Commit ac91b8b8 authored Feb 08, 2021 by Borislav Petkov Committed by Greg Kroah-Hartman Feb 23, 2021

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



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>

parent 1d775f15

arch/x86/Makefile

+3 −3

Original line number	Diff line number	Diff line
		@@ -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
		@@ -132,9 +135,6 @@ 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)