xref: /openbmc/linux/arch/powerpc/kernel/vector.S (revision 4f3db074) 
1#include <asm/processor.h>
2#include <asm/ppc_asm.h>
3#include <asm/reg.h>
4#include <asm/asm-offsets.h>
5#include <asm/cputable.h>
6#include <asm/thread_info.h>
7#include <asm/page.h>
8#include <asm/ptrace.h>
9
10#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
11/* void do_load_up_transact_altivec(struct thread_struct *thread)
12 *
13 * This is similar to load_up_altivec but for the transactional version of the
14 * vector regs.  It doesn't mess with the task MSR or valid flags.
15 * Furthermore, VEC laziness is not supported with TM currently.
16 */
17_GLOBAL(do_load_up_transact_altivec)
18	mfmsr	r6
19	oris	r5,r6,MSR_VEC@h
20	MTMSRD(r5)
21	isync
22
23	li	r4,1
24	stw	r4,THREAD_USED_VR(r3)
25
26	li	r10,THREAD_TRANSACT_VRSTATE+VRSTATE_VSCR
27	lvx	v0,r10,r3
28	mtvscr	v0
29	addi	r10,r3,THREAD_TRANSACT_VRSTATE
30	REST_32VRS(0,r4,r10)
31
32	/* Disable VEC again. */
33	MTMSRD(r6)
34	isync
35
36	blr
37#endif
38
39/*
40 * Enable use of VMX/Altivec for the caller.
41 */
42_GLOBAL(vec_enable)
43	mfmsr	r3
44	oris	r3,r3,MSR_VEC@h
45	MTMSRD(r3)
46	isync
47	blr
48
49/*
50 * Load state from memory into VMX registers including VSCR.
51 * Assumes the caller has enabled VMX in the MSR.
52 */
53_GLOBAL(load_vr_state)
54	li	r4,VRSTATE_VSCR
55	lvx	v0,r4,r3
56	mtvscr	v0
57	REST_32VRS(0,r4,r3)
58	blr
59
60/*
61 * Store VMX state into memory, including VSCR.
62 * Assumes the caller has enabled VMX in the MSR.
63 */
64_GLOBAL(store_vr_state)
65	SAVE_32VRS(0, r4, r3)
66	mfvscr	v0
67	li	r4, VRSTATE_VSCR
68	stvx	v0, r4, r3
69	blr
70
71/*
72 * Disable VMX for the task which had it previously,
73 * and save its vector registers in its thread_struct.
74 * Enables the VMX for use in the kernel on return.
75 * On SMP we know the VMX is free, since we give it up every
76 * switch (ie, no lazy save of the vector registers).
77 *
78 * Note that on 32-bit this can only use registers that will be
79 * restored by fast_exception_return, i.e. r3 - r6, r10 and r11.
80 */
81_GLOBAL(load_up_altivec)
82	mfmsr	r5			/* grab the current MSR */
83	oris	r5,r5,MSR_VEC@h
84	MTMSRD(r5)			/* enable use of AltiVec now */
85	isync
86
87/*
88 * For SMP, we don't do lazy VMX switching because it just gets too
89 * horrendously complex, especially when a task switches from one CPU
90 * to another.  Instead we call giveup_altvec in switch_to.
91 * VRSAVE isn't dealt with here, that is done in the normal context
92 * switch code. Note that we could rely on vrsave value to eventually
93 * avoid saving all of the VREGs here...
94 */
95#ifndef CONFIG_SMP
96	LOAD_REG_ADDRBASE(r3, last_task_used_altivec)
97	toreal(r3)
98	PPC_LL	r4,ADDROFF(last_task_used_altivec)(r3)
99	PPC_LCMPI	0,r4,0
100	beq	1f
101
102	/* Save VMX state to last_task_used_altivec's THREAD struct */
103	toreal(r4)
104	addi	r4,r4,THREAD
105	addi	r6,r4,THREAD_VRSTATE
106	SAVE_32VRS(0,r5,r6)
107	mfvscr	v0
108	li	r10,VRSTATE_VSCR
109	stvx	v0,r10,r6
110	/* Disable VMX for last_task_used_altivec */
111	PPC_LL	r5,PT_REGS(r4)
112	toreal(r5)
113	PPC_LL	r4,_MSR-STACK_FRAME_OVERHEAD(r5)
114	lis	r10,MSR_VEC@h
115	andc	r4,r4,r10
116	PPC_STL	r4,_MSR-STACK_FRAME_OVERHEAD(r5)
1171:
118#endif /* CONFIG_SMP */
119
120	/* Hack: if we get an altivec unavailable trap with VRSAVE
121	 * set to all zeros, we assume this is a broken application
122	 * that fails to set it properly, and thus we switch it to
123	 * all 1's
124	 */
125	mfspr	r4,SPRN_VRSAVE
126	cmpwi	0,r4,0
127	bne+	1f
128	li	r4,-1
129	mtspr	SPRN_VRSAVE,r4
1301:
131	/* enable use of VMX after return */
132#ifdef CONFIG_PPC32
133	mfspr	r5,SPRN_SPRG_THREAD		/* current task's THREAD (phys) */
134	oris	r9,r9,MSR_VEC@h
135#else
136	ld	r4,PACACURRENT(r13)
137	addi	r5,r4,THREAD		/* Get THREAD */
138	oris	r12,r12,MSR_VEC@h
139	std	r12,_MSR(r1)
140#endif
141	addi	r6,r5,THREAD_VRSTATE
142	li	r4,1
143	li	r10,VRSTATE_VSCR
144	stw	r4,THREAD_USED_VR(r5)
145	lvx	v0,r10,r6
146	mtvscr	v0
147	REST_32VRS(0,r4,r6)
148#ifndef CONFIG_SMP
149	/* Update last_task_used_altivec to 'current' */
150	subi	r4,r5,THREAD		/* Back to 'current' */
151	fromreal(r4)
152	PPC_STL	r4,ADDROFF(last_task_used_altivec)(r3)
153#endif /* CONFIG_SMP */
154	/* restore registers and return */
155	blr
156
157_GLOBAL(giveup_altivec_notask)
158	mfmsr	r3
159	andis.	r4,r3,MSR_VEC@h
160	bnelr				/* Already enabled? */
161	oris	r3,r3,MSR_VEC@h
162	SYNC
163	MTMSRD(r3)			/* enable use of VMX now */
164	isync
165	blr
166
167/*
168 * giveup_altivec(tsk)
169 * Disable VMX for the task given as the argument,
170 * and save the vector registers in its thread_struct.
171 * Enables the VMX for use in the kernel on return.
172 */
173_GLOBAL(giveup_altivec)
174	mfmsr	r5
175	oris	r5,r5,MSR_VEC@h
176	SYNC
177	MTMSRD(r5)			/* enable use of VMX now */
178	isync
179	PPC_LCMPI	0,r3,0
180	beqlr				/* if no previous owner, done */
181	addi	r3,r3,THREAD		/* want THREAD of task */
182	PPC_LL	r7,THREAD_VRSAVEAREA(r3)
183	PPC_LL	r5,PT_REGS(r3)
184	PPC_LCMPI	0,r7,0
185	bne	2f
186	addi	r7,r3,THREAD_VRSTATE
1872:	PPC_LCMPI	0,r5,0
188	SAVE_32VRS(0,r4,r7)
189	mfvscr	v0
190	li	r4,VRSTATE_VSCR
191	stvx	v0,r4,r7
192	beq	1f
193	PPC_LL	r4,_MSR-STACK_FRAME_OVERHEAD(r5)
194#ifdef CONFIG_VSX
195BEGIN_FTR_SECTION
196	lis	r3,(MSR_VEC|MSR_VSX)@h
197FTR_SECTION_ELSE
198	lis	r3,MSR_VEC@h
199ALT_FTR_SECTION_END_IFSET(CPU_FTR_VSX)
200#else
201	lis	r3,MSR_VEC@h
202#endif
203	andc	r4,r4,r3		/* disable FP for previous task */
204	PPC_STL	r4,_MSR-STACK_FRAME_OVERHEAD(r5)
2051:
206#ifndef CONFIG_SMP
207	li	r5,0
208	LOAD_REG_ADDRBASE(r4,last_task_used_altivec)
209	PPC_STL	r5,ADDROFF(last_task_used_altivec)(r4)
210#endif /* CONFIG_SMP */
211	blr
212
213#ifdef CONFIG_VSX
214
215#ifdef CONFIG_PPC32
216#error This asm code isn't ready for 32-bit kernels
217#endif
218
219/*
220 * load_up_vsx(unused, unused, tsk)
221 * Disable VSX for the task which had it previously,
222 * and save its vector registers in its thread_struct.
223 * Reuse the fp and vsx saves, but first check to see if they have
224 * been saved already.
225 */
226_GLOBAL(load_up_vsx)
227/* Load FP and VSX registers if they haven't been done yet */
228	andi.	r5,r12,MSR_FP
229	beql+	load_up_fpu		/* skip if already loaded */
230	andis.	r5,r12,MSR_VEC@h
231	beql+	load_up_altivec		/* skip if already loaded */
232
233#ifndef CONFIG_SMP
234	ld	r3,last_task_used_vsx@got(r2)
235	ld	r4,0(r3)
236	cmpdi	0,r4,0
237	beq	1f
238	/* Disable VSX for last_task_used_vsx */
239	addi	r4,r4,THREAD
240	ld	r5,PT_REGS(r4)
241	ld	r4,_MSR-STACK_FRAME_OVERHEAD(r5)
242	lis	r6,MSR_VSX@h
243	andc	r6,r4,r6
244	std	r6,_MSR-STACK_FRAME_OVERHEAD(r5)
2451:
246#endif /* CONFIG_SMP */
247	ld	r4,PACACURRENT(r13)
248	addi	r4,r4,THREAD		/* Get THREAD */
249	li	r6,1
250	stw	r6,THREAD_USED_VSR(r4) /* ... also set thread used vsr */
251	/* enable use of VSX after return */
252	oris	r12,r12,MSR_VSX@h
253	std	r12,_MSR(r1)
254#ifndef CONFIG_SMP
255	/* Update last_task_used_vsx to 'current' */
256	ld	r4,PACACURRENT(r13)
257	std	r4,0(r3)
258#endif /* CONFIG_SMP */
259	b	fast_exception_return
260
261/*
262 * __giveup_vsx(tsk)
263 * Disable VSX for the task given as the argument.
264 * Does NOT save vsx registers.
265 * Enables the VSX for use in the kernel on return.
266 */
267_GLOBAL(__giveup_vsx)
268	mfmsr	r5
269	oris	r5,r5,MSR_VSX@h
270	mtmsrd	r5			/* enable use of VSX now */
271	isync
272
273	cmpdi	0,r3,0
274	beqlr-				/* if no previous owner, done */
275	addi	r3,r3,THREAD		/* want THREAD of task */
276	ld	r5,PT_REGS(r3)
277	cmpdi	0,r5,0
278	beq	1f
279	ld	r4,_MSR-STACK_FRAME_OVERHEAD(r5)
280	lis	r3,MSR_VSX@h
281	andc	r4,r4,r3		/* disable VSX for previous task */
282	std	r4,_MSR-STACK_FRAME_OVERHEAD(r5)
2831:
284#ifndef CONFIG_SMP
285	li	r5,0
286	ld	r4,last_task_used_vsx@got(r2)
287	std	r5,0(r4)
288#endif /* CONFIG_SMP */
289	blr
290
291#endif /* CONFIG_VSX */
292
293
294/*
295 * The routines below are in assembler so we can closely control the
296 * usage of floating-point registers.  These routines must be called
297 * with preempt disabled.
298 */
299#ifdef CONFIG_PPC32
300	.data
301fpzero:
302	.long	0
303fpone:
304	.long	0x3f800000	/* 1.0 in single-precision FP */
305fphalf:
306	.long	0x3f000000	/* 0.5 in single-precision FP */
307
308#define LDCONST(fr, name)	\
309	lis	r11,name@ha;	\
310	lfs	fr,name@l(r11)
311#else
312
313	.section ".toc","aw"
314fpzero:
315	.tc	FD_0_0[TC],0
316fpone:
317	.tc	FD_3ff00000_0[TC],0x3ff0000000000000	/* 1.0 */
318fphalf:
319	.tc	FD_3fe00000_0[TC],0x3fe0000000000000	/* 0.5 */
320
321#define LDCONST(fr, name)	\
322	lfd	fr,name@toc(r2)
323#endif
324
325	.text
326/*
327 * Internal routine to enable floating point and set FPSCR to 0.
328 * Don't call it from C; it doesn't use the normal calling convention.
329 */
330fpenable:
331#ifdef CONFIG_PPC32
332	stwu	r1,-64(r1)
333#else
334	stdu	r1,-64(r1)
335#endif
336	mfmsr	r10
337	ori	r11,r10,MSR_FP
338	mtmsr	r11
339	isync
340	stfd	fr0,24(r1)
341	stfd	fr1,16(r1)
342	stfd	fr31,8(r1)
343	LDCONST(fr1, fpzero)
344	mffs	fr31
345	MTFSF_L(fr1)
346	blr
347
348fpdisable:
349	mtlr	r12
350	MTFSF_L(fr31)
351	lfd	fr31,8(r1)
352	lfd	fr1,16(r1)
353	lfd	fr0,24(r1)
354	mtmsr	r10
355	isync
356	addi	r1,r1,64
357	blr
358
359/*
360 * Vector add, floating point.
361 */
362_GLOBAL(vaddfp)
363	mflr	r12
364	bl	fpenable
365	li	r0,4
366	mtctr	r0
367	li	r6,0
3681:	lfsx	fr0,r4,r6
369	lfsx	fr1,r5,r6
370	fadds	fr0,fr0,fr1
371	stfsx	fr0,r3,r6
372	addi	r6,r6,4
373	bdnz	1b
374	b	fpdisable
375
376/*
377 * Vector subtract, floating point.
378 */
379_GLOBAL(vsubfp)
380	mflr	r12
381	bl	fpenable
382	li	r0,4
383	mtctr	r0
384	li	r6,0
3851:	lfsx	fr0,r4,r6
386	lfsx	fr1,r5,r6
387	fsubs	fr0,fr0,fr1
388	stfsx	fr0,r3,r6
389	addi	r6,r6,4
390	bdnz	1b
391	b	fpdisable
392
393/*
394 * Vector multiply and add, floating point.
395 */
396_GLOBAL(vmaddfp)
397	mflr	r12
398	bl	fpenable
399	stfd	fr2,32(r1)
400	li	r0,4
401	mtctr	r0
402	li	r7,0
4031:	lfsx	fr0,r4,r7
404	lfsx	fr1,r5,r7
405	lfsx	fr2,r6,r7
406	fmadds	fr0,fr0,fr2,fr1
407	stfsx	fr0,r3,r7
408	addi	r7,r7,4
409	bdnz	1b
410	lfd	fr2,32(r1)
411	b	fpdisable
412
413/*
414 * Vector negative multiply and subtract, floating point.
415 */
416_GLOBAL(vnmsubfp)
417	mflr	r12
418	bl	fpenable
419	stfd	fr2,32(r1)
420	li	r0,4
421	mtctr	r0
422	li	r7,0
4231:	lfsx	fr0,r4,r7
424	lfsx	fr1,r5,r7
425	lfsx	fr2,r6,r7
426	fnmsubs	fr0,fr0,fr2,fr1
427	stfsx	fr0,r3,r7
428	addi	r7,r7,4
429	bdnz	1b
430	lfd	fr2,32(r1)
431	b	fpdisable
432
433/*
434 * Vector reciprocal estimate.  We just compute 1.0/x.
435 * r3 -> destination, r4 -> source.
436 */
437_GLOBAL(vrefp)
438	mflr	r12
439	bl	fpenable
440	li	r0,4
441	LDCONST(fr1, fpone)
442	mtctr	r0
443	li	r6,0
4441:	lfsx	fr0,r4,r6
445	fdivs	fr0,fr1,fr0
446	stfsx	fr0,r3,r6
447	addi	r6,r6,4
448	bdnz	1b
449	b	fpdisable
450
451/*
452 * Vector reciprocal square-root estimate, floating point.
453 * We use the frsqrte instruction for the initial estimate followed
454 * by 2 iterations of Newton-Raphson to get sufficient accuracy.
455 * r3 -> destination, r4 -> source.
456 */
457_GLOBAL(vrsqrtefp)
458	mflr	r12
459	bl	fpenable
460	stfd	fr2,32(r1)
461	stfd	fr3,40(r1)
462	stfd	fr4,48(r1)
463	stfd	fr5,56(r1)
464	li	r0,4
465	LDCONST(fr4, fpone)
466	LDCONST(fr5, fphalf)
467	mtctr	r0
468	li	r6,0
4691:	lfsx	fr0,r4,r6
470	frsqrte	fr1,fr0		/* r = frsqrte(s) */
471	fmuls	fr3,fr1,fr0	/* r * s */
472	fmuls	fr2,fr1,fr5	/* r * 0.5 */
473	fnmsubs	fr3,fr1,fr3,fr4	/* 1 - s * r * r */
474	fmadds	fr1,fr2,fr3,fr1	/* r = r + 0.5 * r * (1 - s * r * r) */
475	fmuls	fr3,fr1,fr0	/* r * s */
476	fmuls	fr2,fr1,fr5	/* r * 0.5 */
477	fnmsubs	fr3,fr1,fr3,fr4	/* 1 - s * r * r */
478	fmadds	fr1,fr2,fr3,fr1	/* r = r + 0.5 * r * (1 - s * r * r) */
479	stfsx	fr1,r3,r6
480	addi	r6,r6,4
481	bdnz	1b
482	lfd	fr5,56(r1)
483	lfd	fr4,48(r1)
484	lfd	fr3,40(r1)
485	lfd	fr2,32(r1)
486	b	fpdisable
487