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>
 18#include <asm/cop2.h>
 19#include <asm/msa.h>
 20
 21struct task_struct;
 22
 23enum {
 24	FP_SAVE_NONE	= 0,
 25	FP_SAVE_VECTOR	= -1,
 26	FP_SAVE_SCALAR	= 1,
 27};
 28
 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).
 34 * @fp_save:	Which, if any, FP context to save for prev.
 35 *
 36 * This function is used whilst scheduling to save the context of prev & load
 37 * the context of next. Returns prev.
 38 */
 39extern asmlinkage struct task_struct *resume(struct task_struct *prev,
 40		struct task_struct *next, struct thread_info *next_ti,
 41		s32 fp_save);
 42
 43extern unsigned int ll_bit;
 44extern struct task_struct *ll_task;
 45
 46#ifdef CONFIG_MIPS_MT_FPAFF
 47
 48/*
 49 * Handle the scheduler resume end of FPU affinity management.	We do this
 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)					\
 61do {									\
 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()					\
 78do {									\
 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)					\
 84do {									\
 85	u32 __c0_stat;							\
 86	s32 __fpsave = FP_SAVE_NONE;					\
 87	__mips_mt_fpaff_switch_to(prev);				\
 88	if (cpu_has_dsp)						\
 89		__save_dsp(prev);					\
 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);			\
 95		cop2_save(&prev->thread.cp2);				\
 96		write_c0_status(__c0_stat & ~ST0_CU2);			\
 97	}								\
 98	__clear_software_ll_bit();					\
 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();							\
105} while (0)
106
107#define finish_arch_switch(prev)					\
108do {									\
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);			\
114		cop2_restore(&current->thread.cp2);			\
115		write_c0_status(__c0_stat & ~ST0_CU2);			\
116	}								\
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 */