xref: /openbmc/linux/arch/arm/kernel/iwmmxt.S (revision a2cce7a9) 
1/*
2 *  linux/arch/arm/kernel/iwmmxt.S
3 *
4 *  XScale iWMMXt (Concan) context switching and handling
5 *
6 *  Initial code:
7 *  Copyright (c) 2003, Intel Corporation
8 *
9 *  Full lazy switching support, optimizations and more, by Nicolas Pitre
10*   Copyright (c) 2003-2004, MontaVista Software, Inc.
11 *
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License version 2 as
14 * published by the Free Software Foundation.
15 */
16
17#include <linux/linkage.h>
18#include <asm/ptrace.h>
19#include <asm/thread_info.h>
20#include <asm/asm-offsets.h>
21#include <asm/assembler.h>
22
23#if defined(CONFIG_CPU_PJ4) || defined(CONFIG_CPU_PJ4B)
24#define PJ4(code...)		code
25#define XSC(code...)
26#elif defined(CONFIG_CPU_MOHAWK) || \
27	defined(CONFIG_CPU_XSC3) || \
28	defined(CONFIG_CPU_XSCALE)
29#define PJ4(code...)
30#define XSC(code...)		code
31#else
32#error "Unsupported iWMMXt architecture"
33#endif
34
35#define MMX_WR0		 	(0x00)
36#define MMX_WR1		 	(0x08)
37#define MMX_WR2		 	(0x10)
38#define MMX_WR3			(0x18)
39#define MMX_WR4		 	(0x20)
40#define MMX_WR5		 	(0x28)
41#define MMX_WR6		 	(0x30)
42#define MMX_WR7		 	(0x38)
43#define MMX_WR8		 	(0x40)
44#define MMX_WR9		 	(0x48)
45#define MMX_WR10		(0x50)
46#define MMX_WR11		(0x58)
47#define MMX_WR12		(0x60)
48#define MMX_WR13		(0x68)
49#define MMX_WR14		(0x70)
50#define MMX_WR15		(0x78)
51#define MMX_WCSSF		(0x80)
52#define MMX_WCASF		(0x84)
53#define MMX_WCGR0		(0x88)
54#define MMX_WCGR1		(0x8C)
55#define MMX_WCGR2		(0x90)
56#define MMX_WCGR3		(0x94)
57
58#define MMX_SIZE		(0x98)
59
60	.text
61	.arm
62
63/*
64 * Lazy switching of Concan coprocessor context
65 *
66 * r10 = struct thread_info pointer
67 * r9  = ret_from_exception
68 * lr  = undefined instr exit
69 *
70 * called from prefetch exception handler with interrupts enabled
71 */
72
73ENTRY(iwmmxt_task_enable)
74	inc_preempt_count r10, r3
75
76	XSC(mrc	p15, 0, r2, c15, c1, 0)
77	PJ4(mrc p15, 0, r2, c1, c0, 2)
78	@ CP0 and CP1 accessible?
79	XSC(tst	r2, #0x3)
80	PJ4(tst	r2, #0xf)
81	bne	4f				@ if so no business here
82	@ enable access to CP0 and CP1
83	XSC(orr	r2, r2, #0x3)
84	XSC(mcr	p15, 0, r2, c15, c1, 0)
85	PJ4(orr	r2, r2, #0xf)
86	PJ4(mcr	p15, 0, r2, c1, c0, 2)
87
88	ldr	r3, =concan_owner
89	add	r0, r10, #TI_IWMMXT_STATE	@ get task Concan save area
90	ldr	r2, [sp, #60]			@ current task pc value
91	ldr	r1, [r3]			@ get current Concan owner
92	str	r0, [r3]			@ this task now owns Concan regs
93	sub	r2, r2, #4			@ adjust pc back
94	str	r2, [sp, #60]
95
96	mrc	p15, 0, r2, c2, c0, 0
97	mov	r2, r2				@ cpwait
98	bl	concan_save
99
100#ifdef CONFIG_PREEMPT_COUNT
101	get_thread_info r10
102#endif
1034:	dec_preempt_count r10, r3
104	ret	r9				@ normal exit from exception
105
106concan_save:
107
108	teq	r1, #0				@ test for last ownership
109	beq	concan_load			@ no owner, skip save
110
111	tmrc	r2, wCon
112
113	@ CUP? wCx
114	tst	r2, #0x1
115	beq 	1f
116
117concan_dump:
118
119	wstrw	wCSSF, [r1, #MMX_WCSSF]
120	wstrw	wCASF, [r1, #MMX_WCASF]
121	wstrw	wCGR0, [r1, #MMX_WCGR0]
122	wstrw	wCGR1, [r1, #MMX_WCGR1]
123	wstrw	wCGR2, [r1, #MMX_WCGR2]
124	wstrw	wCGR3, [r1, #MMX_WCGR3]
125
1261:	@ MUP? wRn
127	tst	r2, #0x2
128	beq	2f
129
130	wstrd	wR0,  [r1, #MMX_WR0]
131	wstrd	wR1,  [r1, #MMX_WR1]
132	wstrd	wR2,  [r1, #MMX_WR2]
133	wstrd	wR3,  [r1, #MMX_WR3]
134	wstrd	wR4,  [r1, #MMX_WR4]
135	wstrd	wR5,  [r1, #MMX_WR5]
136	wstrd	wR6,  [r1, #MMX_WR6]
137	wstrd	wR7,  [r1, #MMX_WR7]
138	wstrd	wR8,  [r1, #MMX_WR8]
139	wstrd	wR9,  [r1, #MMX_WR9]
140	wstrd	wR10, [r1, #MMX_WR10]
141	wstrd	wR11, [r1, #MMX_WR11]
142	wstrd	wR12, [r1, #MMX_WR12]
143	wstrd	wR13, [r1, #MMX_WR13]
144	wstrd	wR14, [r1, #MMX_WR14]
145	wstrd	wR15, [r1, #MMX_WR15]
146
1472:	teq	r0, #0				@ anything to load?
148	reteq	lr				@ if not, return
149
150concan_load:
151
152	@ Load wRn
153	wldrd	wR0,  [r0, #MMX_WR0]
154	wldrd	wR1,  [r0, #MMX_WR1]
155	wldrd	wR2,  [r0, #MMX_WR2]
156	wldrd	wR3,  [r0, #MMX_WR3]
157	wldrd	wR4,  [r0, #MMX_WR4]
158	wldrd	wR5,  [r0, #MMX_WR5]
159	wldrd	wR6,  [r0, #MMX_WR6]
160	wldrd	wR7,  [r0, #MMX_WR7]
161	wldrd	wR8,  [r0, #MMX_WR8]
162	wldrd	wR9,  [r0, #MMX_WR9]
163	wldrd	wR10, [r0, #MMX_WR10]
164	wldrd	wR11, [r0, #MMX_WR11]
165	wldrd	wR12, [r0, #MMX_WR12]
166	wldrd	wR13, [r0, #MMX_WR13]
167	wldrd	wR14, [r0, #MMX_WR14]
168	wldrd	wR15, [r0, #MMX_WR15]
169
170	@ Load wCx
171	wldrw	wCSSF, [r0, #MMX_WCSSF]
172	wldrw	wCASF, [r0, #MMX_WCASF]
173	wldrw	wCGR0, [r0, #MMX_WCGR0]
174	wldrw	wCGR1, [r0, #MMX_WCGR1]
175	wldrw	wCGR2, [r0, #MMX_WCGR2]
176	wldrw	wCGR3, [r0, #MMX_WCGR3]
177
178	@ clear CUP/MUP (only if r1 != 0)
179	teq	r1, #0
180	mov 	r2, #0
181	reteq	lr
182
183	tmcr	wCon, r2
184	ret	lr
185
186ENDPROC(iwmmxt_task_enable)
187
188/*
189 * Back up Concan regs to save area and disable access to them
190 * (mainly for gdb or sleep mode usage)
191 *
192 * r0 = struct thread_info pointer of target task or NULL for any
193 */
194
195ENTRY(iwmmxt_task_disable)
196
197	stmfd	sp!, {r4, lr}
198
199	mrs	ip, cpsr
200	orr	r2, ip, #PSR_I_BIT		@ disable interrupts
201	msr	cpsr_c, r2
202
203	ldr	r3, =concan_owner
204	add	r2, r0, #TI_IWMMXT_STATE	@ get task Concan save area
205	ldr	r1, [r3]			@ get current Concan owner
206	teq	r1, #0				@ any current owner?
207	beq	1f				@ no: quit
208	teq	r0, #0				@ any owner?
209	teqne	r1, r2				@ or specified one?
210	bne	1f				@ no: quit
211
212	@ enable access to CP0 and CP1
213	XSC(mrc	p15, 0, r4, c15, c1, 0)
214	XSC(orr	r4, r4, #0x3)
215	XSC(mcr	p15, 0, r4, c15, c1, 0)
216	PJ4(mrc p15, 0, r4, c1, c0, 2)
217	PJ4(orr	r4, r4, #0xf)
218	PJ4(mcr	p15, 0, r4, c1, c0, 2)
219
220	mov	r0, #0				@ nothing to load
221	str	r0, [r3]			@ no more current owner
222	mrc	p15, 0, r2, c2, c0, 0
223	mov	r2, r2				@ cpwait
224	bl	concan_save
225
226	@ disable access to CP0 and CP1
227	XSC(bic	r4, r4, #0x3)
228	XSC(mcr	p15, 0, r4, c15, c1, 0)
229	PJ4(bic	r4, r4, #0xf)
230	PJ4(mcr	p15, 0, r4, c1, c0, 2)
231
232	mrc	p15, 0, r2, c2, c0, 0
233	mov	r2, r2				@ cpwait
234
2351:	msr	cpsr_c, ip			@ restore interrupt mode
236	ldmfd	sp!, {r4, pc}
237
238ENDPROC(iwmmxt_task_disable)
239
240/*
241 * Copy Concan state to given memory address
242 *
243 * r0 = struct thread_info pointer of target task
244 * r1 = memory address where to store Concan state
245 *
246 * this is called mainly in the creation of signal stack frames
247 */
248
249ENTRY(iwmmxt_task_copy)
250
251	mrs	ip, cpsr
252	orr	r2, ip, #PSR_I_BIT		@ disable interrupts
253	msr	cpsr_c, r2
254
255	ldr	r3, =concan_owner
256	add	r2, r0, #TI_IWMMXT_STATE	@ get task Concan save area
257	ldr	r3, [r3]			@ get current Concan owner
258	teq	r2, r3				@ does this task own it...
259	beq	1f
260
261	@ current Concan values are in the task save area
262	msr	cpsr_c, ip			@ restore interrupt mode
263	mov	r0, r1
264	mov	r1, r2
265	mov	r2, #MMX_SIZE
266	b	memcpy
267
2681:	@ this task owns Concan regs -- grab a copy from there
269	mov	r0, #0				@ nothing to load
270	mov	r2, #3				@ save all regs
271	mov	r3, lr				@ preserve return address
272	bl	concan_dump
273	msr	cpsr_c, ip			@ restore interrupt mode
274	ret	r3
275
276ENDPROC(iwmmxt_task_copy)
277
278/*
279 * Restore Concan state from given memory address
280 *
281 * r0 = struct thread_info pointer of target task
282 * r1 = memory address where to get Concan state from
283 *
284 * this is used to restore Concan state when unwinding a signal stack frame
285 */
286
287ENTRY(iwmmxt_task_restore)
288
289	mrs	ip, cpsr
290	orr	r2, ip, #PSR_I_BIT		@ disable interrupts
291	msr	cpsr_c, r2
292
293	ldr	r3, =concan_owner
294	add	r2, r0, #TI_IWMMXT_STATE	@ get task Concan save area
295	ldr	r3, [r3]			@ get current Concan owner
296	bic	r2, r2, #0x7			@ 64-bit alignment
297	teq	r2, r3				@ does this task own it...
298	beq	1f
299
300	@ this task doesn't own Concan regs -- use its save area
301	msr	cpsr_c, ip			@ restore interrupt mode
302	mov	r0, r2
303	mov	r2, #MMX_SIZE
304	b	memcpy
305
3061:	@ this task owns Concan regs -- load them directly
307	mov	r0, r1
308	mov	r1, #0				@ don't clear CUP/MUP
309	mov	r3, lr				@ preserve return address
310	bl	concan_load
311	msr	cpsr_c, ip			@ restore interrupt mode
312	ret	r3
313
314ENDPROC(iwmmxt_task_restore)
315
316/*
317 * Concan handling on task switch
318 *
319 * r0 = next thread_info pointer
320 *
321 * Called only from the iwmmxt notifier with task preemption disabled.
322 */
323ENTRY(iwmmxt_task_switch)
324
325	XSC(mrc	p15, 0, r1, c15, c1, 0)
326	PJ4(mrc	p15, 0, r1, c1, c0, 2)
327	@ CP0 and CP1 accessible?
328	XSC(tst	r1, #0x3)
329	PJ4(tst	r1, #0xf)
330	bne	1f				@ yes: block them for next task
331
332	ldr	r2, =concan_owner
333	add	r3, r0, #TI_IWMMXT_STATE	@ get next task Concan save area
334	ldr	r2, [r2]			@ get current Concan owner
335	teq	r2, r3				@ next task owns it?
336	retne	lr				@ no: leave Concan disabled
337
3381:	@ flip Concan access
339	XSC(eor	r1, r1, #0x3)
340	XSC(mcr	p15, 0, r1, c15, c1, 0)
341	PJ4(eor r1, r1, #0xf)
342	PJ4(mcr	p15, 0, r1, c1, c0, 2)
343
344	mrc	p15, 0, r1, c2, c0, 0
345	sub	pc, lr, r1, lsr #32		@ cpwait and return
346
347ENDPROC(iwmmxt_task_switch)
348
349/*
350 * Remove Concan ownership of given task
351 *
352 * r0 = struct thread_info pointer
353 */
354ENTRY(iwmmxt_task_release)
355
356	mrs	r2, cpsr
357	orr	ip, r2, #PSR_I_BIT		@ disable interrupts
358	msr	cpsr_c, ip
359	ldr	r3, =concan_owner
360	add	r0, r0, #TI_IWMMXT_STATE	@ get task Concan save area
361	ldr	r1, [r3]			@ get current Concan owner
362	eors	r0, r0, r1			@ if equal...
363	streq	r0, [r3]			@ then clear ownership
364	msr	cpsr_c, r2			@ restore interrupts
365	ret	lr
366
367ENDPROC(iwmmxt_task_release)
368
369	.data
370concan_owner:
371	.word	0
372
373