xref: /openbmc/linux/arch/arm/kernel/iwmmxt.S (revision 18afb028) 
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#if defined(CONFIG_CPU_PJ4) || defined(CONFIG_CPU_PJ4B)
22#define PJ4(code...)		code
23#define XSC(code...)
24#elif defined(CONFIG_CPU_MOHAWK) || \
25	defined(CONFIG_CPU_XSC3) || \
26	defined(CONFIG_CPU_XSCALE)
27#define PJ4(code...)
28#define XSC(code...)		code
29#else
30#error "Unsupported iWMMXt architecture"
31#endif
32
33#define MMX_WR0		 	(0x00)
34#define MMX_WR1		 	(0x08)
35#define MMX_WR2		 	(0x10)
36#define MMX_WR3			(0x18)
37#define MMX_WR4		 	(0x20)
38#define MMX_WR5		 	(0x28)
39#define MMX_WR6		 	(0x30)
40#define MMX_WR7		 	(0x38)
41#define MMX_WR8		 	(0x40)
42#define MMX_WR9		 	(0x48)
43#define MMX_WR10		(0x50)
44#define MMX_WR11		(0x58)
45#define MMX_WR12		(0x60)
46#define MMX_WR13		(0x68)
47#define MMX_WR14		(0x70)
48#define MMX_WR15		(0x78)
49#define MMX_WCSSF		(0x80)
50#define MMX_WCASF		(0x84)
51#define MMX_WCGR0		(0x88)
52#define MMX_WCGR1		(0x8C)
53#define MMX_WCGR2		(0x90)
54#define MMX_WCGR3		(0x94)
55
56#define MMX_SIZE		(0x98)
57
58	.text
59	.arm
60
61ENTRY(iwmmxt_undef_handler)
62	push		{r9, r10, lr}
63	get_thread_info	r10
64	mov		r9, pc
65	b		iwmmxt_task_enable
66	mov		r0, #0
67	pop		{r9, r10, pc}
68ENDPROC(iwmmxt_undef_handler)
69
70/*
71 * Lazy switching of Concan coprocessor context
72 *
73 * r0  = struct pt_regs pointer
74 * r10 = struct thread_info pointer
75 * r9  = ret_from_exception
76 * lr  = undefined instr exit
77 *
78 * called from prefetch exception handler with interrupts enabled
79 */
80
81ENTRY(iwmmxt_task_enable)
82	inc_preempt_count r10, r3
83
84	XSC(mrc	p15, 0, r2, c15, c1, 0)
85	PJ4(mrc p15, 0, r2, c1, c0, 2)
86	@ CP0 and CP1 accessible?
87	XSC(tst	r2, #0x3)
88	PJ4(tst	r2, #0xf)
89	bne	4f				@ if so no business here
90	@ enable access to CP0 and CP1
91	XSC(orr	r2, r2, #0x3)
92	XSC(mcr	p15, 0, r2, c15, c1, 0)
93	PJ4(orr	r2, r2, #0xf)
94	PJ4(mcr	p15, 0, r2, c1, c0, 2)
95
96	ldr	r3, =concan_owner
97	ldr	r2, [r0, #S_PC]			@ current task pc value
98	ldr	r1, [r3]			@ get current Concan owner
99	sub	r2, r2, #4			@ adjust pc back
100	str	r2, [r0, #S_PC]
101	add	r0, r10, #TI_IWMMXT_STATE	@ get task Concan save area
102	str	r0, [r3]			@ this task now owns Concan regs
103
104	mrc	p15, 0, r2, c2, c0, 0
105	mov	r2, r2				@ cpwait
106	bl	concan_save
107
108#ifdef CONFIG_PREEMPT_COUNT
109	get_thread_info r10
110#endif
1114:	dec_preempt_count r10, r3
112	ret	r9				@ normal exit from exception
113
114concan_save:
115
116	teq	r1, #0				@ test for last ownership
117	beq	concan_load			@ no owner, skip save
118
119	tmrc	r2, wCon
120
121	@ CUP? wCx
122	tst	r2, #0x1
123	beq 	1f
124
125concan_dump:
126
127	wstrw	wCSSF, r1, MMX_WCSSF
128	wstrw	wCASF, r1, MMX_WCASF
129	wstrw	wCGR0, r1, MMX_WCGR0
130	wstrw	wCGR1, r1, MMX_WCGR1
131	wstrw	wCGR2, r1, MMX_WCGR2
132	wstrw	wCGR3, r1, MMX_WCGR3
133
1341:	@ MUP? wRn
135	tst	r2, #0x2
136	beq	2f
137
138	wstrd	wR0,  r1, MMX_WR0
139	wstrd	wR1,  r1, MMX_WR1
140	wstrd	wR2,  r1, MMX_WR2
141	wstrd	wR3,  r1, MMX_WR3
142	wstrd	wR4,  r1, MMX_WR4
143	wstrd	wR5,  r1, MMX_WR5
144	wstrd	wR6,  r1, MMX_WR6
145	wstrd	wR7,  r1, MMX_WR7
146	wstrd	wR8,  r1, MMX_WR8
147	wstrd	wR9,  r1, MMX_WR9
148	wstrd	wR10, r1, MMX_WR10
149	wstrd	wR11, r1, MMX_WR11
150	wstrd	wR12, r1, MMX_WR12
151	wstrd	wR13, r1, MMX_WR13
152	wstrd	wR14, r1, MMX_WR14
153	wstrd	wR15, r1, MMX_WR15
154
1552:	teq	r0, #0				@ anything to load?
156	reteq	lr				@ if not, return
157
158concan_load:
159
160	@ Load wRn
161	wldrd	wR0,  r0, MMX_WR0
162	wldrd	wR1,  r0, MMX_WR1
163	wldrd	wR2,  r0, MMX_WR2
164	wldrd	wR3,  r0, MMX_WR3
165	wldrd	wR4,  r0, MMX_WR4
166	wldrd	wR5,  r0, MMX_WR5
167	wldrd	wR6,  r0, MMX_WR6
168	wldrd	wR7,  r0, MMX_WR7
169	wldrd	wR8,  r0, MMX_WR8
170	wldrd	wR9,  r0, MMX_WR9
171	wldrd	wR10, r0, MMX_WR10
172	wldrd	wR11, r0, MMX_WR11
173	wldrd	wR12, r0, MMX_WR12
174	wldrd	wR13, r0, MMX_WR13
175	wldrd	wR14, r0, MMX_WR14
176	wldrd	wR15, r0, MMX_WR15
177
178	@ Load wCx
179	wldrw	wCSSF, r0, MMX_WCSSF
180	wldrw	wCASF, r0, MMX_WCASF
181	wldrw	wCGR0, r0, MMX_WCGR0
182	wldrw	wCGR1, r0, MMX_WCGR1
183	wldrw	wCGR2, r0, MMX_WCGR2
184	wldrw	wCGR3, r0, MMX_WCGR3
185
186	@ clear CUP/MUP (only if r1 != 0)
187	teq	r1, #0
188	mov 	r2, #0
189	reteq	lr
190
191	tmcr	wCon, r2
192	ret	lr
193
194ENDPROC(iwmmxt_task_enable)
195
196/*
197 * Back up Concan regs to save area and disable access to them
198 * (mainly for gdb or sleep mode usage)
199 *
200 * r0 = struct thread_info pointer of target task or NULL for any
201 */
202
203ENTRY(iwmmxt_task_disable)
204
205	stmfd	sp!, {r4, lr}
206
207	mrs	ip, cpsr
208	orr	r2, ip, #PSR_I_BIT		@ disable interrupts
209	msr	cpsr_c, r2
210
211	ldr	r3, =concan_owner
212	add	r2, r0, #TI_IWMMXT_STATE	@ get task Concan save area
213	ldr	r1, [r3]			@ get current Concan owner
214	teq	r1, #0				@ any current owner?
215	beq	1f				@ no: quit
216	teq	r0, #0				@ any owner?
217	teqne	r1, r2				@ or specified one?
218	bne	1f				@ no: quit
219
220	@ enable access to CP0 and CP1
221	XSC(mrc	p15, 0, r4, c15, c1, 0)
222	XSC(orr	r4, r4, #0x3)
223	XSC(mcr	p15, 0, r4, c15, c1, 0)
224	PJ4(mrc p15, 0, r4, c1, c0, 2)
225	PJ4(orr	r4, r4, #0xf)
226	PJ4(mcr	p15, 0, r4, c1, c0, 2)
227
228	mov	r0, #0				@ nothing to load
229	str	r0, [r3]			@ no more current owner
230	mrc	p15, 0, r2, c2, c0, 0
231	mov	r2, r2				@ cpwait
232	bl	concan_save
233
234	@ disable access to CP0 and CP1
235	XSC(bic	r4, r4, #0x3)
236	XSC(mcr	p15, 0, r4, c15, c1, 0)
237	PJ4(bic	r4, r4, #0xf)
238	PJ4(mcr	p15, 0, r4, c1, c0, 2)
239
240	mrc	p15, 0, r2, c2, c0, 0
241	mov	r2, r2				@ cpwait
242
2431:	msr	cpsr_c, ip			@ restore interrupt mode
244	ldmfd	sp!, {r4, pc}
245
246ENDPROC(iwmmxt_task_disable)
247
248/*
249 * Copy Concan state to given memory address
250 *
251 * r0 = struct thread_info pointer of target task
252 * r1 = memory address where to store Concan state
253 *
254 * this is called mainly in the creation of signal stack frames
255 */
256
257ENTRY(iwmmxt_task_copy)
258
259	mrs	ip, cpsr
260	orr	r2, ip, #PSR_I_BIT		@ disable interrupts
261	msr	cpsr_c, r2
262
263	ldr	r3, =concan_owner
264	add	r2, r0, #TI_IWMMXT_STATE	@ get task Concan save area
265	ldr	r3, [r3]			@ get current Concan owner
266	teq	r2, r3				@ does this task own it...
267	beq	1f
268
269	@ current Concan values are in the task save area
270	msr	cpsr_c, ip			@ restore interrupt mode
271	mov	r0, r1
272	mov	r1, r2
273	mov	r2, #MMX_SIZE
274	b	memcpy
275
2761:	@ this task owns Concan regs -- grab a copy from there
277	mov	r0, #0				@ nothing to load
278	mov	r2, #3				@ save all regs
279	mov	r3, lr				@ preserve return address
280	bl	concan_dump
281	msr	cpsr_c, ip			@ restore interrupt mode
282	ret	r3
283
284ENDPROC(iwmmxt_task_copy)
285
286/*
287 * Restore Concan state from given memory address
288 *
289 * r0 = struct thread_info pointer of target task
290 * r1 = memory address where to get Concan state from
291 *
292 * this is used to restore Concan state when unwinding a signal stack frame
293 */
294
295ENTRY(iwmmxt_task_restore)
296
297	mrs	ip, cpsr
298	orr	r2, ip, #PSR_I_BIT		@ disable interrupts
299	msr	cpsr_c, r2
300
301	ldr	r3, =concan_owner
302	add	r2, r0, #TI_IWMMXT_STATE	@ get task Concan save area
303	ldr	r3, [r3]			@ get current Concan owner
304	bic	r2, r2, #0x7			@ 64-bit alignment
305	teq	r2, r3				@ does this task own it...
306	beq	1f
307
308	@ this task doesn't own Concan regs -- use its save area
309	msr	cpsr_c, ip			@ restore interrupt mode
310	mov	r0, r2
311	mov	r2, #MMX_SIZE
312	b	memcpy
313
3141:	@ this task owns Concan regs -- load them directly
315	mov	r0, r1
316	mov	r1, #0				@ don't clear CUP/MUP
317	mov	r3, lr				@ preserve return address
318	bl	concan_load
319	msr	cpsr_c, ip			@ restore interrupt mode
320	ret	r3
321
322ENDPROC(iwmmxt_task_restore)
323
324/*
325 * Concan handling on task switch
326 *
327 * r0 = next thread_info pointer
328 *
329 * Called only from the iwmmxt notifier with task preemption disabled.
330 */
331ENTRY(iwmmxt_task_switch)
332
333	XSC(mrc	p15, 0, r1, c15, c1, 0)
334	PJ4(mrc	p15, 0, r1, c1, c0, 2)
335	@ CP0 and CP1 accessible?
336	XSC(tst	r1, #0x3)
337	PJ4(tst	r1, #0xf)
338	bne	1f				@ yes: block them for next task
339
340	ldr	r2, =concan_owner
341	add	r3, r0, #TI_IWMMXT_STATE	@ get next task Concan save area
342	ldr	r2, [r2]			@ get current Concan owner
343	teq	r2, r3				@ next task owns it?
344	retne	lr				@ no: leave Concan disabled
345
3461:	@ flip Concan access
347	XSC(eor	r1, r1, #0x3)
348	XSC(mcr	p15, 0, r1, c15, c1, 0)
349	PJ4(eor r1, r1, #0xf)
350	PJ4(mcr	p15, 0, r1, c1, c0, 2)
351
352	mrc	p15, 0, r1, c2, c0, 0
353	sub	pc, lr, r1, lsr #32		@ cpwait and return
354
355ENDPROC(iwmmxt_task_switch)
356
357/*
358 * Remove Concan ownership of given task
359 *
360 * r0 = struct thread_info pointer
361 */
362ENTRY(iwmmxt_task_release)
363
364	mrs	r2, cpsr
365	orr	ip, r2, #PSR_I_BIT		@ disable interrupts
366	msr	cpsr_c, ip
367	ldr	r3, =concan_owner
368	add	r0, r0, #TI_IWMMXT_STATE	@ get task Concan save area
369	ldr	r1, [r3]			@ get current Concan owner
370	eors	r0, r0, r1			@ if equal...
371	streq	r0, [r3]			@ then clear ownership
372	msr	cpsr_c, r2			@ restore interrupts
373	ret	lr
374
375ENDPROC(iwmmxt_task_release)
376
377	.data
378	.align	2
379concan_owner:
380	.word	0
381
382