mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson
synced 2025-10-31 12:39:23 +00:00
f9d1425007
These compiler versions are known to miscompile __weak functions and
thus generate kernels that don't necessarily work correctly. If a weak
function is int he same compilation unit as a caller, gcc may end up
inlining it, and thus binding the weak function too early.
See
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27781
for details.
Cc: Adrian Bunk <bunk@kernel.org>
Cc: Helge Deller <deller@gmx.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
38 lines
1.3 KiB
C
38 lines
1.3 KiB
C
#ifndef __LINUX_COMPILER_H
|
|
#error "Please don't include <linux/compiler-gcc4.h> directly, include <linux/compiler.h> instead."
|
|
#endif
|
|
|
|
/* GCC 4.1.[01] miscompiles __weak */
|
|
#if __GNUC_MINOR__ == 1 && __GNUC_PATCHLEVEL__ <= 1
|
|
# error Your version of gcc miscompiles the __weak directive
|
|
#endif
|
|
|
|
#define __used __attribute__((__used__))
|
|
#define __must_check __attribute__((warn_unused_result))
|
|
#define __compiler_offsetof(a,b) __builtin_offsetof(a,b)
|
|
#define __always_inline inline __attribute__((always_inline))
|
|
|
|
/*
|
|
* A trick to suppress uninitialized variable warning without generating any
|
|
* code
|
|
*/
|
|
#define uninitialized_var(x) x = x
|
|
|
|
#if __GNUC_MINOR__ >= 3
|
|
/* Mark functions as cold. gcc will assume any path leading to a call
|
|
to them will be unlikely. This means a lot of manual unlikely()s
|
|
are unnecessary now for any paths leading to the usual suspects
|
|
like BUG(), printk(), panic() etc. [but let's keep them for now for
|
|
older compilers]
|
|
|
|
Early snapshots of gcc 4.3 don't support this and we can't detect this
|
|
in the preprocessor, but we can live with this because they're unreleased.
|
|
Maketime probing would be overkill here.
|
|
|
|
gcc also has a __attribute__((__hot__)) to move hot functions into
|
|
a special section, but I don't see any sense in this right now in
|
|
the kernel context */
|
|
#define __cold __attribute__((__cold__))
|
|
|
|
#endif
|