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1 /* $Id: unaligned.c,v 1.23 2001/12/21 00:54:31 davem Exp $
2 * unaligned.c: Unaligned load/store trap handling with special
3 * cases for the kernel to do them more quickly.
4 *
5 * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
6 * Copyright (C) 1996 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
7 */
8
9
10 #include <linux/kernel.h>
11 #include <linux/sched.h>
12 #include <linux/mm.h>
13 #include <linux/module.h>
14 #include <asm/ptrace.h>
15 #include <asm/processor.h>
16 #include <asm/system.h>
17 #include <asm/uaccess.h>
18 #include <linux/smp.h>
19 #include <linux/smp_lock.h>
20
21 /* #define DEBUG_MNA */
22
23 enum direction {
24 load, /* ld, ldd, ldh, ldsh */
25 store, /* st, std, sth, stsh */
26 both, /* Swap, ldstub, etc. */
27 fpload,
28 fpstore,
29 invalid,
30 };
31
32 #ifdef DEBUG_MNA
33 static char *dirstrings[] = {
34 "load", "store", "both", "fpload", "fpstore", "invalid"
35 };
36 #endif
37
38 static inline enum direction decode_direction(unsigned int insn)
39 {
40 unsigned long tmp = (insn >> 21) & 1;
41
42 if(!tmp)
43 return load;
44 else {
45 if(((insn>>19)&0x3f) == 15)
46 return both;
47 else
48 return store;
49 }
50 }
51
52 /* 8 = double-word, 4 = word, 2 = half-word */
53 static inline int decode_access_size(unsigned int insn)
54 {
55 insn = (insn >> 19) & 3;
56
57 if(!insn)
58 return 4;
59 else if(insn == 3)
60 return 8;
61 else if(insn == 2)
62 return 2;
63 else {
64 printk("Impossible unaligned trap. insn=%08x\n", insn);
65 die_if_kernel("Byte sized unaligned access?!?!", current->thread.kregs);
66 return 4; /* just to keep gcc happy. */
67 }
68 }
69
70 /* 0x400000 = signed, 0 = unsigned */
71 static inline int decode_signedness(unsigned int insn)
72 {
73 return (insn & 0x400000);
74 }
75
76 static inline void maybe_flush_windows(unsigned int rs1, unsigned int rs2,
77 unsigned int rd)
78 {
79 if(rs2 >= 16 || rs1 >= 16 || rd >= 16) {
80 /* Wheee... */
81 __asm__ __volatile__("save %sp, -0x40, %sp\n\t"
82 "save %sp, -0x40, %sp\n\t"
83 "save %sp, -0x40, %sp\n\t"
84 "save %sp, -0x40, %sp\n\t"
85 "save %sp, -0x40, %sp\n\t"
86 "save %sp, -0x40, %sp\n\t"
87 "save %sp, -0x40, %sp\n\t"
88 "restore; restore; restore; restore;\n\t"
89 "restore; restore; restore;\n\t");
90 }
91 }
92
93 static inline int sign_extend_imm13(int imm)
94 {
95 return imm << 19 >> 19;
96 }
97
98 static inline unsigned long fetch_reg(unsigned int reg, struct pt_regs *regs)
99 {
100 struct reg_window *win;
101
102 if(reg < 16)
103 return (!reg ? 0 : regs->u_regs[reg]);
104
105 /* Ho hum, the slightly complicated case. */
106 win = (struct reg_window *) regs->u_regs[UREG_FP];
107 return win->locals[reg - 16]; /* yes, I know what this does... */
108 }
109
110 static inline unsigned long safe_fetch_reg(unsigned int reg, struct pt_regs *regs)
111 {
112 struct reg_window __user *win;
113 unsigned long ret;
114
115 if (reg < 16)
116 return (!reg ? 0 : regs->u_regs[reg]);
117
118 /* Ho hum, the slightly complicated case. */
119 win = (struct reg_window __user *) regs->u_regs[UREG_FP];
120
121 if ((unsigned long)win & 3)
122 return -1;
123
124 if (get_user(ret, &win->locals[reg - 16]))
125 return -1;
126
127 return ret;
128 }
129
130 static inline unsigned long *fetch_reg_addr(unsigned int reg, struct pt_regs *regs)
131 {
132 struct reg_window *win;
133
134 if(reg < 16)
135 return &regs->u_regs[reg];
136 win = (struct reg_window *) regs->u_regs[UREG_FP];
137 return &win->locals[reg - 16];
138 }
139
140 static unsigned long compute_effective_address(struct pt_regs *regs,
141 unsigned int insn)
142 {
143 unsigned int rs1 = (insn >> 14) & 0x1f;
144 unsigned int rs2 = insn & 0x1f;
145 unsigned int rd = (insn >> 25) & 0x1f;
146
147 if(insn & 0x2000) {
148 maybe_flush_windows(rs1, 0, rd);
149 return (fetch_reg(rs1, regs) + sign_extend_imm13(insn));
150 } else {
151 maybe_flush_windows(rs1, rs2, rd);
152 return (fetch_reg(rs1, regs) + fetch_reg(rs2, regs));
153 }
154 }
155
156 unsigned long safe_compute_effective_address(struct pt_regs *regs,
157 unsigned int insn)
158 {
159 unsigned int rs1 = (insn >> 14) & 0x1f;
160 unsigned int rs2 = insn & 0x1f;
161 unsigned int rd = (insn >> 25) & 0x1f;
162
163 if(insn & 0x2000) {
164 maybe_flush_windows(rs1, 0, rd);
165 return (safe_fetch_reg(rs1, regs) + sign_extend_imm13(insn));
166 } else {
167 maybe_flush_windows(rs1, rs2, rd);
168 return (safe_fetch_reg(rs1, regs) + safe_fetch_reg(rs2, regs));
169 }
170 }
171
172 /* This is just to make gcc think panic does return... */
173 static void unaligned_panic(char *str)
174 {
175 panic(str);
176 }
177
178 #define do_integer_load(dest_reg, size, saddr, is_signed, errh) ({ \
179 __asm__ __volatile__ ( \
180 "cmp %1, 8\n\t" \
181 "be 9f\n\t" \
182 " cmp %1, 4\n\t" \
183 "be 6f\n" \
184 "4:\t" " ldub [%2], %%l1\n" \
185 "5:\t" "ldub [%2 + 1], %%l2\n\t" \
186 "sll %%l1, 8, %%l1\n\t" \
187 "tst %3\n\t" \
188 "be 3f\n\t" \
189 " add %%l1, %%l2, %%l1\n\t" \
190 "sll %%l1, 16, %%l1\n\t" \
191 "sra %%l1, 16, %%l1\n" \
192 "3:\t" "b 0f\n\t" \
193 " st %%l1, [%0]\n" \
194 "6:\t" "ldub [%2 + 1], %%l2\n\t" \
195 "sll %%l1, 24, %%l1\n" \
196 "7:\t" "ldub [%2 + 2], %%g7\n\t" \
197 "sll %%l2, 16, %%l2\n" \
198 "8:\t" "ldub [%2 + 3], %%g1\n\t" \
199 "sll %%g7, 8, %%g7\n\t" \
200 "or %%l1, %%l2, %%l1\n\t" \
201 "or %%g7, %%g1, %%g7\n\t" \
202 "or %%l1, %%g7, %%l1\n\t" \
203 "b 0f\n\t" \
204 " st %%l1, [%0]\n" \
205 "9:\t" "ldub [%2], %%l1\n" \
206 "10:\t" "ldub [%2 + 1], %%l2\n\t" \
207 "sll %%l1, 24, %%l1\n" \
208 "11:\t" "ldub [%2 + 2], %%g7\n\t" \
209 "sll %%l2, 16, %%l2\n" \
210 "12:\t" "ldub [%2 + 3], %%g1\n\t" \
211 "sll %%g7, 8, %%g7\n\t" \
212 "or %%l1, %%l2, %%l1\n\t" \
213 "or %%g7, %%g1, %%g7\n\t" \
214 "or %%l1, %%g7, %%g7\n" \
215 "13:\t" "ldub [%2 + 4], %%l1\n\t" \
216 "st %%g7, [%0]\n" \
217 "14:\t" "ldub [%2 + 5], %%l2\n\t" \
218 "sll %%l1, 24, %%l1\n" \
219 "15:\t" "ldub [%2 + 6], %%g7\n\t" \
220 "sll %%l2, 16, %%l2\n" \
221 "16:\t" "ldub [%2 + 7], %%g1\n\t" \
222 "sll %%g7, 8, %%g7\n\t" \
223 "or %%l1, %%l2, %%l1\n\t" \
224 "or %%g7, %%g1, %%g7\n\t" \
225 "or %%l1, %%g7, %%g7\n\t" \
226 "st %%g7, [%0 + 4]\n" \
227 "0:\n\n\t" \
228 ".section __ex_table,#alloc\n\t" \
229 ".word 4b, " #errh "\n\t" \
230 ".word 5b, " #errh "\n\t" \
231 ".word 6b, " #errh "\n\t" \
232 ".word 7b, " #errh "\n\t" \
233 ".word 8b, " #errh "\n\t" \
234 ".word 9b, " #errh "\n\t" \
235 ".word 10b, " #errh "\n\t" \
236 ".word 11b, " #errh "\n\t" \
237 ".word 12b, " #errh "\n\t" \
238 ".word 13b, " #errh "\n\t" \
239 ".word 14b, " #errh "\n\t" \
240 ".word 15b, " #errh "\n\t" \
241 ".word 16b, " #errh "\n\n\t" \
242 ".previous\n\t" \
243 : : "r" (dest_reg), "r" (size), "r" (saddr), "r" (is_signed) \
244 : "l1", "l2", "g7", "g1", "cc"); \
245 })
246
247 #define store_common(dst_addr, size, src_val, errh) ({ \
248 __asm__ __volatile__ ( \
249 "ld [%2], %%l1\n" \
250 "cmp %1, 2\n\t" \
251 "be 2f\n\t" \
252 " cmp %1, 4\n\t" \
253 "be 1f\n\t" \
254 " srl %%l1, 24, %%l2\n\t" \
255 "srl %%l1, 16, %%g7\n" \
256 "4:\t" "stb %%l2, [%0]\n\t" \
257 "srl %%l1, 8, %%l2\n" \
258 "5:\t" "stb %%g7, [%0 + 1]\n\t" \
259 "ld [%2 + 4], %%g7\n" \
260 "6:\t" "stb %%l2, [%0 + 2]\n\t" \
261 "srl %%g7, 24, %%l2\n" \
262 "7:\t" "stb %%l1, [%0 + 3]\n\t" \
263 "srl %%g7, 16, %%l1\n" \
264 "8:\t" "stb %%l2, [%0 + 4]\n\t" \
265 "srl %%g7, 8, %%l2\n" \
266 "9:\t" "stb %%l1, [%0 + 5]\n" \
267 "10:\t" "stb %%l2, [%0 + 6]\n\t" \
268 "b 0f\n" \
269 "11:\t" " stb %%g7, [%0 + 7]\n" \
270 "1:\t" "srl %%l1, 16, %%g7\n" \
271 "12:\t" "stb %%l2, [%0]\n\t" \
272 "srl %%l1, 8, %%l2\n" \
273 "13:\t" "stb %%g7, [%0 + 1]\n" \
274 "14:\t" "stb %%l2, [%0 + 2]\n\t" \
275 "b 0f\n" \
276 "15:\t" " stb %%l1, [%0 + 3]\n" \
277 "2:\t" "srl %%l1, 8, %%l2\n" \
278 "16:\t" "stb %%l2, [%0]\n" \
279 "17:\t" "stb %%l1, [%0 + 1]\n" \
280 "0:\n\n\t" \
281 ".section __ex_table,#alloc\n\t" \
282 ".word 4b, " #errh "\n\t" \
283 ".word 5b, " #errh "\n\t" \
284 ".word 6b, " #errh "\n\t" \
285 ".word 7b, " #errh "\n\t" \
286 ".word 8b, " #errh "\n\t" \
287 ".word 9b, " #errh "\n\t" \
288 ".word 10b, " #errh "\n\t" \
289 ".word 11b, " #errh "\n\t" \
290 ".word 12b, " #errh "\n\t" \
291 ".word 13b, " #errh "\n\t" \
292 ".word 14b, " #errh "\n\t" \
293 ".word 15b, " #errh "\n\t" \
294 ".word 16b, " #errh "\n\t" \
295 ".word 17b, " #errh "\n\n\t" \
296 ".previous\n\t" \
297 : : "r" (dst_addr), "r" (size), "r" (src_val) \
298 : "l1", "l2", "g7", "g1", "cc"); \
299 })
300
301 #define do_integer_store(reg_num, size, dst_addr, regs, errh) ({ \
302 unsigned long *src_val; \
303 static unsigned long zero[2] = { 0, }; \
304 \
305 if (reg_num) src_val = fetch_reg_addr(reg_num, regs); \
306 else { \
307 src_val = &zero[0]; \
308 if (size == 8) \
309 zero[1] = fetch_reg(1, regs); \
310 } \
311 store_common(dst_addr, size, src_val, errh); \
312 })
313
314 extern void smp_capture(void);
315 extern void smp_release(void);
316
317 #define do_atomic(srcdest_reg, mem, errh) ({ \
318 unsigned long flags, tmp; \
319 \
320 smp_capture(); \
321 local_irq_save(flags); \
322 tmp = *srcdest_reg; \
323 do_integer_load(srcdest_reg, 4, mem, 0, errh); \
324 store_common(mem, 4, &tmp, errh); \
325 local_irq_restore(flags); \
326 smp_release(); \
327 })
328
329 static inline void advance(struct pt_regs *regs)
330 {
331 regs->pc = regs->npc;
332 regs->npc += 4;
333 }
334
335 static inline int floating_point_load_or_store_p(unsigned int insn)
336 {
337 return (insn >> 24) & 1;
338 }
339
340 static inline int ok_for_kernel(unsigned int insn)
341 {
342 return !floating_point_load_or_store_p(insn);
343 }
344
345 void kernel_mna_trap_fault(struct pt_regs *regs, unsigned int insn) __asm__ ("kernel_mna_trap_fault");
346
347 void kernel_mna_trap_fault(struct pt_regs *regs, unsigned int insn)
348 {
349 unsigned long g2 = regs->u_regs [UREG_G2];
350 unsigned long fixup = search_extables_range(regs->pc, &g2);
351
352 if (!fixup) {
353 unsigned long address = compute_effective_address(regs, insn);
354 if(address < PAGE_SIZE) {
355 printk(KERN_ALERT "Unable to handle kernel NULL pointer dereference in mna handler");
356 } else
357 printk(KERN_ALERT "Unable to handle kernel paging request in mna handler");
358 printk(KERN_ALERT " at virtual address %08lx\n",address);
359 printk(KERN_ALERT "current->{mm,active_mm}->context = %08lx\n",
360 (current->mm ? current->mm->context :
361 current->active_mm->context));
362 printk(KERN_ALERT "current->{mm,active_mm}->pgd = %08lx\n",
363 (current->mm ? (unsigned long) current->mm->pgd :
364 (unsigned long) current->active_mm->pgd));
365 die_if_kernel("Oops", regs);
366 /* Not reached */
367 }
368 regs->pc = fixup;
369 regs->npc = regs->pc + 4;
370 regs->u_regs [UREG_G2] = g2;
371 }
372
373 asmlinkage void kernel_unaligned_trap(struct pt_regs *regs, unsigned int insn)
374 {
375 enum direction dir = decode_direction(insn);
376 int size = decode_access_size(insn);
377
378 if(!ok_for_kernel(insn) || dir == both) {
379 printk("Unsupported unaligned load/store trap for kernel at <%08lx>.\n",
380 regs->pc);
381 unaligned_panic("Wheee. Kernel does fpu/atomic unaligned load/store.");
382
383 __asm__ __volatile__ ("\n"
384 "kernel_unaligned_trap_fault:\n\t"
385 "mov %0, %%o0\n\t"
386 "call kernel_mna_trap_fault\n\t"
387 " mov %1, %%o1\n\t"
388 :
389 : "r" (regs), "r" (insn)
390 : "o0", "o1", "o2", "o3", "o4", "o5", "o7",
391 "g1", "g2", "g3", "g4", "g5", "g7", "cc");
392 } else {
393 unsigned long addr = compute_effective_address(regs, insn);
394
395 #ifdef DEBUG_MNA
396 printk("KMNA: pc=%08lx [dir=%s addr=%08lx size=%d] retpc[%08lx]\n",
397 regs->pc, dirstrings[dir], addr, size, regs->u_regs[UREG_RETPC]);
398 #endif
399 switch(dir) {
400 case load:
401 do_integer_load(fetch_reg_addr(((insn>>25)&0x1f), regs),
402 size, (unsigned long *) addr,
403 decode_signedness(insn),
404 kernel_unaligned_trap_fault);
405 break;
406
407 case store:
408 do_integer_store(((insn>>25)&0x1f), size,
409 (unsigned long *) addr, regs,
410 kernel_unaligned_trap_fault);
411 break;
412 #if 0 /* unsupported */
413 case both:
414 do_atomic(fetch_reg_addr(((insn>>25)&0x1f), regs),
415 (unsigned long *) addr,
416 kernel_unaligned_trap_fault);
417 break;
418 #endif
419 default:
420 panic("Impossible kernel unaligned trap.");
421 /* Not reached... */
422 }
423 advance(regs);
424 }
425 }
426
427 static inline int ok_for_user(struct pt_regs *regs, unsigned int insn,
428 enum direction dir)
429 {
430 unsigned int reg;
431 int check = (dir == load) ? VERIFY_READ : VERIFY_WRITE;
432 int size = ((insn >> 19) & 3) == 3 ? 8 : 4;
433
434 if ((regs->pc | regs->npc) & 3)
435 return 0;
436
437 /* Must access_ok() in all the necessary places. */
438 #define WINREG_ADDR(regnum) \
439 ((void __user *)(((unsigned long *)regs->u_regs[UREG_FP])+(regnum)))
440
441 reg = (insn >> 25) & 0x1f;
442 if (reg >= 16) {
443 if (!access_ok(check, WINREG_ADDR(reg - 16), size))
444 return -EFAULT;
445 }
446 reg = (insn >> 14) & 0x1f;
447 if (reg >= 16) {
448 if (!access_ok(check, WINREG_ADDR(reg - 16), size))
449 return -EFAULT;
450 }
451 if (!(insn & 0x2000)) {
452 reg = (insn & 0x1f);
453 if (reg >= 16) {
454 if (!access_ok(check, WINREG_ADDR(reg - 16), size))
455 return -EFAULT;
456 }
457 }
458 #undef WINREG_ADDR
459 return 0;
460 }
461
462 void user_mna_trap_fault(struct pt_regs *regs, unsigned int insn) __asm__ ("user_mna_trap_fault");
463
464 void user_mna_trap_fault(struct pt_regs *regs, unsigned int insn)
465 {
466 siginfo_t info;
467
468 info.si_signo = SIGBUS;
469 info.si_errno = 0;
470 info.si_code = BUS_ADRALN;
471 info.si_addr = (void __user *)safe_compute_effective_address(regs, insn);
472 info.si_trapno = 0;
473 send_sig_info(SIGBUS, &info, current);
474 }
475
476 asmlinkage void user_unaligned_trap(struct pt_regs *regs, unsigned int insn)
477 {
478 enum direction dir;
479
480 lock_kernel();
481 if(!(current->thread.flags & SPARC_FLAG_UNALIGNED) ||
482 (((insn >> 30) & 3) != 3))
483 goto kill_user;
484 dir = decode_direction(insn);
485 if(!ok_for_user(regs, insn, dir)) {
486 goto kill_user;
487 } else {
488 int size = decode_access_size(insn);
489 unsigned long addr;
490
491 if(floating_point_load_or_store_p(insn)) {
492 printk("User FPU load/store unaligned unsupported.\n");
493 goto kill_user;
494 }
495
496 addr = compute_effective_address(regs, insn);
497 switch(dir) {
498 case load:
499 do_integer_load(fetch_reg_addr(((insn>>25)&0x1f), regs),
500 size, (unsigned long *) addr,
501 decode_signedness(insn),
502 user_unaligned_trap_fault);
503 break;
504
505 case store:
506 do_integer_store(((insn>>25)&0x1f), size,
507 (unsigned long *) addr, regs,
508 user_unaligned_trap_fault);
509 break;
510
511 case both:
512 #if 0 /* unsupported */
513 do_atomic(fetch_reg_addr(((insn>>25)&0x1f), regs),
514 (unsigned long *) addr,
515 user_unaligned_trap_fault);
516 #else
517 /*
518 * This was supported in 2.4. However, we question
519 * the value of SWAP instruction across word boundaries.
520 */
521 printk("Unaligned SWAP unsupported.\n");
522 goto kill_user;
523 #endif
524 break;
525
526 default:
527 unaligned_panic("Impossible user unaligned trap.");
528
529 __asm__ __volatile__ ("\n"
530 "user_unaligned_trap_fault:\n\t"
531 "mov %0, %%o0\n\t"
532 "call user_mna_trap_fault\n\t"
533 " mov %1, %%o1\n\t"
534 :
535 : "r" (regs), "r" (insn)
536 : "o0", "o1", "o2", "o3", "o4", "o5", "o7",
537 "g1", "g2", "g3", "g4", "g5", "g7", "cc");
538 goto out;
539 }
540 advance(regs);
541 goto out;
542 }
543
544 kill_user:
545 user_mna_trap_fault(regs, insn);
546 out:
547 unlock_kernel();
548 }
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