diff options
| -rw-r--r-- | include/linux/compiler-gcc4.h | 14 | ||||
| -rw-r--r-- | include/linux/compiler.h | 5 |
2 files changed, 19 insertions, 0 deletions
diff --git a/include/linux/compiler-gcc4.h b/include/linux/compiler-gcc4.h index 450fa597c94d..ab3af40a53c6 100644 --- a/include/linux/compiler-gcc4.h +++ b/include/linux/compiler-gcc4.h @@ -36,4 +36,18 @@ the kernel context */ #define __cold __attribute__((__cold__)) + +#if __GNUC_MINOR__ >= 5 +/* + * Mark a position in code as unreachable. This can be used to + * suppress control flow warnings after asm blocks that transfer + * control elsewhere. + * + * Early snapshots of gcc 4.5 don't support this and we can't detect + * this in the preprocessor, but we can live with this because they're + * unreleased. Really, we need to have autoconf for the kernel. + */ +#define unreachable() __builtin_unreachable() +#endif + #endif diff --git a/include/linux/compiler.h b/include/linux/compiler.h index 04fb5135b4e1..59f208926d13 100644 --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -144,6 +144,11 @@ void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect); # define barrier() __memory_barrier() #endif +/* Unreachable code */ +#ifndef unreachable +# define unreachable() do { } while (1) +#endif + #ifndef RELOC_HIDE # define RELOC_HIDE(ptr, off) \ ({ unsigned long __ptr; \ |