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
19struct task_struct;
20
21/*
22 * switch_to(n) should switch tasks to task nr n, first
23 * checking that n isn't the current task, in which case it does nothing.
24 */
25extern asmlinkage void *resume(void *last, void *next, void *next_ti, u32 __usedfpu);
26
27extern unsigned int ll_bit;
28extern struct task_struct *ll_task;
29
30#ifdef CONFIG_MIPS_MT_FPAFF
31
32/*
33 * Handle the scheduler resume end of FPU affinity management.  We do this
34 * inline to try to keep the overhead down. If we have been forced to run on
35 * a "CPU" with an FPU because of a previous high level of FP computation,
36 * but did not actually use the FPU during the most recent time-slice (CU1
37 * isn't set), we undo the restriction on cpus_allowed.
38 *
39 * We're not calling set_cpus_allowed() here, because we have no need to
40 * force prompt migration - we're already switching the current CPU to a
41 * different thread.
42 */
43
44#define __mips_mt_fpaff_switch_to(prev)					\
45do {									\
46	struct thread_info *__prev_ti = task_thread_info(prev);		\
47									\
48	if (cpu_has_fpu &&						\
49	    test_ti_thread_flag(__prev_ti, TIF_FPUBOUND) &&		\
50	    (!(KSTK_STATUS(prev) & ST0_CU1))) {				\
51		clear_ti_thread_flag(__prev_ti, TIF_FPUBOUND);		\
52		prev->cpus_allowed = prev->thread.user_cpus_allowed;	\
53	}								\
54	next->thread.emulated_fp = 0;					\
55} while(0)
56
57#else
58#define __mips_mt_fpaff_switch_to(prev) do { (void) (prev); } while (0)
59#endif
60
61#define __clear_software_ll_bit()					\
62do {									\
63	if (!__builtin_constant_p(cpu_has_llsc) || !cpu_has_llsc)	\
64		ll_bit = 0;						\
65} while (0)
66
67#define switch_to(prev, next, last)					\
68do {									\
69	u32 __usedfpu;							\
70	__mips_mt_fpaff_switch_to(prev);				\
71	if (cpu_has_dsp)						\
72		__save_dsp(prev);					\
73	__clear_software_ll_bit();					\
74	__usedfpu = test_and_clear_tsk_thread_flag(prev, TIF_USEDFPU);	\
75	(last) = resume(prev, next, task_thread_info(next), __usedfpu);	\
76} while (0)
77
78#define finish_arch_switch(prev)					\
79do {									\
80	if (cpu_has_dsp)						\
81		__restore_dsp(current);					\
82	if (cpu_has_userlocal)						\
83		write_c0_userlocal(current_thread_info()->tp_value);	\
84	__restore_watch();						\
85} while (0)
86
87#endif /* _ASM_SWITCH_TO_H */