After fixing the HAVE_STACKPROTECTER checks for clang's in-progress per-task stack protector support [1], the build fails during prepare0 because '-mstack-protector-guard-offset' has not been added to KBUILD_CFLAGS yet but the other '-mstack-protector-guard' flags have.
clang: error: '-mstack-protector-guard=tls' is used without '-mstack-protector-guard-offset', and there is no default clang: error: '-mstack-protector-guard=tls' is used without '-mstack-protector-guard-offset', and there is no default make[4]: *** [scripts/Makefile.build:229: scripts/mod/empty.o] Error 1 make[4]: *** [scripts/Makefile.build:102: scripts/mod/devicetable-offsets.s] Error 1
Mirror other architectures and add all '-mstack-protector-guard' flags to KBUILD_CFLAGS atomically during stack_protector_prepare, which resolves the issue and allows clang's implementation to fully work with the kernel.
Cc: stable@vger.kernel.org # 6.1+ Link: https://github.com/llvm/llvm-project/pull/110928 [1] Reviewed-by: Keith Packard keithp@keithp.com Tested-by: Keith Packard keithp@keithp.com Signed-off-by: Nathan Chancellor nathan@kernel.org --- arch/powerpc/Makefile | 13 ++++--------- 1 file changed, 4 insertions(+), 9 deletions(-)
diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile index bbfe4a1f06ef9db9b2f2e48e02096b1e0500a14b..cbb353ddacb7adc5de28cd1fde893de3efdd8272 100644 --- a/arch/powerpc/Makefile +++ b/arch/powerpc/Makefile @@ -100,13 +100,6 @@ KBUILD_AFLAGS += -m$(BITS) KBUILD_LDFLAGS += -m elf$(BITS)$(LDEMULATION) endif
-cflags-$(CONFIG_STACKPROTECTOR) += -mstack-protector-guard=tls -ifdef CONFIG_PPC64 -cflags-$(CONFIG_STACKPROTECTOR) += -mstack-protector-guard-reg=r13 -else -cflags-$(CONFIG_STACKPROTECTOR) += -mstack-protector-guard-reg=r2 -endif - LDFLAGS_vmlinux-y := -Bstatic LDFLAGS_vmlinux-$(CONFIG_RELOCATABLE) := -pie LDFLAGS_vmlinux-$(CONFIG_RELOCATABLE) += -z notext @@ -402,9 +395,11 @@ prepare: stack_protector_prepare PHONY += stack_protector_prepare stack_protector_prepare: prepare0 ifdef CONFIG_PPC64 - $(eval KBUILD_CFLAGS += -mstack-protector-guard-offset=$(shell awk '{if ($$2 == "PACA_CANARY") print $$3;}' include/generated/asm-offsets.h)) + $(eval KBUILD_CFLAGS += -mstack-protector-guard=tls -mstack-protector-guard-reg=r13 \ + -mstack-protector-guard-offset=$(shell awk '{if ($$2 == "PACA_CANARY") print $$3;}' include/generated/asm-offsets.h)) else - $(eval KBUILD_CFLAGS += -mstack-protector-guard-offset=$(shell awk '{if ($$2 == "TASK_CANARY") print $$3;}' include/generated/asm-offsets.h)) + $(eval KBUILD_CFLAGS += -mstack-protector-guard=tls -mstack-protector-guard-reg=r2 \ + -mstack-protector-guard-offset=$(shell awk '{if ($$2 == "TASK_CANARY") print $$3;}' include/generated/asm-offsets.h)) endif endif