[tip: x86/urgent] x86/build: Turn off -fcf-protection for realmode targets

[tip-bot2 for Arnd Bergmann]

The following commit has been merged into the x86/urgent branch of tip:

Commit-ID:     9fcb51c14da2953de585c5c6e50697b8a6e91a7b
Gitweb:        https://git.kernel.org/tip/9fcb51c14da2953de585c5c6e50697b8a6e91a7b
Author:        Arnd Bergmann <arnd@xxxxxxxx>
AuthorDate:    Tue, 23 Mar 2021 13:48:36 +01:00
Committer:     Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Tue, 23 Mar 2021 16:36:01 +01:00

x86/build: Turn off -fcf-protection for realmode targets

The new Ubuntu GCC packages turn on -fcf-protection globally,
which causes a build failure in the x86 realmode code:

  cc1: error: ‘-fcf-protection’ is not compatible with this target

Turn it off explicitly on compilers that understand this option.

Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20210323124846.1584944-1-arnd@xxxxxxxxxx
---
 arch/x86/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index 2d6d5a2..9a85eae 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -27,7 +27,7 @@ endif
 REALMODE_CFLAGS	:= -m16 -g -Os -DDISABLE_BRANCH_PROFILING \
 		   -Wall -Wstrict-prototypes -march=i386 -mregparm=3 \
 		   -fno-strict-aliasing -fomit-frame-pointer -fno-pic \
-		   -mno-mmx -mno-sse
+		   -mno-mmx -mno-sse $(call cc-option,-fcf-protection=none)
 
 REALMODE_CFLAGS += -ffreestanding
 REALMODE_CFLAGS += -fno-stack-protector