[linux-2.6-block.git] / arch / tile / include / asm / switch_to.h

/*
 * Copyright 2010 Tilera Corporation. All Rights Reserved.
 *
 *   This program is free software; you can redistribute it and/or
 *   modify it under the terms of the GNU General Public License
 *   as published by the Free Software Foundation, version 2.
 *
 *   This program is distributed in the hope that it will be useful, but
 *   WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
 *   NON INFRINGEMENT.  See the GNU General Public License for
 *   more details.
 */

#ifndef _ASM_TILE_SWITCH_TO_H
#define _ASM_TILE_SWITCH_TO_H

#include <arch/sim_def.h>

/*
 * switch_to(n) should switch tasks to task nr n, first
 * checking that n isn't the current task, in which case it does nothing.
 * The number of callee-saved registers saved on the kernel stack
 * is defined here for use in copy_thread() and must agree with __switch_to().
 */
#define CALLEE_SAVED_FIRST_REG 30
#define CALLEE_SAVED_REGS_COUNT 24   /* r30 to r52, plus an empty to align */

#ifndef __ASSEMBLY__

struct task_struct;

/*
 * Pause the DMA engine and static network before task switching.
 */
#define prepare_arch_switch(next) _prepare_arch_switch(next)
void _prepare_arch_switch(struct task_struct *next);

struct task_struct;
#define switch_to(prev, next, last) ((last) = _switch_to((prev), (next)))
extern struct task_struct *_switch_to(struct task_struct *prev,
				      struct task_struct *next);

/* Helper function for _switch_to(). */
extern struct task_struct *__switch_to(struct task_struct *prev,
				       struct task_struct *next,
				       unsigned long new_system_save_k_0);

/* Address that switched-away from tasks are at. */
extern unsigned long get_switch_to_pc(void);

/*
 * Kernel threads can check to see if they need to migrate their
 * stack whenever they return from a context switch; for user
 * threads, we defer until they are returning to user-space.
 * We defer homecache migration until the runqueue lock is released.
 */
#define finish_arch_post_lock_switch() do {                               \
	__insn_mtspr(SPR_SIM_CONTROL, SIM_CONTROL_OS_SWITCH |             \
		(current->pid << _SIM_CONTROL_OPERATOR_BITS));            \
	if (current->mm == NULL && !kstack_hash &&                        \
	    current_thread_info()->homecache_cpu != raw_smp_processor_id()) \
		homecache_migrate_kthread();                              \
} while (0)

/* Support function for forking a new task. */
void ret_from_fork(void);

/* Support function for forking a new kernel thread. */
void ret_from_kernel_thread(void *fn, void *arg);

/* Called from ret_from_xxx() when a new process starts up. */
struct task_struct *sim_notify_fork(struct task_struct *prev);

#endif /* !__ASSEMBLY__ */

#endif /* _ASM_TILE_SWITCH_TO_H */
Commit	Line	Data
bd119c69 DH	1	/*
	2	* Copyright 2010 Tilera Corporation. All Rights Reserved.
	3	*
	4	* This program is free software; you can redistribute it and/or
	5	* modify it under the terms of the GNU General Public License
	6	* as published by the Free Software Foundation, version 2.
	7	*
	8	* This program is distributed in the hope that it will be useful, but
	9	* WITHOUT ANY WARRANTY; without even the implied warranty of
	10	* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
	11	* NON INFRINGEMENT. See the GNU General Public License for
	12	* more details.
	13	*/
	14
	15	#ifndef _ASM_TILE_SWITCH_TO_H
	16	#define _ASM_TILE_SWITCH_TO_H
	17
	18	#include <arch/sim_def.h>
	19
	20	/*
	21	* switch_to(n) should switch tasks to task nr n, first
	22	* checking that n isn't the current task, in which case it does nothing.
	23	* The number of callee-saved registers saved on the kernel stack
	24	* is defined here for use in copy_thread() and must agree with __switch_to().
	25	*/
	26	#define CALLEE_SAVED_FIRST_REG 30
	27	#define CALLEE_SAVED_REGS_COUNT 24 /* r30 to r52, plus an empty to align */
	28
	29	#ifndef __ASSEMBLY__
	30
	31	struct task_struct;
	32
	33	/*
	34	* Pause the DMA engine and static network before task switching.
	35	*/
	36	#define prepare_arch_switch(next) _prepare_arch_switch(next)
	37	void _prepare_arch_switch(struct task_struct *next);
	38
	39	struct task_struct;
	40	#define switch_to(prev, next, last) ((last) = _switch_to((prev), (next)))
	41	extern struct task_struct _switch_to(struct task_struct prev,
	42	struct task_struct *next);
	43
	44	/* Helper function for _switch_to(). */
	45	extern struct task_struct __switch_to(struct task_struct prev,
	46	struct task_struct *next,
	47	unsigned long new_system_save_k_0);
	48
	49	/* Address that switched-away from tasks are at. */
	50	extern unsigned long get_switch_to_pc(void);
	51
	52	/*
	53	* Kernel threads can check to see if they need to migrate their
	54	* stack whenever they return from a context switch; for user
	55	* threads, we defer until they are returning to user-space.
fe363adb	56	* We defer homecache migration until the runqueue lock is released.
bd119c69	57	*/
fe363adb	58	#define finish_arch_post_lock_switch() do { \
1eaef888 CM	59	__insn_mtspr(SPR_SIM_CONTROL, SIM_CONTROL_OS_SWITCH \| \
1eaef888 CM	60	(current->pid << _SIM_CONTROL_OPERATOR_BITS)); \
bd119c69	61	if (current->mm == NULL && !kstack_hash && \
fe363adb	62	current_thread_info()->homecache_cpu != raw_smp_processor_id()) \
bd119c69 DH	63	homecache_migrate_kthread(); \
	64	} while (0)
	65
	66	/* Support function for forking a new task. */
	67	void ret_from_fork(void);
	68
0f8b9838 CM	69	/* Support function for forking a new kernel thread. */
	70	void ret_from_kernel_thread(void fn, void arg);
	71
	72	/* Called from ret_from_xxx() when a new process starts up. */
bd119c69 DH	73	struct task_struct sim_notify_fork(struct task_struct prev);
	74
	75	#endif /* !__ASSEMBLY__ */
	76
	77	#endif /* _ASM_TILE_SWITCH_TO_H */