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

stable inclusion
from stable-5.10.17
commit 03bf0f163df2b777c73739f15d723c90b76df5e8
bugzilla: 48169

--------------------------------

[ Upstream commit 256b92af ]

Commit

  20bf2b37 ("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: 20bf2b37 ("x86/build: Disable CET instrumentation in the kernel")
Reported-by: NAC <achirvasub@gmail.com>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Acked-by: NJosh Poimboeuf <jpoimboe@redhat.com>
Tested-by: NAC <achirvasub@gmail.com>
Link: https://lkml.kernel.org/r/YCCIgMHkzh/xT4ex@arch-chirva.localdomainSigned-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>
Acked-by: NXie XiuQi <xiexiuqi@huawei.com>

arch/x86/Makefile

@@ -57,6 +57,9 @@ 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
@@ -127,9 +130,6 @@ 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