mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-11-17 09:14:19 +08:00
bfe5d83419
There are several instances of per_cpu(foo, raw_smp_processor_id()), which is semantically equivalent to __get_cpu_var(foo) but without the warning that smp_processor_id() can give if CONFIG_DEBUG_PREEMPT is enabled. For those architectures with optimized per-cpu implementations, namely ia64, powerpc, s390, sparc64 and x86_64, per_cpu() turns into more and slower code than __get_cpu_var(), so it would be preferable to use __get_cpu_var on those platforms. This defines a __raw_get_cpu_var(x) macro which turns into per_cpu(x, raw_smp_processor_id()) on architectures that use the generic per-cpu implementation, and turns into __get_cpu_var(x) on the architectures that have an optimized per-cpu implementation. Signed-off-by: Paul Mackerras <paulus@samba.org> Acked-by: David S. Miller <davem@davemloft.net> Acked-by: Ingo Molnar <mingo@elte.hu> Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
54 lines
1.7 KiB
C
54 lines
1.7 KiB
C
#ifndef _ASM_X8664_PERCPU_H_
|
|
#define _ASM_X8664_PERCPU_H_
|
|
#include <linux/compiler.h>
|
|
|
|
/* Same as asm-generic/percpu.h, except that we store the per cpu offset
|
|
in the PDA. Longer term the PDA and every per cpu variable
|
|
should be just put into a single section and referenced directly
|
|
from %gs */
|
|
|
|
#ifdef CONFIG_SMP
|
|
|
|
#include <asm/pda.h>
|
|
|
|
#define __per_cpu_offset(cpu) (cpu_pda(cpu)->data_offset)
|
|
#define __my_cpu_offset() read_pda(data_offset)
|
|
|
|
/* Separate out the type, so (int[3], foo) works. */
|
|
#define DEFINE_PER_CPU(type, name) \
|
|
__attribute__((__section__(".data.percpu"))) __typeof__(type) per_cpu__##name
|
|
|
|
/* var is in discarded region: offset to particular copy we want */
|
|
#define per_cpu(var, cpu) (*RELOC_HIDE(&per_cpu__##var, __per_cpu_offset(cpu)))
|
|
#define __get_cpu_var(var) (*RELOC_HIDE(&per_cpu__##var, __my_cpu_offset()))
|
|
#define __raw_get_cpu_var(var) (*RELOC_HIDE(&per_cpu__##var, __my_cpu_offset()))
|
|
|
|
/* A macro to avoid #include hell... */
|
|
#define percpu_modcopy(pcpudst, src, size) \
|
|
do { \
|
|
unsigned int __i; \
|
|
for_each_possible_cpu(__i) \
|
|
memcpy((pcpudst)+__per_cpu_offset(__i), \
|
|
(src), (size)); \
|
|
} while (0)
|
|
|
|
extern void setup_per_cpu_areas(void);
|
|
|
|
#else /* ! SMP */
|
|
|
|
#define DEFINE_PER_CPU(type, name) \
|
|
__typeof__(type) per_cpu__##name
|
|
|
|
#define per_cpu(var, cpu) (*((void)(cpu), &per_cpu__##var))
|
|
#define __get_cpu_var(var) per_cpu__##var
|
|
#define __raw_get_cpu_var(var) per_cpu__##var
|
|
|
|
#endif /* SMP */
|
|
|
|
#define DECLARE_PER_CPU(type, name) extern __typeof__(type) per_cpu__##name
|
|
|
|
#define EXPORT_PER_CPU_SYMBOL(var) EXPORT_SYMBOL(per_cpu__##var)
|
|
#define EXPORT_PER_CPU_SYMBOL_GPL(var) EXPORT_SYMBOL_GPL(per_cpu__##var)
|
|
|
|
#endif /* _ASM_X8664_PERCPU_H_ */
|