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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * Handle unaligned accesses by emulation. | |
3 | * | |
4 | * This file is subject to the terms and conditions of the GNU General Public | |
5 | * License. See the file "COPYING" in the main directory of this archive | |
6 | * for more details. | |
7 | * | |
8 | * Copyright (C) 1996, 1998, 1999, 2002 by Ralf Baechle | |
9 | * Copyright (C) 1999 Silicon Graphics, Inc. | |
10 | * | |
11 | * This file contains exception handler for address error exception with the | |
12 | * special capability to execute faulting instructions in software. The | |
13 | * handler does not try to handle the case when the program counter points | |
14 | * to an address not aligned to a word boundary. | |
15 | * | |
16 | * Putting data to unaligned addresses is a bad practice even on Intel where | |
17 | * only the performance is affected. Much worse is that such code is non- | |
18 | * portable. Due to several programs that die on MIPS due to alignment | |
19 | * problems I decided to implement this handler anyway though I originally | |
20 | * didn't intend to do this at all for user code. | |
21 | * | |
22 | * For now I enable fixing of address errors by default to make life easier. | |
23 | * I however intend to disable this somewhen in the future when the alignment | |
70342287 | 24 | * problems with user programs have been fixed. For programmers this is the |
1da177e4 LT |
25 | * right way to go. |
26 | * | |
27 | * Fixing address errors is a per process option. The option is inherited | |
70342287 | 28 | * across fork(2) and execve(2) calls. If you really want to use the |
1da177e4 LT |
29 | * option in your user programs - I discourage the use of the software |
30 | * emulation strongly - use the following code in your userland stuff: | |
31 | * | |
32 | * #include <sys/sysmips.h> | |
33 | * | |
34 | * ... | |
35 | * sysmips(MIPS_FIXADE, x); | |
36 | * ... | |
37 | * | |
38 | * The argument x is 0 for disabling software emulation, enabled otherwise. | |
39 | * | |
40 | * Below a little program to play around with this feature. | |
41 | * | |
42 | * #include <stdio.h> | |
43 | * #include <sys/sysmips.h> | |
44 | * | |
45 | * struct foo { | |
70342287 | 46 | * unsigned char bar[8]; |
1da177e4 LT |
47 | * }; |
48 | * | |
49 | * main(int argc, char *argv[]) | |
50 | * { | |
70342287 RB |
51 | * struct foo x = {0, 1, 2, 3, 4, 5, 6, 7}; |
52 | * unsigned int *p = (unsigned int *) (x.bar + 3); | |
53 | * int i; | |
1da177e4 | 54 | * |
70342287 RB |
55 | * if (argc > 1) |
56 | * sysmips(MIPS_FIXADE, atoi(argv[1])); | |
1da177e4 | 57 | * |
70342287 | 58 | * printf("*p = %08lx\n", *p); |
1da177e4 | 59 | * |
70342287 | 60 | * *p = 0xdeadface; |
1da177e4 | 61 | * |
70342287 RB |
62 | * for(i = 0; i <= 7; i++) |
63 | * printf("%02x ", x.bar[i]); | |
64 | * printf("\n"); | |
1da177e4 LT |
65 | * } |
66 | * | |
67 | * Coprocessor loads are not supported; I think this case is unimportant | |
68 | * in the practice. | |
69 | * | |
70 | * TODO: Handle ndc (attempted store to doubleword in uncached memory) | |
70342287 RB |
71 | * exception for the R6000. |
72 | * A store crossing a page boundary might be executed only partially. | |
73 | * Undo the partial store in this case. | |
1da177e4 | 74 | */ |
1da177e4 | 75 | #include <linux/mm.h> |
1da177e4 LT |
76 | #include <linux/signal.h> |
77 | #include <linux/smp.h> | |
e8edc6e0 | 78 | #include <linux/sched.h> |
6312e0ee | 79 | #include <linux/debugfs.h> |
7f788d2d DZ |
80 | #include <linux/perf_event.h> |
81 | ||
1da177e4 LT |
82 | #include <asm/asm.h> |
83 | #include <asm/branch.h> | |
84 | #include <asm/byteorder.h> | |
69f3a7de | 85 | #include <asm/cop2.h> |
102cedc3 LY |
86 | #include <asm/fpu.h> |
87 | #include <asm/fpu_emulator.h> | |
1da177e4 LT |
88 | #include <asm/inst.h> |
89 | #include <asm/uaccess.h> | |
1da177e4 | 90 | |
70342287 | 91 | #define STR(x) __STR(x) |
1da177e4 LT |
92 | #define __STR(x) #x |
93 | ||
6312e0ee AN |
94 | enum { |
95 | UNALIGNED_ACTION_QUIET, | |
96 | UNALIGNED_ACTION_SIGNAL, | |
97 | UNALIGNED_ACTION_SHOW, | |
98 | }; | |
99 | #ifdef CONFIG_DEBUG_FS | |
100 | static u32 unaligned_instructions; | |
101 | static u32 unaligned_action; | |
102 | #else | |
103 | #define unaligned_action UNALIGNED_ACTION_QUIET | |
1da177e4 | 104 | #endif |
6312e0ee | 105 | extern void show_registers(struct pt_regs *regs); |
1da177e4 | 106 | |
7f18f151 RB |
107 | static void emulate_load_store_insn(struct pt_regs *regs, |
108 | void __user *addr, unsigned int __user *pc) | |
1da177e4 LT |
109 | { |
110 | union mips_instruction insn; | |
111 | unsigned long value; | |
112 | unsigned int res; | |
102cedc3 | 113 | void __user *fault_addr = NULL; |
1da177e4 | 114 | |
a8b0ca17 | 115 | perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS, 1, regs, 0); |
7f788d2d | 116 | |
1da177e4 LT |
117 | /* |
118 | * This load never faults. | |
119 | */ | |
fe00f943 | 120 | __get_user(insn.word, pc); |
1da177e4 LT |
121 | |
122 | switch (insn.i_format.opcode) { | |
123 | /* | |
124 | * These are instructions that a compiler doesn't generate. We | |
125 | * can assume therefore that the code is MIPS-aware and | |
126 | * really buggy. Emulating these instructions would break the | |
127 | * semantics anyway. | |
128 | */ | |
129 | case ll_op: | |
130 | case lld_op: | |
131 | case sc_op: | |
132 | case scd_op: | |
133 | ||
134 | /* | |
135 | * For these instructions the only way to create an address | |
136 | * error is an attempted access to kernel/supervisor address | |
137 | * space. | |
138 | */ | |
139 | case ldl_op: | |
140 | case ldr_op: | |
141 | case lwl_op: | |
142 | case lwr_op: | |
143 | case sdl_op: | |
144 | case sdr_op: | |
145 | case swl_op: | |
146 | case swr_op: | |
147 | case lb_op: | |
148 | case lbu_op: | |
149 | case sb_op: | |
150 | goto sigbus; | |
151 | ||
152 | /* | |
153 | * The remaining opcodes are the ones that are really of interest. | |
154 | */ | |
155 | case lh_op: | |
156 | if (!access_ok(VERIFY_READ, addr, 2)) | |
157 | goto sigbus; | |
158 | ||
159 | __asm__ __volatile__ (".set\tnoat\n" | |
160 | #ifdef __BIG_ENDIAN | |
161 | "1:\tlb\t%0, 0(%2)\n" | |
162 | "2:\tlbu\t$1, 1(%2)\n\t" | |
163 | #endif | |
164 | #ifdef __LITTLE_ENDIAN | |
165 | "1:\tlb\t%0, 1(%2)\n" | |
166 | "2:\tlbu\t$1, 0(%2)\n\t" | |
167 | #endif | |
168 | "sll\t%0, 0x8\n\t" | |
169 | "or\t%0, $1\n\t" | |
170 | "li\t%1, 0\n" | |
171 | "3:\t.set\tat\n\t" | |
172 | ".section\t.fixup,\"ax\"\n\t" | |
173 | "4:\tli\t%1, %3\n\t" | |
174 | "j\t3b\n\t" | |
175 | ".previous\n\t" | |
176 | ".section\t__ex_table,\"a\"\n\t" | |
177 | STR(PTR)"\t1b, 4b\n\t" | |
178 | STR(PTR)"\t2b, 4b\n\t" | |
179 | ".previous" | |
180 | : "=&r" (value), "=r" (res) | |
181 | : "r" (addr), "i" (-EFAULT)); | |
182 | if (res) | |
183 | goto fault; | |
7f18f151 RB |
184 | compute_return_epc(regs); |
185 | regs->regs[insn.i_format.rt] = value; | |
1da177e4 LT |
186 | break; |
187 | ||
188 | case lw_op: | |
189 | if (!access_ok(VERIFY_READ, addr, 4)) | |
190 | goto sigbus; | |
191 | ||
192 | __asm__ __volatile__ ( | |
193 | #ifdef __BIG_ENDIAN | |
194 | "1:\tlwl\t%0, (%2)\n" | |
195 | "2:\tlwr\t%0, 3(%2)\n\t" | |
196 | #endif | |
197 | #ifdef __LITTLE_ENDIAN | |
198 | "1:\tlwl\t%0, 3(%2)\n" | |
199 | "2:\tlwr\t%0, (%2)\n\t" | |
200 | #endif | |
201 | "li\t%1, 0\n" | |
202 | "3:\t.section\t.fixup,\"ax\"\n\t" | |
203 | "4:\tli\t%1, %3\n\t" | |
204 | "j\t3b\n\t" | |
205 | ".previous\n\t" | |
206 | ".section\t__ex_table,\"a\"\n\t" | |
207 | STR(PTR)"\t1b, 4b\n\t" | |
208 | STR(PTR)"\t2b, 4b\n\t" | |
209 | ".previous" | |
210 | : "=&r" (value), "=r" (res) | |
211 | : "r" (addr), "i" (-EFAULT)); | |
212 | if (res) | |
213 | goto fault; | |
7f18f151 RB |
214 | compute_return_epc(regs); |
215 | regs->regs[insn.i_format.rt] = value; | |
1da177e4 LT |
216 | break; |
217 | ||
218 | case lhu_op: | |
219 | if (!access_ok(VERIFY_READ, addr, 2)) | |
220 | goto sigbus; | |
221 | ||
222 | __asm__ __volatile__ ( | |
223 | ".set\tnoat\n" | |
224 | #ifdef __BIG_ENDIAN | |
225 | "1:\tlbu\t%0, 0(%2)\n" | |
226 | "2:\tlbu\t$1, 1(%2)\n\t" | |
227 | #endif | |
228 | #ifdef __LITTLE_ENDIAN | |
229 | "1:\tlbu\t%0, 1(%2)\n" | |
230 | "2:\tlbu\t$1, 0(%2)\n\t" | |
231 | #endif | |
232 | "sll\t%0, 0x8\n\t" | |
233 | "or\t%0, $1\n\t" | |
234 | "li\t%1, 0\n" | |
235 | "3:\t.set\tat\n\t" | |
236 | ".section\t.fixup,\"ax\"\n\t" | |
237 | "4:\tli\t%1, %3\n\t" | |
238 | "j\t3b\n\t" | |
239 | ".previous\n\t" | |
240 | ".section\t__ex_table,\"a\"\n\t" | |
241 | STR(PTR)"\t1b, 4b\n\t" | |
242 | STR(PTR)"\t2b, 4b\n\t" | |
243 | ".previous" | |
244 | : "=&r" (value), "=r" (res) | |
245 | : "r" (addr), "i" (-EFAULT)); | |
246 | if (res) | |
247 | goto fault; | |
7f18f151 RB |
248 | compute_return_epc(regs); |
249 | regs->regs[insn.i_format.rt] = value; | |
1da177e4 LT |
250 | break; |
251 | ||
252 | case lwu_op: | |
875d43e7 | 253 | #ifdef CONFIG_64BIT |
1da177e4 LT |
254 | /* |
255 | * A 32-bit kernel might be running on a 64-bit processor. But | |
256 | * if we're on a 32-bit processor and an i-cache incoherency | |
257 | * or race makes us see a 64-bit instruction here the sdl/sdr | |
258 | * would blow up, so for now we don't handle unaligned 64-bit | |
259 | * instructions on 32-bit kernels. | |
260 | */ | |
261 | if (!access_ok(VERIFY_READ, addr, 4)) | |
262 | goto sigbus; | |
263 | ||
264 | __asm__ __volatile__ ( | |
265 | #ifdef __BIG_ENDIAN | |
266 | "1:\tlwl\t%0, (%2)\n" | |
267 | "2:\tlwr\t%0, 3(%2)\n\t" | |
268 | #endif | |
269 | #ifdef __LITTLE_ENDIAN | |
270 | "1:\tlwl\t%0, 3(%2)\n" | |
271 | "2:\tlwr\t%0, (%2)\n\t" | |
272 | #endif | |
273 | "dsll\t%0, %0, 32\n\t" | |
274 | "dsrl\t%0, %0, 32\n\t" | |
275 | "li\t%1, 0\n" | |
276 | "3:\t.section\t.fixup,\"ax\"\n\t" | |
277 | "4:\tli\t%1, %3\n\t" | |
278 | "j\t3b\n\t" | |
279 | ".previous\n\t" | |
280 | ".section\t__ex_table,\"a\"\n\t" | |
281 | STR(PTR)"\t1b, 4b\n\t" | |
282 | STR(PTR)"\t2b, 4b\n\t" | |
283 | ".previous" | |
284 | : "=&r" (value), "=r" (res) | |
285 | : "r" (addr), "i" (-EFAULT)); | |
286 | if (res) | |
287 | goto fault; | |
7f18f151 RB |
288 | compute_return_epc(regs); |
289 | regs->regs[insn.i_format.rt] = value; | |
1da177e4 | 290 | break; |
875d43e7 | 291 | #endif /* CONFIG_64BIT */ |
1da177e4 LT |
292 | |
293 | /* Cannot handle 64-bit instructions in 32-bit kernel */ | |
294 | goto sigill; | |
295 | ||
296 | case ld_op: | |
875d43e7 | 297 | #ifdef CONFIG_64BIT |
1da177e4 LT |
298 | /* |
299 | * A 32-bit kernel might be running on a 64-bit processor. But | |
300 | * if we're on a 32-bit processor and an i-cache incoherency | |
301 | * or race makes us see a 64-bit instruction here the sdl/sdr | |
302 | * would blow up, so for now we don't handle unaligned 64-bit | |
303 | * instructions on 32-bit kernels. | |
304 | */ | |
305 | if (!access_ok(VERIFY_READ, addr, 8)) | |
306 | goto sigbus; | |
307 | ||
308 | __asm__ __volatile__ ( | |
309 | #ifdef __BIG_ENDIAN | |
310 | "1:\tldl\t%0, (%2)\n" | |
311 | "2:\tldr\t%0, 7(%2)\n\t" | |
312 | #endif | |
313 | #ifdef __LITTLE_ENDIAN | |
314 | "1:\tldl\t%0, 7(%2)\n" | |
315 | "2:\tldr\t%0, (%2)\n\t" | |
316 | #endif | |
317 | "li\t%1, 0\n" | |
318 | "3:\t.section\t.fixup,\"ax\"\n\t" | |
319 | "4:\tli\t%1, %3\n\t" | |
320 | "j\t3b\n\t" | |
321 | ".previous\n\t" | |
322 | ".section\t__ex_table,\"a\"\n\t" | |
323 | STR(PTR)"\t1b, 4b\n\t" | |
324 | STR(PTR)"\t2b, 4b\n\t" | |
325 | ".previous" | |
326 | : "=&r" (value), "=r" (res) | |
327 | : "r" (addr), "i" (-EFAULT)); | |
328 | if (res) | |
329 | goto fault; | |
7f18f151 RB |
330 | compute_return_epc(regs); |
331 | regs->regs[insn.i_format.rt] = value; | |
1da177e4 | 332 | break; |
875d43e7 | 333 | #endif /* CONFIG_64BIT */ |
1da177e4 LT |
334 | |
335 | /* Cannot handle 64-bit instructions in 32-bit kernel */ | |
336 | goto sigill; | |
337 | ||
338 | case sh_op: | |
339 | if (!access_ok(VERIFY_WRITE, addr, 2)) | |
340 | goto sigbus; | |
341 | ||
342 | value = regs->regs[insn.i_format.rt]; | |
343 | __asm__ __volatile__ ( | |
344 | #ifdef __BIG_ENDIAN | |
345 | ".set\tnoat\n" | |
346 | "1:\tsb\t%1, 1(%2)\n\t" | |
347 | "srl\t$1, %1, 0x8\n" | |
348 | "2:\tsb\t$1, 0(%2)\n\t" | |
349 | ".set\tat\n\t" | |
350 | #endif | |
351 | #ifdef __LITTLE_ENDIAN | |
352 | ".set\tnoat\n" | |
353 | "1:\tsb\t%1, 0(%2)\n\t" | |
354 | "srl\t$1,%1, 0x8\n" | |
355 | "2:\tsb\t$1, 1(%2)\n\t" | |
356 | ".set\tat\n\t" | |
357 | #endif | |
358 | "li\t%0, 0\n" | |
359 | "3:\n\t" | |
360 | ".section\t.fixup,\"ax\"\n\t" | |
361 | "4:\tli\t%0, %3\n\t" | |
362 | "j\t3b\n\t" | |
363 | ".previous\n\t" | |
364 | ".section\t__ex_table,\"a\"\n\t" | |
365 | STR(PTR)"\t1b, 4b\n\t" | |
366 | STR(PTR)"\t2b, 4b\n\t" | |
367 | ".previous" | |
368 | : "=r" (res) | |
369 | : "r" (value), "r" (addr), "i" (-EFAULT)); | |
370 | if (res) | |
371 | goto fault; | |
7f18f151 | 372 | compute_return_epc(regs); |
1da177e4 LT |
373 | break; |
374 | ||
375 | case sw_op: | |
376 | if (!access_ok(VERIFY_WRITE, addr, 4)) | |
377 | goto sigbus; | |
378 | ||
379 | value = regs->regs[insn.i_format.rt]; | |
380 | __asm__ __volatile__ ( | |
381 | #ifdef __BIG_ENDIAN | |
382 | "1:\tswl\t%1,(%2)\n" | |
383 | "2:\tswr\t%1, 3(%2)\n\t" | |
384 | #endif | |
385 | #ifdef __LITTLE_ENDIAN | |
386 | "1:\tswl\t%1, 3(%2)\n" | |
387 | "2:\tswr\t%1, (%2)\n\t" | |
388 | #endif | |
389 | "li\t%0, 0\n" | |
390 | "3:\n\t" | |
391 | ".section\t.fixup,\"ax\"\n\t" | |
392 | "4:\tli\t%0, %3\n\t" | |
393 | "j\t3b\n\t" | |
394 | ".previous\n\t" | |
395 | ".section\t__ex_table,\"a\"\n\t" | |
396 | STR(PTR)"\t1b, 4b\n\t" | |
397 | STR(PTR)"\t2b, 4b\n\t" | |
398 | ".previous" | |
399 | : "=r" (res) | |
400 | : "r" (value), "r" (addr), "i" (-EFAULT)); | |
401 | if (res) | |
402 | goto fault; | |
7f18f151 | 403 | compute_return_epc(regs); |
1da177e4 LT |
404 | break; |
405 | ||
406 | case sd_op: | |
875d43e7 | 407 | #ifdef CONFIG_64BIT |
1da177e4 LT |
408 | /* |
409 | * A 32-bit kernel might be running on a 64-bit processor. But | |
410 | * if we're on a 32-bit processor and an i-cache incoherency | |
411 | * or race makes us see a 64-bit instruction here the sdl/sdr | |
412 | * would blow up, so for now we don't handle unaligned 64-bit | |
413 | * instructions on 32-bit kernels. | |
414 | */ | |
415 | if (!access_ok(VERIFY_WRITE, addr, 8)) | |
416 | goto sigbus; | |
417 | ||
418 | value = regs->regs[insn.i_format.rt]; | |
419 | __asm__ __volatile__ ( | |
420 | #ifdef __BIG_ENDIAN | |
421 | "1:\tsdl\t%1,(%2)\n" | |
422 | "2:\tsdr\t%1, 7(%2)\n\t" | |
423 | #endif | |
424 | #ifdef __LITTLE_ENDIAN | |
425 | "1:\tsdl\t%1, 7(%2)\n" | |
426 | "2:\tsdr\t%1, (%2)\n\t" | |
427 | #endif | |
428 | "li\t%0, 0\n" | |
429 | "3:\n\t" | |
430 | ".section\t.fixup,\"ax\"\n\t" | |
431 | "4:\tli\t%0, %3\n\t" | |
432 | "j\t3b\n\t" | |
433 | ".previous\n\t" | |
434 | ".section\t__ex_table,\"a\"\n\t" | |
435 | STR(PTR)"\t1b, 4b\n\t" | |
436 | STR(PTR)"\t2b, 4b\n\t" | |
437 | ".previous" | |
438 | : "=r" (res) | |
439 | : "r" (value), "r" (addr), "i" (-EFAULT)); | |
440 | if (res) | |
441 | goto fault; | |
7f18f151 | 442 | compute_return_epc(regs); |
1da177e4 | 443 | break; |
875d43e7 | 444 | #endif /* CONFIG_64BIT */ |
1da177e4 LT |
445 | |
446 | /* Cannot handle 64-bit instructions in 32-bit kernel */ | |
447 | goto sigill; | |
448 | ||
449 | case lwc1_op: | |
450 | case ldc1_op: | |
451 | case swc1_op: | |
452 | case sdc1_op: | |
102cedc3 LY |
453 | die_if_kernel("Unaligned FP access in kernel code", regs); |
454 | BUG_ON(!used_math()); | |
455 | BUG_ON(!is_fpu_owner()); | |
456 | ||
457 | lose_fpu(1); /* Save FPU state for the emulator. */ | |
458 | res = fpu_emulator_cop1Handler(regs, ¤t->thread.fpu, 1, | |
459 | &fault_addr); | |
460 | own_fpu(1); /* Restore FPU state. */ | |
461 | ||
462 | /* Signal if something went wrong. */ | |
463 | process_fpemu_return(res, fault_addr); | |
464 | ||
465 | if (res == 0) | |
466 | break; | |
467 | return; | |
1da177e4 | 468 | |
69f3a7de RB |
469 | /* |
470 | * COP2 is available to implementor for application specific use. | |
471 | * It's up to applications to register a notifier chain and do | |
472 | * whatever they have to do, including possible sending of signals. | |
473 | */ | |
1da177e4 | 474 | case lwc2_op: |
69f3a7de RB |
475 | cu2_notifier_call_chain(CU2_LWC2_OP, regs); |
476 | break; | |
477 | ||
1da177e4 | 478 | case ldc2_op: |
69f3a7de RB |
479 | cu2_notifier_call_chain(CU2_LDC2_OP, regs); |
480 | break; | |
481 | ||
1da177e4 | 482 | case swc2_op: |
69f3a7de RB |
483 | cu2_notifier_call_chain(CU2_SWC2_OP, regs); |
484 | break; | |
485 | ||
1da177e4 | 486 | case sdc2_op: |
69f3a7de RB |
487 | cu2_notifier_call_chain(CU2_SDC2_OP, regs); |
488 | break; | |
489 | ||
1da177e4 LT |
490 | default: |
491 | /* | |
492 | * Pheeee... We encountered an yet unknown instruction or | |
493 | * cache coherence problem. Die sucker, die ... | |
494 | */ | |
495 | goto sigill; | |
496 | } | |
497 | ||
6312e0ee | 498 | #ifdef CONFIG_DEBUG_FS |
1da177e4 LT |
499 | unaligned_instructions++; |
500 | #endif | |
501 | ||
7f18f151 | 502 | return; |
1da177e4 LT |
503 | |
504 | fault: | |
505 | /* Did we have an exception handler installed? */ | |
506 | if (fixup_exception(regs)) | |
7f18f151 | 507 | return; |
1da177e4 | 508 | |
49a89efb | 509 | die_if_kernel("Unhandled kernel unaligned access", regs); |
a6d5ff04 | 510 | force_sig(SIGSEGV, current); |
1da177e4 | 511 | |
7f18f151 | 512 | return; |
1da177e4 LT |
513 | |
514 | sigbus: | |
515 | die_if_kernel("Unhandled kernel unaligned access", regs); | |
a6d5ff04 | 516 | force_sig(SIGBUS, current); |
1da177e4 | 517 | |
7f18f151 | 518 | return; |
1da177e4 LT |
519 | |
520 | sigill: | |
521 | die_if_kernel("Unhandled kernel unaligned access or invalid instruction", regs); | |
a6d5ff04 | 522 | force_sig(SIGILL, current); |
1da177e4 LT |
523 | } |
524 | ||
525 | asmlinkage void do_ade(struct pt_regs *regs) | |
526 | { | |
fe00f943 | 527 | unsigned int __user *pc; |
1da177e4 | 528 | mm_segment_t seg; |
1da177e4 | 529 | |
7f788d2d | 530 | perf_sw_event(PERF_COUNT_SW_ALIGNMENT_FAULTS, |
a8b0ca17 | 531 | 1, regs, regs->cp0_badvaddr); |
1da177e4 LT |
532 | /* |
533 | * Did we catch a fault trying to load an instruction? | |
534 | * Or are we running in MIPS16 mode? | |
535 | */ | |
536 | if ((regs->cp0_badvaddr == regs->cp0_epc) || (regs->cp0_epc & 0x1)) | |
537 | goto sigbus; | |
538 | ||
fe00f943 | 539 | pc = (unsigned int __user *) exception_epc(regs); |
293c5bd1 | 540 | if (user_mode(regs) && !test_thread_flag(TIF_FIXADE)) |
1da177e4 | 541 | goto sigbus; |
6312e0ee AN |
542 | if (unaligned_action == UNALIGNED_ACTION_SIGNAL) |
543 | goto sigbus; | |
544 | else if (unaligned_action == UNALIGNED_ACTION_SHOW) | |
545 | show_registers(regs); | |
1da177e4 LT |
546 | |
547 | /* | |
548 | * Do branch emulation only if we didn't forward the exception. | |
549 | * This is all so but ugly ... | |
550 | */ | |
551 | seg = get_fs(); | |
552 | if (!user_mode(regs)) | |
553 | set_fs(KERNEL_DS); | |
7f18f151 | 554 | emulate_load_store_insn(regs, (void __user *)regs->cp0_badvaddr, pc); |
1da177e4 LT |
555 | set_fs(seg); |
556 | ||
557 | return; | |
558 | ||
559 | sigbus: | |
560 | die_if_kernel("Kernel unaligned instruction access", regs); | |
561 | force_sig(SIGBUS, current); | |
562 | ||
563 | /* | |
564 | * XXX On return from the signal handler we should advance the epc | |
565 | */ | |
566 | } | |
6312e0ee AN |
567 | |
568 | #ifdef CONFIG_DEBUG_FS | |
569 | extern struct dentry *mips_debugfs_dir; | |
570 | static int __init debugfs_unaligned(void) | |
571 | { | |
572 | struct dentry *d; | |
573 | ||
574 | if (!mips_debugfs_dir) | |
575 | return -ENODEV; | |
576 | d = debugfs_create_u32("unaligned_instructions", S_IRUGO, | |
577 | mips_debugfs_dir, &unaligned_instructions); | |
b517531c Z |
578 | if (!d) |
579 | return -ENOMEM; | |
6312e0ee AN |
580 | d = debugfs_create_u32("unaligned_action", S_IRUGO | S_IWUSR, |
581 | mips_debugfs_dir, &unaligned_action); | |
b517531c Z |
582 | if (!d) |
583 | return -ENOMEM; | |
6312e0ee AN |
584 | return 0; |
585 | } | |
586 | __initcall(debugfs_unaligned); | |
587 | #endif |