x86: Allow generating user-space headers without a compiler

commit 829fe4aa9ac16417a904ad1de1307de906854bcf upstream.

When bootstrapping an architecture, it's usual to generate the kernel's
user-space headers (make headers_install) before building a compiler.  Move
the compiler check (for asm goto support) to the archprepare target so that
it is only done when building code for the target.

Fixes: e501ce957a78 ("x86: Force asm-goto")
Reported-by: Helmut Grohne <helmutg@debian.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20180829194317.GA4765@decadent.org.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index a08e82856563ddc34079e96b592e5c60edbc30aa..d944b52649a4b5424331405f2593edbd3bfd224a 100644 (file)
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -180,10 +180,6 @@ ifdef CONFIG_FUNCTION_GRAPH_TRACER
   endif
 endif
 
-ifndef CC_HAVE_ASM_GOTO
-  $(error Compiler lacks asm-goto support.)
-endif
-
 #
 # Jump labels need '-maccumulate-outgoing-args' for gcc < 4.5.2 to prevent a
 # GCC bug (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=46226).  There's no way
@@ -317,6 +313,13 @@ PHONY += vdso_install
 vdso_install:
        $(Q)$(MAKE) $(build)=arch/x86/entry/vdso $@
 
+archprepare: checkbin
+checkbin:
+ifndef CC_HAVE_ASM_GOTO
+       @echo Compiler lacks asm-goto support.
+       @exit 1
+endif
+
 archclean:
        $(Q)rm -rf $(objtree)/arch/i386
        $(Q)rm -rf $(objtree)/arch/x86_64