linux_kernel/arch/s390/include/asm/switch_to.h

/*
 * Copyright IBM Corp. 1999, 2009
 *
 * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
 */

#ifndef __ASM_SWITCH_TO_H
#define __ASM_SWITCH_TO_H

#include <linux/thread_info.h>
#include <asm/fpu/api.h>
#include <asm/ptrace.h>
#include <asm/guarded_storage.h>

extern struct task_struct *__switch_to(void *, void *);
extern void update_cr_regs(struct task_struct *task);

static inline void save_access_regs(unsigned int *acrs)
{
	typedef struct { int _[NUM_ACRS]; } acrstype;

	asm volatile("stam 0,15,%0" : "=Q" (*(acrstype *)acrs));
}

static inline void restore_access_regs(unsigned int *acrs)
{
	typedef struct { int _[NUM_ACRS]; } acrstype;

	asm volatile("lam 0,15,%0" : : "Q" (*(acrstype *)acrs));
}

#define switch_to(prev,next,last) do {					\
	if (prev->mm) {							\
		save_fpu_regs();					\
		save_access_regs(&prev->thread.acrs[0]);		\
		save_ri_cb(prev->thread.ri_cb);				\
		save_gs_cb(prev->thread.gs_cb);				\
	}								\
	if (next->mm) {							\
		update_cr_regs(next);					\
		set_cpu_flag(CIF_FPU);					\
		restore_access_regs(&next->thread.acrs[0]);		\
		restore_ri_cb(next->thread.ri_cb, prev->thread.ri_cb);	\
		restore_gs_cb(next->thread.gs_cb);			\
	}								\
	prev = __switch_to(prev,next);					\
} while (0)

#endif /* __ASM_SWITCH_TO_H */