[PATCH v4 13/15] x86, cpu: Use LTO for cpu.c with CFI

[Sami Tolvanen]

Allow LTO to be used for cpu.c when CONFIG_CFI_CLANG is enabled to avoid
indirect call failures. CFI requires Clang >= 13, which doesn't have the
stack protector inlining bug.

Signed-off-by: Sami Tolvanen <samitolvanen@xxxxxxxxxx>
Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
Reviewed-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
---
 arch/x86/power/Makefile | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/x86/power/Makefile b/arch/x86/power/Makefile
index 379777572bc9..a0532851fed7 100644
--- a/arch/x86/power/Makefile
+++ b/arch/x86/power/Makefile
@@ -4,9 +4,11 @@
 # itself be stack-protected
 CFLAGS_cpu.o	:= -fno-stack-protector
 
+ifndef CONFIG_CFI_CLANG
 # Clang may incorrectly inline functions with stack protector enabled into
 # __restore_processor_state(): https://bugs.llvm.org/show_bug.cgi?id=47479
 CFLAGS_REMOVE_cpu.o := $(CC_FLAGS_LTO)
+endif
 
 obj-$(CONFIG_PM_SLEEP)		+= cpu.o
 obj-$(CONFIG_HIBERNATION)	+= hibernate_$(BITS).o hibernate_asm_$(BITS).o hibernate.o
-- 
2.33.0.800.g4c38ced690-goog