Re: PROBLEM: 5.11.0-rc7 fails to compile with error: ‘-mindirect-branch’ and ‘-fcf-protection’ are not compatible

[Borislav Petkov]

On Sun, Feb 07, 2021 at 07:40:32PM -0500, Stuart Little wrote:
> > On Sun, Feb 07, 2021 at 06:31:22PM -0500, Stuart Little wrote:
> > > I am trying to compile on an x86_64 host for a 32-bit system; my config is at
> > > 
> > > https://termbin.com/v8jl
> > > 
> > > I am getting numerous errors of the form
> > > 
> > > ./include/linux/kasan-checks.h:17:1: error: ‘-mindirect-branch’ and ‘-fcf-protection’ are not compatible

Does this fix it?

---

diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index 5857917f83ee..30920d70b48b 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


-- 
Regards/Gruss,
    Boris.

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