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1da177e4 LT |
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, 1995, 1996, 1998, 1999, 2002, 2003 Ralf Baechle | |
7 | * Copyright (C) 1996 David S. Miller (dm@engr.sgi.com) | |
8 | * Copyright (C) 1994, 1995, 1996, by Andreas Busse | |
9 | * Copyright (C) 1999 Silicon Graphics, Inc. | |
10 | * Copyright (C) 2000 MIPS Technologies, Inc. | |
11 | * written by Carsten Langgaard, carstenl@mips.com | |
12 | */ | |
13 | #include <linux/config.h> | |
14 | #include <asm/asm.h> | |
15 | #include <asm/cachectl.h> | |
16 | #include <asm/fpregdef.h> | |
17 | #include <asm/mipsregs.h> | |
18 | #include <asm/offset.h> | |
19 | #include <asm/page.h> | |
20 | #include <asm/pgtable-bits.h> | |
21 | #include <asm/regdef.h> | |
22 | #include <asm/stackframe.h> | |
23 | #include <asm/thread_info.h> | |
24 | ||
25 | #include <asm/asmmacro.h> | |
26 | ||
27 | /* | |
28 | * Offset to the current process status flags, the first 32 bytes of the | |
29 | * stack are not used. | |
30 | */ | |
31 | #define ST_OFF (_THREAD_SIZE - 32 - PT_SIZE + PT_STATUS) | |
32 | ||
33 | /* | |
34 | * FPU context is saved iff the process has used it's FPU in the current | |
35 | * time slice as indicated by _TIF_USEDFPU. In any case, the CU1 bit for user | |
36 | * space STATUS register should be 0, so that a process *always* starts its | |
37 | * userland with FPU disabled after each context switch. | |
38 | * | |
39 | * FPU will be enabled as soon as the process accesses FPU again, through | |
40 | * do_cpu() trap. | |
41 | */ | |
42 | ||
43 | /* | |
44 | * task_struct *resume(task_struct *prev, task_struct *next, | |
45 | * struct thread_info *next_ti) | |
46 | */ | |
47 | .align 5 | |
48 | LEAF(resume) | |
49 | #ifndef CONFIG_CPU_HAS_LLSC | |
50 | sw zero, ll_bit | |
51 | #endif | |
52 | mfc0 t1, CP0_STATUS | |
53 | LONG_S t1, THREAD_STATUS(a0) | |
54 | cpu_save_nonscratch a0 | |
55 | LONG_S ra, THREAD_REG31(a0) | |
56 | ||
57 | /* | |
58 | * check if we need to save FPU registers | |
59 | */ | |
60 | PTR_L t3, TASK_THREAD_INFO(a0) | |
61 | LONG_L t0, TI_FLAGS(t3) | |
62 | li t1, _TIF_USEDFPU | |
63 | and t2, t0, t1 | |
64 | beqz t2, 1f | |
65 | nor t1, zero, t1 | |
66 | ||
67 | and t0, t0, t1 | |
68 | LONG_S t0, TI_FLAGS(t3) | |
69 | ||
70 | /* | |
71 | * clear saved user stack CU1 bit | |
72 | */ | |
73 | LONG_L t0, ST_OFF(t3) | |
74 | li t1, ~ST0_CU1 | |
75 | and t0, t0, t1 | |
76 | LONG_S t0, ST_OFF(t3) | |
77 | ||
78 | fpu_save_double a0 t1 t0 t2 # c0_status passed in t1 | |
79 | # clobbers t0 and t2 | |
80 | 1: | |
81 | ||
82 | /* | |
83 | * The order of restoring the registers takes care of the race | |
84 | * updating $28, $29 and kernelsp without disabling ints. | |
85 | */ | |
86 | move $28, a2 | |
87 | cpu_restore_nonscratch a1 | |
88 | ||
89 | PTR_ADDIU t0, $28, _THREAD_SIZE - 32 | |
90 | set_saved_sp t0, t1, t2 | |
91 | ||
92 | mfc0 t1, CP0_STATUS /* Do we really need this? */ | |
93 | li a3, 0xff01 | |
94 | and t1, a3 | |
95 | LONG_L a2, THREAD_STATUS(a1) | |
96 | nor a3, $0, a3 | |
97 | and a2, a3 | |
98 | or a2, t1 | |
99 | mtc0 a2, CP0_STATUS | |
100 | move v0, a0 | |
101 | jr ra | |
102 | END(resume) | |
103 | ||
104 | /* | |
105 | * Save a thread's fp context. | |
106 | */ | |
107 | LEAF(_save_fp) | |
875d43e7 | 108 | #ifdef CONFIG_64BIT |
1da177e4 LT |
109 | mfc0 t1, CP0_STATUS |
110 | #endif | |
111 | fpu_save_double a0 t1 t0 t2 # clobbers t1 | |
112 | jr ra | |
113 | END(_save_fp) | |
114 | ||
115 | /* | |
116 | * Restore a thread's fp context. | |
117 | */ | |
118 | LEAF(_restore_fp) | |
119 | fpu_restore_double a0, t1 # clobbers t1 | |
120 | jr ra | |
121 | END(_restore_fp) | |
122 | ||
123 | /* | |
124 | * Load the FPU with signalling NANS. This bit pattern we're using has | |
125 | * the property that no matter whether considered as single or as double | |
126 | * precision represents signaling NANS. | |
127 | * | |
128 | * We initialize fcr31 to rounding to nearest, no exceptions. | |
129 | */ | |
130 | ||
131 | #define FPU_DEFAULT 0x00000000 | |
132 | ||
133 | LEAF(_init_fpu) | |
134 | mfc0 t0, CP0_STATUS | |
135 | li t1, ST0_CU1 | |
136 | or t0, t1 | |
137 | mtc0 t0, CP0_STATUS | |
138 | fpu_enable_hazard | |
139 | ||
140 | li t1, FPU_DEFAULT | |
141 | ctc1 t1, fcr31 | |
142 | ||
143 | li t1, -1 # SNaN | |
144 | ||
875d43e7 | 145 | #ifdef CONFIG_64BIT |
1da177e4 LT |
146 | sll t0, t0, 5 |
147 | bgez t0, 1f # 16 / 32 register mode? | |
148 | ||
149 | dmtc1 t1, $f1 | |
150 | dmtc1 t1, $f3 | |
151 | dmtc1 t1, $f5 | |
152 | dmtc1 t1, $f7 | |
153 | dmtc1 t1, $f9 | |
154 | dmtc1 t1, $f11 | |
155 | dmtc1 t1, $f13 | |
156 | dmtc1 t1, $f15 | |
157 | dmtc1 t1, $f17 | |
158 | dmtc1 t1, $f19 | |
159 | dmtc1 t1, $f21 | |
160 | dmtc1 t1, $f23 | |
161 | dmtc1 t1, $f25 | |
162 | dmtc1 t1, $f27 | |
163 | dmtc1 t1, $f29 | |
164 | dmtc1 t1, $f31 | |
165 | 1: | |
166 | #endif | |
167 | ||
168 | #ifdef CONFIG_CPU_MIPS32 | |
169 | mtc1 t1, $f0 | |
170 | mtc1 t1, $f1 | |
171 | mtc1 t1, $f2 | |
172 | mtc1 t1, $f3 | |
173 | mtc1 t1, $f4 | |
174 | mtc1 t1, $f5 | |
175 | mtc1 t1, $f6 | |
176 | mtc1 t1, $f7 | |
177 | mtc1 t1, $f8 | |
178 | mtc1 t1, $f9 | |
179 | mtc1 t1, $f10 | |
180 | mtc1 t1, $f11 | |
181 | mtc1 t1, $f12 | |
182 | mtc1 t1, $f13 | |
183 | mtc1 t1, $f14 | |
184 | mtc1 t1, $f15 | |
185 | mtc1 t1, $f16 | |
186 | mtc1 t1, $f17 | |
187 | mtc1 t1, $f18 | |
188 | mtc1 t1, $f19 | |
189 | mtc1 t1, $f20 | |
190 | mtc1 t1, $f21 | |
191 | mtc1 t1, $f22 | |
192 | mtc1 t1, $f23 | |
193 | mtc1 t1, $f24 | |
194 | mtc1 t1, $f25 | |
195 | mtc1 t1, $f26 | |
196 | mtc1 t1, $f27 | |
197 | mtc1 t1, $f28 | |
198 | mtc1 t1, $f29 | |
199 | mtc1 t1, $f30 | |
200 | mtc1 t1, $f31 | |
201 | #else | |
202 | .set mips3 | |
203 | dmtc1 t1, $f0 | |
204 | dmtc1 t1, $f2 | |
205 | dmtc1 t1, $f4 | |
206 | dmtc1 t1, $f6 | |
207 | dmtc1 t1, $f8 | |
208 | dmtc1 t1, $f10 | |
209 | dmtc1 t1, $f12 | |
210 | dmtc1 t1, $f14 | |
211 | dmtc1 t1, $f16 | |
212 | dmtc1 t1, $f18 | |
213 | dmtc1 t1, $f20 | |
214 | dmtc1 t1, $f22 | |
215 | dmtc1 t1, $f24 | |
216 | dmtc1 t1, $f26 | |
217 | dmtc1 t1, $f28 | |
218 | dmtc1 t1, $f30 | |
219 | #endif | |
220 | jr ra | |
221 | END(_init_fpu) |