x86/asm: Error out if asm/jump_label.h is included inappropriately

Rather than potentially generating incorrect code on a
non-HAVE_JUMP_LABEL kernel if someone includes asm/jump_label.h,
error out.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/99407f0ac7fa3ab03a3d31ce076d47b5c2f44795.1447361906.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Andy Lutomirski 2015-11-12 12:59:02 -08:00 committed by Ingo Molnar
parent ed11a7f1b3
commit c28454332f

View File

@ -1,6 +1,19 @@
#ifndef _ASM_X86_JUMP_LABEL_H
#define _ASM_X86_JUMP_LABEL_H
#ifndef HAVE_JUMP_LABEL
/*
* For better or for worse, if jump labels (the gcc extension) are missing,
* then the entire static branch patching infrastructure is compiled out.
* If that happens, the code in here will malfunction. Raise a compiler
* error instead.
*
* In theory, jump labels and the static branch patching infrastructure
* could be decoupled to fix this.
*/
#error asm/jump_label.h included on a non-jump-label kernel
#endif
#ifndef __ASSEMBLY__
#include <linux/stringify.h>