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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 (davem@davemloft.net)
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 <asm/asm.h>
14#include <asm/cachectl.h>
15#include <asm/mipsregs.h>
16#include <asm/asm-offsets.h>
17#include <asm/regdef.h>
18#include <asm/stackframe.h>
19#include <asm/thread_info.h>
20
21#include <asm/asmmacro.h>
22
23/*
24 * task_struct *resume(task_struct *prev, task_struct *next,
25 * struct thread_info *next_ti)
26 */
27 .align 5
28 LEAF(resume)
29 mfc0 t1, CP0_STATUS
30 LONG_S t1, THREAD_STATUS(a0)
31 cpu_save_nonscratch a0
32 LONG_S ra, THREAD_REG31(a0)
33
34#if defined(CONFIG_STACKPROTECTOR) && !defined(CONFIG_SMP)
35 PTR_LA t8, __stack_chk_guard
36 LONG_L t9, TASK_STACK_CANARY(a1)
37 LONG_S t9, 0(t8)
38#endif
39
40 /*
41 * The order of restoring the registers takes care of the race
42 * updating $28, $29 and kernelsp without disabling ints.
43 */
44 move $28, a2
45 cpu_restore_nonscratch a1
46
47 PTR_ADDU t0, $28, _THREAD_SIZE - 32
48 set_saved_sp t0, t1, t2
49 mfc0 t1, CP0_STATUS /* Do we really need this? */
50 li a3, 0xff01
51 and t1, a3
52 LONG_L a2, THREAD_STATUS(a1)
53 nor a3, $0, a3
54 and a2, a3
55 or a2, t1
56 mtc0 a2, CP0_STATUS
57 move v0, a0
58 jr ra
59 END(resume)
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 (davem@davemloft.net)
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 <asm/asm.h>
14#include <asm/cachectl.h>
15#include <asm/fpregdef.h>
16#include <asm/mipsregs.h>
17#include <asm/asm-offsets.h>
18#include <asm/page.h>
19#include <asm/pgtable-bits.h>
20#include <asm/regdef.h>
21#include <asm/stackframe.h>
22#include <asm/thread_info.h>
23
24#include <asm/asmmacro.h>
25
26/*
27 * Offset to the current process status flags, the first 32 bytes of the
28 * stack are not used.
29 */
30#define ST_OFF (_THREAD_SIZE - 32 - PT_SIZE + PT_STATUS)
31
32/*
33 * FPU context is saved iff the process has used it's FPU in the current
34 * time slice as indicated by _TIF_USEDFPU. In any case, the CU1 bit for user
35 * space STATUS register should be 0, so that a process *always* starts its
36 * userland with FPU disabled after each context switch.
37 *
38 * FPU will be enabled as soon as the process accesses FPU again, through
39 * do_cpu() trap.
40 */
41
42/*
43 * task_struct *resume(task_struct *prev, task_struct *next,
44 * struct thread_info *next_ti)
45 */
46 .align 5
47 LEAF(resume)
48 mfc0 t1, CP0_STATUS
49 LONG_S t1, THREAD_STATUS(a0)
50 cpu_save_nonscratch a0
51 LONG_S ra, THREAD_REG31(a0)
52
53 /*
54 * check if we need to save FPU registers
55 */
56 PTR_L t3, TASK_THREAD_INFO(a0)
57 LONG_L t0, TI_FLAGS(t3)
58 li t1, _TIF_USEDFPU
59 and t2, t0, t1
60 beqz t2, 1f
61 nor t1, zero, t1
62
63 and t0, t0, t1
64 LONG_S t0, TI_FLAGS(t3)
65
66 /*
67 * clear saved user stack CU1 bit
68 */
69 LONG_L t0, ST_OFF(t3)
70 li t1, ~ST0_CU1
71 and t0, t0, t1
72 LONG_S t0, ST_OFF(t3)
73
74 fpu_save_double a0 t0 t1 # c0_status passed in t0
75 # clobbers t1
761:
77
78 /*
79 * The order of restoring the registers takes care of the race
80 * updating $28, $29 and kernelsp without disabling ints.
81 */
82 move $28, a2
83 cpu_restore_nonscratch a1
84
85 PTR_ADDU t0, $28, _THREAD_SIZE - 32
86 set_saved_sp t0, t1, t2
87#ifdef CONFIG_MIPS_MT_SMTC
88 /* Read-modify-writes of Status must be atomic on a VPE */
89 mfc0 t2, CP0_TCSTATUS
90 ori t1, t2, TCSTATUS_IXMT
91 mtc0 t1, CP0_TCSTATUS
92 andi t2, t2, TCSTATUS_IXMT
93 _ehb
94 DMT 8 # dmt t0
95 move t1,ra
96 jal mips_ihb
97 move ra,t1
98#endif /* CONFIG_MIPS_MT_SMTC */
99 mfc0 t1, CP0_STATUS /* Do we really need this? */
100 li a3, 0xff01
101 and t1, a3
102 LONG_L a2, THREAD_STATUS(a1)
103 nor a3, $0, a3
104 and a2, a3
105 or a2, t1
106 mtc0 a2, CP0_STATUS
107#ifdef CONFIG_MIPS_MT_SMTC
108 _ehb
109 andi t0, t0, VPECONTROL_TE
110 beqz t0, 1f
111 emt
1121:
113 mfc0 t1, CP0_TCSTATUS
114 xori t1, t1, TCSTATUS_IXMT
115 or t1, t1, t2
116 mtc0 t1, CP0_TCSTATUS
117 _ehb
118#endif /* CONFIG_MIPS_MT_SMTC */
119 move v0, a0
120 jr ra
121 END(resume)
122
123/*
124 * Save a thread's fp context.
125 */
126LEAF(_save_fp)
127#ifdef CONFIG_64BIT
128 mfc0 t0, CP0_STATUS
129#endif
130 fpu_save_double a0 t0 t1 # clobbers t1
131 jr ra
132 END(_save_fp)
133
134/*
135 * Restore a thread's fp context.
136 */
137LEAF(_restore_fp)
138#ifdef CONFIG_64BIT
139 mfc0 t0, CP0_STATUS
140#endif
141 fpu_restore_double a0 t0 t1 # clobbers t1
142 jr ra
143 END(_restore_fp)
144
145/*
146 * Load the FPU with signalling NANS. This bit pattern we're using has
147 * the property that no matter whether considered as single or as double
148 * precision represents signaling NANS.
149 *
150 * We initialize fcr31 to rounding to nearest, no exceptions.
151 */
152
153#define FPU_DEFAULT 0x00000000
154
155LEAF(_init_fpu)
156#ifdef CONFIG_MIPS_MT_SMTC
157 /* Rather than manipulate per-VPE Status, set per-TC bit in TCStatus */
158 mfc0 t0, CP0_TCSTATUS
159 /* Bit position is the same for Status, TCStatus */
160 li t1, ST0_CU1
161 or t0, t1
162 mtc0 t0, CP0_TCSTATUS
163#else /* Normal MIPS CU1 enable */
164 mfc0 t0, CP0_STATUS
165 li t1, ST0_CU1
166 or t0, t1
167 mtc0 t0, CP0_STATUS
168#endif /* CONFIG_MIPS_MT_SMTC */
169 enable_fpu_hazard
170
171 li t1, FPU_DEFAULT
172 ctc1 t1, fcr31
173
174 li t1, -1 # SNaN
175
176#ifdef CONFIG_64BIT
177 sll t0, t0, 5
178 bgez t0, 1f # 16 / 32 register mode?
179
180 dmtc1 t1, $f1
181 dmtc1 t1, $f3
182 dmtc1 t1, $f5
183 dmtc1 t1, $f7
184 dmtc1 t1, $f9
185 dmtc1 t1, $f11
186 dmtc1 t1, $f13
187 dmtc1 t1, $f15
188 dmtc1 t1, $f17
189 dmtc1 t1, $f19
190 dmtc1 t1, $f21
191 dmtc1 t1, $f23
192 dmtc1 t1, $f25
193 dmtc1 t1, $f27
194 dmtc1 t1, $f29
195 dmtc1 t1, $f31
1961:
197#endif
198
199#ifdef CONFIG_CPU_MIPS32
200 mtc1 t1, $f0
201 mtc1 t1, $f1
202 mtc1 t1, $f2
203 mtc1 t1, $f3
204 mtc1 t1, $f4
205 mtc1 t1, $f5
206 mtc1 t1, $f6
207 mtc1 t1, $f7
208 mtc1 t1, $f8
209 mtc1 t1, $f9
210 mtc1 t1, $f10
211 mtc1 t1, $f11
212 mtc1 t1, $f12
213 mtc1 t1, $f13
214 mtc1 t1, $f14
215 mtc1 t1, $f15
216 mtc1 t1, $f16
217 mtc1 t1, $f17
218 mtc1 t1, $f18
219 mtc1 t1, $f19
220 mtc1 t1, $f20
221 mtc1 t1, $f21
222 mtc1 t1, $f22
223 mtc1 t1, $f23
224 mtc1 t1, $f24
225 mtc1 t1, $f25
226 mtc1 t1, $f26
227 mtc1 t1, $f27
228 mtc1 t1, $f28
229 mtc1 t1, $f29
230 mtc1 t1, $f30
231 mtc1 t1, $f31
232#else
233 .set mips3
234 dmtc1 t1, $f0
235 dmtc1 t1, $f2
236 dmtc1 t1, $f4
237 dmtc1 t1, $f6
238 dmtc1 t1, $f8
239 dmtc1 t1, $f10
240 dmtc1 t1, $f12
241 dmtc1 t1, $f14
242 dmtc1 t1, $f16
243 dmtc1 t1, $f18
244 dmtc1 t1, $f20
245 dmtc1 t1, $f22
246 dmtc1 t1, $f24
247 dmtc1 t1, $f26
248 dmtc1 t1, $f28
249 dmtc1 t1, $f30
250#endif
251 jr ra
252 END(_init_fpu)