1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3 * linux/arch/arm/kernel/iwmmxt.S
4 *
5 * XScale iWMMXt (Concan) context switching and handling
6 *
7 * Initial code:
8 * Copyright (c) 2003, Intel Corporation
9 *
10 * Full lazy switching support, optimizations and more, by Nicolas Pitre
11 * Copyright (c) 2003-2004, MontaVista Software, Inc.
12 */
13
14 #include <linux/linkage.h>
15 #include <asm/ptrace.h>
16 #include <asm/thread_info.h>
17 #include <asm/asm-offsets.h>
18 #include <asm/assembler.h>
19 #include "iwmmxt.h"
20
21 #define MMX_WR0 (0x00)
22 #define MMX_WR1 (0x08)
23 #define MMX_WR2 (0x10)
24 #define MMX_WR3 (0x18)
25 #define MMX_WR4 (0x20)
26 #define MMX_WR5 (0x28)
27 #define MMX_WR6 (0x30)
28 #define MMX_WR7 (0x38)
29 #define MMX_WR8 (0x40)
30 #define MMX_WR9 (0x48)
31 #define MMX_WR10 (0x50)
32 #define MMX_WR11 (0x58)
33 #define MMX_WR12 (0x60)
34 #define MMX_WR13 (0x68)
35 #define MMX_WR14 (0x70)
36 #define MMX_WR15 (0x78)
37 #define MMX_WCSSF (0x80)
38 #define MMX_WCASF (0x84)
39 #define MMX_WCGR0 (0x88)
40 #define MMX_WCGR1 (0x8C)
41 #define MMX_WCGR2 (0x90)
42 #define MMX_WCGR3 (0x94)
43
44 #define MMX_SIZE (0x98)
45
46 .text
47 .arm
48
49 ENTRY(iwmmxt_undef_handler)
50 push {r9, r10, lr}
51 get_thread_info r10
52 mov r9, pc
53 b iwmmxt_task_enable
54 mov r0, #0
55 pop {r9, r10, pc}
56 ENDPROC(iwmmxt_undef_handler)
57
58 /*
59 * Lazy switching of Concan coprocessor context
60 *
61 * r0 = struct pt_regs pointer
62 * r10 = struct thread_info pointer
63 * r9 = ret_from_exception
64 * lr = undefined instr exit
65 *
66 * called from prefetch exception handler with interrupts enabled
67 */
68
69 ENTRY(iwmmxt_task_enable)
70 inc_preempt_count r10, r3
71
72 mrc p15, 0, r2, c15, c1, 0
73 @ CP0 and CP1 accessible?
74 tst r2, #0x3
75 bne 4f @ if so no business here
76 @ enable access to CP0 and CP1
77 orr r2, r2, #0x3
78 mcr p15, 0, r2, c15, c1, 0
79
80 ldr r3, =concan_owner
81 ldr r2, [r0, #S_PC] @ current task pc value
82 ldr r1, [r3] @ get current Concan owner
83 sub r2, r2, #4 @ adjust pc back
84 str r2, [r0, #S_PC]
85 add r0, r10, #TI_IWMMXT_STATE @ get task Concan save area
86 str r0, [r3] @ this task now owns Concan regs
87
88 mrc p15, 0, r2, c2, c0, 0
89 mov r2, r2 @ cpwait
90 bl concan_save
91
92 #ifdef CONFIG_PREEMPT_COUNT
93 get_thread_info r10
94 #endif
95 4: dec_preempt_count r10, r3
96 ret r9 @ normal exit from exception
97
98 concan_save:
99
100 teq r1, #0 @ test for last ownership
101 beq concan_load @ no owner, skip save
102
103 tmrc r2, wCon
104
105 @ CUP? wCx
106 tst r2, #0x1
107 beq 1f
108
109 concan_dump:
110
111 wstrw wCSSF, r1, MMX_WCSSF
112 wstrw wCASF, r1, MMX_WCASF
113 wstrw wCGR0, r1, MMX_WCGR0
114 wstrw wCGR1, r1, MMX_WCGR1
115 wstrw wCGR2, r1, MMX_WCGR2
116 wstrw wCGR3, r1, MMX_WCGR3
117
118 1: @ MUP? wRn
119 tst r2, #0x2
120 beq 2f
121
122 wstrd wR0, r1, MMX_WR0
123 wstrd wR1, r1, MMX_WR1
124 wstrd wR2, r1, MMX_WR2
125 wstrd wR3, r1, MMX_WR3
126 wstrd wR4, r1, MMX_WR4
127 wstrd wR5, r1, MMX_WR5
128 wstrd wR6, r1, MMX_WR6
129 wstrd wR7, r1, MMX_WR7
130 wstrd wR8, r1, MMX_WR8
131 wstrd wR9, r1, MMX_WR9
132 wstrd wR10, r1, MMX_WR10
133 wstrd wR11, r1, MMX_WR11
134 wstrd wR12, r1, MMX_WR12
135 wstrd wR13, r1, MMX_WR13
136 wstrd wR14, r1, MMX_WR14
137 wstrd wR15, r1, MMX_WR15
138
139 2: teq r0, #0 @ anything to load?
140 reteq lr @ if not, return
141
142 concan_load:
143
144 @ Load wRn
145 wldrd wR0, r0, MMX_WR0
146 wldrd wR1, r0, MMX_WR1
147 wldrd wR2, r0, MMX_WR2
148 wldrd wR3, r0, MMX_WR3
149 wldrd wR4, r0, MMX_WR4
150 wldrd wR5, r0, MMX_WR5
151 wldrd wR6, r0, MMX_WR6
152 wldrd wR7, r0, MMX_WR7
153 wldrd wR8, r0, MMX_WR8
154 wldrd wR9, r0, MMX_WR9
155 wldrd wR10, r0, MMX_WR10
156 wldrd wR11, r0, MMX_WR11
157 wldrd wR12, r0, MMX_WR12
158 wldrd wR13, r0, MMX_WR13
159 wldrd wR14, r0, MMX_WR14
160 wldrd wR15, r0, MMX_WR15
161
162 @ Load wCx
163 wldrw wCSSF, r0, MMX_WCSSF
164 wldrw wCASF, r0, MMX_WCASF
165 wldrw wCGR0, r0, MMX_WCGR0
166 wldrw wCGR1, r0, MMX_WCGR1
167 wldrw wCGR2, r0, MMX_WCGR2
168 wldrw wCGR3, r0, MMX_WCGR3
169
170 @ clear CUP/MUP (only if r1 != 0)
171 teq r1, #0
172 mov r2, #0
173 reteq lr
174
175 tmcr wCon, r2
176 ret lr
177
178 ENDPROC(iwmmxt_task_enable)
179
180 /*
181 * Back up Concan regs to save area and disable access to them
182 * (mainly for gdb or sleep mode usage)
183 *
184 * r0 = struct thread_info pointer of target task or NULL for any
185 */
186
187 ENTRY(iwmmxt_task_disable)
188
189 stmfd sp!, {r4, lr}
190
191 mrs ip, cpsr
192 orr r2, ip, #PSR_I_BIT @ disable interrupts
193 msr cpsr_c, r2
194
195 ldr r3, =concan_owner
196 add r2, r0, #TI_IWMMXT_STATE @ get task Concan save area
197 ldr r1, [r3] @ get current Concan owner
198 teq r1, #0 @ any current owner?
199 beq 1f @ no: quit
200 teq r0, #0 @ any owner?
201 teqne r1, r2 @ or specified one?
202 bne 1f @ no: quit
203
204 @ enable access to CP0 and CP1
205 mrc p15, 0, r4, c15, c1, 0
206 orr r4, r4, #0x3
207 mcr p15, 0, r4, c15, c1, 0
208
209 mov r0, #0 @ nothing to load
210 str r0, [r3] @ no more current owner
211 mrc p15, 0, r2, c2, c0, 0
212 mov r2, r2 @ cpwait
213 bl concan_save
214
215 @ disable access to CP0 and CP1
216 bic r4, r4, #0x3
217 mcr p15, 0, r4, c15, c1, 0
218
219 mrc p15, 0, r2, c2, c0, 0
220 mov r2, r2 @ cpwait
221
222 1: msr cpsr_c, ip @ restore interrupt mode
223 ldmfd sp!, {r4, pc}
224
225 ENDPROC(iwmmxt_task_disable)
226
227 /*
228 * Copy Concan state to given memory address
229 *
230 * r0 = struct thread_info pointer of target task
231 * r1 = memory address where to store Concan state
232 *
233 * this is called mainly in the creation of signal stack frames
234 */
235
236 ENTRY(iwmmxt_task_copy)
237
238 mrs ip, cpsr
239 orr r2, ip, #PSR_I_BIT @ disable interrupts
240 msr cpsr_c, r2
241
242 ldr r3, =concan_owner
243 add r2, r0, #TI_IWMMXT_STATE @ get task Concan save area
244 ldr r3, [r3] @ get current Concan owner
245 teq r2, r3 @ does this task own it...
246 beq 1f
247
248 @ current Concan values are in the task save area
249 msr cpsr_c, ip @ restore interrupt mode
250 mov r0, r1
251 mov r1, r2
252 mov r2, #MMX_SIZE
253 b memcpy
254
255 1: @ this task owns Concan regs -- grab a copy from there
256 mov r0, #0 @ nothing to load
257 mov r2, #3 @ save all regs
258 mov r3, lr @ preserve return address
259 bl concan_dump
260 msr cpsr_c, ip @ restore interrupt mode
261 ret r3
262
263 ENDPROC(iwmmxt_task_copy)
264
265 /*
266 * Restore Concan state from given memory address
267 *
268 * r0 = struct thread_info pointer of target task
269 * r1 = memory address where to get Concan state from
270 *
271 * this is used to restore Concan state when unwinding a signal stack frame
272 */
273
274 ENTRY(iwmmxt_task_restore)
275
276 mrs ip, cpsr
277 orr r2, ip, #PSR_I_BIT @ disable interrupts
278 msr cpsr_c, r2
279
280 ldr r3, =concan_owner
281 add r2, r0, #TI_IWMMXT_STATE @ get task Concan save area
282 ldr r3, [r3] @ get current Concan owner
283 bic r2, r2, #0x7 @ 64-bit alignment
284 teq r2, r3 @ does this task own it...
285 beq 1f
286
287 @ this task doesn't own Concan regs -- use its save area
288 msr cpsr_c, ip @ restore interrupt mode
289 mov r0, r2
290 mov r2, #MMX_SIZE
291 b memcpy
292
293 1: @ this task owns Concan regs -- load them directly
294 mov r0, r1
295 mov r1, #0 @ don't clear CUP/MUP
296 mov r3, lr @ preserve return address
297 bl concan_load
298 msr cpsr_c, ip @ restore interrupt mode
299 ret r3
300
301 ENDPROC(iwmmxt_task_restore)
302
303 /*
304 * Concan handling on task switch
305 *
306 * r0 = next thread_info pointer
307 *
308 * Called only from the iwmmxt notifier with task preemption disabled.
309 */
310 ENTRY(iwmmxt_task_switch)
311
312 mrc p15, 0, r1, c15, c1, 0
313 @ CP0 and CP1 accessible?
314 tst r1, #0x3
315 bne 1f @ yes: block them for next task
316
317 ldr r2, =concan_owner
318 add r3, r0, #TI_IWMMXT_STATE @ get next task Concan save area
319 ldr r2, [r2] @ get current Concan owner
320 teq r2, r3 @ next task owns it?
321 retne lr @ no: leave Concan disabled
322
323 1: @ flip Concan access
324 eor r1, r1, #0x3
325 mcr p15, 0, r1, c15, c1, 0
326
327 mrc p15, 0, r1, c2, c0, 0
328 sub pc, lr, r1, lsr #32 @ cpwait and return
329
330 ENDPROC(iwmmxt_task_switch)
331
332 /*
333 * Remove Concan ownership of given task
334 *
335 * r0 = struct thread_info pointer
336 */
337 ENTRY(iwmmxt_task_release)
338
339 mrs r2, cpsr
340 orr ip, r2, #PSR_I_BIT @ disable interrupts
341 msr cpsr_c, ip
342 ldr r3, =concan_owner
343 add r0, r0, #TI_IWMMXT_STATE @ get task Concan save area
344 ldr r1, [r3] @ get current Concan owner
345 eors r0, r0, r1 @ if equal...
346 streq r0, [r3] @ then clear ownership
347 msr cpsr_c, r2 @ restore interrupts
348 ret lr
349
350 ENDPROC(iwmmxt_task_release)
351
352 .data
353 .align 2
354 concan_owner:
355 .word 0
356
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