arch/arm/include/asm/switch_to.h

Source file repositories/reference/linux-study-clean/arch/arm/include/asm/switch_to.h

File Facts

System
Linux kernel
Corpus path
arch/arm/include/asm/switch_to.h
Extension
.h
Size
1195 bytes
Lines
36
Domain
Architecture Layer
Bucket
arch/arm
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_ARM_SWITCH_TO_H
#define __ASM_ARM_SWITCH_TO_H

#include <linux/thread_info.h>
#include <asm/smp_plat.h>

/*
 * For v7 SMP cores running a preemptible kernel we may be pre-empted
 * during a TLB maintenance operation, so execute an inner-shareable dsb
 * to ensure that the maintenance completes in case we migrate to another
 * CPU.
 */
#if defined(CONFIG_PREEMPTION) && defined(CONFIG_SMP) && defined(CONFIG_CPU_V7)
#define __complete_pending_tlbi()	dsb(ish)
#else
#define __complete_pending_tlbi()
#endif

/*
 * switch_to(prev, next) should switch from task `prev' to `next'
 * `prev' will never be the same as `next'.  schedule() itself
 * contains the memory barrier to tell GCC not to cache `current'.
 */
extern struct task_struct *__switch_to(struct task_struct *, struct thread_info *, struct thread_info *);

#define switch_to(prev,next,last)					\
do {									\
	__complete_pending_tlbi();					\
	if (IS_ENABLED(CONFIG_CURRENT_POINTER_IN_TPIDRURO) || is_smp())	\
		__this_cpu_write(__entry_task, next);			\
	last = __switch_to(prev,task_thread_info(prev), task_thread_info(next));	\
} while (0)

#endif /* __ASM_ARM_SWITCH_TO_H */

Annotation

Implementation Notes