[deliverable/linux.git] / arch / mips / include / asm / switch_to.h

/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) 1994, 95, 96, 97, 98, 99, 2003, 06 by Ralf Baechle
 * Copyright (C) 1996 by Paul M. Antoine
 * Copyright (C) 1999 Silicon Graphics
 * Kevin D. Kissell, kevink@mips.org and Carsten Langgaard, carstenl@mips.com
 * Copyright (C) 2000 MIPS Technologies, Inc.
 */
#ifndef _ASM_SWITCH_TO_H
#define _ASM_SWITCH_TO_H

#include <asm/cpu-features.h>
#include <asm/watch.h>
#include <asm/dsp.h>
#include <asm/cop2.h>
#include <asm/msa.h>

struct task_struct;

enum {
	FP_SAVE_NONE	= 0,
	FP_SAVE_VECTOR	= -1,
	FP_SAVE_SCALAR	= 1,
};

/**
 * resume - resume execution of a task
 * @prev:	The task previously executed.
 * @next:	The task to begin executing.
 * @next_ti:	task_thread_info(next).
 * @fp_save:	Which, if any, FP context to save for prev.
 *
 * This function is used whilst scheduling to save the context of prev & load
 * the context of next. Returns prev.
 */
extern asmlinkage struct task_struct *resume(struct task_struct *prev,
		struct task_struct *next, struct thread_info *next_ti,
		s32 fp_save);

extern unsigned int ll_bit;
extern struct task_struct *ll_task;

#ifdef CONFIG_MIPS_MT_FPAFF

/*
 * Handle the scheduler resume end of FPU affinity management.	We do this
 * inline to try to keep the overhead down. If we have been forced to run on
 * a "CPU" with an FPU because of a previous high level of FP computation,
 * but did not actually use the FPU during the most recent time-slice (CU1
 * isn't set), we undo the restriction on cpus_allowed.
 *
 * We're not calling set_cpus_allowed() here, because we have no need to
 * force prompt migration - we're already switching the current CPU to a
 * different thread.
 */

#define __mips_mt_fpaff_switch_to(prev)					\
do {									\
	struct thread_info *__prev_ti = task_thread_info(prev);		\
									\
	if (cpu_has_fpu &&						\
	    test_ti_thread_flag(__prev_ti, TIF_FPUBOUND) &&		\
	    (!(KSTK_STATUS(prev) & ST0_CU1))) {				\
		clear_ti_thread_flag(__prev_ti, TIF_FPUBOUND);		\
		prev->cpus_allowed = prev->thread.user_cpus_allowed;	\
	}								\
	next->thread.emulated_fp = 0;					\
} while(0)

#else
#define __mips_mt_fpaff_switch_to(prev) do { (void) (prev); } while (0)
#endif

#define __clear_software_ll_bit()					\
do {									\
	if (!__builtin_constant_p(cpu_has_llsc) || !cpu_has_llsc)	\
		ll_bit = 0;						\
} while (0)

#define switch_to(prev, next, last)					\
do {									\
	u32 __c0_stat;							\
	s32 __fpsave = FP_SAVE_NONE;					\
	__mips_mt_fpaff_switch_to(prev);				\
	if (cpu_has_dsp)						\
		__save_dsp(prev);					\
	if (cop2_present && (KSTK_STATUS(prev) & ST0_CU2)) {		\
		if (cop2_lazy_restore)					\
			KSTK_STATUS(prev) &= ~ST0_CU2;			\
		__c0_stat = read_c0_status();				\
		write_c0_status(__c0_stat | ST0_CU2);			\
		cop2_save(prev);					\
		write_c0_status(__c0_stat & ~ST0_CU2);			\
	}								\
	__clear_software_ll_bit();					\
	if (test_and_clear_tsk_thread_flag(prev, TIF_USEDFPU))		\
		__fpsave = FP_SAVE_SCALAR;				\
	if (test_and_clear_tsk_thread_flag(prev, TIF_USEDMSA))		\
		__fpsave = FP_SAVE_VECTOR;				\
	(last) = resume(prev, next, task_thread_info(next), __fpsave);	\
	disable_msa();							\
} while (0)

#define finish_arch_switch(prev)					\
do {									\
	u32 __c0_stat;							\
	if (cop2_present && !cop2_lazy_restore &&			\
			(KSTK_STATUS(current) & ST0_CU2)) {		\
		__c0_stat = read_c0_status();				\
		write_c0_status(__c0_stat | ST0_CU2);			\
		cop2_restore(current);					\
		write_c0_status(__c0_stat & ~ST0_CU2);			\
	}								\
	if (cpu_has_dsp)						\
		__restore_dsp(current);					\
	if (cpu_has_userlocal)						\
		write_c0_userlocal(current_thread_info()->tp_value);	\
	__restore_watch();						\
} while (0)

#endif /* _ASM_SWITCH_TO_H */
Commit	Line	Data
b81947c6 DH	1	/*
	2	* This file is subject to the terms and conditions of the GNU General Public
	3	* License. See the file "COPYING" in the main directory of this archive
	4	* for more details.
	5	*
	6	* Copyright (C) 1994, 95, 96, 97, 98, 99, 2003, 06 by Ralf Baechle
	7	* Copyright (C) 1996 by Paul M. Antoine
	8	* Copyright (C) 1999 Silicon Graphics
	9	* Kevin D. Kissell, kevink@mips.org and Carsten Langgaard, carstenl@mips.com
	10	* Copyright (C) 2000 MIPS Technologies, Inc.
	11	*/
	12	#ifndef _ASM_SWITCH_TO_H
	13	#define _ASM_SWITCH_TO_H
	14
	15	#include <asm/cpu-features.h>
	16	#include <asm/watch.h>
	17	#include <asm/dsp.h>
2c952e06	18	#include <asm/cop2.h>
1db1af84	19	#include <asm/msa.h>
b81947c6 DH	20
	21	struct task_struct;
	22
1db1af84 PB	23	enum {
	24	FP_SAVE_NONE = 0,
	25	FP_SAVE_VECTOR = -1,
	26	FP_SAVE_SCALAR = 1,
	27	};
	28
8c0f8ab0 PB	29	/**
	30	* resume - resume execution of a task
	31	* @prev: The task previously executed.
	32	* @next: The task to begin executing.
	33	* @next_ti: task_thread_info(next).
1db1af84	34	* @fp_save: Which, if any, FP context to save for prev.
8c0f8ab0 PB	35	*
	36	* This function is used whilst scheduling to save the context of prev & load
	37	* the context of next. Returns prev.
b81947c6	38	*/
8c0f8ab0 PB	39	extern asmlinkage struct task_struct resume(struct task_struct prev,
8c0f8ab0 PB	40	struct task_struct next, struct thread_info next_ti,
1db1af84	41	s32 fp_save);
b81947c6 DH	42
	43	extern unsigned int ll_bit;
	44	extern struct task_struct *ll_task;
	45
	46	#ifdef CONFIG_MIPS_MT_FPAFF
	47
	48	/*
70342287	49	* Handle the scheduler resume end of FPU affinity management. We do this
b81947c6 DH	50	* inline to try to keep the overhead down. If we have been forced to run on
	51	* a "CPU" with an FPU because of a previous high level of FP computation,
	52	* but did not actually use the FPU during the most recent time-slice (CU1
	53	* isn't set), we undo the restriction on cpus_allowed.
	54	*
	55	* We're not calling set_cpus_allowed() here, because we have no need to
	56	* force prompt migration - we're already switching the current CPU to a
	57	* different thread.
	58	*/
	59
	60	#define __mips_mt_fpaff_switch_to(prev) \
	61	do { \
	62	struct thread_info *__prev_ti = task_thread_info(prev); \
	63	\
	64	if (cpu_has_fpu && \
	65	test_ti_thread_flag(__prev_ti, TIF_FPUBOUND) && \
	66	(!(KSTK_STATUS(prev) & ST0_CU1))) { \
	67	clear_ti_thread_flag(__prev_ti, TIF_FPUBOUND); \
	68	prev->cpus_allowed = prev->thread.user_cpus_allowed; \
	69	} \
	70	next->thread.emulated_fp = 0; \
	71	} while(0)
	72
	73	#else
	74	#define __mips_mt_fpaff_switch_to(prev) do { (void) (prev); } while (0)
	75	#endif
	76
	77	#define __clear_software_ll_bit() \
	78	do { \
	79	if (!__builtin_constant_p(cpu_has_llsc) \|\| !cpu_has_llsc) \
	80	ll_bit = 0; \
	81	} while (0)
	82
	83	#define switch_to(prev, next, last) \
	84	do { \
1db1af84 PB	85	u32 __c0_stat; \
1db1af84 PB	86	s32 __fpsave = FP_SAVE_NONE; \
b81947c6 DH	87	__mips_mt_fpaff_switch_to(prev); \
	88	if (cpu_has_dsp) \
	89	__save_dsp(prev); \
2c952e06 J	90	if (cop2_present && (KSTK_STATUS(prev) & ST0_CU2)) { \
	91	if (cop2_lazy_restore) \
	92	KSTK_STATUS(prev) &= ~ST0_CU2; \
	93	__c0_stat = read_c0_status(); \
	94	write_c0_status(__c0_stat \| ST0_CU2); \
68c77d8a	95	cop2_save(prev); \
2c952e06 J	96	write_c0_status(__c0_stat & ~ST0_CU2); \
2c952e06 J	97	} \
b81947c6	98	__clear_software_ll_bit(); \
1db1af84 PB	99	if (test_and_clear_tsk_thread_flag(prev, TIF_USEDFPU)) \
	100	__fpsave = FP_SAVE_SCALAR; \
	101	if (test_and_clear_tsk_thread_flag(prev, TIF_USEDMSA)) \
	102	__fpsave = FP_SAVE_VECTOR; \
	103	(last) = resume(prev, next, task_thread_info(next), __fpsave); \
	104	disable_msa(); \
b81947c6 DH	105	} while (0)
	106
	107	#define finish_arch_switch(prev) \
	108	do { \
2c952e06 J	109	u32 __c0_stat; \
	110	if (cop2_present && !cop2_lazy_restore && \
	111	(KSTK_STATUS(current) & ST0_CU2)) { \
	112	__c0_stat = read_c0_status(); \
	113	write_c0_status(__c0_stat \| ST0_CU2); \
68c77d8a	114	cop2_restore(current); \
2c952e06 J	115	write_c0_status(__c0_stat & ~ST0_CU2); \
2c952e06 J	116	} \
b81947c6 DH	117	if (cpu_has_dsp) \
	118	__restore_dsp(current); \
	119	if (cpu_has_userlocal) \
	120	write_c0_userlocal(current_thread_info()->tp_value); \
	121	__restore_watch(); \
	122	} while (0)
	123
	124	#endif /* _ASM_SWITCH_TO_H */