MIPS: Get rid of finish_arch_switch().
[linux-drm-fsl-dcu.git] / arch / mips / include / asm / switch_to.h
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
21 struct task_struct;
22
23 enum {
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  */
39 extern asmlinkage struct task_struct *resume(struct task_struct *prev,
40                 struct task_struct *next, struct thread_info *next_ti,
41                 s32 fp_save);
42
43 extern unsigned int ll_bit;
44 extern 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)                                 \
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 {    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         }                                                               \
84 } while (0)
85
86 /*
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  */
92 #define switch_to(prev, next, last)                                     \
93 do {                                                                    \
94         s32 __fpsave = FP_SAVE_NONE;                                    \
95         __mips_mt_fpaff_switch_to(prev);                                \
96         if (cpu_has_dsp) {                                              \
97                 __save_dsp(prev);                                       \
98                 __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);                               \
112         }                                                               \
113         __clear_software_ll_bit();                                      \
114         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;                              \
118         if (cpu_has_userlocal)                                          \
119                 write_c0_userlocal(task_thread_info(next)->tp_value);   \
120         __restore_watch();                                              \
121         disable_msa();                                                  \
122         (last) = resume(prev, next, task_thread_info(next), __fpsave);  \
123 } while (0)
124
125 #endif /* _ASM_SWITCH_TO_H */