blob: 9733cd0266e4b948879e9ec924622c606b59f770 [file] [log] [blame]
David Howellsb81947c2012-03-28 18:30:02 +01001/*
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>
Jayachandran C2c952e02013-06-10 06:30:00 +000018#include <asm/cop2.h>
Paul Burton1db1af82014-01-27 15:23:11 +000019#include <asm/msa.h>
David Howellsb81947c2012-03-28 18:30:02 +010020
21struct task_struct;
22
Paul Burton1db1af82014-01-27 15:23:11 +000023enum {
24 FP_SAVE_NONE = 0,
25 FP_SAVE_VECTOR = -1,
26 FP_SAVE_SCALAR = 1,
27};
28
Paul Burton8c0f8ab2013-11-19 17:30:37 +000029/**
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).
Paul Burton1db1af82014-01-27 15:23:11 +000034 * @fp_save: Which, if any, FP context to save for prev.
Paul Burton8c0f8ab2013-11-19 17:30:37 +000035 *
36 * This function is used whilst scheduling to save the context of prev & load
37 * the context of next. Returns prev.
David Howellsb81947c2012-03-28 18:30:02 +010038 */
Paul Burton8c0f8ab2013-11-19 17:30:37 +000039extern asmlinkage struct task_struct *resume(struct task_struct *prev,
40 struct task_struct *next, struct thread_info *next_ti,
Paul Burton1db1af82014-01-27 15:23:11 +000041 s32 fp_save);
David Howellsb81947c2012-03-28 18:30:02 +010042
43extern unsigned int ll_bit;
44extern struct task_struct *ll_task;
45
46#ifdef CONFIG_MIPS_MT_FPAFF
47
48/*
Ralf Baechle70342282013-01-22 12:59:30 +010049 * Handle the scheduler resume end of FPU affinity management. We do this
David Howellsb81947c2012-03-28 18:30:02 +010050 * 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() \
Markos Chandras7c151d32014-12-03 12:37:32 +000078do { if (cpu_has_rw_llb) { \
79 write_c0_lladdr(0); \
80 } else { \
81 if (!__builtin_constant_p(cpu_has_llsc) || !cpu_has_llsc)\
82 ll_bit = 0; \
83 } \
David Howellsb81947c2012-03-28 18:30:02 +010084} while (0)
85
Ralf Baechle6916ce32015-07-29 12:14:42 +020086/*
87 * For newly created kernel threads switch_to() will return to
88 * ret_from_kernel_thread, newly created user threads to ret_from_fork.
89 * That is, everything following resume() will be skipped for new threads.
90 * So everything that matters to new threads should be placed before resume().
91 */
David Howellsb81947c2012-03-28 18:30:02 +010092#define switch_to(prev, next, last) \
93do { \
Paul Burton1db1af82014-01-27 15:23:11 +000094 s32 __fpsave = FP_SAVE_NONE; \
David Howellsb81947c2012-03-28 18:30:02 +010095 __mips_mt_fpaff_switch_to(prev); \
Ralf Baechle6916ce32015-07-29 12:14:42 +020096 if (cpu_has_dsp) { \
David Howellsb81947c2012-03-28 18:30:02 +010097 __save_dsp(prev); \
Ralf Baechle6916ce32015-07-29 12:14:42 +020098 __restore_dsp(next); \
99 } \
100 if (cop2_present) { \
101 set_c0_status(ST0_CU2); \
102 if ((KSTK_STATUS(prev) & ST0_CU2)) { \
103 if (cop2_lazy_restore) \
104 KSTK_STATUS(prev) &= ~ST0_CU2; \
105 cop2_save(prev); \
106 } \
107 if (KSTK_STATUS(next) & ST0_CU2 && \
108 !cop2_lazy_restore) { \
109 cop2_restore(next); \
110 } \
111 clear_c0_status(ST0_CU2); \
Jayachandran C2c952e02013-06-10 06:30:00 +0000112 } \
David Howellsb81947c2012-03-28 18:30:02 +0100113 __clear_software_ll_bit(); \
Paul Burton1db1af82014-01-27 15:23:11 +0000114 if (test_and_clear_tsk_thread_flag(prev, TIF_USEDFPU)) \
115 __fpsave = FP_SAVE_SCALAR; \
116 if (test_and_clear_tsk_thread_flag(prev, TIF_USEDMSA)) \
117 __fpsave = FP_SAVE_VECTOR; \
David Howellsb81947c2012-03-28 18:30:02 +0100118 if (cpu_has_userlocal) \
Ralf Baechle6916ce32015-07-29 12:14:42 +0200119 write_c0_userlocal(task_thread_info(next)->tp_value); \
David Howellsb81947c2012-03-28 18:30:02 +0100120 __restore_watch(); \
Ralf Baechle9cc719a2015-05-23 01:20:19 +0200121 disable_msa(); \
Ralf Baechle6916ce32015-07-29 12:14:42 +0200122 (last) = resume(prev, next, task_thread_info(next), __fpsave); \
David Howellsb81947c2012-03-28 18:30:02 +0100123} while (0)
124
125#endif /* _ASM_SWITCH_TO_H */