On Fri, Jun 26, 2020 at 01:25:27PM -0700, Nick Desaulniers wrote: > Ah, right. Thanks for pointing that out. I'm still curious if the > CFLAGS_<file>.o rules get appended or overwrite all flags for that > translation unit? CFLAGS_file.o gets appended to the CFLAGS. For example, after my updated patch[1], the command line for syscall_64.o looks like this: gcc -Wp,-MMD,arch/x86/entry/.syscall_64.o.d -nostdinc -isystem \ ... -Wframe-larger-than=2048 -fstack-protector-strong \ ... -fno-stack-protector -Wno-override-init \ -DKBUILD_MODFILE='"arch/x86/entry/syscall_64"' \ -DKBUILD_BASENAME='"syscall_64"' \ -DKBUILD_MODNAME='"syscall_64"' \ -c -o arch/x86/entry/syscall_64.o \ arch/x86/entry/syscall_64.c -Kees [1] https://lore.kernel.org/lkml/202006261333.585319CA6B@keescook/ -- Kees Cook