[tip: x86/urgent] x86/build: Disable CET instrumentation in the kernel for 32-bit too

From: tip-bot2 for Borislav Petkov
Date: Tue Feb 09 2021 - 05:55:02 EST


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

Commit-ID: 256b92af784d5043eeb7d559b6d5963dcc2ecb10
Gitweb: https://git.kernel.org/tip/256b92af784d5043eeb7d559b6d5963dcc2ecb10
Author: Borislav Petkov <bp@xxxxxxx>
AuthorDate: Mon, 08 Feb 2021 16:43:30 +01:00
Committer: Borislav Petkov <bp@xxxxxxx>
CommitterDate: Tue, 09 Feb 2021 11:23:47 +01:00

x86/build: Disable CET instrumentation in the kernel for 32-bit too

Commit

20bf2b378729 ("x86/build: Disable CET instrumentation in the kernel")

disabled CET instrumentation which gets added by default by the Ubuntu
gcc9 and 10 by default, but did that only for 64-bit builds. It would
still fail when building a 32-bit target. So disable CET for all x86
builds.

Fixes: 20bf2b378729 ("x86/build: Disable CET instrumentation in the kernel")
Reported-by: AC <achirvasub@xxxxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Acked-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Tested-by: AC <achirvasub@xxxxxxxxx>
Link: https://lkml.kernel.org/r/YCCIgMHkzh/xT4ex@arch-chirva.localdomain
---
arch/x86/Makefile | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index 5857917..30920d7 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -50,6 +50,9 @@ export BITS
KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow
KBUILD_CFLAGS += $(call cc-option,-mno-avx,)

+# Intel CET isn't enabled in the kernel
+KBUILD_CFLAGS += $(call cc-option,-fcf-protection=none)
+
ifeq ($(CONFIG_X86_32),y)
BITS := 32
UTS_MACHINE := i386
@@ -120,9 +123,6 @@ else

KBUILD_CFLAGS += -mno-red-zone
KBUILD_CFLAGS += -mcmodel=kernel
-
- # Intel CET isn't enabled in the kernel
- KBUILD_CFLAGS += $(call cc-option,-fcf-protection=none)
endif

ifdef CONFIG_X86_X32