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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, AC <achirvasub@gmail.com>,
        Borislav Petkov <bp@suse.de>,
        Josh Poimboeuf <jpoimboe@redhat.com>
Subject: [PATCH 4.9 35/49] x86/build: Disable CET instrumentation in the kernel for 32-bit too
Date:   Mon, 22 Feb 2021 13:36:33 +0100
Message-Id: <20210222121027.537898402@linuxfoundation.org>
In-Reply-To: <20210222121022.546148341@linuxfoundation.org>
References: <20210222121022.546148341@linuxfoundation.org>
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From: Borislav Petkov <bp@suse.de>

commit 256b92af784d5043eeb7d559b6d5963dcc2ecb10 upstream.

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@gmail.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Tested-by: AC <achirvasub@gmail.com>
Link: https://lkml.kernel.org/r/YCCIgMHkzh/xT4ex@arch-chirva.localdomain
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/x86/Makefile |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -61,6 +61,9 @@ endif
 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
@@ -137,9 +140,6 @@ 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)
-
         # -funit-at-a-time shrinks the kernel .text considerably
         # unfortunately it makes reading oopses harder.
         KBUILD_CFLAGS += $(call cc-option,-funit-at-a-time)