diff options
author | Dave Airlie <airlied@gmail.com> | 2011-01-25 08:41:58 +1000 |
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committer | Dave Airlie <airlied@gmail.com> | 2011-01-25 08:41:58 +1000 |
commit | abb72c828878a2c69b2cfb33ac30007c8ecd735e (patch) | |
tree | a95ace4f34d86d55b3307bd53354d335e9f23563 /include/linux/kernel.h | |
parent | 58bbf018a70c562437eeae121a5d021ba7fe56a5 (diff) | |
parent | 8e934dbf264418afe4d1dff34ce074ecc14280db (diff) |
Merge branch 'drm-intel-fixes-2' of ssh://master.kernel.org/pub/scm/linux/kernel/git/ickle/drm-intel into drm-fixes
* 'drm-intel-fixes-2' of ssh://master.kernel.org/pub/scm/linux/kernel/git/ickle/drm-intel: (30 commits)
drm/i915: Prevent uninitialised reads during error state capture
drm/i915: Use consistent mappings for OpRegion between ACPI and i915
drm/i915: Handle the no-interrupts case for UMS by polling
drm/i915: Disable high-precision vblank timestamping for UMS
drm/i915: Increase the amount of defense before computing vblank timestamps
drm/i915,agp/intel: Do not clear stolen entries
Remove MAYBE_BUILD_BUG_ON
BUILD_BUG_ON: make it handle more cases
module: fix missing semicolons in MODULE macro usage
param: add null statement to compiled-in module params
module: fix linker error for MODULE_VERSION when !MODULE and CONFIG_SYSFS=n
module: show version information for built-in modules in sysfs
selinux: return -ENOMEM when memory allocation fails
tpm: fix panic caused by "tpm: Autodetect itpm devices"
TPM: Long default timeout fix
trusted keys: Fix a memory leak in trusted_update().
keys: add trusted and encrypted maintainers
encrypted-keys: rename encrypted_defined files to encrypted
trusted-keys: rename trusted_defined files to trusted
drm/i915: Recognise non-VGA display devices
...
Diffstat (limited to 'include/linux/kernel.h')
-rw-r--r-- | include/linux/kernel.h | 32 |
1 files changed, 26 insertions, 6 deletions
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__) |