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Merge with /pub/scm/linux/kernel/git/torvalds/linux-2.6.git
[deliverable/linux.git] / arch / powerpc / kernel / align.c
1 /* align.c - handle alignment exceptions for the Power PC.
2 *
3 * Copyright (c) 1996 Paul Mackerras <paulus@cs.anu.edu.au>
4 * Copyright (c) 1998-1999 TiVo, Inc.
5 * PowerPC 403GCX modifications.
6 * Copyright (c) 1999 Grant Erickson <grant@lcse.umn.edu>
7 * PowerPC 403GCX/405GP modifications.
8 * Copyright (c) 2001-2002 PPC64 team, IBM Corp
9 * 64-bit and Power4 support
10 * Copyright (c) 2005 Benjamin Herrenschmidt, IBM Corp
11 * <benh@kernel.crashing.org>
12 * Merge ppc32 and ppc64 implementations
13 *
14 * This program is free software; you can redistribute it and/or
15 * modify it under the terms of the GNU General Public License
16 * as published by the Free Software Foundation; either version
17 * 2 of the License, or (at your option) any later version.
18 */
19
20 #include <linux/kernel.h>
21 #include <linux/mm.h>
22 #include <asm/processor.h>
23 #include <asm/uaccess.h>
24 #include <asm/system.h>
25 #include <asm/cache.h>
26 #include <asm/cputable.h>
27
28 struct aligninfo {
29 unsigned char len;
30 unsigned char flags;
31 };
32
33 #define IS_XFORM(inst) (((inst) >> 26) == 31)
34 #define IS_DSFORM(inst) (((inst) >> 26) >= 56)
35
36 #define INVALID { 0, 0 }
37
38 #define LD 1 /* load */
39 #define ST 2 /* store */
40 #define SE 4 /* sign-extend value */
41 #define F 8 /* to/from fp regs */
42 #define U 0x10 /* update index register */
43 #define M 0x20 /* multiple load/store */
44 #define SW 0x40 /* byte swap int or ... */
45 #define S 0x40 /* ... single-precision fp */
46 #define SX 0x40 /* byte count in XER */
47 #define HARD 0x80 /* string, stwcx. */
48
49 #define DCBZ 0x5f /* 8xx/82xx dcbz faults when cache not enabled */
50
51 #define SWAP(a, b) (t = (a), (a) = (b), (b) = t)
52
53 /*
54 * The PowerPC stores certain bits of the instruction that caused the
55 * alignment exception in the DSISR register. This array maps those
56 * bits to information about the operand length and what the
57 * instruction would do.
58 */
59 static struct aligninfo aligninfo[128] = {
60 { 4, LD }, /* 00 0 0000: lwz / lwarx */
61 INVALID, /* 00 0 0001 */
62 { 4, ST }, /* 00 0 0010: stw */
63 INVALID, /* 00 0 0011 */
64 { 2, LD }, /* 00 0 0100: lhz */
65 { 2, LD+SE }, /* 00 0 0101: lha */
66 { 2, ST }, /* 00 0 0110: sth */
67 { 4, LD+M }, /* 00 0 0111: lmw */
68 { 4, LD+F+S }, /* 00 0 1000: lfs */
69 { 8, LD+F }, /* 00 0 1001: lfd */
70 { 4, ST+F+S }, /* 00 0 1010: stfs */
71 { 8, ST+F }, /* 00 0 1011: stfd */
72 INVALID, /* 00 0 1100 */
73 { 8, LD }, /* 00 0 1101: ld/ldu/lwa */
74 INVALID, /* 00 0 1110 */
75 { 8, ST }, /* 00 0 1111: std/stdu */
76 { 4, LD+U }, /* 00 1 0000: lwzu */
77 INVALID, /* 00 1 0001 */
78 { 4, ST+U }, /* 00 1 0010: stwu */
79 INVALID, /* 00 1 0011 */
80 { 2, LD+U }, /* 00 1 0100: lhzu */
81 { 2, LD+SE+U }, /* 00 1 0101: lhau */
82 { 2, ST+U }, /* 00 1 0110: sthu */
83 { 4, ST+M }, /* 00 1 0111: stmw */
84 { 4, LD+F+S+U }, /* 00 1 1000: lfsu */
85 { 8, LD+F+U }, /* 00 1 1001: lfdu */
86 { 4, ST+F+S+U }, /* 00 1 1010: stfsu */
87 { 8, ST+F+U }, /* 00 1 1011: stfdu */
88 INVALID, /* 00 1 1100 */
89 INVALID, /* 00 1 1101 */
90 INVALID, /* 00 1 1110 */
91 INVALID, /* 00 1 1111 */
92 { 8, LD }, /* 01 0 0000: ldx */
93 INVALID, /* 01 0 0001 */
94 { 8, ST }, /* 01 0 0010: stdx */
95 INVALID, /* 01 0 0011 */
96 INVALID, /* 01 0 0100 */
97 { 4, LD+SE }, /* 01 0 0101: lwax */
98 INVALID, /* 01 0 0110 */
99 INVALID, /* 01 0 0111 */
100 { 4, LD+M+HARD+SX }, /* 01 0 1000: lswx */
101 { 4, LD+M+HARD }, /* 01 0 1001: lswi */
102 { 4, ST+M+HARD+SX }, /* 01 0 1010: stswx */
103 { 4, ST+M+HARD }, /* 01 0 1011: stswi */
104 INVALID, /* 01 0 1100 */
105 { 8, LD+U }, /* 01 0 1101: ldu */
106 INVALID, /* 01 0 1110 */
107 { 8, ST+U }, /* 01 0 1111: stdu */
108 { 8, LD+U }, /* 01 1 0000: ldux */
109 INVALID, /* 01 1 0001 */
110 { 8, ST+U }, /* 01 1 0010: stdux */
111 INVALID, /* 01 1 0011 */
112 INVALID, /* 01 1 0100 */
113 { 4, LD+SE+U }, /* 01 1 0101: lwaux */
114 INVALID, /* 01 1 0110 */
115 INVALID, /* 01 1 0111 */
116 INVALID, /* 01 1 1000 */
117 INVALID, /* 01 1 1001 */
118 INVALID, /* 01 1 1010 */
119 INVALID, /* 01 1 1011 */
120 INVALID, /* 01 1 1100 */
121 INVALID, /* 01 1 1101 */
122 INVALID, /* 01 1 1110 */
123 INVALID, /* 01 1 1111 */
124 INVALID, /* 10 0 0000 */
125 INVALID, /* 10 0 0001 */
126 INVALID, /* 10 0 0010: stwcx. */
127 INVALID, /* 10 0 0011 */
128 INVALID, /* 10 0 0100 */
129 INVALID, /* 10 0 0101 */
130 INVALID, /* 10 0 0110 */
131 INVALID, /* 10 0 0111 */
132 { 4, LD+SW }, /* 10 0 1000: lwbrx */
133 INVALID, /* 10 0 1001 */
134 { 4, ST+SW }, /* 10 0 1010: stwbrx */
135 INVALID, /* 10 0 1011 */
136 { 2, LD+SW }, /* 10 0 1100: lhbrx */
137 { 4, LD+SE }, /* 10 0 1101 lwa */
138 { 2, ST+SW }, /* 10 0 1110: sthbrx */
139 INVALID, /* 10 0 1111 */
140 INVALID, /* 10 1 0000 */
141 INVALID, /* 10 1 0001 */
142 INVALID, /* 10 1 0010 */
143 INVALID, /* 10 1 0011 */
144 INVALID, /* 10 1 0100 */
145 INVALID, /* 10 1 0101 */
146 INVALID, /* 10 1 0110 */
147 INVALID, /* 10 1 0111 */
148 INVALID, /* 10 1 1000 */
149 INVALID, /* 10 1 1001 */
150 INVALID, /* 10 1 1010 */
151 INVALID, /* 10 1 1011 */
152 INVALID, /* 10 1 1100 */
153 INVALID, /* 10 1 1101 */
154 INVALID, /* 10 1 1110 */
155 { 0, ST+HARD }, /* 10 1 1111: dcbz */
156 { 4, LD }, /* 11 0 0000: lwzx */
157 INVALID, /* 11 0 0001 */
158 { 4, ST }, /* 11 0 0010: stwx */
159 INVALID, /* 11 0 0011 */
160 { 2, LD }, /* 11 0 0100: lhzx */
161 { 2, LD+SE }, /* 11 0 0101: lhax */
162 { 2, ST }, /* 11 0 0110: sthx */
163 INVALID, /* 11 0 0111 */
164 { 4, LD+F+S }, /* 11 0 1000: lfsx */
165 { 8, LD+F }, /* 11 0 1001: lfdx */
166 { 4, ST+F+S }, /* 11 0 1010: stfsx */
167 { 8, ST+F }, /* 11 0 1011: stfdx */
168 INVALID, /* 11 0 1100 */
169 { 8, LD+M }, /* 11 0 1101: lmd */
170 INVALID, /* 11 0 1110 */
171 { 8, ST+M }, /* 11 0 1111: stmd */
172 { 4, LD+U }, /* 11 1 0000: lwzux */
173 INVALID, /* 11 1 0001 */
174 { 4, ST+U }, /* 11 1 0010: stwux */
175 INVALID, /* 11 1 0011 */
176 { 2, LD+U }, /* 11 1 0100: lhzux */
177 { 2, LD+SE+U }, /* 11 1 0101: lhaux */
178 { 2, ST+U }, /* 11 1 0110: sthux */
179 INVALID, /* 11 1 0111 */
180 { 4, LD+F+S+U }, /* 11 1 1000: lfsux */
181 { 8, LD+F+U }, /* 11 1 1001: lfdux */
182 { 4, ST+F+S+U }, /* 11 1 1010: stfsux */
183 { 8, ST+F+U }, /* 11 1 1011: stfdux */
184 INVALID, /* 11 1 1100 */
185 INVALID, /* 11 1 1101 */
186 INVALID, /* 11 1 1110 */
187 INVALID, /* 11 1 1111 */
188 };
189
190 /*
191 * Create a DSISR value from the instruction
192 */
193 static inline unsigned make_dsisr(unsigned instr)
194 {
195 unsigned dsisr;
196
197
198 /* bits 6:15 --> 22:31 */
199 dsisr = (instr & 0x03ff0000) >> 16;
200
201 if (IS_XFORM(instr)) {
202 /* bits 29:30 --> 15:16 */
203 dsisr |= (instr & 0x00000006) << 14;
204 /* bit 25 --> 17 */
205 dsisr |= (instr & 0x00000040) << 8;
206 /* bits 21:24 --> 18:21 */
207 dsisr |= (instr & 0x00000780) << 3;
208 } else {
209 /* bit 5 --> 17 */
210 dsisr |= (instr & 0x04000000) >> 12;
211 /* bits 1: 4 --> 18:21 */
212 dsisr |= (instr & 0x78000000) >> 17;
213 /* bits 30:31 --> 12:13 */
214 if (IS_DSFORM(instr))
215 dsisr |= (instr & 0x00000003) << 18;
216 }
217
218 return dsisr;
219 }
220
221 /*
222 * The dcbz (data cache block zero) instruction
223 * gives an alignment fault if used on non-cacheable
224 * memory. We handle the fault mainly for the
225 * case when we are running with the cache disabled
226 * for debugging.
227 */
228 static int emulate_dcbz(struct pt_regs *regs, unsigned char __user *addr)
229 {
230 long __user *p;
231 int i, size;
232
233 #ifdef __powerpc64__
234 size = ppc64_caches.dline_size;
235 #else
236 size = L1_CACHE_BYTES;
237 #endif
238 p = (long __user *) (regs->dar & -size);
239 if (user_mode(regs) && !access_ok(VERIFY_WRITE, p, size))
240 return -EFAULT;
241 for (i = 0; i < size / sizeof(long); ++i)
242 if (__put_user(0, p+i))
243 return -EFAULT;
244 return 1;
245 }
246
247 /*
248 * Emulate load & store multiple instructions
249 * On 64-bit machines, these instructions only affect/use the
250 * bottom 4 bytes of each register, and the loads clear the
251 * top 4 bytes of the affected register.
252 */
253 #ifdef CONFIG_PPC64
254 #define REG_BYTE(rp, i) *((u8 *)((rp) + ((i) >> 2)) + ((i) & 3) + 4)
255 #else
256 #define REG_BYTE(rp, i) *((u8 *)(rp) + (i))
257 #endif
258
259 static int emulate_multiple(struct pt_regs *regs, unsigned char __user *addr,
260 unsigned int reg, unsigned int nb,
261 unsigned int flags, unsigned int instr)
262 {
263 unsigned long *rptr;
264 unsigned int nb0, i;
265
266 /*
267 * We do not try to emulate 8 bytes multiple as they aren't really
268 * available in our operating environments and we don't try to
269 * emulate multiples operations in kernel land as they should never
270 * be used/generated there at least not on unaligned boundaries
271 */
272 if (unlikely((nb > 4) || !user_mode(regs)))
273 return 0;
274
275 /* lmw, stmw, lswi/x, stswi/x */
276 nb0 = 0;
277 if (flags & HARD) {
278 if (flags & SX) {
279 nb = regs->xer & 127;
280 if (nb == 0)
281 return 1;
282 } else {
283 if (__get_user(instr,
284 (unsigned int __user *)regs->nip))
285 return -EFAULT;
286 nb = (instr >> 11) & 0x1f;
287 if (nb == 0)
288 nb = 32;
289 }
290 if (nb + reg * 4 > 128) {
291 nb0 = nb + reg * 4 - 128;
292 nb = 128 - reg * 4;
293 }
294 } else {
295 /* lwm, stmw */
296 nb = (32 - reg) * 4;
297 }
298
299 if (!access_ok((flags & ST ? VERIFY_WRITE: VERIFY_READ), addr, nb+nb0))
300 return -EFAULT; /* bad address */
301
302 rptr = &regs->gpr[reg];
303 if (flags & LD) {
304 /*
305 * This zeroes the top 4 bytes of the affected registers
306 * in 64-bit mode, and also zeroes out any remaining
307 * bytes of the last register for lsw*.
308 */
309 memset(rptr, 0, ((nb + 3) / 4) * sizeof(unsigned long));
310 if (nb0 > 0)
311 memset(&regs->gpr[0], 0,
312 ((nb0 + 3) / 4) * sizeof(unsigned long));
313
314 for (i = 0; i < nb; ++i)
315 if (__get_user(REG_BYTE(rptr, i), addr + i))
316 return -EFAULT;
317 if (nb0 > 0) {
318 rptr = &regs->gpr[0];
319 addr += nb;
320 for (i = 0; i < nb0; ++i)
321 if (__get_user(REG_BYTE(rptr, i), addr + i))
322 return -EFAULT;
323 }
324
325 } else {
326 for (i = 0; i < nb; ++i)
327 if (__put_user(REG_BYTE(rptr, i), addr + i))
328 return -EFAULT;
329 if (nb0 > 0) {
330 rptr = &regs->gpr[0];
331 addr += nb;
332 for (i = 0; i < nb0; ++i)
333 if (__put_user(REG_BYTE(rptr, i), addr + i))
334 return -EFAULT;
335 }
336 }
337 return 1;
338 }
339
340
341 /*
342 * Called on alignment exception. Attempts to fixup
343 *
344 * Return 1 on success
345 * Return 0 if unable to handle the interrupt
346 * Return -EFAULT if data address is bad
347 */
348
349 int fix_alignment(struct pt_regs *regs)
350 {
351 unsigned int instr, nb, flags;
352 unsigned int reg, areg;
353 unsigned int dsisr;
354 unsigned char __user *addr;
355 unsigned char __user *p;
356 int ret, t;
357 union {
358 u64 ll;
359 double dd;
360 unsigned char v[8];
361 struct {
362 unsigned hi32;
363 int low32;
364 } x32;
365 struct {
366 unsigned char hi48[6];
367 short low16;
368 } x16;
369 } data;
370
371 /*
372 * We require a complete register set, if not, then our assembly
373 * is broken
374 */
375 CHECK_FULL_REGS(regs);
376
377 dsisr = regs->dsisr;
378
379 /* Some processors don't provide us with a DSISR we can use here,
380 * let's make one up from the instruction
381 */
382 if (cpu_has_feature(CPU_FTR_NODSISRALIGN)) {
383 unsigned int real_instr;
384 if (unlikely(__get_user(real_instr,
385 (unsigned int __user *)regs->nip)))
386 return -EFAULT;
387 dsisr = make_dsisr(real_instr);
388 }
389
390 /* extract the operation and registers from the dsisr */
391 reg = (dsisr >> 5) & 0x1f; /* source/dest register */
392 areg = dsisr & 0x1f; /* register to update */
393 instr = (dsisr >> 10) & 0x7f;
394 instr |= (dsisr >> 13) & 0x60;
395
396 /* Lookup the operation in our table */
397 nb = aligninfo[instr].len;
398 flags = aligninfo[instr].flags;
399
400 /* DAR has the operand effective address */
401 addr = (unsigned char __user *)regs->dar;
402
403 /* A size of 0 indicates an instruction we don't support, with
404 * the exception of DCBZ which is handled as a special case here
405 */
406 if (instr == DCBZ)
407 return emulate_dcbz(regs, addr);
408 if (unlikely(nb == 0))
409 return 0;
410
411 /* Load/Store Multiple instructions are handled in their own
412 * function
413 */
414 if (flags & M)
415 return emulate_multiple(regs, addr, reg, nb, flags, instr);
416
417 /* Verify the address of the operand */
418 if (unlikely(user_mode(regs) &&
419 !access_ok((flags & ST ? VERIFY_WRITE : VERIFY_READ),
420 addr, nb)))
421 return -EFAULT;
422
423 /* Force the fprs into the save area so we can reference them */
424 if (flags & F) {
425 /* userland only */
426 if (unlikely(!user_mode(regs)))
427 return 0;
428 flush_fp_to_thread(current);
429 }
430
431 /* If we are loading, get the data from user space, else
432 * get it from register values
433 */
434 if (flags & LD) {
435 data.ll = 0;
436 ret = 0;
437 p = addr;
438 switch (nb) {
439 case 8:
440 ret |= __get_user(data.v[0], p++);
441 ret |= __get_user(data.v[1], p++);
442 ret |= __get_user(data.v[2], p++);
443 ret |= __get_user(data.v[3], p++);
444 case 4:
445 ret |= __get_user(data.v[4], p++);
446 ret |= __get_user(data.v[5], p++);
447 case 2:
448 ret |= __get_user(data.v[6], p++);
449 ret |= __get_user(data.v[7], p++);
450 if (unlikely(ret))
451 return -EFAULT;
452 }
453 } else if (flags & F)
454 data.dd = current->thread.fpr[reg];
455 else
456 data.ll = regs->gpr[reg];
457
458 /* Perform other misc operations like sign extension, byteswap,
459 * or floating point single precision conversion
460 */
461 switch (flags & ~U) {
462 case LD+SE: /* sign extend */
463 if ( nb == 2 )
464 data.ll = data.x16.low16;
465 else /* nb must be 4 */
466 data.ll = data.x32.low32;
467 break;
468 case LD+S: /* byte-swap */
469 case ST+S:
470 if (nb == 2) {
471 SWAP(data.v[6], data.v[7]);
472 } else {
473 SWAP(data.v[4], data.v[7]);
474 SWAP(data.v[5], data.v[6]);
475 }
476 break;
477
478 /* Single-precision FP load and store require conversions... */
479 case LD+F+S:
480 #ifdef CONFIG_PPC_FPU
481 preempt_disable();
482 enable_kernel_fp();
483 cvt_fd((float *)&data.v[4], &data.dd, &current->thread);
484 preempt_enable();
485 #else
486 return 0;
487 #endif
488 break;
489 case ST+F+S:
490 #ifdef CONFIG_PPC_FPU
491 preempt_disable();
492 enable_kernel_fp();
493 cvt_df(&data.dd, (float *)&data.v[4], &current->thread);
494 preempt_enable();
495 #else
496 return 0;
497 #endif
498 break;
499 }
500
501 /* Store result to memory or update registers */
502 if (flags & ST) {
503 ret = 0;
504 p = addr;
505 switch (nb) {
506 case 8:
507 ret |= __put_user(data.v[0], p++);
508 ret |= __put_user(data.v[1], p++);
509 ret |= __put_user(data.v[2], p++);
510 ret |= __put_user(data.v[3], p++);
511 case 4:
512 ret |= __put_user(data.v[4], p++);
513 ret |= __put_user(data.v[5], p++);
514 case 2:
515 ret |= __put_user(data.v[6], p++);
516 ret |= __put_user(data.v[7], p++);
517 }
518 if (unlikely(ret))
519 return -EFAULT;
520 } else if (flags & F)
521 current->thread.fpr[reg] = data.dd;
522 else
523 regs->gpr[reg] = data.ll;
524
525 /* Update RA as needed */
526 if (flags & U)
527 regs->gpr[areg] = regs->dar;
528
529 return 1;
530 }
Linux kernel - Deliverables
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