xref: /openbmc/linux/arch/mips/kernel/r4k_switch.S (revision 2c684d89)
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/pgtable-bits.h>
19#include <asm/regdef.h>
20#include <asm/stackframe.h>
21#include <asm/thread_info.h>
22
23#include <asm/asmmacro.h>
24
25/* preprocessor replaces the fp in ".set fp=64" with $30 otherwise */
26#undef fp
27
28/*
29 * Offset to the current process status flags, the first 32 bytes of the
30 * stack are not used.
31 */
32#define ST_OFF (_THREAD_SIZE - 32 - PT_SIZE + PT_STATUS)
33
34#ifndef USE_ALTERNATE_RESUME_IMPL
35/*
36 * task_struct *resume(task_struct *prev, task_struct *next,
37 *		       struct thread_info *next_ti)
38 */
39	.align	5
40	LEAF(resume)
41	mfc0	t1, CP0_STATUS
42	LONG_S	t1, THREAD_STATUS(a0)
43	cpu_save_nonscratch a0
44	LONG_S	ra, THREAD_REG31(a0)
45
46#if defined(CONFIG_CC_STACKPROTECTOR) && !defined(CONFIG_SMP)
47	PTR_LA	t8, __stack_chk_guard
48	LONG_L	t9, TASK_STACK_CANARY(a1)
49	LONG_S	t9, 0(t8)
50#endif
51
52	/*
53	 * The order of restoring the registers takes care of the race
54	 * updating $28, $29 and kernelsp without disabling ints.
55	 */
56	move	$28, a2
57	cpu_restore_nonscratch a1
58
59	PTR_ADDU	t0, $28, _THREAD_SIZE - 32
60	set_saved_sp	t0, t1, t2
61	mfc0	t1, CP0_STATUS		/* Do we really need this? */
62	li	a3, 0xff01
63	and	t1, a3
64	LONG_L	a2, THREAD_STATUS(a1)
65	nor	a3, $0, a3
66	and	a2, a3
67	or	a2, t1
68	mtc0	a2, CP0_STATUS
69	move	v0, a0
70	jr	ra
71	END(resume)
72
73#endif /* USE_ALTERNATE_RESUME_IMPL */
74
75/*
76 * Save a thread's fp context.
77 */
78LEAF(_save_fp)
79#if defined(CONFIG_64BIT) || defined(CONFIG_CPU_MIPS32_R2) || \
80		defined(CONFIG_CPU_MIPS32_R6)
81	mfc0	t0, CP0_STATUS
82#endif
83	fpu_save_double a0 t0 t1		# clobbers t1
84	jr	ra
85	END(_save_fp)
86
87/*
88 * Restore a thread's fp context.
89 */
90LEAF(_restore_fp)
91#if defined(CONFIG_64BIT) || defined(CONFIG_CPU_MIPS32_R2) || \
92		defined(CONFIG_CPU_MIPS32_R6)
93	mfc0	t0, CP0_STATUS
94#endif
95	fpu_restore_double a0 t0 t1		# clobbers t1
96	jr	ra
97	END(_restore_fp)
98
99#ifdef CONFIG_CPU_HAS_MSA
100
101/*
102 * Save a thread's MSA vector context.
103 */
104LEAF(_save_msa)
105	msa_save_all	a0
106	jr	ra
107	END(_save_msa)
108
109/*
110 * Restore a thread's MSA vector context.
111 */
112LEAF(_restore_msa)
113	msa_restore_all	a0
114	jr	ra
115	END(_restore_msa)
116
117LEAF(_init_msa_upper)
118	msa_init_all_upper
119	jr	ra
120	END(_init_msa_upper)
121
122#endif
123
124/*
125 * Load the FPU with signalling NANS.  This bit pattern we're using has
126 * the property that no matter whether considered as single or as double
127 * precision represents signaling NANS.
128 *
129 * The value to initialize fcr31 to comes in $a0.
130 */
131
132	.set push
133	SET_HARDFLOAT
134
135LEAF(_init_fpu)
136	mfc0	t0, CP0_STATUS
137	li	t1, ST0_CU1
138	or	t0, t1
139	mtc0	t0, CP0_STATUS
140	enable_fpu_hazard
141
142	ctc1	a0, fcr31
143
144	li	t1, -1				# SNaN
145
146#ifdef CONFIG_64BIT
147	sll	t0, t0, 5
148	bgez	t0, 1f				# 16 / 32 register mode?
149
150	dmtc1	t1, $f1
151	dmtc1	t1, $f3
152	dmtc1	t1, $f5
153	dmtc1	t1, $f7
154	dmtc1	t1, $f9
155	dmtc1	t1, $f11
156	dmtc1	t1, $f13
157	dmtc1	t1, $f15
158	dmtc1	t1, $f17
159	dmtc1	t1, $f19
160	dmtc1	t1, $f21
161	dmtc1	t1, $f23
162	dmtc1	t1, $f25
163	dmtc1	t1, $f27
164	dmtc1	t1, $f29
165	dmtc1	t1, $f31
1661:
167#endif
168
169#ifdef CONFIG_CPU_MIPS32
170	mtc1	t1, $f0
171	mtc1	t1, $f1
172	mtc1	t1, $f2
173	mtc1	t1, $f3
174	mtc1	t1, $f4
175	mtc1	t1, $f5
176	mtc1	t1, $f6
177	mtc1	t1, $f7
178	mtc1	t1, $f8
179	mtc1	t1, $f9
180	mtc1	t1, $f10
181	mtc1	t1, $f11
182	mtc1	t1, $f12
183	mtc1	t1, $f13
184	mtc1	t1, $f14
185	mtc1	t1, $f15
186	mtc1	t1, $f16
187	mtc1	t1, $f17
188	mtc1	t1, $f18
189	mtc1	t1, $f19
190	mtc1	t1, $f20
191	mtc1	t1, $f21
192	mtc1	t1, $f22
193	mtc1	t1, $f23
194	mtc1	t1, $f24
195	mtc1	t1, $f25
196	mtc1	t1, $f26
197	mtc1	t1, $f27
198	mtc1	t1, $f28
199	mtc1	t1, $f29
200	mtc1	t1, $f30
201	mtc1	t1, $f31
202
203#if defined(CONFIG_CPU_MIPS32_R2) || defined(CONFIG_CPU_MIPS32_R6)
204	.set    push
205	.set    MIPS_ISA_LEVEL_RAW
206	.set	fp=64
207	sll     t0, t0, 5			# is Status.FR set?
208	bgez    t0, 1f				# no: skip setting upper 32b
209
210	mthc1   t1, $f0
211	mthc1   t1, $f1
212	mthc1   t1, $f2
213	mthc1   t1, $f3
214	mthc1   t1, $f4
215	mthc1   t1, $f5
216	mthc1   t1, $f6
217	mthc1   t1, $f7
218	mthc1   t1, $f8
219	mthc1   t1, $f9
220	mthc1   t1, $f10
221	mthc1   t1, $f11
222	mthc1   t1, $f12
223	mthc1   t1, $f13
224	mthc1   t1, $f14
225	mthc1   t1, $f15
226	mthc1   t1, $f16
227	mthc1   t1, $f17
228	mthc1   t1, $f18
229	mthc1   t1, $f19
230	mthc1   t1, $f20
231	mthc1   t1, $f21
232	mthc1   t1, $f22
233	mthc1   t1, $f23
234	mthc1   t1, $f24
235	mthc1   t1, $f25
236	mthc1   t1, $f26
237	mthc1   t1, $f27
238	mthc1   t1, $f28
239	mthc1   t1, $f29
240	mthc1   t1, $f30
241	mthc1   t1, $f31
2421:	.set    pop
243#endif /* CONFIG_CPU_MIPS32_R2 || CONFIG_CPU_MIPS32_R6 */
244#else
245	.set	MIPS_ISA_ARCH_LEVEL_RAW
246	dmtc1	t1, $f0
247	dmtc1	t1, $f2
248	dmtc1	t1, $f4
249	dmtc1	t1, $f6
250	dmtc1	t1, $f8
251	dmtc1	t1, $f10
252	dmtc1	t1, $f12
253	dmtc1	t1, $f14
254	dmtc1	t1, $f16
255	dmtc1	t1, $f18
256	dmtc1	t1, $f20
257	dmtc1	t1, $f22
258	dmtc1	t1, $f24
259	dmtc1	t1, $f26
260	dmtc1	t1, $f28
261	dmtc1	t1, $f30
262#endif
263	jr	ra
264	END(_init_fpu)
265
266	.set pop	/* SET_HARDFLOAT */
267