o := -I $(srctree)/$(src)/../include/asm/trace > > diff --git a/arch/x86/power/Makefile b/arch/x86/power/Makefile > index 37923d715741..6907b523e856 100644 > --- a/arch/x86/power/Makefile > +++ b/arch/x86/power/Makefile > @@ -3,8 +3,7 @@ OBJECT_FILES_NON_STANDARD_hibernate_asm_$(BITS).o := y > > # __restore_processor_state() restores %gs after S3 resume and so should not > # itself be stack-protected > -nostackp := $(call cc-option, -fno-stack-protector) > -CFLAGS_cpu.o := $(nostackp) > +CFLAGS_cpu.o := -fno-stack-protector > > obj-$(CONFIG_PM_SLEEP) += cpu.o > obj-$(CONFIG_HIBERNATION) += hibernate_$(BITS).o hibernate_asm_$(BITS).o hibernate.o > diff --git a/arch/x86/purgatory/Makefile b/arch/x86/purgatory/Makefile > index 088bd764e0b7..183ac60e5990 100644 > --- a/arch/x86/purgatory/Makefile > +++ b/arch/x86/purgatory/Makefile > @@ -34,7 +34,7 @@ KCOV_INSTRUMENT := n > PURGATORY_CFLAGS_REMOVE := -mcmodel=kernel > PURGATORY_CFLAGS := -mcmodel=large -ffreestanding -fno-zero-initialized-in-bss > PURGATORY_CFLAGS += $(DISABLE_STACKLEAK_PLUGIN) -DDISABLE_BRANCH_PROFILING > -PURGATORY_CFLAGS += $(call cc-option,-fno-stack-protector) > +PURGATORY_CFLAGS += -fno-stack-protector > > # Default KBUILD_CFLAGS can have -pg option set when FTRACE is enabled. That > # in turn leaves some undefined symbols like __fentry__ in purgatory and not > diff --git a/arch/x86/um/vdso/Makefile b/arch/x86/um/vdso/Makefile > index 0caddd6acb22..5943387e3f35 100644 > --- a/arch/x86/um/vdso/Makefile > +++ b/arch/x86/um/vdso/Makefile > @@ -42,7 +42,7 @@ $(obj)/%.so: $(obj)/%.so.dbg FORCE > # optimize sibling calls. > # > CFL := $(PROFILING) -mcmodel=small -fPIC -O2 -fasynchronous-unwind-tables -m64 \ > - $(filter -g%,$(KBUILD_CFLAGS)) $(call cc-option, -fno-stack-protector) \ > + $(filter -g%,$(KBUILD_CFLAGS)) -fno-stack-protector \ > -fno-omit-frame-pointer -foptimize-sibling-calls > > $(vobjs): KBUILD_CFLAGS += $(CFL) > diff --git a/arch/x86/xen/Makefile b/arch/x86/xen/Makefile > index 084de77a109e..5f1db522d06b 100644 > --- a/arch/x86/xen/Makefile > +++ b/arch/x86/xen/Makefile > @@ -9,9 +9,8 @@ CFLAGS_REMOVE_irq.o = -pg > endif > > # Make sure early boot has no stackprotector > -nostackp := $(call cc-option, -fno-stack-protector) > -CFLAGS_enlighten_pv.o := $(nostackp) > -CFLAGS_mmu_pv.o := $(nostackp) > +CFLAGS_enlighten_pv.o := -fno-stack-protector > +CFLAGS_mmu_pv.o := -fno-stack-protector > > obj-y += enlighten.o > obj-y += mmu.o > diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile > index 75daaf20374e..f8418763cd79 100644 > --- a/drivers/firmware/efi/libstub/Makefile > +++ b/drivers/firmware/efi/libstub/Makefile > @@ -29,7 +29,7 @@ KBUILD_CFLAGS := $(cflags-y) -Os -DDISABLE_BRANCH_PROFILING \ > -include $(srctree)/drivers/firmware/efi/libstub/hidden.h \ > -D__NO_FORTIFY \ > $(call cc-option,-ffreestanding) \ > - $(call cc-option,-fno-stack-protector) \ > + -fno-stack-protector \ > $(call cc-option,-fno-addrsig) \ > -D__DISABLE_EXPORTS > > diff --git a/drivers/xen/Makefile b/drivers/xen/Makefile > index 0d322f3d90cd..c25c9a699b48 100644 > --- a/drivers/xen/Makefile > +++ b/drivers/xen/Makefile > @@ -5,8 +5,7 @@ obj-y += mem-reservation.o > obj-y += events/ > obj-y += xenbus/ > > -nostackp := $(call cc-option, -fno-stack-protector) > -CFLAGS_features.o := $(nostackp) > +CFLAGS_features.o := -fno-stack-protector > > dom0-$(CONFIG_ARM64) += arm-device.o > dom0-$(CONFIG_PCI) += pci.o > diff --git a/kernel/kcsan/Makefile b/kernel/kcsan/Makefile > index d4999b38d1be..d111f32bd5fd 100644 > --- a/kernel/kcsan/Makefile > +++ b/kernel/kcsan/Makefile > @@ -7,8 +7,7 @@ CFLAGS_REMOVE_core.o = $(CC_FLAGS_FTRACE) > CFLAGS_REMOVE_debugfs.o = $(CC_FLAGS_FTRACE) > CFLAGS_REMOVE_report.o = $(CC_FLAGS_FTRACE) > > -CFLAGS_core.o := $(call cc-option,-fno-conserve-stack,) \ > - $(call cc-option,-fno-stack-protector,) > +CFLAGS_core.o := $(call cc-option,-fno-conserve-stack,) -fno-stack-protector > > obj-y := core.o debugfs.o report.o > obj-$(CONFIG_KCSAN_SELFTEST) += test.o > diff --git a/lib/Makefile b/lib/Makefile > index b1c42c10073b..0cda70649f1c 100644 > --- a/lib/Makefile > +++ b/lib/Makefile > @@ -22,7 +22,7 @@ KCOV_INSTRUMENT_fault-inject.o := n > ifdef CONFIG_AMD_MEM_ENCRYPT > KASAN_SANITIZE_string.o := n > > -CFLAGS_string.o := $(call cc-option, -fno-stack-protector) > +CFLAGS_string.o := -fno-stack-protector > endif > > # Used by KCSAN while enabled, avoid recursion. > @@ -300,7 +300,7 @@ endif > UBSAN_SANITIZE_ubsan.o := n > KASAN_SANITIZE_ubsan.o := n > KCSAN_SANITIZE_ubsan.o := n > -CFLAGS_ubsan.o := $(call cc-option, -fno-stack-protector) $(DISABLE_STACKLEAK_PLUGIN) > +CFLAGS_ubsan.o := -fno-stack-protector $(DISABLE_STACKLEAK_PLUGIN) > > obj-$(CONFIG_SBITMAP) += sbitmap.o > > diff --git a/mm/kasan/Makefile b/mm/kasan/Makefile > index d532c2587731..370d970e5ab5 100644 > --- a/mm/kasan/Makefile > +++ b/mm/kasan/Makefile > @@ -16,7 +16,7 @@ CFLAGS_REMOVE_tags_report.o = $(CC_FLAGS_FTRACE) > # Function splitter causes unnecessary splits in __asan_load1/__asan_store1 > # see: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63533 > CC_FLAGS_KASAN_RUNTIME := $(call cc-option, -fno-conserve-stack) > -CC_FLAGS_KASAN_RUNTIME += $(call cc-option, -fno-stack-protector) > +CC_FLAGS_KASAN_RUNTIME += -fno-stack-protector > # Disable branch tracing to avoid recursion. > CC_FLAGS_KASAN_RUNTIME += -DDISABLE_BRANCH_PROFILING > > -- > 2.25.1 >
