x86/asm: Make objtool unreachable macros independent from GCC version

jpoimboe · Ingo Molnar · commit 1ee6f00d1164 · 2017-07-25T16:54:07.000+02:00
The ASM_UNREACHABLE macro isn't GCC version-specific, so move it outside the GCC 4.5+ check. Otherwise the 0-day robot will report objtool warnings for uses of ASM_UNREACHABLE with GCC 4.4. Also move the annotate_unreachable() macro so the related macros can stay together. Reported-by: kbuild test robot <fengguang.wu@intel.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes: aa5d1b8 ("x86/asm: Add ASM_UNREACHABLE") Link: http://lkml.kernel.org/r/fb18337dbf230fd36450d9faf19a2b2533dbcba1.1500993873.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
@@ -128,6 +128,22 @@
 #define __always_unused		__attribute__((unused))
 #define __mode(x)               __attribute__((mode(x)))
 
+#ifdef CONFIG_STACK_VALIDATION
+#define annotate_unreachable() ({					\
+	asm("%c0:\n\t"							\
+	    ".pushsection .discard.unreachable\n\t"			\
+	    ".long %c0b - .\n\t"					\
+	    ".popsection\n\t" : : "i" (__LINE__));			\
+})
+#define ASM_UNREACHABLE							\
+	"999:\n\t"							\
+	".pushsection .discard.unreachable\n\t"				\
+	".long 999b - .\n\t"						\
+	".popsection\n\t"
+#else
+#define annotate_unreachable()
+#endif
+
 /* gcc version specific checks */
 
 #if GCC_VERSION < 30200
@@ -201,22 +217,6 @@
 #endif
 #endif
 
-#ifdef CONFIG_STACK_VALIDATION
-#define annotate_unreachable() ({					\
-	asm("%c0:\n\t"							\
-	    ".pushsection .discard.unreachable\n\t"			\
-	    ".long %c0b - .\n\t"					\
-	    ".popsection\n\t" : : "i" (__LINE__));			\
-})
-#define ASM_UNREACHABLE							\
-	"999:\n\t"							\
-	".pushsection .discard.unreachable\n\t"				\
-	".long 999b - .\n\t"						\
-	".popsection\n\t"
-#else
-#define annotate_unreachable()
-#endif
-
 /*
  * Mark a position in code as unreachable.  This can be used to
  * suppress control flow warnings after asm blocks that transfer
