arch/csky/include/asm/barrier.h

Source file repositories/reference/linux-study-clean/arch/csky/include/asm/barrier.h

File Facts

System
Linux kernel
Corpus path
arch/csky/include/asm/barrier.h
Extension
.h
Size
2597 bytes
Lines
89
Domain
Architecture Layer
Bucket
arch/csky
Inferred role
Architecture Layer: implementation source
Status
source implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

#ifndef __ASM_CSKY_BARRIER_H
#define __ASM_CSKY_BARRIER_H

#ifndef __ASSEMBLER__

#define nop()	asm volatile ("nop\n":::"memory")

#ifdef CONFIG_SMP

/*
 * bar.brwarws: ordering barrier for all load/store instructions
 *              before/after
 *
 * |31|30 26|25 21|20 16|15  10|9   5|4           0|
 *  1  10000 00000 00000 100001	00001 0 bw br aw ar
 *
 * b: before
 * a: after
 * r: read
 * w: write
 *
 * Here are all combinations:
 *
 * bar.brw
 * bar.br
 * bar.bw
 * bar.arw
 * bar.ar
 * bar.aw
 * bar.brwarw
 * bar.brarw
 * bar.bwarw
 * bar.brwar
 * bar.brwaw
 * bar.brar
 * bar.bwaw
 */
#define FULL_FENCE		".long 0x842fc000\n"
#define ACQUIRE_FENCE		".long 0x8427c000\n"
#define RELEASE_FENCE		".long 0x842ec000\n"

#define __bar_brw()	asm volatile (".long 0x842cc000\n":::"memory")
#define __bar_br()	asm volatile (".long 0x8424c000\n":::"memory")
#define __bar_bw()	asm volatile (".long 0x8428c000\n":::"memory")
#define __bar_arw()	asm volatile (".long 0x8423c000\n":::"memory")
#define __bar_ar()	asm volatile (".long 0x8421c000\n":::"memory")
#define __bar_aw()	asm volatile (".long 0x8422c000\n":::"memory")
#define __bar_brwarw()	asm volatile (FULL_FENCE:::"memory")
#define __bar_brarw()	asm volatile (ACQUIRE_FENCE:::"memory")
#define __bar_bwarw()	asm volatile (".long 0x842bc000\n":::"memory")
#define __bar_brwar()	asm volatile (".long 0x842dc000\n":::"memory")
#define __bar_brwaw()	asm volatile (RELEASE_FENCE:::"memory")
#define __bar_brar()	asm volatile (".long 0x8425c000\n":::"memory")
#define __bar_brar()	asm volatile (".long 0x8425c000\n":::"memory")
#define __bar_bwaw()	asm volatile (".long 0x842ac000\n":::"memory")

#define __smp_mb()	__bar_brwarw()
#define __smp_rmb()	__bar_brar()
#define __smp_wmb()	__bar_bwaw()

#define __smp_acquire_fence()	__bar_brarw()
#define __smp_release_fence()	__bar_brwaw()

#endif /* CONFIG_SMP */

/*
 * sync:        completion barrier, all sync.xx instructions
 *              guarantee the last response received by bus transaction
 *              made by ld/st instructions before sync.s
 * sync.s:      inherit from sync, but also shareable to other cores
 * sync.i:      inherit from sync, but also flush cpu pipeline
 * sync.is:     the same with sync.i + sync.s
 */
#define mb()		asm volatile ("sync\n":::"memory")

#ifdef CONFIG_CPU_HAS_CACHEV2
/*
 * Using three sync.is to prevent speculative PTW
 */
#define sync_is()	asm volatile ("sync.is\nsync.is\nsync.is\n":::"memory")
#endif

#include <asm-generic/barrier.h>

#endif /* __ASSEMBLER__ */
#endif /* __ASM_CSKY_BARRIER_H */

Annotation

Implementation Notes