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1da177e4 LT |
1 | /* |
2 | * linux/arch/arm/mm/alignment.c | |
3 | * | |
4 | * Copyright (C) 1995 Linus Torvalds | |
5 | * Modifications for ARM processor (c) 1995-2001 Russell King | |
6cbdc8c5 | 6 | * Thumb alignment fault fixups (c) 2004 MontaVista Software, Inc. |
1da177e4 LT |
7 | * - Adapted from gdb/sim/arm/thumbemu.c -- Thumb instruction emulation. |
8 | * Copyright (C) 1996, Cygnus Software Technologies Ltd. | |
9 | * | |
10 | * This program is free software; you can redistribute it and/or modify | |
11 | * it under the terms of the GNU General Public License version 2 as | |
12 | * published by the Free Software Foundation. | |
13 | */ | |
1da177e4 LT |
14 | #include <linux/compiler.h> |
15 | #include <linux/kernel.h> | |
16 | #include <linux/errno.h> | |
17 | #include <linux/string.h> | |
1da177e4 LT |
18 | #include <linux/proc_fs.h> |
19 | #include <linux/init.h> | |
87c52578 | 20 | #include <linux/sched.h> |
33fa9b13 | 21 | #include <linux/uaccess.h> |
1da177e4 | 22 | |
1da177e4 LT |
23 | #include <asm/unaligned.h> |
24 | ||
25 | #include "fault.h" | |
26 | ||
27 | /* | |
28 | * 32-bit misaligned trap handler (c) 1998 San Mehat (CCC) -July 1998 | |
29 | * /proc/sys/debug/alignment, modified and integrated into | |
30 | * Linux 2.1 by Russell King | |
31 | * | |
32 | * Speed optimisations and better fault handling by Russell King. | |
33 | * | |
34 | * *** NOTE *** | |
35 | * This code is not portable to processors with late data abort handling. | |
36 | */ | |
37 | #define CODING_BITS(i) (i & 0x0e000000) | |
38 | ||
39 | #define LDST_I_BIT(i) (i & (1 << 26)) /* Immediate constant */ | |
40 | #define LDST_P_BIT(i) (i & (1 << 24)) /* Preindex */ | |
41 | #define LDST_U_BIT(i) (i & (1 << 23)) /* Add offset */ | |
42 | #define LDST_W_BIT(i) (i & (1 << 21)) /* Writeback */ | |
43 | #define LDST_L_BIT(i) (i & (1 << 20)) /* Load */ | |
44 | ||
45 | #define LDST_P_EQ_U(i) ((((i) ^ ((i) >> 1)) & (1 << 23)) == 0) | |
46 | ||
f21ee2d4 | 47 | #define LDSTHD_I_BIT(i) (i & (1 << 22)) /* double/half-word immed */ |
1da177e4 LT |
48 | #define LDM_S_BIT(i) (i & (1 << 22)) /* write CPSR from SPSR */ |
49 | ||
50 | #define RN_BITS(i) ((i >> 16) & 15) /* Rn */ | |
51 | #define RD_BITS(i) ((i >> 12) & 15) /* Rd */ | |
52 | #define RM_BITS(i) (i & 15) /* Rm */ | |
53 | ||
54 | #define REGMASK_BITS(i) (i & 0xffff) | |
55 | #define OFFSET_BITS(i) (i & 0x0fff) | |
56 | ||
57 | #define IS_SHIFT(i) (i & 0x0ff0) | |
58 | #define SHIFT_BITS(i) ((i >> 7) & 0x1f) | |
59 | #define SHIFT_TYPE(i) (i & 0x60) | |
60 | #define SHIFT_LSL 0x00 | |
61 | #define SHIFT_LSR 0x20 | |
62 | #define SHIFT_ASR 0x40 | |
63 | #define SHIFT_RORRRX 0x60 | |
64 | ||
c2860d43 GD |
65 | #define BAD_INSTR 0xdeadc0de |
66 | ||
67 | /* Thumb-2 32 bit format per ARMv7 DDI0406A A6.3, either f800h,e800h,f800h */ | |
68 | #define IS_T32(hi16) \ | |
69 | (((hi16) & 0xe000) == 0xe000 && ((hi16) & 0x1800)) | |
70 | ||
1da177e4 LT |
71 | static unsigned long ai_user; |
72 | static unsigned long ai_sys; | |
73 | static unsigned long ai_skipped; | |
74 | static unsigned long ai_half; | |
75 | static unsigned long ai_word; | |
f21ee2d4 | 76 | static unsigned long ai_dword; |
1da177e4 LT |
77 | static unsigned long ai_multi; |
78 | static int ai_usermode; | |
79 | ||
baa745a3 RK |
80 | #define UM_WARN (1 << 0) |
81 | #define UM_FIXUP (1 << 1) | |
82 | #define UM_SIGNAL (1 << 2) | |
83 | ||
1da177e4 LT |
84 | #ifdef CONFIG_PROC_FS |
85 | static const char *usermode_action[] = { | |
86 | "ignored", | |
87 | "warn", | |
88 | "fixup", | |
89 | "fixup+warn", | |
90 | "signal", | |
91 | "signal+warn" | |
92 | }; | |
93 | ||
94 | static int | |
95 | proc_alignment_read(char *page, char **start, off_t off, int count, int *eof, | |
96 | void *data) | |
97 | { | |
98 | char *p = page; | |
99 | int len; | |
100 | ||
101 | p += sprintf(p, "User:\t\t%lu\n", ai_user); | |
102 | p += sprintf(p, "System:\t\t%lu\n", ai_sys); | |
103 | p += sprintf(p, "Skipped:\t%lu\n", ai_skipped); | |
104 | p += sprintf(p, "Half:\t\t%lu\n", ai_half); | |
105 | p += sprintf(p, "Word:\t\t%lu\n", ai_word); | |
f21ee2d4 SL |
106 | if (cpu_architecture() >= CPU_ARCH_ARMv5TE) |
107 | p += sprintf(p, "DWord:\t\t%lu\n", ai_dword); | |
1da177e4 LT |
108 | p += sprintf(p, "Multi:\t\t%lu\n", ai_multi); |
109 | p += sprintf(p, "User faults:\t%i (%s)\n", ai_usermode, | |
110 | usermode_action[ai_usermode]); | |
111 | ||
112 | len = (p - page) - off; | |
113 | if (len < 0) | |
114 | len = 0; | |
115 | ||
116 | *eof = (len <= count) ? 1 : 0; | |
117 | *start = page + off; | |
118 | ||
119 | return len; | |
120 | } | |
121 | ||
122 | static int proc_alignment_write(struct file *file, const char __user *buffer, | |
737d0bb7 | 123 | unsigned long count, void *data) |
1da177e4 LT |
124 | { |
125 | char mode; | |
126 | ||
127 | if (count > 0) { | |
128 | if (get_user(mode, buffer)) | |
129 | return -EFAULT; | |
130 | if (mode >= '0' && mode <= '5') | |
737d0bb7 | 131 | ai_usermode = mode - '0'; |
1da177e4 LT |
132 | } |
133 | return count; | |
134 | } | |
135 | ||
136 | #endif /* CONFIG_PROC_FS */ | |
137 | ||
138 | union offset_union { | |
139 | unsigned long un; | |
140 | signed long sn; | |
141 | }; | |
142 | ||
143 | #define TYPE_ERROR 0 | |
144 | #define TYPE_FAULT 1 | |
145 | #define TYPE_LDST 2 | |
146 | #define TYPE_DONE 3 | |
147 | ||
148 | #ifdef __ARMEB__ | |
149 | #define BE 1 | |
150 | #define FIRST_BYTE_16 "mov %1, %1, ror #8\n" | |
151 | #define FIRST_BYTE_32 "mov %1, %1, ror #24\n" | |
152 | #define NEXT_BYTE "ror #24" | |
153 | #else | |
154 | #define BE 0 | |
155 | #define FIRST_BYTE_16 | |
156 | #define FIRST_BYTE_32 | |
157 | #define NEXT_BYTE "lsr #8" | |
158 | #endif | |
159 | ||
160 | #define __get8_unaligned_check(ins,val,addr,err) \ | |
161 | __asm__( \ | |
347c8b70 CM |
162 | ARM( "1: "ins" %1, [%2], #1\n" ) \ |
163 | THUMB( "1: "ins" %1, [%2]\n" ) \ | |
164 | THUMB( " add %2, %2, #1\n" ) \ | |
1da177e4 LT |
165 | "2:\n" \ |
166 | " .section .fixup,\"ax\"\n" \ | |
167 | " .align 2\n" \ | |
168 | "3: mov %0, #1\n" \ | |
169 | " b 2b\n" \ | |
170 | " .previous\n" \ | |
171 | " .section __ex_table,\"a\"\n" \ | |
172 | " .align 3\n" \ | |
173 | " .long 1b, 3b\n" \ | |
174 | " .previous\n" \ | |
175 | : "=r" (err), "=&r" (val), "=r" (addr) \ | |
176 | : "0" (err), "2" (addr)) | |
177 | ||
178 | #define __get16_unaligned_check(ins,val,addr) \ | |
179 | do { \ | |
180 | unsigned int err = 0, v, a = addr; \ | |
181 | __get8_unaligned_check(ins,v,a,err); \ | |
182 | val = v << ((BE) ? 8 : 0); \ | |
183 | __get8_unaligned_check(ins,v,a,err); \ | |
184 | val |= v << ((BE) ? 0 : 8); \ | |
185 | if (err) \ | |
186 | goto fault; \ | |
187 | } while (0) | |
188 | ||
189 | #define get16_unaligned_check(val,addr) \ | |
190 | __get16_unaligned_check("ldrb",val,addr) | |
191 | ||
192 | #define get16t_unaligned_check(val,addr) \ | |
193 | __get16_unaligned_check("ldrbt",val,addr) | |
194 | ||
195 | #define __get32_unaligned_check(ins,val,addr) \ | |
196 | do { \ | |
197 | unsigned int err = 0, v, a = addr; \ | |
198 | __get8_unaligned_check(ins,v,a,err); \ | |
199 | val = v << ((BE) ? 24 : 0); \ | |
200 | __get8_unaligned_check(ins,v,a,err); \ | |
201 | val |= v << ((BE) ? 16 : 8); \ | |
202 | __get8_unaligned_check(ins,v,a,err); \ | |
203 | val |= v << ((BE) ? 8 : 16); \ | |
204 | __get8_unaligned_check(ins,v,a,err); \ | |
205 | val |= v << ((BE) ? 0 : 24); \ | |
206 | if (err) \ | |
207 | goto fault; \ | |
208 | } while (0) | |
209 | ||
210 | #define get32_unaligned_check(val,addr) \ | |
211 | __get32_unaligned_check("ldrb",val,addr) | |
212 | ||
213 | #define get32t_unaligned_check(val,addr) \ | |
214 | __get32_unaligned_check("ldrbt",val,addr) | |
215 | ||
216 | #define __put16_unaligned_check(ins,val,addr) \ | |
217 | do { \ | |
218 | unsigned int err = 0, v = val, a = addr; \ | |
219 | __asm__( FIRST_BYTE_16 \ | |
347c8b70 CM |
220 | ARM( "1: "ins" %1, [%2], #1\n" ) \ |
221 | THUMB( "1: "ins" %1, [%2]\n" ) \ | |
222 | THUMB( " add %2, %2, #1\n" ) \ | |
1da177e4 LT |
223 | " mov %1, %1, "NEXT_BYTE"\n" \ |
224 | "2: "ins" %1, [%2]\n" \ | |
225 | "3:\n" \ | |
226 | " .section .fixup,\"ax\"\n" \ | |
227 | " .align 2\n" \ | |
228 | "4: mov %0, #1\n" \ | |
229 | " b 3b\n" \ | |
230 | " .previous\n" \ | |
231 | " .section __ex_table,\"a\"\n" \ | |
232 | " .align 3\n" \ | |
233 | " .long 1b, 4b\n" \ | |
234 | " .long 2b, 4b\n" \ | |
235 | " .previous\n" \ | |
236 | : "=r" (err), "=&r" (v), "=&r" (a) \ | |
237 | : "0" (err), "1" (v), "2" (a)); \ | |
238 | if (err) \ | |
239 | goto fault; \ | |
240 | } while (0) | |
241 | ||
242 | #define put16_unaligned_check(val,addr) \ | |
243 | __put16_unaligned_check("strb",val,addr) | |
244 | ||
245 | #define put16t_unaligned_check(val,addr) \ | |
246 | __put16_unaligned_check("strbt",val,addr) | |
247 | ||
248 | #define __put32_unaligned_check(ins,val,addr) \ | |
249 | do { \ | |
250 | unsigned int err = 0, v = val, a = addr; \ | |
251 | __asm__( FIRST_BYTE_32 \ | |
347c8b70 CM |
252 | ARM( "1: "ins" %1, [%2], #1\n" ) \ |
253 | THUMB( "1: "ins" %1, [%2]\n" ) \ | |
254 | THUMB( " add %2, %2, #1\n" ) \ | |
1da177e4 | 255 | " mov %1, %1, "NEXT_BYTE"\n" \ |
347c8b70 CM |
256 | ARM( "2: "ins" %1, [%2], #1\n" ) \ |
257 | THUMB( "2: "ins" %1, [%2]\n" ) \ | |
258 | THUMB( " add %2, %2, #1\n" ) \ | |
1da177e4 | 259 | " mov %1, %1, "NEXT_BYTE"\n" \ |
347c8b70 CM |
260 | ARM( "3: "ins" %1, [%2], #1\n" ) \ |
261 | THUMB( "3: "ins" %1, [%2]\n" ) \ | |
262 | THUMB( " add %2, %2, #1\n" ) \ | |
1da177e4 LT |
263 | " mov %1, %1, "NEXT_BYTE"\n" \ |
264 | "4: "ins" %1, [%2]\n" \ | |
265 | "5:\n" \ | |
266 | " .section .fixup,\"ax\"\n" \ | |
267 | " .align 2\n" \ | |
268 | "6: mov %0, #1\n" \ | |
269 | " b 5b\n" \ | |
270 | " .previous\n" \ | |
271 | " .section __ex_table,\"a\"\n" \ | |
272 | " .align 3\n" \ | |
273 | " .long 1b, 6b\n" \ | |
274 | " .long 2b, 6b\n" \ | |
275 | " .long 3b, 6b\n" \ | |
276 | " .long 4b, 6b\n" \ | |
277 | " .previous\n" \ | |
278 | : "=r" (err), "=&r" (v), "=&r" (a) \ | |
279 | : "0" (err), "1" (v), "2" (a)); \ | |
280 | if (err) \ | |
281 | goto fault; \ | |
282 | } while (0) | |
283 | ||
737d0bb7 | 284 | #define put32_unaligned_check(val,addr) \ |
1da177e4 LT |
285 | __put32_unaligned_check("strb", val, addr) |
286 | ||
287 | #define put32t_unaligned_check(val,addr) \ | |
288 | __put32_unaligned_check("strbt", val, addr) | |
289 | ||
290 | static void | |
291 | do_alignment_finish_ldst(unsigned long addr, unsigned long instr, struct pt_regs *regs, union offset_union offset) | |
292 | { | |
293 | if (!LDST_U_BIT(instr)) | |
294 | offset.un = -offset.un; | |
295 | ||
296 | if (!LDST_P_BIT(instr)) | |
297 | addr += offset.un; | |
298 | ||
299 | if (!LDST_P_BIT(instr) || LDST_W_BIT(instr)) | |
300 | regs->uregs[RN_BITS(instr)] = addr; | |
301 | } | |
302 | ||
303 | static int | |
304 | do_alignment_ldrhstrh(unsigned long addr, unsigned long instr, struct pt_regs *regs) | |
305 | { | |
306 | unsigned int rd = RD_BITS(instr); | |
307 | ||
1da177e4 LT |
308 | ai_half += 1; |
309 | ||
310 | if (user_mode(regs)) | |
311 | goto user; | |
312 | ||
313 | if (LDST_L_BIT(instr)) { | |
314 | unsigned long val; | |
315 | get16_unaligned_check(val, addr); | |
316 | ||
317 | /* signed half-word? */ | |
318 | if (instr & 0x40) | |
319 | val = (signed long)((signed short) val); | |
320 | ||
321 | regs->uregs[rd] = val; | |
322 | } else | |
323 | put16_unaligned_check(regs->uregs[rd], addr); | |
324 | ||
325 | return TYPE_LDST; | |
326 | ||
327 | user: | |
737d0bb7 GD |
328 | if (LDST_L_BIT(instr)) { |
329 | unsigned long val; | |
330 | get16t_unaligned_check(val, addr); | |
1da177e4 | 331 | |
737d0bb7 GD |
332 | /* signed half-word? */ |
333 | if (instr & 0x40) | |
334 | val = (signed long)((signed short) val); | |
1da177e4 | 335 | |
737d0bb7 GD |
336 | regs->uregs[rd] = val; |
337 | } else | |
338 | put16t_unaligned_check(regs->uregs[rd], addr); | |
1da177e4 | 339 | |
737d0bb7 | 340 | return TYPE_LDST; |
1da177e4 | 341 | |
f21ee2d4 SL |
342 | fault: |
343 | return TYPE_FAULT; | |
344 | } | |
345 | ||
346 | static int | |
347 | do_alignment_ldrdstrd(unsigned long addr, unsigned long instr, | |
348 | struct pt_regs *regs) | |
349 | { | |
350 | unsigned int rd = RD_BITS(instr); | |
c2860d43 GD |
351 | unsigned int rd2; |
352 | int load; | |
353 | ||
354 | if ((instr & 0xfe000000) == 0xe8000000) { | |
355 | /* ARMv7 Thumb-2 32-bit LDRD/STRD */ | |
356 | rd2 = (instr >> 8) & 0xf; | |
357 | load = !!(LDST_L_BIT(instr)); | |
358 | } else if (((rd & 1) == 1) || (rd == 14)) | |
19da83f6 | 359 | goto bad; |
c2860d43 GD |
360 | else { |
361 | load = ((instr & 0xf0) == 0xd0); | |
362 | rd2 = rd + 1; | |
363 | } | |
19da83f6 | 364 | |
f21ee2d4 SL |
365 | ai_dword += 1; |
366 | ||
367 | if (user_mode(regs)) | |
368 | goto user; | |
369 | ||
c2860d43 | 370 | if (load) { |
f21ee2d4 SL |
371 | unsigned long val; |
372 | get32_unaligned_check(val, addr); | |
373 | regs->uregs[rd] = val; | |
737d0bb7 | 374 | get32_unaligned_check(val, addr + 4); |
c2860d43 | 375 | regs->uregs[rd2] = val; |
f21ee2d4 SL |
376 | } else { |
377 | put32_unaligned_check(regs->uregs[rd], addr); | |
c2860d43 | 378 | put32_unaligned_check(regs->uregs[rd2], addr + 4); |
f21ee2d4 SL |
379 | } |
380 | ||
381 | return TYPE_LDST; | |
382 | ||
383 | user: | |
c2860d43 | 384 | if (load) { |
f21ee2d4 SL |
385 | unsigned long val; |
386 | get32t_unaligned_check(val, addr); | |
387 | regs->uregs[rd] = val; | |
737d0bb7 | 388 | get32t_unaligned_check(val, addr + 4); |
c2860d43 | 389 | regs->uregs[rd2] = val; |
f21ee2d4 SL |
390 | } else { |
391 | put32t_unaligned_check(regs->uregs[rd], addr); | |
c2860d43 | 392 | put32t_unaligned_check(regs->uregs[rd2], addr + 4); |
f21ee2d4 SL |
393 | } |
394 | ||
395 | return TYPE_LDST; | |
19da83f6 GD |
396 | bad: |
397 | return TYPE_ERROR; | |
1da177e4 LT |
398 | fault: |
399 | return TYPE_FAULT; | |
400 | } | |
401 | ||
402 | static int | |
403 | do_alignment_ldrstr(unsigned long addr, unsigned long instr, struct pt_regs *regs) | |
404 | { | |
405 | unsigned int rd = RD_BITS(instr); | |
406 | ||
407 | ai_word += 1; | |
408 | ||
409 | if ((!LDST_P_BIT(instr) && LDST_W_BIT(instr)) || user_mode(regs)) | |
410 | goto trans; | |
411 | ||
412 | if (LDST_L_BIT(instr)) { | |
413 | unsigned int val; | |
414 | get32_unaligned_check(val, addr); | |
415 | regs->uregs[rd] = val; | |
416 | } else | |
417 | put32_unaligned_check(regs->uregs[rd], addr); | |
418 | return TYPE_LDST; | |
419 | ||
420 | trans: | |
421 | if (LDST_L_BIT(instr)) { | |
422 | unsigned int val; | |
423 | get32t_unaligned_check(val, addr); | |
424 | regs->uregs[rd] = val; | |
425 | } else | |
426 | put32t_unaligned_check(regs->uregs[rd], addr); | |
427 | return TYPE_LDST; | |
428 | ||
429 | fault: | |
430 | return TYPE_FAULT; | |
431 | } | |
432 | ||
433 | /* | |
434 | * LDM/STM alignment handler. | |
435 | * | |
436 | * There are 4 variants of this instruction: | |
437 | * | |
438 | * B = rn pointer before instruction, A = rn pointer after instruction | |
439 | * ------ increasing address -----> | |
440 | * | | r0 | r1 | ... | rx | | | |
441 | * PU = 01 B A | |
442 | * PU = 11 B A | |
443 | * PU = 00 A B | |
444 | * PU = 10 A B | |
445 | */ | |
446 | static int | |
447 | do_alignment_ldmstm(unsigned long addr, unsigned long instr, struct pt_regs *regs) | |
448 | { | |
449 | unsigned int rd, rn, correction, nr_regs, regbits; | |
450 | unsigned long eaddr, newaddr; | |
451 | ||
452 | if (LDM_S_BIT(instr)) | |
453 | goto bad; | |
454 | ||
455 | correction = 4; /* processor implementation defined */ | |
456 | regs->ARM_pc += correction; | |
457 | ||
458 | ai_multi += 1; | |
459 | ||
460 | /* count the number of registers in the mask to be transferred */ | |
461 | nr_regs = hweight16(REGMASK_BITS(instr)) * 4; | |
462 | ||
463 | rn = RN_BITS(instr); | |
464 | newaddr = eaddr = regs->uregs[rn]; | |
465 | ||
466 | if (!LDST_U_BIT(instr)) | |
467 | nr_regs = -nr_regs; | |
468 | newaddr += nr_regs; | |
469 | if (!LDST_U_BIT(instr)) | |
470 | eaddr = newaddr; | |
471 | ||
472 | if (LDST_P_EQ_U(instr)) /* U = P */ | |
473 | eaddr += 4; | |
474 | ||
737d0bb7 | 475 | /* |
1da177e4 LT |
476 | * For alignment faults on the ARM922T/ARM920T the MMU makes |
477 | * the FSR (and hence addr) equal to the updated base address | |
478 | * of the multiple access rather than the restored value. | |
479 | * Switch this message off if we've got a ARM92[02], otherwise | |
480 | * [ls]dm alignment faults are noisy! | |
481 | */ | |
482 | #if !(defined CONFIG_CPU_ARM922T) && !(defined CONFIG_CPU_ARM920T) | |
483 | /* | |
484 | * This is a "hint" - we already have eaddr worked out by the | |
485 | * processor for us. | |
486 | */ | |
487 | if (addr != eaddr) { | |
488 | printk(KERN_ERR "LDMSTM: PC = %08lx, instr = %08lx, " | |
489 | "addr = %08lx, eaddr = %08lx\n", | |
490 | instruction_pointer(regs), instr, addr, eaddr); | |
491 | show_regs(regs); | |
492 | } | |
493 | #endif | |
494 | ||
495 | if (user_mode(regs)) { | |
496 | for (regbits = REGMASK_BITS(instr), rd = 0; regbits; | |
497 | regbits >>= 1, rd += 1) | |
498 | if (regbits & 1) { | |
499 | if (LDST_L_BIT(instr)) { | |
500 | unsigned int val; | |
501 | get32t_unaligned_check(val, eaddr); | |
502 | regs->uregs[rd] = val; | |
503 | } else | |
504 | put32t_unaligned_check(regs->uregs[rd], eaddr); | |
505 | eaddr += 4; | |
506 | } | |
507 | } else { | |
508 | for (regbits = REGMASK_BITS(instr), rd = 0; regbits; | |
509 | regbits >>= 1, rd += 1) | |
510 | if (regbits & 1) { | |
511 | if (LDST_L_BIT(instr)) { | |
512 | unsigned int val; | |
513 | get32_unaligned_check(val, eaddr); | |
514 | regs->uregs[rd] = val; | |
515 | } else | |
516 | put32_unaligned_check(regs->uregs[rd], eaddr); | |
517 | eaddr += 4; | |
518 | } | |
519 | } | |
520 | ||
521 | if (LDST_W_BIT(instr)) | |
522 | regs->uregs[rn] = newaddr; | |
523 | if (!LDST_L_BIT(instr) || !(REGMASK_BITS(instr) & (1 << 15))) | |
524 | regs->ARM_pc -= correction; | |
525 | return TYPE_DONE; | |
526 | ||
527 | fault: | |
528 | regs->ARM_pc -= correction; | |
529 | return TYPE_FAULT; | |
530 | ||
531 | bad: | |
532 | printk(KERN_ERR "Alignment trap: not handling ldm with s-bit set\n"); | |
533 | return TYPE_ERROR; | |
534 | } | |
535 | ||
536 | /* | |
537 | * Convert Thumb ld/st instruction forms to equivalent ARM instructions so | |
538 | * we can reuse ARM userland alignment fault fixups for Thumb. | |
539 | * | |
540 | * This implementation was initially based on the algorithm found in | |
541 | * gdb/sim/arm/thumbemu.c. It is basically just a code reduction of same | |
542 | * to convert only Thumb ld/st instruction forms to equivalent ARM forms. | |
543 | * | |
544 | * NOTES: | |
545 | * 1. Comments below refer to ARM ARM DDI0100E Thumb Instruction sections. | |
546 | * 2. If for some reason we're passed an non-ld/st Thumb instruction to | |
547 | * decode, we return 0xdeadc0de. This should never happen under normal | |
548 | * circumstances but if it does, we've got other problems to deal with | |
549 | * elsewhere and we obviously can't fix those problems here. | |
550 | */ | |
551 | ||
552 | static unsigned long | |
553 | thumb2arm(u16 tinstr) | |
554 | { | |
555 | u32 L = (tinstr & (1<<11)) >> 11; | |
556 | ||
557 | switch ((tinstr & 0xf800) >> 11) { | |
558 | /* 6.5.1 Format 1: */ | |
559 | case 0x6000 >> 11: /* 7.1.52 STR(1) */ | |
560 | case 0x6800 >> 11: /* 7.1.26 LDR(1) */ | |
561 | case 0x7000 >> 11: /* 7.1.55 STRB(1) */ | |
562 | case 0x7800 >> 11: /* 7.1.30 LDRB(1) */ | |
563 | return 0xe5800000 | | |
564 | ((tinstr & (1<<12)) << (22-12)) | /* fixup */ | |
565 | (L<<20) | /* L==1? */ | |
566 | ((tinstr & (7<<0)) << (12-0)) | /* Rd */ | |
567 | ((tinstr & (7<<3)) << (16-3)) | /* Rn */ | |
568 | ((tinstr & (31<<6)) >> /* immed_5 */ | |
569 | (6 - ((tinstr & (1<<12)) ? 0 : 2))); | |
570 | case 0x8000 >> 11: /* 7.1.57 STRH(1) */ | |
571 | case 0x8800 >> 11: /* 7.1.32 LDRH(1) */ | |
572 | return 0xe1c000b0 | | |
573 | (L<<20) | /* L==1? */ | |
574 | ((tinstr & (7<<0)) << (12-0)) | /* Rd */ | |
575 | ((tinstr & (7<<3)) << (16-3)) | /* Rn */ | |
576 | ((tinstr & (7<<6)) >> (6-1)) | /* immed_5[2:0] */ | |
577 | ((tinstr & (3<<9)) >> (9-8)); /* immed_5[4:3] */ | |
578 | ||
579 | /* 6.5.1 Format 2: */ | |
580 | case 0x5000 >> 11: | |
581 | case 0x5800 >> 11: | |
582 | { | |
583 | static const u32 subset[8] = { | |
584 | 0xe7800000, /* 7.1.53 STR(2) */ | |
585 | 0xe18000b0, /* 7.1.58 STRH(2) */ | |
586 | 0xe7c00000, /* 7.1.56 STRB(2) */ | |
587 | 0xe19000d0, /* 7.1.34 LDRSB */ | |
588 | 0xe7900000, /* 7.1.27 LDR(2) */ | |
589 | 0xe19000b0, /* 7.1.33 LDRH(2) */ | |
590 | 0xe7d00000, /* 7.1.31 LDRB(2) */ | |
591 | 0xe19000f0 /* 7.1.35 LDRSH */ | |
592 | }; | |
593 | return subset[(tinstr & (7<<9)) >> 9] | | |
594 | ((tinstr & (7<<0)) << (12-0)) | /* Rd */ | |
595 | ((tinstr & (7<<3)) << (16-3)) | /* Rn */ | |
596 | ((tinstr & (7<<6)) >> (6-0)); /* Rm */ | |
597 | } | |
598 | ||
599 | /* 6.5.1 Format 3: */ | |
600 | case 0x4800 >> 11: /* 7.1.28 LDR(3) */ | |
601 | /* NOTE: This case is not technically possible. We're | |
737d0bb7 | 602 | * loading 32-bit memory data via PC relative |
1da177e4 LT |
603 | * addressing mode. So we can and should eliminate |
604 | * this case. But I'll leave it here for now. | |
605 | */ | |
606 | return 0xe59f0000 | | |
607 | ((tinstr & (7<<8)) << (12-8)) | /* Rd */ | |
608 | ((tinstr & 255) << (2-0)); /* immed_8 */ | |
609 | ||
610 | /* 6.5.1 Format 4: */ | |
611 | case 0x9000 >> 11: /* 7.1.54 STR(3) */ | |
612 | case 0x9800 >> 11: /* 7.1.29 LDR(4) */ | |
613 | return 0xe58d0000 | | |
614 | (L<<20) | /* L==1? */ | |
615 | ((tinstr & (7<<8)) << (12-8)) | /* Rd */ | |
616 | ((tinstr & 255) << 2); /* immed_8 */ | |
617 | ||
618 | /* 6.6.1 Format 1: */ | |
619 | case 0xc000 >> 11: /* 7.1.51 STMIA */ | |
620 | case 0xc800 >> 11: /* 7.1.25 LDMIA */ | |
621 | { | |
622 | u32 Rn = (tinstr & (7<<8)) >> 8; | |
623 | u32 W = ((L<<Rn) & (tinstr&255)) ? 0 : 1<<21; | |
624 | ||
625 | return 0xe8800000 | W | (L<<20) | (Rn<<16) | | |
626 | (tinstr&255); | |
627 | } | |
628 | ||
629 | /* 6.6.1 Format 2: */ | |
630 | case 0xb000 >> 11: /* 7.1.48 PUSH */ | |
631 | case 0xb800 >> 11: /* 7.1.47 POP */ | |
632 | if ((tinstr & (3 << 9)) == 0x0400) { | |
633 | static const u32 subset[4] = { | |
634 | 0xe92d0000, /* STMDB sp!,{registers} */ | |
635 | 0xe92d4000, /* STMDB sp!,{registers,lr} */ | |
636 | 0xe8bd0000, /* LDMIA sp!,{registers} */ | |
637 | 0xe8bd8000 /* LDMIA sp!,{registers,pc} */ | |
638 | }; | |
639 | return subset[(L<<1) | ((tinstr & (1<<8)) >> 8)] | | |
640 | (tinstr & 255); /* register_list */ | |
641 | } | |
642 | /* Else fall through for illegal instruction case */ | |
643 | ||
644 | default: | |
c2860d43 GD |
645 | return BAD_INSTR; |
646 | } | |
647 | } | |
648 | ||
649 | /* | |
650 | * Convert Thumb-2 32 bit LDM, STM, LDRD, STRD to equivalent instruction | |
651 | * handlable by ARM alignment handler, also find the corresponding handler, | |
652 | * so that we can reuse ARM userland alignment fault fixups for Thumb. | |
653 | * | |
654 | * @pinstr: original Thumb-2 instruction; returns new handlable instruction | |
655 | * @regs: register context. | |
656 | * @poffset: return offset from faulted addr for later writeback | |
657 | * | |
658 | * NOTES: | |
659 | * 1. Comments below refer to ARMv7 DDI0406A Thumb Instruction sections. | |
660 | * 2. Register name Rt from ARMv7 is same as Rd from ARMv6 (Rd is Rt) | |
661 | */ | |
662 | static void * | |
663 | do_alignment_t32_to_handler(unsigned long *pinstr, struct pt_regs *regs, | |
664 | union offset_union *poffset) | |
665 | { | |
666 | unsigned long instr = *pinstr; | |
667 | u16 tinst1 = (instr >> 16) & 0xffff; | |
668 | u16 tinst2 = instr & 0xffff; | |
669 | poffset->un = 0; | |
670 | ||
671 | switch (tinst1 & 0xffe0) { | |
672 | /* A6.3.5 Load/Store multiple */ | |
673 | case 0xe880: /* STM/STMIA/STMEA,LDM/LDMIA, PUSH/POP T2 */ | |
674 | case 0xe8a0: /* ...above writeback version */ | |
675 | case 0xe900: /* STMDB/STMFD, LDMDB/LDMEA */ | |
676 | case 0xe920: /* ...above writeback version */ | |
677 | /* no need offset decision since handler calculates it */ | |
678 | return do_alignment_ldmstm; | |
679 | ||
680 | case 0xf840: /* POP/PUSH T3 (single register) */ | |
681 | if (RN_BITS(instr) == 13 && (tinst2 & 0x09ff) == 0x0904) { | |
682 | u32 L = !!(LDST_L_BIT(instr)); | |
683 | const u32 subset[2] = { | |
684 | 0xe92d0000, /* STMDB sp!,{registers} */ | |
685 | 0xe8bd0000, /* LDMIA sp!,{registers} */ | |
686 | }; | |
687 | *pinstr = subset[L] | (1<<RD_BITS(instr)); | |
688 | return do_alignment_ldmstm; | |
689 | } | |
690 | /* Else fall through for illegal instruction case */ | |
691 | break; | |
692 | ||
693 | /* A6.3.6 Load/store double, STRD/LDRD(immed, lit, reg) */ | |
694 | case 0xe860: | |
695 | case 0xe960: | |
696 | case 0xe8e0: | |
697 | case 0xe9e0: | |
698 | poffset->un = (tinst2 & 0xff) << 2; | |
699 | case 0xe940: | |
700 | case 0xe9c0: | |
701 | return do_alignment_ldrdstrd; | |
702 | ||
703 | /* | |
704 | * No need to handle load/store instructions up to word size | |
705 | * since ARMv6 and later CPUs can perform unaligned accesses. | |
706 | */ | |
707 | default: | |
708 | break; | |
1da177e4 | 709 | } |
c2860d43 | 710 | return NULL; |
1da177e4 LT |
711 | } |
712 | ||
713 | static int | |
714 | do_alignment(unsigned long addr, unsigned int fsr, struct pt_regs *regs) | |
715 | { | |
716 | union offset_union offset; | |
717 | unsigned long instr = 0, instrptr; | |
718 | int (*handler)(unsigned long addr, unsigned long instr, struct pt_regs *regs); | |
719 | unsigned int type; | |
720 | mm_segment_t fs; | |
721 | unsigned int fault; | |
722 | u16 tinstr = 0; | |
c2860d43 GD |
723 | int isize = 4; |
724 | int thumb2_32b = 0; | |
1da177e4 LT |
725 | |
726 | instrptr = instruction_pointer(regs); | |
727 | ||
728 | fs = get_fs(); | |
729 | set_fs(KERNEL_DS); | |
f8343685 | 730 | if (thumb_mode(regs)) { |
1da177e4 | 731 | fault = __get_user(tinstr, (u16 *)(instrptr & ~1)); |
c2860d43 GD |
732 | if (!fault) { |
733 | if (cpu_architecture() >= CPU_ARCH_ARMv7 && | |
734 | IS_T32(tinstr)) { | |
735 | /* Thumb-2 32-bit */ | |
736 | u16 tinst2 = 0; | |
737 | fault = __get_user(tinst2, (u16 *)(instrptr+2)); | |
738 | instr = (tinstr << 16) | tinst2; | |
739 | thumb2_32b = 1; | |
740 | } else { | |
741 | isize = 2; | |
742 | instr = thumb2arm(tinstr); | |
743 | } | |
744 | } | |
1da177e4 LT |
745 | } else |
746 | fault = __get_user(instr, (u32 *)instrptr); | |
747 | set_fs(fs); | |
748 | ||
749 | if (fault) { | |
750 | type = TYPE_FAULT; | |
737d0bb7 | 751 | goto bad_or_fault; |
1da177e4 LT |
752 | } |
753 | ||
754 | if (user_mode(regs)) | |
755 | goto user; | |
756 | ||
757 | ai_sys += 1; | |
758 | ||
759 | fixup: | |
760 | ||
c2860d43 | 761 | regs->ARM_pc += isize; |
1da177e4 LT |
762 | |
763 | switch (CODING_BITS(instr)) { | |
f21ee2d4 SL |
764 | case 0x00000000: /* 3.13.4 load/store instruction extensions */ |
765 | if (LDSTHD_I_BIT(instr)) | |
1da177e4 LT |
766 | offset.un = (instr & 0xf00) >> 4 | (instr & 15); |
767 | else | |
768 | offset.un = regs->uregs[RM_BITS(instr)]; | |
f21ee2d4 SL |
769 | |
770 | if ((instr & 0x000000f0) == 0x000000b0 || /* LDRH, STRH */ | |
771 | (instr & 0x001000f0) == 0x001000f0) /* LDRSH */ | |
772 | handler = do_alignment_ldrhstrh; | |
773 | else if ((instr & 0x001000f0) == 0x000000d0 || /* LDRD */ | |
774 | (instr & 0x001000f0) == 0x000000f0) /* STRD */ | |
775 | handler = do_alignment_ldrdstrd; | |
19da83f6 GD |
776 | else if ((instr & 0x01f00ff0) == 0x01000090) /* SWP */ |
777 | goto swp; | |
f21ee2d4 SL |
778 | else |
779 | goto bad; | |
1da177e4 LT |
780 | break; |
781 | ||
782 | case 0x04000000: /* ldr or str immediate */ | |
783 | offset.un = OFFSET_BITS(instr); | |
784 | handler = do_alignment_ldrstr; | |
785 | break; | |
786 | ||
787 | case 0x06000000: /* ldr or str register */ | |
788 | offset.un = regs->uregs[RM_BITS(instr)]; | |
789 | ||
790 | if (IS_SHIFT(instr)) { | |
791 | unsigned int shiftval = SHIFT_BITS(instr); | |
792 | ||
793 | switch(SHIFT_TYPE(instr)) { | |
794 | case SHIFT_LSL: | |
795 | offset.un <<= shiftval; | |
796 | break; | |
797 | ||
798 | case SHIFT_LSR: | |
799 | offset.un >>= shiftval; | |
800 | break; | |
801 | ||
802 | case SHIFT_ASR: | |
803 | offset.sn >>= shiftval; | |
804 | break; | |
805 | ||
806 | case SHIFT_RORRRX: | |
807 | if (shiftval == 0) { | |
808 | offset.un >>= 1; | |
809 | if (regs->ARM_cpsr & PSR_C_BIT) | |
810 | offset.un |= 1 << 31; | |
811 | } else | |
812 | offset.un = offset.un >> shiftval | | |
813 | offset.un << (32 - shiftval); | |
814 | break; | |
815 | } | |
816 | } | |
817 | handler = do_alignment_ldrstr; | |
818 | break; | |
819 | ||
c2860d43 GD |
820 | case 0x08000000: /* ldm or stm, or thumb-2 32bit instruction */ |
821 | if (thumb2_32b) | |
822 | handler = do_alignment_t32_to_handler(&instr, regs, &offset); | |
823 | else | |
824 | handler = do_alignment_ldmstm; | |
1da177e4 LT |
825 | break; |
826 | ||
827 | default: | |
828 | goto bad; | |
829 | } | |
830 | ||
c2860d43 GD |
831 | if (!handler) |
832 | goto bad; | |
1da177e4 LT |
833 | type = handler(addr, instr, regs); |
834 | ||
c2860d43 GD |
835 | if (type == TYPE_ERROR || type == TYPE_FAULT) { |
836 | regs->ARM_pc -= isize; | |
1da177e4 | 837 | goto bad_or_fault; |
c2860d43 | 838 | } |
1da177e4 LT |
839 | |
840 | if (type == TYPE_LDST) | |
841 | do_alignment_finish_ldst(addr, instr, regs, offset); | |
842 | ||
843 | return 0; | |
844 | ||
845 | bad_or_fault: | |
846 | if (type == TYPE_ERROR) | |
847 | goto bad; | |
1da177e4 LT |
848 | /* |
849 | * We got a fault - fix it up, or die. | |
850 | */ | |
e5beac37 | 851 | do_bad_area(addr, fsr, regs); |
1da177e4 LT |
852 | return 0; |
853 | ||
19da83f6 GD |
854 | swp: |
855 | printk(KERN_ERR "Alignment trap: not handling swp instruction\n"); | |
856 | ||
1da177e4 LT |
857 | bad: |
858 | /* | |
859 | * Oops, we didn't handle the instruction. | |
860 | */ | |
861 | printk(KERN_ERR "Alignment trap: not handling instruction " | |
862 | "%0*lx at [<%08lx>]\n", | |
c2860d43 GD |
863 | isize << 1, |
864 | isize == 2 ? tinstr : instr, instrptr); | |
1da177e4 LT |
865 | ai_skipped += 1; |
866 | return 1; | |
867 | ||
868 | user: | |
869 | ai_user += 1; | |
870 | ||
baa745a3 | 871 | if (ai_usermode & UM_WARN) |
1da177e4 LT |
872 | printk("Alignment trap: %s (%d) PC=0x%08lx Instr=0x%0*lx " |
873 | "Address=0x%08lx FSR 0x%03x\n", current->comm, | |
19c5870c | 874 | task_pid_nr(current), instrptr, |
c2860d43 GD |
875 | isize << 1, |
876 | isize == 2 ? tinstr : instr, | |
1da177e4 LT |
877 | addr, fsr); |
878 | ||
baa745a3 | 879 | if (ai_usermode & UM_FIXUP) |
1da177e4 LT |
880 | goto fixup; |
881 | ||
baa745a3 | 882 | if (ai_usermode & UM_SIGNAL) |
1da177e4 LT |
883 | force_sig(SIGBUS, current); |
884 | else | |
885 | set_cr(cr_no_alignment); | |
886 | ||
887 | return 0; | |
888 | } | |
889 | ||
890 | /* | |
891 | * This needs to be done after sysctl_init, otherwise sys/ will be | |
892 | * overwritten. Actually, this shouldn't be in sys/ at all since | |
893 | * it isn't a sysctl, and it doesn't contain sysctl information. | |
894 | * We now locate it in /proc/cpu/alignment instead. | |
895 | */ | |
896 | static int __init alignment_init(void) | |
897 | { | |
898 | #ifdef CONFIG_PROC_FS | |
899 | struct proc_dir_entry *res; | |
900 | ||
e119bfff | 901 | res = create_proc_entry("cpu/alignment", S_IWUSR | S_IRUGO, NULL); |
1da177e4 LT |
902 | if (!res) |
903 | return -ENOMEM; | |
904 | ||
905 | res->read_proc = proc_alignment_read; | |
906 | res->write_proc = proc_alignment_write; | |
907 | #endif | |
908 | ||
baa745a3 RK |
909 | /* |
910 | * ARMv6 and later CPUs can perform unaligned accesses for | |
911 | * most single load and store instructions up to word size. | |
912 | * LDM, STM, LDRD and STRD still need to be handled. | |
913 | * | |
914 | * Ignoring the alignment fault is not an option on these | |
915 | * CPUs since we spin re-faulting the instruction without | |
916 | * making any progress. | |
917 | */ | |
918 | if (cpu_architecture() >= CPU_ARCH_ARMv6 && (cr_alignment & CR_U)) { | |
919 | cr_alignment &= ~CR_A; | |
920 | cr_no_alignment &= ~CR_A; | |
921 | set_cr(cr_alignment); | |
922 | ai_usermode = UM_FIXUP; | |
923 | } | |
924 | ||
1da177e4 LT |
925 | hook_fault_code(1, do_alignment, SIGILL, "alignment exception"); |
926 | hook_fault_code(3, do_alignment, SIGILL, "alignment exception"); | |
927 | ||
928 | return 0; | |
929 | } | |
930 | ||
931 | fs_initcall(alignment_init); |