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Commit | Line | Data |
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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 | */ | |
d944d549 | 14 | #include <linux/moduleparam.h> |
1da177e4 LT |
15 | #include <linux/compiler.h> |
16 | #include <linux/kernel.h> | |
17 | #include <linux/errno.h> | |
18 | #include <linux/string.h> | |
1da177e4 | 19 | #include <linux/proc_fs.h> |
b7072c63 | 20 | #include <linux/seq_file.h> |
1da177e4 | 21 | #include <linux/init.h> |
87c52578 | 22 | #include <linux/sched.h> |
33fa9b13 | 23 | #include <linux/uaccess.h> |
1da177e4 | 24 | |
15d07dc9 | 25 | #include <asm/cp15.h> |
9f97da78 | 26 | #include <asm/system_info.h> |
1da177e4 | 27 | #include <asm/unaligned.h> |
8592edf0 | 28 | #include <asm/opcodes.h> |
1da177e4 LT |
29 | |
30 | #include "fault.h" | |
b4b20ad8 | 31 | #include "mm.h" |
1da177e4 LT |
32 | |
33 | /* | |
34 | * 32-bit misaligned trap handler (c) 1998 San Mehat (CCC) -July 1998 | |
35 | * /proc/sys/debug/alignment, modified and integrated into | |
36 | * Linux 2.1 by Russell King | |
37 | * | |
38 | * Speed optimisations and better fault handling by Russell King. | |
39 | * | |
40 | * *** NOTE *** | |
41 | * This code is not portable to processors with late data abort handling. | |
42 | */ | |
43 | #define CODING_BITS(i) (i & 0x0e000000) | |
5ca918e5 | 44 | #define COND_BITS(i) (i & 0xf0000000) |
1da177e4 LT |
45 | |
46 | #define LDST_I_BIT(i) (i & (1 << 26)) /* Immediate constant */ | |
47 | #define LDST_P_BIT(i) (i & (1 << 24)) /* Preindex */ | |
48 | #define LDST_U_BIT(i) (i & (1 << 23)) /* Add offset */ | |
49 | #define LDST_W_BIT(i) (i & (1 << 21)) /* Writeback */ | |
50 | #define LDST_L_BIT(i) (i & (1 << 20)) /* Load */ | |
51 | ||
52 | #define LDST_P_EQ_U(i) ((((i) ^ ((i) >> 1)) & (1 << 23)) == 0) | |
53 | ||
f21ee2d4 | 54 | #define LDSTHD_I_BIT(i) (i & (1 << 22)) /* double/half-word immed */ |
1da177e4 LT |
55 | #define LDM_S_BIT(i) (i & (1 << 22)) /* write CPSR from SPSR */ |
56 | ||
57 | #define RN_BITS(i) ((i >> 16) & 15) /* Rn */ | |
58 | #define RD_BITS(i) ((i >> 12) & 15) /* Rd */ | |
59 | #define RM_BITS(i) (i & 15) /* Rm */ | |
60 | ||
61 | #define REGMASK_BITS(i) (i & 0xffff) | |
62 | #define OFFSET_BITS(i) (i & 0x0fff) | |
63 | ||
64 | #define IS_SHIFT(i) (i & 0x0ff0) | |
65 | #define SHIFT_BITS(i) ((i >> 7) & 0x1f) | |
66 | #define SHIFT_TYPE(i) (i & 0x60) | |
67 | #define SHIFT_LSL 0x00 | |
68 | #define SHIFT_LSR 0x20 | |
69 | #define SHIFT_ASR 0x40 | |
70 | #define SHIFT_RORRRX 0x60 | |
71 | ||
c2860d43 GD |
72 | #define BAD_INSTR 0xdeadc0de |
73 | ||
74 | /* Thumb-2 32 bit format per ARMv7 DDI0406A A6.3, either f800h,e800h,f800h */ | |
75 | #define IS_T32(hi16) \ | |
76 | (((hi16) & 0xe000) == 0xe000 && ((hi16) & 0x1800)) | |
77 | ||
1da177e4 LT |
78 | static unsigned long ai_user; |
79 | static unsigned long ai_sys; | |
1e7e3211 | 80 | static void *ai_sys_last_pc; |
1da177e4 LT |
81 | static unsigned long ai_skipped; |
82 | static unsigned long ai_half; | |
83 | static unsigned long ai_word; | |
f21ee2d4 | 84 | static unsigned long ai_dword; |
1da177e4 LT |
85 | static unsigned long ai_multi; |
86 | static int ai_usermode; | |
0aeb3408 | 87 | static unsigned long cr_no_alignment; |
1da177e4 | 88 | |
d944d549 RK |
89 | core_param(alignment, ai_usermode, int, 0600); |
90 | ||
baa745a3 RK |
91 | #define UM_WARN (1 << 0) |
92 | #define UM_FIXUP (1 << 1) | |
93 | #define UM_SIGNAL (1 << 2) | |
94 | ||
088c01f1 DM |
95 | /* Return true if and only if the ARMv6 unaligned access model is in use. */ |
96 | static bool cpu_is_v6_unaligned(void) | |
97 | { | |
4585eaff | 98 | return cpu_architecture() >= CPU_ARCH_ARMv6 && get_cr() & CR_U; |
088c01f1 DM |
99 | } |
100 | ||
101 | static int safe_usermode(int new_usermode, bool warn) | |
102 | { | |
103 | /* | |
104 | * ARMv6 and later CPUs can perform unaligned accesses for | |
105 | * most single load and store instructions up to word size. | |
106 | * LDM, STM, LDRD and STRD still need to be handled. | |
107 | * | |
108 | * Ignoring the alignment fault is not an option on these | |
109 | * CPUs since we spin re-faulting the instruction without | |
110 | * making any progress. | |
111 | */ | |
112 | if (cpu_is_v6_unaligned() && !(new_usermode & (UM_FIXUP | UM_SIGNAL))) { | |
113 | new_usermode |= UM_FIXUP; | |
114 | ||
115 | if (warn) | |
4ed89f22 | 116 | pr_warn("alignment: ignoring faults is unsafe on this CPU. Defaulting to fixup mode.\n"); |
088c01f1 DM |
117 | } |
118 | ||
119 | return new_usermode; | |
120 | } | |
121 | ||
ffc660c5 AB |
122 | #ifdef CONFIG_PROC_FS |
123 | static const char *usermode_action[] = { | |
124 | "ignored", | |
125 | "warn", | |
126 | "fixup", | |
127 | "fixup+warn", | |
128 | "signal", | |
129 | "signal+warn" | |
130 | }; | |
131 | ||
b7072c63 | 132 | static int alignment_proc_show(struct seq_file *m, void *v) |
1da177e4 | 133 | { |
b7072c63 | 134 | seq_printf(m, "User:\t\t%lu\n", ai_user); |
1e7e3211 | 135 | seq_printf(m, "System:\t\t%lu (%pF)\n", ai_sys, ai_sys_last_pc); |
b7072c63 AD |
136 | seq_printf(m, "Skipped:\t%lu\n", ai_skipped); |
137 | seq_printf(m, "Half:\t\t%lu\n", ai_half); | |
138 | seq_printf(m, "Word:\t\t%lu\n", ai_word); | |
f21ee2d4 | 139 | if (cpu_architecture() >= CPU_ARCH_ARMv5TE) |
b7072c63 AD |
140 | seq_printf(m, "DWord:\t\t%lu\n", ai_dword); |
141 | seq_printf(m, "Multi:\t\t%lu\n", ai_multi); | |
142 | seq_printf(m, "User faults:\t%i (%s)\n", ai_usermode, | |
1da177e4 LT |
143 | usermode_action[ai_usermode]); |
144 | ||
b7072c63 AD |
145 | return 0; |
146 | } | |
1da177e4 | 147 | |
b7072c63 AD |
148 | static int alignment_proc_open(struct inode *inode, struct file *file) |
149 | { | |
150 | return single_open(file, alignment_proc_show, NULL); | |
1da177e4 LT |
151 | } |
152 | ||
b7072c63 AD |
153 | static ssize_t alignment_proc_write(struct file *file, const char __user *buffer, |
154 | size_t count, loff_t *pos) | |
1da177e4 LT |
155 | { |
156 | char mode; | |
157 | ||
158 | if (count > 0) { | |
159 | if (get_user(mode, buffer)) | |
160 | return -EFAULT; | |
161 | if (mode >= '0' && mode <= '5') | |
088c01f1 | 162 | ai_usermode = safe_usermode(mode - '0', true); |
1da177e4 LT |
163 | } |
164 | return count; | |
165 | } | |
166 | ||
b7072c63 AD |
167 | static const struct file_operations alignment_proc_fops = { |
168 | .open = alignment_proc_open, | |
169 | .read = seq_read, | |
170 | .llseek = seq_lseek, | |
171 | .release = single_release, | |
172 | .write = alignment_proc_write, | |
173 | }; | |
1da177e4 LT |
174 | #endif /* CONFIG_PROC_FS */ |
175 | ||
176 | union offset_union { | |
177 | unsigned long un; | |
178 | signed long sn; | |
179 | }; | |
180 | ||
181 | #define TYPE_ERROR 0 | |
182 | #define TYPE_FAULT 1 | |
183 | #define TYPE_LDST 2 | |
184 | #define TYPE_DONE 3 | |
185 | ||
186 | #ifdef __ARMEB__ | |
187 | #define BE 1 | |
188 | #define FIRST_BYTE_16 "mov %1, %1, ror #8\n" | |
189 | #define FIRST_BYTE_32 "mov %1, %1, ror #24\n" | |
190 | #define NEXT_BYTE "ror #24" | |
191 | #else | |
192 | #define BE 0 | |
193 | #define FIRST_BYTE_16 | |
194 | #define FIRST_BYTE_32 | |
195 | #define NEXT_BYTE "lsr #8" | |
196 | #endif | |
197 | ||
198 | #define __get8_unaligned_check(ins,val,addr,err) \ | |
199 | __asm__( \ | |
347c8b70 CM |
200 | ARM( "1: "ins" %1, [%2], #1\n" ) \ |
201 | THUMB( "1: "ins" %1, [%2]\n" ) \ | |
202 | THUMB( " add %2, %2, #1\n" ) \ | |
1da177e4 | 203 | "2:\n" \ |
4260415f | 204 | " .pushsection .fixup,\"ax\"\n" \ |
1da177e4 LT |
205 | " .align 2\n" \ |
206 | "3: mov %0, #1\n" \ | |
207 | " b 2b\n" \ | |
4260415f RK |
208 | " .popsection\n" \ |
209 | " .pushsection __ex_table,\"a\"\n" \ | |
1da177e4 LT |
210 | " .align 3\n" \ |
211 | " .long 1b, 3b\n" \ | |
4260415f | 212 | " .popsection\n" \ |
1da177e4 LT |
213 | : "=r" (err), "=&r" (val), "=r" (addr) \ |
214 | : "0" (err), "2" (addr)) | |
215 | ||
216 | #define __get16_unaligned_check(ins,val,addr) \ | |
217 | do { \ | |
218 | unsigned int err = 0, v, a = addr; \ | |
219 | __get8_unaligned_check(ins,v,a,err); \ | |
220 | val = v << ((BE) ? 8 : 0); \ | |
221 | __get8_unaligned_check(ins,v,a,err); \ | |
222 | val |= v << ((BE) ? 0 : 8); \ | |
223 | if (err) \ | |
224 | goto fault; \ | |
225 | } while (0) | |
226 | ||
227 | #define get16_unaligned_check(val,addr) \ | |
228 | __get16_unaligned_check("ldrb",val,addr) | |
229 | ||
230 | #define get16t_unaligned_check(val,addr) \ | |
231 | __get16_unaligned_check("ldrbt",val,addr) | |
232 | ||
233 | #define __get32_unaligned_check(ins,val,addr) \ | |
234 | do { \ | |
235 | unsigned int err = 0, v, a = addr; \ | |
236 | __get8_unaligned_check(ins,v,a,err); \ | |
237 | val = v << ((BE) ? 24 : 0); \ | |
238 | __get8_unaligned_check(ins,v,a,err); \ | |
239 | val |= v << ((BE) ? 16 : 8); \ | |
240 | __get8_unaligned_check(ins,v,a,err); \ | |
241 | val |= v << ((BE) ? 8 : 16); \ | |
242 | __get8_unaligned_check(ins,v,a,err); \ | |
243 | val |= v << ((BE) ? 0 : 24); \ | |
244 | if (err) \ | |
245 | goto fault; \ | |
246 | } while (0) | |
247 | ||
248 | #define get32_unaligned_check(val,addr) \ | |
249 | __get32_unaligned_check("ldrb",val,addr) | |
250 | ||
251 | #define get32t_unaligned_check(val,addr) \ | |
252 | __get32_unaligned_check("ldrbt",val,addr) | |
253 | ||
254 | #define __put16_unaligned_check(ins,val,addr) \ | |
255 | do { \ | |
256 | unsigned int err = 0, v = val, a = addr; \ | |
257 | __asm__( FIRST_BYTE_16 \ | |
347c8b70 CM |
258 | ARM( "1: "ins" %1, [%2], #1\n" ) \ |
259 | THUMB( "1: "ins" %1, [%2]\n" ) \ | |
260 | THUMB( " add %2, %2, #1\n" ) \ | |
1da177e4 LT |
261 | " mov %1, %1, "NEXT_BYTE"\n" \ |
262 | "2: "ins" %1, [%2]\n" \ | |
263 | "3:\n" \ | |
4260415f | 264 | " .pushsection .fixup,\"ax\"\n" \ |
1da177e4 LT |
265 | " .align 2\n" \ |
266 | "4: mov %0, #1\n" \ | |
267 | " b 3b\n" \ | |
4260415f RK |
268 | " .popsection\n" \ |
269 | " .pushsection __ex_table,\"a\"\n" \ | |
1da177e4 LT |
270 | " .align 3\n" \ |
271 | " .long 1b, 4b\n" \ | |
272 | " .long 2b, 4b\n" \ | |
4260415f | 273 | " .popsection\n" \ |
1da177e4 LT |
274 | : "=r" (err), "=&r" (v), "=&r" (a) \ |
275 | : "0" (err), "1" (v), "2" (a)); \ | |
276 | if (err) \ | |
277 | goto fault; \ | |
278 | } while (0) | |
279 | ||
280 | #define put16_unaligned_check(val,addr) \ | |
281 | __put16_unaligned_check("strb",val,addr) | |
282 | ||
283 | #define put16t_unaligned_check(val,addr) \ | |
284 | __put16_unaligned_check("strbt",val,addr) | |
285 | ||
286 | #define __put32_unaligned_check(ins,val,addr) \ | |
287 | do { \ | |
288 | unsigned int err = 0, v = val, a = addr; \ | |
289 | __asm__( FIRST_BYTE_32 \ | |
347c8b70 CM |
290 | ARM( "1: "ins" %1, [%2], #1\n" ) \ |
291 | THUMB( "1: "ins" %1, [%2]\n" ) \ | |
292 | THUMB( " add %2, %2, #1\n" ) \ | |
1da177e4 | 293 | " mov %1, %1, "NEXT_BYTE"\n" \ |
347c8b70 CM |
294 | ARM( "2: "ins" %1, [%2], #1\n" ) \ |
295 | THUMB( "2: "ins" %1, [%2]\n" ) \ | |
296 | THUMB( " add %2, %2, #1\n" ) \ | |
1da177e4 | 297 | " mov %1, %1, "NEXT_BYTE"\n" \ |
347c8b70 CM |
298 | ARM( "3: "ins" %1, [%2], #1\n" ) \ |
299 | THUMB( "3: "ins" %1, [%2]\n" ) \ | |
300 | THUMB( " add %2, %2, #1\n" ) \ | |
1da177e4 LT |
301 | " mov %1, %1, "NEXT_BYTE"\n" \ |
302 | "4: "ins" %1, [%2]\n" \ | |
303 | "5:\n" \ | |
4260415f | 304 | " .pushsection .fixup,\"ax\"\n" \ |
1da177e4 LT |
305 | " .align 2\n" \ |
306 | "6: mov %0, #1\n" \ | |
307 | " b 5b\n" \ | |
4260415f RK |
308 | " .popsection\n" \ |
309 | " .pushsection __ex_table,\"a\"\n" \ | |
1da177e4 LT |
310 | " .align 3\n" \ |
311 | " .long 1b, 6b\n" \ | |
312 | " .long 2b, 6b\n" \ | |
313 | " .long 3b, 6b\n" \ | |
314 | " .long 4b, 6b\n" \ | |
4260415f | 315 | " .popsection\n" \ |
1da177e4 LT |
316 | : "=r" (err), "=&r" (v), "=&r" (a) \ |
317 | : "0" (err), "1" (v), "2" (a)); \ | |
318 | if (err) \ | |
319 | goto fault; \ | |
320 | } while (0) | |
321 | ||
737d0bb7 | 322 | #define put32_unaligned_check(val,addr) \ |
1da177e4 LT |
323 | __put32_unaligned_check("strb", val, addr) |
324 | ||
325 | #define put32t_unaligned_check(val,addr) \ | |
326 | __put32_unaligned_check("strbt", val, addr) | |
327 | ||
328 | static void | |
329 | do_alignment_finish_ldst(unsigned long addr, unsigned long instr, struct pt_regs *regs, union offset_union offset) | |
330 | { | |
331 | if (!LDST_U_BIT(instr)) | |
332 | offset.un = -offset.un; | |
333 | ||
334 | if (!LDST_P_BIT(instr)) | |
335 | addr += offset.un; | |
336 | ||
337 | if (!LDST_P_BIT(instr) || LDST_W_BIT(instr)) | |
338 | regs->uregs[RN_BITS(instr)] = addr; | |
339 | } | |
340 | ||
341 | static int | |
342 | do_alignment_ldrhstrh(unsigned long addr, unsigned long instr, struct pt_regs *regs) | |
343 | { | |
344 | unsigned int rd = RD_BITS(instr); | |
345 | ||
1da177e4 LT |
346 | ai_half += 1; |
347 | ||
348 | if (user_mode(regs)) | |
349 | goto user; | |
350 | ||
351 | if (LDST_L_BIT(instr)) { | |
352 | unsigned long val; | |
353 | get16_unaligned_check(val, addr); | |
354 | ||
355 | /* signed half-word? */ | |
356 | if (instr & 0x40) | |
357 | val = (signed long)((signed short) val); | |
358 | ||
359 | regs->uregs[rd] = val; | |
360 | } else | |
361 | put16_unaligned_check(regs->uregs[rd], addr); | |
362 | ||
363 | return TYPE_LDST; | |
364 | ||
365 | user: | |
737d0bb7 GD |
366 | if (LDST_L_BIT(instr)) { |
367 | unsigned long val; | |
368 | get16t_unaligned_check(val, addr); | |
1da177e4 | 369 | |
737d0bb7 GD |
370 | /* signed half-word? */ |
371 | if (instr & 0x40) | |
372 | val = (signed long)((signed short) val); | |
1da177e4 | 373 | |
737d0bb7 GD |
374 | regs->uregs[rd] = val; |
375 | } else | |
376 | put16t_unaligned_check(regs->uregs[rd], addr); | |
1da177e4 | 377 | |
737d0bb7 | 378 | return TYPE_LDST; |
1da177e4 | 379 | |
f21ee2d4 SL |
380 | fault: |
381 | return TYPE_FAULT; | |
382 | } | |
383 | ||
384 | static int | |
385 | do_alignment_ldrdstrd(unsigned long addr, unsigned long instr, | |
386 | struct pt_regs *regs) | |
387 | { | |
388 | unsigned int rd = RD_BITS(instr); | |
c2860d43 GD |
389 | unsigned int rd2; |
390 | int load; | |
391 | ||
392 | if ((instr & 0xfe000000) == 0xe8000000) { | |
393 | /* ARMv7 Thumb-2 32-bit LDRD/STRD */ | |
394 | rd2 = (instr >> 8) & 0xf; | |
395 | load = !!(LDST_L_BIT(instr)); | |
396 | } else if (((rd & 1) == 1) || (rd == 14)) | |
19da83f6 | 397 | goto bad; |
c2860d43 GD |
398 | else { |
399 | load = ((instr & 0xf0) == 0xd0); | |
400 | rd2 = rd + 1; | |
401 | } | |
19da83f6 | 402 | |
f21ee2d4 SL |
403 | ai_dword += 1; |
404 | ||
405 | if (user_mode(regs)) | |
406 | goto user; | |
407 | ||
c2860d43 | 408 | if (load) { |
f21ee2d4 SL |
409 | unsigned long val; |
410 | get32_unaligned_check(val, addr); | |
411 | regs->uregs[rd] = val; | |
737d0bb7 | 412 | get32_unaligned_check(val, addr + 4); |
c2860d43 | 413 | regs->uregs[rd2] = val; |
f21ee2d4 SL |
414 | } else { |
415 | put32_unaligned_check(regs->uregs[rd], addr); | |
c2860d43 | 416 | put32_unaligned_check(regs->uregs[rd2], addr + 4); |
f21ee2d4 SL |
417 | } |
418 | ||
419 | return TYPE_LDST; | |
420 | ||
421 | user: | |
c2860d43 | 422 | if (load) { |
f21ee2d4 SL |
423 | unsigned long val; |
424 | get32t_unaligned_check(val, addr); | |
425 | regs->uregs[rd] = val; | |
737d0bb7 | 426 | get32t_unaligned_check(val, addr + 4); |
c2860d43 | 427 | regs->uregs[rd2] = val; |
f21ee2d4 SL |
428 | } else { |
429 | put32t_unaligned_check(regs->uregs[rd], addr); | |
c2860d43 | 430 | put32t_unaligned_check(regs->uregs[rd2], addr + 4); |
f21ee2d4 SL |
431 | } |
432 | ||
433 | return TYPE_LDST; | |
19da83f6 GD |
434 | bad: |
435 | return TYPE_ERROR; | |
1da177e4 LT |
436 | fault: |
437 | return TYPE_FAULT; | |
438 | } | |
439 | ||
440 | static int | |
441 | do_alignment_ldrstr(unsigned long addr, unsigned long instr, struct pt_regs *regs) | |
442 | { | |
443 | unsigned int rd = RD_BITS(instr); | |
444 | ||
445 | ai_word += 1; | |
446 | ||
447 | if ((!LDST_P_BIT(instr) && LDST_W_BIT(instr)) || user_mode(regs)) | |
448 | goto trans; | |
449 | ||
450 | if (LDST_L_BIT(instr)) { | |
451 | unsigned int val; | |
452 | get32_unaligned_check(val, addr); | |
453 | regs->uregs[rd] = val; | |
454 | } else | |
455 | put32_unaligned_check(regs->uregs[rd], addr); | |
456 | return TYPE_LDST; | |
457 | ||
458 | trans: | |
459 | if (LDST_L_BIT(instr)) { | |
460 | unsigned int val; | |
461 | get32t_unaligned_check(val, addr); | |
462 | regs->uregs[rd] = val; | |
463 | } else | |
464 | put32t_unaligned_check(regs->uregs[rd], addr); | |
465 | return TYPE_LDST; | |
466 | ||
467 | fault: | |
468 | return TYPE_FAULT; | |
469 | } | |
470 | ||
471 | /* | |
472 | * LDM/STM alignment handler. | |
473 | * | |
474 | * There are 4 variants of this instruction: | |
475 | * | |
476 | * B = rn pointer before instruction, A = rn pointer after instruction | |
477 | * ------ increasing address -----> | |
478 | * | | r0 | r1 | ... | rx | | | |
479 | * PU = 01 B A | |
480 | * PU = 11 B A | |
481 | * PU = 00 A B | |
482 | * PU = 10 A B | |
483 | */ | |
484 | static int | |
485 | do_alignment_ldmstm(unsigned long addr, unsigned long instr, struct pt_regs *regs) | |
486 | { | |
487 | unsigned int rd, rn, correction, nr_regs, regbits; | |
488 | unsigned long eaddr, newaddr; | |
489 | ||
490 | if (LDM_S_BIT(instr)) | |
491 | goto bad; | |
492 | ||
493 | correction = 4; /* processor implementation defined */ | |
494 | regs->ARM_pc += correction; | |
495 | ||
496 | ai_multi += 1; | |
497 | ||
498 | /* count the number of registers in the mask to be transferred */ | |
499 | nr_regs = hweight16(REGMASK_BITS(instr)) * 4; | |
500 | ||
501 | rn = RN_BITS(instr); | |
502 | newaddr = eaddr = regs->uregs[rn]; | |
503 | ||
504 | if (!LDST_U_BIT(instr)) | |
505 | nr_regs = -nr_regs; | |
506 | newaddr += nr_regs; | |
507 | if (!LDST_U_BIT(instr)) | |
508 | eaddr = newaddr; | |
509 | ||
510 | if (LDST_P_EQ_U(instr)) /* U = P */ | |
511 | eaddr += 4; | |
512 | ||
737d0bb7 | 513 | /* |
1da177e4 LT |
514 | * For alignment faults on the ARM922T/ARM920T the MMU makes |
515 | * the FSR (and hence addr) equal to the updated base address | |
516 | * of the multiple access rather than the restored value. | |
517 | * Switch this message off if we've got a ARM92[02], otherwise | |
518 | * [ls]dm alignment faults are noisy! | |
519 | */ | |
520 | #if !(defined CONFIG_CPU_ARM922T) && !(defined CONFIG_CPU_ARM920T) | |
521 | /* | |
522 | * This is a "hint" - we already have eaddr worked out by the | |
523 | * processor for us. | |
524 | */ | |
525 | if (addr != eaddr) { | |
4ed89f22 | 526 | pr_err("LDMSTM: PC = %08lx, instr = %08lx, " |
1da177e4 LT |
527 | "addr = %08lx, eaddr = %08lx\n", |
528 | instruction_pointer(regs), instr, addr, eaddr); | |
529 | show_regs(regs); | |
530 | } | |
531 | #endif | |
532 | ||
533 | if (user_mode(regs)) { | |
534 | for (regbits = REGMASK_BITS(instr), rd = 0; regbits; | |
535 | regbits >>= 1, rd += 1) | |
536 | if (regbits & 1) { | |
537 | if (LDST_L_BIT(instr)) { | |
538 | unsigned int val; | |
539 | get32t_unaligned_check(val, eaddr); | |
540 | regs->uregs[rd] = val; | |
541 | } else | |
542 | put32t_unaligned_check(regs->uregs[rd], eaddr); | |
543 | eaddr += 4; | |
544 | } | |
545 | } else { | |
546 | for (regbits = REGMASK_BITS(instr), rd = 0; regbits; | |
547 | regbits >>= 1, rd += 1) | |
548 | if (regbits & 1) { | |
549 | if (LDST_L_BIT(instr)) { | |
550 | unsigned int val; | |
551 | get32_unaligned_check(val, eaddr); | |
552 | regs->uregs[rd] = val; | |
553 | } else | |
554 | put32_unaligned_check(regs->uregs[rd], eaddr); | |
555 | eaddr += 4; | |
556 | } | |
557 | } | |
558 | ||
559 | if (LDST_W_BIT(instr)) | |
560 | regs->uregs[rn] = newaddr; | |
561 | if (!LDST_L_BIT(instr) || !(REGMASK_BITS(instr) & (1 << 15))) | |
562 | regs->ARM_pc -= correction; | |
563 | return TYPE_DONE; | |
564 | ||
565 | fault: | |
566 | regs->ARM_pc -= correction; | |
567 | return TYPE_FAULT; | |
568 | ||
569 | bad: | |
4ed89f22 | 570 | pr_err("Alignment trap: not handling ldm with s-bit set\n"); |
1da177e4 LT |
571 | return TYPE_ERROR; |
572 | } | |
573 | ||
574 | /* | |
575 | * Convert Thumb ld/st instruction forms to equivalent ARM instructions so | |
576 | * we can reuse ARM userland alignment fault fixups for Thumb. | |
577 | * | |
578 | * This implementation was initially based on the algorithm found in | |
579 | * gdb/sim/arm/thumbemu.c. It is basically just a code reduction of same | |
580 | * to convert only Thumb ld/st instruction forms to equivalent ARM forms. | |
581 | * | |
582 | * NOTES: | |
583 | * 1. Comments below refer to ARM ARM DDI0100E Thumb Instruction sections. | |
584 | * 2. If for some reason we're passed an non-ld/st Thumb instruction to | |
585 | * decode, we return 0xdeadc0de. This should never happen under normal | |
586 | * circumstances but if it does, we've got other problems to deal with | |
587 | * elsewhere and we obviously can't fix those problems here. | |
588 | */ | |
589 | ||
590 | static unsigned long | |
591 | thumb2arm(u16 tinstr) | |
592 | { | |
593 | u32 L = (tinstr & (1<<11)) >> 11; | |
594 | ||
595 | switch ((tinstr & 0xf800) >> 11) { | |
596 | /* 6.5.1 Format 1: */ | |
597 | case 0x6000 >> 11: /* 7.1.52 STR(1) */ | |
598 | case 0x6800 >> 11: /* 7.1.26 LDR(1) */ | |
599 | case 0x7000 >> 11: /* 7.1.55 STRB(1) */ | |
600 | case 0x7800 >> 11: /* 7.1.30 LDRB(1) */ | |
601 | return 0xe5800000 | | |
602 | ((tinstr & (1<<12)) << (22-12)) | /* fixup */ | |
603 | (L<<20) | /* L==1? */ | |
604 | ((tinstr & (7<<0)) << (12-0)) | /* Rd */ | |
605 | ((tinstr & (7<<3)) << (16-3)) | /* Rn */ | |
606 | ((tinstr & (31<<6)) >> /* immed_5 */ | |
607 | (6 - ((tinstr & (1<<12)) ? 0 : 2))); | |
608 | case 0x8000 >> 11: /* 7.1.57 STRH(1) */ | |
609 | case 0x8800 >> 11: /* 7.1.32 LDRH(1) */ | |
610 | return 0xe1c000b0 | | |
611 | (L<<20) | /* L==1? */ | |
612 | ((tinstr & (7<<0)) << (12-0)) | /* Rd */ | |
613 | ((tinstr & (7<<3)) << (16-3)) | /* Rn */ | |
614 | ((tinstr & (7<<6)) >> (6-1)) | /* immed_5[2:0] */ | |
615 | ((tinstr & (3<<9)) >> (9-8)); /* immed_5[4:3] */ | |
616 | ||
617 | /* 6.5.1 Format 2: */ | |
618 | case 0x5000 >> 11: | |
619 | case 0x5800 >> 11: | |
620 | { | |
621 | static const u32 subset[8] = { | |
622 | 0xe7800000, /* 7.1.53 STR(2) */ | |
623 | 0xe18000b0, /* 7.1.58 STRH(2) */ | |
624 | 0xe7c00000, /* 7.1.56 STRB(2) */ | |
625 | 0xe19000d0, /* 7.1.34 LDRSB */ | |
626 | 0xe7900000, /* 7.1.27 LDR(2) */ | |
627 | 0xe19000b0, /* 7.1.33 LDRH(2) */ | |
628 | 0xe7d00000, /* 7.1.31 LDRB(2) */ | |
629 | 0xe19000f0 /* 7.1.35 LDRSH */ | |
630 | }; | |
631 | return subset[(tinstr & (7<<9)) >> 9] | | |
632 | ((tinstr & (7<<0)) << (12-0)) | /* Rd */ | |
633 | ((tinstr & (7<<3)) << (16-3)) | /* Rn */ | |
634 | ((tinstr & (7<<6)) >> (6-0)); /* Rm */ | |
635 | } | |
636 | ||
637 | /* 6.5.1 Format 3: */ | |
638 | case 0x4800 >> 11: /* 7.1.28 LDR(3) */ | |
639 | /* NOTE: This case is not technically possible. We're | |
737d0bb7 | 640 | * loading 32-bit memory data via PC relative |
1da177e4 LT |
641 | * addressing mode. So we can and should eliminate |
642 | * this case. But I'll leave it here for now. | |
643 | */ | |
644 | return 0xe59f0000 | | |
645 | ((tinstr & (7<<8)) << (12-8)) | /* Rd */ | |
646 | ((tinstr & 255) << (2-0)); /* immed_8 */ | |
647 | ||
648 | /* 6.5.1 Format 4: */ | |
649 | case 0x9000 >> 11: /* 7.1.54 STR(3) */ | |
650 | case 0x9800 >> 11: /* 7.1.29 LDR(4) */ | |
651 | return 0xe58d0000 | | |
652 | (L<<20) | /* L==1? */ | |
653 | ((tinstr & (7<<8)) << (12-8)) | /* Rd */ | |
654 | ((tinstr & 255) << 2); /* immed_8 */ | |
655 | ||
656 | /* 6.6.1 Format 1: */ | |
657 | case 0xc000 >> 11: /* 7.1.51 STMIA */ | |
658 | case 0xc800 >> 11: /* 7.1.25 LDMIA */ | |
659 | { | |
660 | u32 Rn = (tinstr & (7<<8)) >> 8; | |
661 | u32 W = ((L<<Rn) & (tinstr&255)) ? 0 : 1<<21; | |
662 | ||
663 | return 0xe8800000 | W | (L<<20) | (Rn<<16) | | |
664 | (tinstr&255); | |
665 | } | |
666 | ||
667 | /* 6.6.1 Format 2: */ | |
668 | case 0xb000 >> 11: /* 7.1.48 PUSH */ | |
669 | case 0xb800 >> 11: /* 7.1.47 POP */ | |
670 | if ((tinstr & (3 << 9)) == 0x0400) { | |
671 | static const u32 subset[4] = { | |
672 | 0xe92d0000, /* STMDB sp!,{registers} */ | |
673 | 0xe92d4000, /* STMDB sp!,{registers,lr} */ | |
674 | 0xe8bd0000, /* LDMIA sp!,{registers} */ | |
675 | 0xe8bd8000 /* LDMIA sp!,{registers,pc} */ | |
676 | }; | |
677 | return subset[(L<<1) | ((tinstr & (1<<8)) >> 8)] | | |
678 | (tinstr & 255); /* register_list */ | |
679 | } | |
680 | /* Else fall through for illegal instruction case */ | |
681 | ||
682 | default: | |
c2860d43 GD |
683 | return BAD_INSTR; |
684 | } | |
685 | } | |
686 | ||
687 | /* | |
688 | * Convert Thumb-2 32 bit LDM, STM, LDRD, STRD to equivalent instruction | |
689 | * handlable by ARM alignment handler, also find the corresponding handler, | |
690 | * so that we can reuse ARM userland alignment fault fixups for Thumb. | |
691 | * | |
692 | * @pinstr: original Thumb-2 instruction; returns new handlable instruction | |
693 | * @regs: register context. | |
694 | * @poffset: return offset from faulted addr for later writeback | |
695 | * | |
696 | * NOTES: | |
697 | * 1. Comments below refer to ARMv7 DDI0406A Thumb Instruction sections. | |
698 | * 2. Register name Rt from ARMv7 is same as Rd from ARMv6 (Rd is Rt) | |
699 | */ | |
700 | static void * | |
701 | do_alignment_t32_to_handler(unsigned long *pinstr, struct pt_regs *regs, | |
702 | union offset_union *poffset) | |
703 | { | |
704 | unsigned long instr = *pinstr; | |
705 | u16 tinst1 = (instr >> 16) & 0xffff; | |
706 | u16 tinst2 = instr & 0xffff; | |
c2860d43 GD |
707 | |
708 | switch (tinst1 & 0xffe0) { | |
709 | /* A6.3.5 Load/Store multiple */ | |
710 | case 0xe880: /* STM/STMIA/STMEA,LDM/LDMIA, PUSH/POP T2 */ | |
711 | case 0xe8a0: /* ...above writeback version */ | |
712 | case 0xe900: /* STMDB/STMFD, LDMDB/LDMEA */ | |
713 | case 0xe920: /* ...above writeback version */ | |
714 | /* no need offset decision since handler calculates it */ | |
715 | return do_alignment_ldmstm; | |
716 | ||
717 | case 0xf840: /* POP/PUSH T3 (single register) */ | |
718 | if (RN_BITS(instr) == 13 && (tinst2 & 0x09ff) == 0x0904) { | |
719 | u32 L = !!(LDST_L_BIT(instr)); | |
720 | const u32 subset[2] = { | |
721 | 0xe92d0000, /* STMDB sp!,{registers} */ | |
722 | 0xe8bd0000, /* LDMIA sp!,{registers} */ | |
723 | }; | |
724 | *pinstr = subset[L] | (1<<RD_BITS(instr)); | |
725 | return do_alignment_ldmstm; | |
726 | } | |
727 | /* Else fall through for illegal instruction case */ | |
728 | break; | |
729 | ||
730 | /* A6.3.6 Load/store double, STRD/LDRD(immed, lit, reg) */ | |
731 | case 0xe860: | |
732 | case 0xe960: | |
733 | case 0xe8e0: | |
734 | case 0xe9e0: | |
735 | poffset->un = (tinst2 & 0xff) << 2; | |
736 | case 0xe940: | |
737 | case 0xe9c0: | |
738 | return do_alignment_ldrdstrd; | |
739 | ||
740 | /* | |
741 | * No need to handle load/store instructions up to word size | |
742 | * since ARMv6 and later CPUs can perform unaligned accesses. | |
743 | */ | |
744 | default: | |
745 | break; | |
1da177e4 | 746 | } |
c2860d43 | 747 | return NULL; |
1da177e4 LT |
748 | } |
749 | ||
750 | static int | |
751 | do_alignment(unsigned long addr, unsigned int fsr, struct pt_regs *regs) | |
752 | { | |
6404f0b7 | 753 | union offset_union uninitialized_var(offset); |
1da177e4 LT |
754 | unsigned long instr = 0, instrptr; |
755 | int (*handler)(unsigned long addr, unsigned long instr, struct pt_regs *regs); | |
756 | unsigned int type; | |
1da177e4 LT |
757 | unsigned int fault; |
758 | u16 tinstr = 0; | |
c2860d43 GD |
759 | int isize = 4; |
760 | int thumb2_32b = 0; | |
1da177e4 | 761 | |
02fe2845 RK |
762 | if (interrupts_enabled(regs)) |
763 | local_irq_enable(); | |
764 | ||
1da177e4 LT |
765 | instrptr = instruction_pointer(regs); |
766 | ||
f8343685 | 767 | if (thumb_mode(regs)) { |
b255188f RK |
768 | u16 *ptr = (u16 *)(instrptr & ~1); |
769 | fault = probe_kernel_address(ptr, tinstr); | |
8592edf0 | 770 | tinstr = __mem_to_opcode_thumb16(tinstr); |
c2860d43 GD |
771 | if (!fault) { |
772 | if (cpu_architecture() >= CPU_ARCH_ARMv7 && | |
773 | IS_T32(tinstr)) { | |
774 | /* Thumb-2 32-bit */ | |
775 | u16 tinst2 = 0; | |
b255188f | 776 | fault = probe_kernel_address(ptr + 1, tinst2); |
8592edf0 BD |
777 | tinst2 = __mem_to_opcode_thumb16(tinst2); |
778 | instr = __opcode_thumb32_compose(tinstr, tinst2); | |
c2860d43 GD |
779 | thumb2_32b = 1; |
780 | } else { | |
781 | isize = 2; | |
782 | instr = thumb2arm(tinstr); | |
783 | } | |
784 | } | |
8592edf0 | 785 | } else { |
b255188f | 786 | fault = probe_kernel_address(instrptr, instr); |
8592edf0 BD |
787 | instr = __mem_to_opcode_arm(instr); |
788 | } | |
1da177e4 LT |
789 | |
790 | if (fault) { | |
791 | type = TYPE_FAULT; | |
737d0bb7 | 792 | goto bad_or_fault; |
1da177e4 LT |
793 | } |
794 | ||
795 | if (user_mode(regs)) | |
796 | goto user; | |
797 | ||
798 | ai_sys += 1; | |
1e7e3211 | 799 | ai_sys_last_pc = (void *)instruction_pointer(regs); |
1da177e4 LT |
800 | |
801 | fixup: | |
802 | ||
c2860d43 | 803 | regs->ARM_pc += isize; |
1da177e4 LT |
804 | |
805 | switch (CODING_BITS(instr)) { | |
f21ee2d4 SL |
806 | case 0x00000000: /* 3.13.4 load/store instruction extensions */ |
807 | if (LDSTHD_I_BIT(instr)) | |
1da177e4 LT |
808 | offset.un = (instr & 0xf00) >> 4 | (instr & 15); |
809 | else | |
810 | offset.un = regs->uregs[RM_BITS(instr)]; | |
f21ee2d4 SL |
811 | |
812 | if ((instr & 0x000000f0) == 0x000000b0 || /* LDRH, STRH */ | |
813 | (instr & 0x001000f0) == 0x001000f0) /* LDRSH */ | |
814 | handler = do_alignment_ldrhstrh; | |
815 | else if ((instr & 0x001000f0) == 0x000000d0 || /* LDRD */ | |
816 | (instr & 0x001000f0) == 0x000000f0) /* STRD */ | |
817 | handler = do_alignment_ldrdstrd; | |
19da83f6 GD |
818 | else if ((instr & 0x01f00ff0) == 0x01000090) /* SWP */ |
819 | goto swp; | |
f21ee2d4 SL |
820 | else |
821 | goto bad; | |
1da177e4 LT |
822 | break; |
823 | ||
824 | case 0x04000000: /* ldr or str immediate */ | |
5ca918e5 RM |
825 | if (COND_BITS(instr) == 0xf0000000) /* NEON VLDn, VSTn */ |
826 | goto bad; | |
1da177e4 LT |
827 | offset.un = OFFSET_BITS(instr); |
828 | handler = do_alignment_ldrstr; | |
829 | break; | |
830 | ||
831 | case 0x06000000: /* ldr or str register */ | |
832 | offset.un = regs->uregs[RM_BITS(instr)]; | |
833 | ||
834 | if (IS_SHIFT(instr)) { | |
835 | unsigned int shiftval = SHIFT_BITS(instr); | |
836 | ||
837 | switch(SHIFT_TYPE(instr)) { | |
838 | case SHIFT_LSL: | |
839 | offset.un <<= shiftval; | |
840 | break; | |
841 | ||
842 | case SHIFT_LSR: | |
843 | offset.un >>= shiftval; | |
844 | break; | |
845 | ||
846 | case SHIFT_ASR: | |
847 | offset.sn >>= shiftval; | |
848 | break; | |
849 | ||
850 | case SHIFT_RORRRX: | |
851 | if (shiftval == 0) { | |
852 | offset.un >>= 1; | |
853 | if (regs->ARM_cpsr & PSR_C_BIT) | |
854 | offset.un |= 1 << 31; | |
855 | } else | |
856 | offset.un = offset.un >> shiftval | | |
857 | offset.un << (32 - shiftval); | |
858 | break; | |
859 | } | |
860 | } | |
861 | handler = do_alignment_ldrstr; | |
862 | break; | |
863 | ||
c2860d43 | 864 | case 0x08000000: /* ldm or stm, or thumb-2 32bit instruction */ |
a761cebf RK |
865 | if (thumb2_32b) { |
866 | offset.un = 0; | |
c2860d43 | 867 | handler = do_alignment_t32_to_handler(&instr, regs, &offset); |
31d2a638 AB |
868 | } else { |
869 | offset.un = 0; | |
c2860d43 | 870 | handler = do_alignment_ldmstm; |
31d2a638 | 871 | } |
1da177e4 LT |
872 | break; |
873 | ||
874 | default: | |
875 | goto bad; | |
876 | } | |
877 | ||
c2860d43 GD |
878 | if (!handler) |
879 | goto bad; | |
1da177e4 LT |
880 | type = handler(addr, instr, regs); |
881 | ||
c2860d43 GD |
882 | if (type == TYPE_ERROR || type == TYPE_FAULT) { |
883 | regs->ARM_pc -= isize; | |
1da177e4 | 884 | goto bad_or_fault; |
c2860d43 | 885 | } |
1da177e4 LT |
886 | |
887 | if (type == TYPE_LDST) | |
888 | do_alignment_finish_ldst(addr, instr, regs, offset); | |
889 | ||
890 | return 0; | |
891 | ||
892 | bad_or_fault: | |
893 | if (type == TYPE_ERROR) | |
894 | goto bad; | |
1da177e4 LT |
895 | /* |
896 | * We got a fault - fix it up, or die. | |
897 | */ | |
e5beac37 | 898 | do_bad_area(addr, fsr, regs); |
1da177e4 LT |
899 | return 0; |
900 | ||
19da83f6 | 901 | swp: |
4ed89f22 | 902 | pr_err("Alignment trap: not handling swp instruction\n"); |
19da83f6 | 903 | |
1da177e4 LT |
904 | bad: |
905 | /* | |
906 | * Oops, we didn't handle the instruction. | |
907 | */ | |
4ed89f22 | 908 | pr_err("Alignment trap: not handling instruction " |
1da177e4 | 909 | "%0*lx at [<%08lx>]\n", |
c2860d43 GD |
910 | isize << 1, |
911 | isize == 2 ? tinstr : instr, instrptr); | |
1da177e4 LT |
912 | ai_skipped += 1; |
913 | return 1; | |
914 | ||
915 | user: | |
916 | ai_user += 1; | |
917 | ||
baa745a3 | 918 | if (ai_usermode & UM_WARN) |
1da177e4 LT |
919 | printk("Alignment trap: %s (%d) PC=0x%08lx Instr=0x%0*lx " |
920 | "Address=0x%08lx FSR 0x%03x\n", current->comm, | |
19c5870c | 921 | task_pid_nr(current), instrptr, |
c2860d43 GD |
922 | isize << 1, |
923 | isize == 2 ? tinstr : instr, | |
1da177e4 LT |
924 | addr, fsr); |
925 | ||
baa745a3 | 926 | if (ai_usermode & UM_FIXUP) |
1da177e4 LT |
927 | goto fixup; |
928 | ||
2102a65e DM |
929 | if (ai_usermode & UM_SIGNAL) { |
930 | siginfo_t si; | |
931 | ||
932 | si.si_signo = SIGBUS; | |
933 | si.si_errno = 0; | |
934 | si.si_code = BUS_ADRALN; | |
935 | si.si_addr = (void __user *)addr; | |
936 | ||
937 | force_sig_info(si.si_signo, &si, current); | |
938 | } else { | |
2f27bf83 NP |
939 | /* |
940 | * We're about to disable the alignment trap and return to | |
941 | * user space. But if an interrupt occurs before actually | |
942 | * reaching user space, then the IRQ vector entry code will | |
943 | * notice that we were still in kernel space and therefore | |
944 | * the alignment trap won't be re-enabled in that case as it | |
945 | * is presumed to be always on from kernel space. | |
946 | * Let's prevent that race by disabling interrupts here (they | |
947 | * are disabled on the way back to user space anyway in | |
948 | * entry-common.S) and disable the alignment trap only if | |
949 | * there is no work pending for this thread. | |
950 | */ | |
951 | raw_local_irq_disable(); | |
952 | if (!(current_thread_info()->flags & _TIF_WORK_MASK)) | |
953 | set_cr(cr_no_alignment); | |
954 | } | |
1da177e4 LT |
955 | |
956 | return 0; | |
957 | } | |
958 | ||
175352a5 RK |
959 | static int __init noalign_setup(char *__unused) |
960 | { | |
961 | set_cr(__clear_cr(CR_A)); | |
962 | return 1; | |
963 | } | |
964 | __setup("noalign", noalign_setup); | |
965 | ||
1da177e4 LT |
966 | /* |
967 | * This needs to be done after sysctl_init, otherwise sys/ will be | |
968 | * overwritten. Actually, this shouldn't be in sys/ at all since | |
969 | * it isn't a sysctl, and it doesn't contain sysctl information. | |
970 | * We now locate it in /proc/cpu/alignment instead. | |
971 | */ | |
972 | static int __init alignment_init(void) | |
973 | { | |
974 | #ifdef CONFIG_PROC_FS | |
975 | struct proc_dir_entry *res; | |
976 | ||
b7072c63 AD |
977 | res = proc_create("cpu/alignment", S_IWUSR | S_IRUGO, NULL, |
978 | &alignment_proc_fops); | |
1da177e4 LT |
979 | if (!res) |
980 | return -ENOMEM; | |
1da177e4 LT |
981 | #endif |
982 | ||
088c01f1 | 983 | if (cpu_is_v6_unaligned()) { |
b4b20ad8 | 984 | set_cr(__clear_cr(CR_A)); |
088c01f1 | 985 | ai_usermode = safe_usermode(ai_usermode, false); |
baa745a3 RK |
986 | } |
987 | ||
0aeb3408 RK |
988 | cr_no_alignment = get_cr() & ~CR_A; |
989 | ||
f7b8156d | 990 | hook_fault_code(FAULT_CODE_ALIGNMENT, do_alignment, SIGBUS, BUS_ADRALN, |
6338a6aa | 991 | "alignment exception"); |
b8ab5397 KS |
992 | |
993 | /* | |
994 | * ARMv6K and ARMv7 use fault status 3 (0b00011) as Access Flag section | |
995 | * fault, not as alignment error. | |
996 | * | |
997 | * TODO: handle ARMv6K properly. Runtime check for 'K' extension is | |
998 | * needed. | |
999 | */ | |
1000 | if (cpu_architecture() <= CPU_ARCH_ARMv6) { | |
1001 | hook_fault_code(3, do_alignment, SIGBUS, BUS_ADRALN, | |
1002 | "alignment exception"); | |
1003 | } | |
1da177e4 LT |
1004 | |
1005 | return 0; | |
1006 | } | |
1007 | ||
1008 | fs_initcall(alignment_init); |