xref: /openbmc/linux/arch/arm/kernel/iwmmxt.S (revision 8d81cd1a) 
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
49ENTRY(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}
56ENDPROC(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
69ENTRY(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
954:	dec_preempt_count r10, r3
96	ret	r9				@ normal exit from exception
97
98concan_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
109concan_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
1181:	@ 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
1392:	teq	r0, #0				@ anything to load?
140	reteq	lr				@ if not, return
141
142concan_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
178ENDPROC(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
187ENTRY(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
2221:	msr	cpsr_c, ip			@ restore interrupt mode
223	ldmfd	sp!, {r4, pc}
224
225ENDPROC(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
236ENTRY(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
2551:	@ 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
263ENDPROC(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
274ENTRY(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
2931:	@ 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
301ENDPROC(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 */
310ENTRY(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
3231:	@ 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
330ENDPROC(iwmmxt_task_switch)
331
332/*
333 * Remove Concan ownership of given task
334 *
335 * r0 = struct thread_info pointer
336 */
337ENTRY(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
350ENDPROC(iwmmxt_task_release)
351
352	.data
353	.align	2
354concan_owner:
355	.word	0
356
357