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| author | David Daney <ddaney@caviumnetworks.com> | 2009-12-04 17:44:50 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-12-05 09:10:12 -0800 |
| commit | 38938c879eb0c39edf85d5164aa0cffe2874304c (patch) | |
| tree | fdcc22972a02219dcb385dae868f6e708523dfe7 /include/linux/compiler.h | |
| parent | 22763c5cf3690a681551162c15d34d935308c8d7 (diff) | |
| download | op-kernel-dev-38938c879eb0c39edf85d5164aa0cffe2874304c.zip op-kernel-dev-38938c879eb0c39edf85d5164aa0cffe2874304c.tar.gz | |
Add support for GCC-4.5's __builtin_unreachable() to compiler.h (v2)
Starting with version 4.5, GCC has a new built-in function
__builtin_unreachable() that can be used in places like the kernel's
BUG() where inline assembly is used to transfer control flow. This
eliminated the need for an endless loop in these places.
The patch adds a new macro 'unreachable()' that will expand to either
__builtin_unreachable() or an endless loop depending on the compiler
version.
Change from v1: Simplify unreachable() for non-GCC 4.5 case.
Signed-off-by: David Daney <ddaney@caviumnetworks.com>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/compiler.h')
| -rw-r--r-- | include/linux/compiler.h | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/include/linux/compiler.h b/include/linux/compiler.h index 04fb513..59f2089 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; \ |
