[PATCH AUTOSEL for 4.9 009/281] x86/boot: Declare error() as noreturn

[Sasha Levin]

From: Kees Cook <keescook@xxxxxxxxxxxx>

[ Upstream commit 60854a12d281e2fa25662fa32ac8022bbff17432 ]

The compressed boot function error() is used to halt execution, but it
wasn't marked with "noreturn". This fixes that in preparation for
supporting kernel FORTIFY_SOURCE, which uses the noreturn annotation
on panic, and calls error(). GCC would warn about a noreturn function
calling a non-noreturn function:

  arch/x86/boot/compressed/misc.c: In function âfortify_panicâ:
  arch/x86/boot/compressed/misc.c:416:1: warning: ânoreturnâ function does return
   }
 ^

Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Daniel Micay <danielmicay@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Link: http://lkml.kernel.org/r/20170506045116.GA2879@beast
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
---
 arch/x86/boot/compressed/error.h | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/x86/boot/compressed/error.h b/arch/x86/boot/compressed/error.h
index 2e59dac07f9e..d732e608e3af 100644
--- a/arch/x86/boot/compressed/error.h
+++ b/arch/x86/boot/compressed/error.h
@@ -1,7 +1,9 @@
 #ifndef BOOT_COMPRESSED_ERROR_H
 #define BOOT_COMPRESSED_ERROR_H
 
+#include <linux/compiler.h>
+
 void warn(char *m);
-void error(char *m);
+void error(char *m) __noreturn;
 
 #endif /* BOOT_COMPRESSED_ERROR_H */
-- 
2.14.1