xref: /openbmc/linux/arch/arm/kernel/iwmmxt.S (revision 588b48ca) 
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
62/*
63 * Lazy switching of Concan coprocessor context
64 *
65 * r10 = struct thread_info pointer
66 * r9  = ret_from_exception
67 * lr  = undefined instr exit
68 *
69 * called from prefetch exception handler with interrupts enabled
70 */
71
72ENTRY(iwmmxt_task_enable)
73	inc_preempt_count r10, r3
74
75	XSC(mrc	p15, 0, r2, c15, c1, 0)
76	PJ4(mrc p15, 0, r2, c1, c0, 2)
77	@ CP0 and CP1 accessible?
78	XSC(tst	r2, #0x3)
79	PJ4(tst	r2, #0xf)
80	bne	4f				@ if so no business here
81	@ enable access to CP0 and CP1
82	XSC(orr	r2, r2, #0x3)
83	XSC(mcr	p15, 0, r2, c15, c1, 0)
84	PJ4(orr	r2, r2, #0xf)
85	PJ4(mcr	p15, 0, r2, c1, c0, 2)
86
87	ldr	r3, =concan_owner
88	add	r0, r10, #TI_IWMMXT_STATE	@ get task Concan save area
89	ldr	r2, [sp, #60]			@ current task pc value
90	ldr	r1, [r3]			@ get current Concan owner
91	str	r0, [r3]			@ this task now owns Concan regs
92	sub	r2, r2, #4			@ adjust pc back
93	str	r2, [sp, #60]
94
95	mrc	p15, 0, r2, c2, c0, 0
96	mov	r2, r2				@ cpwait
97	bl	concan_save
98
99#ifdef CONFIG_PREEMPT_COUNT
100	get_thread_info r10
101#endif
1024:	dec_preempt_count r10, r3
103	ret	r9				@ normal exit from exception
104
105concan_save:
106
107	teq	r1, #0				@ test for last ownership
108	beq	concan_load			@ no owner, skip save
109
110	tmrc	r2, wCon
111
112	@ CUP? wCx
113	tst	r2, #0x1
114	beq 	1f
115
116concan_dump:
117
118	wstrw	wCSSF, [r1, #MMX_WCSSF]
119	wstrw	wCASF, [r1, #MMX_WCASF]
120	wstrw	wCGR0, [r1, #MMX_WCGR0]
121	wstrw	wCGR1, [r1, #MMX_WCGR1]
122	wstrw	wCGR2, [r1, #MMX_WCGR2]
123	wstrw	wCGR3, [r1, #MMX_WCGR3]
124
1251:	@ MUP? wRn
126	tst	r2, #0x2
127	beq	2f
128
129	wstrd	wR0,  [r1, #MMX_WR0]
130	wstrd	wR1,  [r1, #MMX_WR1]
131	wstrd	wR2,  [r1, #MMX_WR2]
132	wstrd	wR3,  [r1, #MMX_WR3]
133	wstrd	wR4,  [r1, #MMX_WR4]
134	wstrd	wR5,  [r1, #MMX_WR5]
135	wstrd	wR6,  [r1, #MMX_WR6]
136	wstrd	wR7,  [r1, #MMX_WR7]
137	wstrd	wR8,  [r1, #MMX_WR8]
138	wstrd	wR9,  [r1, #MMX_WR9]
139	wstrd	wR10, [r1, #MMX_WR10]
140	wstrd	wR11, [r1, #MMX_WR11]
141	wstrd	wR12, [r1, #MMX_WR12]
142	wstrd	wR13, [r1, #MMX_WR13]
143	wstrd	wR14, [r1, #MMX_WR14]
144	wstrd	wR15, [r1, #MMX_WR15]
145
1462:	teq	r0, #0				@ anything to load?
147	reteq	lr				@ if not, return
148
149concan_load:
150
151	@ Load wRn
152	wldrd	wR0,  [r0, #MMX_WR0]
153	wldrd	wR1,  [r0, #MMX_WR1]
154	wldrd	wR2,  [r0, #MMX_WR2]
155	wldrd	wR3,  [r0, #MMX_WR3]
156	wldrd	wR4,  [r0, #MMX_WR4]
157	wldrd	wR5,  [r0, #MMX_WR5]
158	wldrd	wR6,  [r0, #MMX_WR6]
159	wldrd	wR7,  [r0, #MMX_WR7]
160	wldrd	wR8,  [r0, #MMX_WR8]
161	wldrd	wR9,  [r0, #MMX_WR9]
162	wldrd	wR10, [r0, #MMX_WR10]
163	wldrd	wR11, [r0, #MMX_WR11]
164	wldrd	wR12, [r0, #MMX_WR12]
165	wldrd	wR13, [r0, #MMX_WR13]
166	wldrd	wR14, [r0, #MMX_WR14]
167	wldrd	wR15, [r0, #MMX_WR15]
168
169	@ Load wCx
170	wldrw	wCSSF, [r0, #MMX_WCSSF]
171	wldrw	wCASF, [r0, #MMX_WCASF]
172	wldrw	wCGR0, [r0, #MMX_WCGR0]
173	wldrw	wCGR1, [r0, #MMX_WCGR1]
174	wldrw	wCGR2, [r0, #MMX_WCGR2]
175	wldrw	wCGR3, [r0, #MMX_WCGR3]
176
177	@ clear CUP/MUP (only if r1 != 0)
178	teq	r1, #0
179	mov 	r2, #0
180	reteq	lr
181
182	tmcr	wCon, r2
183	ret	lr
184
185/*
186 * Back up Concan regs to save area and disable access to them
187 * (mainly for gdb or sleep mode usage)
188 *
189 * r0 = struct thread_info pointer of target task or NULL for any
190 */
191
192ENTRY(iwmmxt_task_disable)
193
194	stmfd	sp!, {r4, lr}
195
196	mrs	ip, cpsr
197	orr	r2, ip, #PSR_I_BIT		@ disable interrupts
198	msr	cpsr_c, r2
199
200	ldr	r3, =concan_owner
201	add	r2, r0, #TI_IWMMXT_STATE	@ get task Concan save area
202	ldr	r1, [r3]			@ get current Concan owner
203	teq	r1, #0				@ any current owner?
204	beq	1f				@ no: quit
205	teq	r0, #0				@ any owner?
206	teqne	r1, r2				@ or specified one?
207	bne	1f				@ no: quit
208
209	@ enable access to CP0 and CP1
210	XSC(mrc	p15, 0, r4, c15, c1, 0)
211	XSC(orr	r4, r4, #0x3)
212	XSC(mcr	p15, 0, r4, c15, c1, 0)
213	PJ4(mrc p15, 0, r4, c1, c0, 2)
214	PJ4(orr	r4, r4, #0xf)
215	PJ4(mcr	p15, 0, r4, c1, c0, 2)
216
217	mov	r0, #0				@ nothing to load
218	str	r0, [r3]			@ no more current owner
219	mrc	p15, 0, r2, c2, c0, 0
220	mov	r2, r2				@ cpwait
221	bl	concan_save
222
223	@ disable access to CP0 and CP1
224	XSC(bic	r4, r4, #0x3)
225	XSC(mcr	p15, 0, r4, c15, c1, 0)
226	PJ4(bic	r4, r4, #0xf)
227	PJ4(mcr	p15, 0, r4, c1, c0, 2)
228
229	mrc	p15, 0, r2, c2, c0, 0
230	mov	r2, r2				@ cpwait
231
2321:	msr	cpsr_c, ip			@ restore interrupt mode
233	ldmfd	sp!, {r4, pc}
234
235/*
236 * Copy Concan state to given memory address
237 *
238 * r0 = struct thread_info pointer of target task
239 * r1 = memory address where to store Concan state
240 *
241 * this is called mainly in the creation of signal stack frames
242 */
243
244ENTRY(iwmmxt_task_copy)
245
246	mrs	ip, cpsr
247	orr	r2, ip, #PSR_I_BIT		@ disable interrupts
248	msr	cpsr_c, r2
249
250	ldr	r3, =concan_owner
251	add	r2, r0, #TI_IWMMXT_STATE	@ get task Concan save area
252	ldr	r3, [r3]			@ get current Concan owner
253	teq	r2, r3				@ does this task own it...
254	beq	1f
255
256	@ current Concan values are in the task save area
257	msr	cpsr_c, ip			@ restore interrupt mode
258	mov	r0, r1
259	mov	r1, r2
260	mov	r2, #MMX_SIZE
261	b	memcpy
262
2631:	@ this task owns Concan regs -- grab a copy from there
264	mov	r0, #0				@ nothing to load
265	mov	r2, #3				@ save all regs
266	mov	r3, lr				@ preserve return address
267	bl	concan_dump
268	msr	cpsr_c, ip			@ restore interrupt mode
269	ret	r3
270
271/*
272 * Restore Concan state from given memory address
273 *
274 * r0 = struct thread_info pointer of target task
275 * r1 = memory address where to get Concan state from
276 *
277 * this is used to restore Concan state when unwinding a signal stack frame
278 */
279
280ENTRY(iwmmxt_task_restore)
281
282	mrs	ip, cpsr
283	orr	r2, ip, #PSR_I_BIT		@ disable interrupts
284	msr	cpsr_c, r2
285
286	ldr	r3, =concan_owner
287	add	r2, r0, #TI_IWMMXT_STATE	@ get task Concan save area
288	ldr	r3, [r3]			@ get current Concan owner
289	bic	r2, r2, #0x7			@ 64-bit alignment
290	teq	r2, r3				@ does this task own it...
291	beq	1f
292
293	@ this task doesn't own Concan regs -- use its save area
294	msr	cpsr_c, ip			@ restore interrupt mode
295	mov	r0, r2
296	mov	r2, #MMX_SIZE
297	b	memcpy
298
2991:	@ this task owns Concan regs -- load them directly
300	mov	r0, r1
301	mov	r1, #0				@ don't clear CUP/MUP
302	mov	r3, lr				@ preserve return address
303	bl	concan_load
304	msr	cpsr_c, ip			@ restore interrupt mode
305	ret	r3
306
307/*
308 * Concan handling on task switch
309 *
310 * r0 = next thread_info pointer
311 *
312 * Called only from the iwmmxt notifier with task preemption disabled.
313 */
314ENTRY(iwmmxt_task_switch)
315
316	XSC(mrc	p15, 0, r1, c15, c1, 0)
317	PJ4(mrc	p15, 0, r1, c1, c0, 2)
318	@ CP0 and CP1 accessible?
319	XSC(tst	r1, #0x3)
320	PJ4(tst	r1, #0xf)
321	bne	1f				@ yes: block them for next task
322
323	ldr	r2, =concan_owner
324	add	r3, r0, #TI_IWMMXT_STATE	@ get next task Concan save area
325	ldr	r2, [r2]			@ get current Concan owner
326	teq	r2, r3				@ next task owns it?
327	retne	lr				@ no: leave Concan disabled
328
3291:	@ flip Concan access
330	XSC(eor	r1, r1, #0x3)
331	XSC(mcr	p15, 0, r1, c15, c1, 0)
332	PJ4(eor r1, r1, #0xf)
333	PJ4(mcr	p15, 0, r1, c1, c0, 2)
334
335	mrc	p15, 0, r1, c2, c0, 0
336	sub	pc, lr, r1, lsr #32		@ cpwait and return
337
338/*
339 * Remove Concan ownership of given task
340 *
341 * r0 = struct thread_info pointer
342 */
343ENTRY(iwmmxt_task_release)
344
345	mrs	r2, cpsr
346	orr	ip, r2, #PSR_I_BIT		@ disable interrupts
347	msr	cpsr_c, ip
348	ldr	r3, =concan_owner
349	add	r0, r0, #TI_IWMMXT_STATE	@ get task Concan save area
350	ldr	r1, [r3]			@ get current Concan owner
351	eors	r0, r0, r1			@ if equal...
352	streq	r0, [r3]			@ then clear ownership
353	msr	cpsr_c, r2			@ restore interrupts
354	ret	lr
355
356	.data
357concan_owner:
358	.word	0
359
360