From ac5f5ed8810cc918b20fb6d27e73f31ca8f2da6a Mon Sep 17 00:00:00 2001 From: WANG Xuerui Date: Sun, 6 Aug 2023 18:36:20 +0800 Subject: [PATCH] LoongArch: Replace -ffreestanding with finer-grained -fno-builtin's As explained by Nick in the original issue: the kernel usually does a good job of providing library helpers that have similar semantics as their ordinary userspace libc equivalents, but -ffreestanding disables such libcall optimization and other related features in the compiler, which can lead to unexpected things such as CONFIG_FORTIFY_SOURCE not working (!). However, due to the desire for better control over unaligned accesses with respect to CONFIG_ARCH_STRICT_ALIGN, and also for avoiding the GCC bug https://gcc.gnu.org/PR109465, we do want to still disable optimizations for the memory libcalls (memcpy, memmove and memset for now). Use finer-grained -fno-builtin-* toggles to achieve this without losing source fortification and other libcall optimizations. Closes: https://github.com/ClangBuiltLinux/linux/issues/1897 Reported-by: Nathan Chancellor Suggested-by: Nick Desaulniers Signed-off-by: WANG Xuerui Signed-off-by: Huacai Chen --- arch/loongarch/Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/loongarch/Makefile b/arch/loongarch/Makefile index b1e5db51b61ca..ef87bab46754e 100644 --- a/arch/loongarch/Makefile +++ b/arch/loongarch/Makefile @@ -83,8 +83,8 @@ KBUILD_CFLAGS_KERNEL += -fPIE LDFLAGS_vmlinux += -static -pie --no-dynamic-linker -z notext endif -cflags-y += -ffreestanding cflags-y += $(call cc-option, -mno-check-zero-division) +cflags-y += -fno-builtin-memcpy -fno-builtin-memmove -fno-builtin-memset load-y = 0x9000000000200000 bootvars-y = VMLINUX_LOAD_ADDRESS=$(load-y)