diff options
| -rw-r--r-- | include/linux/gfp.h | 2 | ||||
| -rw-r--r-- | include/linux/kernel.h | 32 | ||||
| -rw-r--r-- | include/linux/kmemcheck.h | 2 | ||||
| -rw-r--r-- | include/linux/virtio_config.h | 5 |
4 files changed, 32 insertions, 9 deletions
diff --git a/include/linux/gfp.h b/include/linux/gfp.h index a3b148a91874..0b84c61607e8 100644 --- a/include/linux/gfp.h +++ b/include/linux/gfp.h @@ -249,7 +249,7 @@ static inline enum zone_type gfp_zone(gfp_t flags) ((1 << ZONES_SHIFT) - 1); if (__builtin_constant_p(bit)) - MAYBE_BUILD_BUG_ON((GFP_ZONE_BAD >> bit) & 1); + BUILD_BUG_ON((GFP_ZONE_BAD >> bit) & 1); else { #ifdef CONFIG_DEBUG_VM BUG_ON((GFP_ZONE_BAD >> bit) & 1); diff --git a/include/linux/kernel.h b/include/linux/kernel.h index d07d8057e440..e2f4d6af2125 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -575,12 +575,6 @@ struct sysinfo { char _f[20-2*sizeof(long)-sizeof(int)]; /* Padding: libc5 uses this.. */ }; -/* Force a compilation error if condition is true */ -#define BUILD_BUG_ON(condition) ((void)BUILD_BUG_ON_ZERO(condition)) - -/* Force a compilation error if condition is constant and true */ -#define MAYBE_BUILD_BUG_ON(cond) ((void)sizeof(char[1 - 2 * !!(cond)])) - /* Force a compilation error if a constant expression is not a power of 2 */ #define BUILD_BUG_ON_NOT_POWER_OF_2(n) \ BUILD_BUG_ON((n) == 0 || (((n) & ((n) - 1)) != 0)) @@ -592,6 +586,32 @@ struct sysinfo { #define BUILD_BUG_ON_ZERO(e) (sizeof(struct { int:-!!(e); })) #define BUILD_BUG_ON_NULL(e) ((void *)sizeof(struct { int:-!!(e); })) +/** + * BUILD_BUG_ON - break compile if a condition is true. + * @cond: the condition which the compiler should know is false. + * + * If you have some code which relies on certain constants being equal, or + * other compile-time-evaluated condition, you should use BUILD_BUG_ON to + * detect if someone changes it. + * + * The implementation uses gcc's reluctance to create a negative array, but + * gcc (as of 4.4) only emits that error for obvious cases (eg. not arguments + * to inline functions). So as a fallback we use the optimizer; if it can't + * prove the condition is false, it will cause a link error on the undefined + * "__build_bug_on_failed". This error message can be harder to track down + * though, hence the two different methods. + */ +#ifndef __OPTIMIZE__ +#define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)])) +#else +extern int __build_bug_on_failed; +#define BUILD_BUG_ON(condition) \ + do { \ + ((void)sizeof(char[1 - 2*!!(condition)])); \ + if (condition) __build_bug_on_failed = 1; \ + } while(0) +#endif + /* Trap pasters of __FUNCTION__ at compile-time */ #define __FUNCTION__ (__func__) diff --git a/include/linux/kmemcheck.h b/include/linux/kmemcheck.h index 08d7dc4ddf40..39f8453239f7 100644 --- a/include/linux/kmemcheck.h +++ b/include/linux/kmemcheck.h @@ -76,7 +76,7 @@ bool kmemcheck_is_obj_initialized(unsigned long addr, size_t size); \ _n = (long) &((ptr)->name##_end) \ - (long) &((ptr)->name##_begin); \ - MAYBE_BUILD_BUG_ON(_n < 0); \ + BUILD_BUG_ON(_n < 0); \ \ kmemcheck_mark_initialized(&((ptr)->name##_begin), _n); \ } while (0) diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h index 0093dd7c1d6f..800617b4ddd5 100644 --- a/include/linux/virtio_config.h +++ b/include/linux/virtio_config.h @@ -109,7 +109,10 @@ static inline bool virtio_has_feature(const struct virtio_device *vdev, unsigned int fbit) { /* Did you forget to fix assumptions on max features? */ - MAYBE_BUILD_BUG_ON(fbit >= 32); + if (__builtin_constant_p(fbit)) + BUILD_BUG_ON(fbit >= 32); + else + BUG_ON(fbit >= 32); if (fbit < VIRTIO_TRANSPORT_F_START) virtio_check_driver_offered_feature(vdev, fbit); |