mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-15 03:46:47 +07:00
cf66bb93e0
Since GCC 4.4, there have been __builtin_bswap32() and __builtin_bswap16() intrinsics. A __builtin_bswap16() came a little later (4.6 for PowerPC, 48 for other platforms). By using these instead of the inline assembler that most architectures have in their __arch_swabXX() macros, we let the compiler see what's actually happening. The resulting code should be at least as good, and much *better* in the cases where it can be combined with a nearby load or store, using a load-and-byteswap or store-and-byteswap instruction (e.g. lwbrx/stwbrx on PowerPC, movbe on Atom). When GCC is sufficiently recent *and* the architecture opts in to using the intrinsics by setting CONFIG_ARCH_USE_BUILTIN_BSWAP, they will be used in preference to the __arch_swabXX() macros. An architecture which does not set ARCH_USE_BUILTIN_BSWAP will continue to use its own hand-crafted macros. Signed-off-by: David Woodhouse <David.Woodhouse@intel.com> Acked-by: H. Peter Anvin <hpa@linux.intel.com>
76 lines
2.5 KiB
C
76 lines
2.5 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 */
|
|
#ifdef __KERNEL__
|
|
# if __GNUC_MINOR__ == 1 && __GNUC_PATCHLEVEL__ <= 1
|
|
# error Your version of gcc miscompiles the __weak directive
|
|
# endif
|
|
#endif
|
|
|
|
#define __used __attribute__((__used__))
|
|
#define __must_check __attribute__((warn_unused_result))
|
|
#define __compiler_offsetof(a,b) __builtin_offsetof(a,b)
|
|
|
|
#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__))
|
|
|
|
#define __linktime_error(message) __attribute__((__error__(message)))
|
|
|
|
#if __GNUC_MINOR__ >= 5
|
|
/*
|
|
* Mark a position in code as unreachable. This can be used to
|
|
* suppress control flow warnings after asm blocks that transfer
|
|
* control elsewhere.
|
|
*
|
|
* Early snapshots of gcc 4.5 don't support this and we can't detect
|
|
* this in the preprocessor, but we can live with this because they're
|
|
* unreleased. Really, we need to have autoconf for the kernel.
|
|
*/
|
|
#define unreachable() __builtin_unreachable()
|
|
|
|
/* Mark a function definition as prohibited from being cloned. */
|
|
#define __noclone __attribute__((__noclone__))
|
|
|
|
#endif
|
|
#endif
|
|
|
|
#if __GNUC_MINOR__ >= 6
|
|
/*
|
|
* Tell the optimizer that something else uses this function or variable.
|
|
*/
|
|
#define __visible __attribute__((externally_visible))
|
|
#endif
|
|
|
|
#if __GNUC_MINOR__ > 0
|
|
#define __compiletime_object_size(obj) __builtin_object_size(obj, 0)
|
|
#endif
|
|
#if __GNUC_MINOR__ >= 3 && !defined(__CHECKER__)
|
|
#define __compiletime_warning(message) __attribute__((warning(message)))
|
|
#define __compiletime_error(message) __attribute__((error(message)))
|
|
#endif
|
|
|
|
#ifdef CONFIG_ARCH_USE_BUILTIN_BSWAP
|
|
#if __GNUC_MINOR__ >= 4
|
|
#define __HAVE_BUILTIN_BSWAP32__
|
|
#define __HAVE_BUILTIN_BSWAP64__
|
|
#endif
|
|
#if __GNUC_MINOR__ >= 8 || (defined(__powerpc__) && __GNUC_MINOR__ >= 6)
|
|
#define __HAVE_BUILTIN_BSWAP16__
|
|
#endif
|
|
#endif
|