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[v5,28/29] x86, cpu: disable LTO for cpu.c

Message ID 20201009161338.657380-29-samitolvanen@google.com
State New
Headers show
Series Add support for Clang LTO | expand

Commit Message

Sami Tolvanen Oct. 9, 2020, 4:13 p.m. UTC
Clang incorrectly inlines functions with differing stack protector
attributes, which breaks __restore_processor_state() that relies on
stack protector being disabled. This change disables LTO for cpu.c
to work aroung the bug.

Link: https://bugs.llvm.org/show_bug.cgi?id=47479
Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
 arch/x86/power/Makefile | 4 ++++
 1 file changed, 4 insertions(+)
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diff --git a/arch/x86/power/Makefile b/arch/x86/power/Makefile
index 6907b523e856..5f711a441623 100644
--- a/arch/x86/power/Makefile
+++ b/arch/x86/power/Makefile
@@ -5,5 +5,9 @@  OBJECT_FILES_NON_STANDARD_hibernate_asm_$(BITS).o := y
 # itself be stack-protected
 CFLAGS_cpu.o	:= -fno-stack-protector
+# Clang may incorrectly inline functions with stack protector enabled into
+# __restore_processor_state(): https://bugs.llvm.org/show_bug.cgi?id=47479
 obj-$(CONFIG_PM_SLEEP)		+= cpu.o
 obj-$(CONFIG_HIBERNATION)	+= hibernate_$(BITS).o hibernate_asm_$(BITS).o hibernate.o