bianbu-repo-mirror/bianbu-linux-6.6
1
0
Fork 0
mirror of https://gitee.com/bianbu-linux/linux-6.6 synced 2025-07-01 23:53:16 -04:00
Code Issues Projects Releases Packages Wiki Activity Actions

Add support for GCC-4.5's __builtin_unreachable() to compiler.h (v2)

Browse source 
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>
This commit is contained in:
David Daney 2009-12-04 17:44:50 -08:00 • committed by Linus Torvalds
parent 22763c5cf3
commit 38938c879e
2 changed files with 19 additions and 0 deletions
Download patch file Download diff file Expand all files Collapse all files

5
include/linux/compiler.h
View file

@ -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; \