Commit | Line | Data |
---|---|---|
88278ca2 | 1 | /* |
1da177e4 LT |
2 | * fault.c: Page fault handlers for the Sparc. |
3 | * | |
4 | * Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu) | |
5 | * Copyright (C) 1996 Eddie C. Dost (ecd@skynet.be) | |
6 | * Copyright (C) 1997 Jakub Jelinek (jj@sunsite.mff.cuni.cz) | |
7 | */ | |
8 | ||
9 | #include <asm/head.h> | |
10 | ||
11 | #include <linux/string.h> | |
12 | #include <linux/types.h> | |
13 | #include <linux/sched.h> | |
14 | #include <linux/ptrace.h> | |
15 | #include <linux/mman.h> | |
16 | #include <linux/threads.h> | |
17 | #include <linux/kernel.h> | |
18 | #include <linux/signal.h> | |
19 | #include <linux/mm.h> | |
20 | #include <linux/smp.h> | |
a084b667 | 21 | #include <linux/perf_event.h> |
1da177e4 | 22 | #include <linux/interrupt.h> |
1eeb66a1 | 23 | #include <linux/kdebug.h> |
1da177e4 | 24 | |
1da177e4 LT |
25 | #include <asm/page.h> |
26 | #include <asm/pgtable.h> | |
1da177e4 LT |
27 | #include <asm/openprom.h> |
28 | #include <asm/oplib.h> | |
29 | #include <asm/smp.h> | |
30 | #include <asm/traps.h> | |
1da177e4 LT |
31 | #include <asm/uaccess.h> |
32 | ||
4b177647 DM |
33 | int show_unhandled_signals = 1; |
34 | ||
1da177e4 LT |
35 | static void unhandled_fault(unsigned long, struct task_struct *, |
36 | struct pt_regs *) __attribute__ ((noreturn)); | |
37 | ||
70168dfa SR |
38 | static void __noreturn unhandled_fault(unsigned long address, |
39 | struct task_struct *tsk, | |
40 | struct pt_regs *regs) | |
1da177e4 | 41 | { |
70168dfa | 42 | if ((unsigned long) address < PAGE_SIZE) { |
1da177e4 LT |
43 | printk(KERN_ALERT |
44 | "Unable to handle kernel NULL pointer dereference\n"); | |
45 | } else { | |
70168dfa SR |
46 | printk(KERN_ALERT "Unable to handle kernel paging request at virtual address %08lx\n", |
47 | address); | |
1da177e4 LT |
48 | } |
49 | printk(KERN_ALERT "tsk->{mm,active_mm}->context = %08lx\n", | |
50 | (tsk->mm ? tsk->mm->context : tsk->active_mm->context)); | |
51 | printk(KERN_ALERT "tsk->{mm,active_mm}->pgd = %08lx\n", | |
52 | (tsk->mm ? (unsigned long) tsk->mm->pgd : | |
70168dfa | 53 | (unsigned long) tsk->active_mm->pgd)); |
1da177e4 LT |
54 | die_if_kernel("Oops", regs); |
55 | } | |
56 | ||
70168dfa | 57 | asmlinkage int lookup_fault(unsigned long pc, unsigned long ret_pc, |
1da177e4 LT |
58 | unsigned long address) |
59 | { | |
60 | struct pt_regs regs; | |
61 | unsigned long g2; | |
62 | unsigned int insn; | |
63 | int i; | |
70168dfa | 64 | |
1da177e4 LT |
65 | i = search_extables_range(ret_pc, &g2); |
66 | switch (i) { | |
67 | case 3: | |
68 | /* load & store will be handled by fixup */ | |
69 | return 3; | |
70 | ||
71 | case 1: | |
72 | /* store will be handled by fixup, load will bump out */ | |
73 | /* for _to_ macros */ | |
74 | insn = *((unsigned int *) pc); | |
75 | if ((insn >> 21) & 1) | |
76 | return 1; | |
77 | break; | |
78 | ||
79 | case 2: | |
80 | /* load will be handled by fixup, store will bump out */ | |
81 | /* for _from_ macros */ | |
82 | insn = *((unsigned int *) pc); | |
83 | if (!((insn >> 21) & 1) || ((insn>>19)&0x3f) == 15) | |
70168dfa SR |
84 | return 2; |
85 | break; | |
1da177e4 LT |
86 | |
87 | default: | |
88 | break; | |
6cb79b3f | 89 | } |
1da177e4 | 90 | |
70168dfa | 91 | memset(®s, 0, sizeof(regs)); |
1da177e4 LT |
92 | regs.pc = pc; |
93 | regs.npc = pc + 4; | |
94 | __asm__ __volatile__( | |
95 | "rd %%psr, %0\n\t" | |
96 | "nop\n\t" | |
97 | "nop\n\t" | |
98 | "nop\n" : "=r" (regs.psr)); | |
99 | unhandled_fault(address, current, ®s); | |
100 | ||
101 | /* Not reached */ | |
102 | return 0; | |
103 | } | |
104 | ||
4b177647 DM |
105 | static inline void |
106 | show_signal_msg(struct pt_regs *regs, int sig, int code, | |
107 | unsigned long address, struct task_struct *tsk) | |
108 | { | |
109 | if (!unhandled_signal(tsk, sig)) | |
110 | return; | |
111 | ||
112 | if (!printk_ratelimit()) | |
113 | return; | |
114 | ||
115 | printk("%s%s[%d]: segfault at %lx ip %p (rpc %p) sp %p error %x", | |
116 | task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG, | |
117 | tsk->comm, task_pid_nr(tsk), address, | |
118 | (void *)regs->pc, (void *)regs->u_regs[UREG_I7], | |
119 | (void *)regs->u_regs[UREG_FP], code); | |
120 | ||
121 | print_vma_addr(KERN_CONT " in ", regs->pc); | |
122 | ||
123 | printk(KERN_CONT "\n"); | |
124 | } | |
125 | ||
126 | static void __do_fault_siginfo(int code, int sig, struct pt_regs *regs, | |
127 | unsigned long addr) | |
128 | { | |
129 | siginfo_t info; | |
130 | ||
131 | info.si_signo = sig; | |
132 | info.si_code = code; | |
133 | info.si_errno = 0; | |
134 | info.si_addr = (void __user *) addr; | |
135 | info.si_trapno = 0; | |
136 | ||
137 | if (unlikely(show_unhandled_signals)) | |
138 | show_signal_msg(regs, sig, info.si_code, | |
139 | addr, current); | |
140 | ||
141 | force_sig_info (sig, &info, current); | |
142 | } | |
143 | ||
1da177e4 LT |
144 | extern unsigned long safe_compute_effective_address(struct pt_regs *, |
145 | unsigned int); | |
146 | ||
147 | static unsigned long compute_si_addr(struct pt_regs *regs, int text_fault) | |
148 | { | |
149 | unsigned int insn; | |
150 | ||
151 | if (text_fault) | |
152 | return regs->pc; | |
153 | ||
70168dfa | 154 | if (regs->psr & PSR_PS) |
1da177e4 | 155 | insn = *(unsigned int *) regs->pc; |
70168dfa | 156 | else |
1da177e4 | 157 | __get_user(insn, (unsigned int *) regs->pc); |
1da177e4 LT |
158 | |
159 | return safe_compute_effective_address(regs, insn); | |
160 | } | |
161 | ||
4b177647 DM |
162 | static noinline void do_fault_siginfo(int code, int sig, struct pt_regs *regs, |
163 | int text_fault) | |
164 | { | |
165 | unsigned long addr = compute_si_addr(regs, text_fault); | |
166 | ||
167 | __do_fault_siginfo(code, sig, regs, addr); | |
168 | } | |
169 | ||
1da177e4 LT |
170 | asmlinkage void do_sparc_fault(struct pt_regs *regs, int text_fault, int write, |
171 | unsigned long address) | |
172 | { | |
173 | struct vm_area_struct *vma; | |
174 | struct task_struct *tsk = current; | |
175 | struct mm_struct *mm = tsk->mm; | |
176 | unsigned int fixup; | |
177 | unsigned long g2; | |
1da177e4 | 178 | int from_user = !(regs->psr & PSR_PS); |
4b177647 | 179 | int fault, code; |
e2ec2c2b | 180 | unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; |
1da177e4 | 181 | |
70168dfa | 182 | if (text_fault) |
1da177e4 LT |
183 | address = regs->pc; |
184 | ||
185 | /* | |
186 | * We fault-in kernel-space virtual memory on-demand. The | |
187 | * 'reference' page table is init_mm.pgd. | |
188 | * | |
189 | * NOTE! We MUST NOT take any locks for this case. We may | |
190 | * be in an interrupt or a critical region, and should | |
191 | * only copy the information from the master page table, | |
192 | * nothing more. | |
193 | */ | |
c816be7b | 194 | code = SEGV_MAPERR; |
582a0bae | 195 | if (address >= TASK_SIZE) |
1da177e4 LT |
196 | goto vmalloc_fault; |
197 | ||
1da177e4 LT |
198 | /* |
199 | * If we're in an interrupt or have no user | |
200 | * context, we must not take the fault.. | |
201 | */ | |
70168dfa SR |
202 | if (in_atomic() || !mm) |
203 | goto no_context; | |
1da177e4 | 204 | |
a8b0ca17 | 205 | perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address); |
a084b667 | 206 | |
c29554f5 | 207 | retry: |
1da177e4 LT |
208 | down_read(&mm->mmap_sem); |
209 | ||
70168dfa | 210 | if (!from_user && address >= PAGE_OFFSET) |
1da177e4 LT |
211 | goto bad_area; |
212 | ||
213 | vma = find_vma(mm, address); | |
70168dfa | 214 | if (!vma) |
1da177e4 | 215 | goto bad_area; |
70168dfa | 216 | if (vma->vm_start <= address) |
1da177e4 | 217 | goto good_area; |
70168dfa | 218 | if (!(vma->vm_flags & VM_GROWSDOWN)) |
1da177e4 | 219 | goto bad_area; |
70168dfa | 220 | if (expand_stack(vma, address)) |
1da177e4 LT |
221 | goto bad_area; |
222 | /* | |
223 | * Ok, we have a good vm_area for this memory access, so | |
224 | * we can handle it.. | |
225 | */ | |
226 | good_area: | |
4b177647 | 227 | code = SEGV_ACCERR; |
70168dfa SR |
228 | if (write) { |
229 | if (!(vma->vm_flags & VM_WRITE)) | |
1da177e4 LT |
230 | goto bad_area; |
231 | } else { | |
232 | /* Allow reads even for write-only mappings */ | |
70168dfa | 233 | if (!(vma->vm_flags & (VM_READ | VM_EXEC))) |
1da177e4 LT |
234 | goto bad_area; |
235 | } | |
236 | ||
e2ec2c2b JW |
237 | if (from_user) |
238 | flags |= FAULT_FLAG_USER; | |
239 | if (write) | |
240 | flags |= FAULT_FLAG_WRITE; | |
241 | ||
1da177e4 LT |
242 | /* |
243 | * If for any reason at all we couldn't handle the fault, | |
244 | * make sure we exit gracefully rather than endlessly redo | |
245 | * the fault. | |
246 | */ | |
c29554f5 KC |
247 | fault = handle_mm_fault(mm, vma, address, flags); |
248 | ||
249 | if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) | |
250 | return; | |
251 | ||
83c54070 NP |
252 | if (unlikely(fault & VM_FAULT_ERROR)) { |
253 | if (fault & VM_FAULT_OOM) | |
254 | goto out_of_memory; | |
0c42d1fb LT |
255 | else if (fault & VM_FAULT_SIGSEGV) |
256 | goto bad_area; | |
83c54070 NP |
257 | else if (fault & VM_FAULT_SIGBUS) |
258 | goto do_sigbus; | |
259 | BUG(); | |
260 | } | |
c29554f5 KC |
261 | |
262 | if (flags & FAULT_FLAG_ALLOW_RETRY) { | |
263 | if (fault & VM_FAULT_MAJOR) { | |
264 | current->maj_flt++; | |
265 | perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, | |
266 | 1, regs, address); | |
267 | } else { | |
268 | current->min_flt++; | |
269 | perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, | |
270 | 1, regs, address); | |
271 | } | |
272 | if (fault & VM_FAULT_RETRY) { | |
273 | flags &= ~FAULT_FLAG_ALLOW_RETRY; | |
45cac65b | 274 | flags |= FAULT_FLAG_TRIED; |
c29554f5 KC |
275 | |
276 | /* No need to up_read(&mm->mmap_sem) as we would | |
277 | * have already released it in __lock_page_or_retry | |
278 | * in mm/filemap.c. | |
279 | */ | |
280 | ||
281 | goto retry; | |
282 | } | |
a084b667 | 283 | } |
c29554f5 | 284 | |
1da177e4 LT |
285 | up_read(&mm->mmap_sem); |
286 | return; | |
287 | ||
288 | /* | |
289 | * Something tried to access memory that isn't in our memory map.. | |
290 | * Fix it, but check if it's kernel or user first.. | |
291 | */ | |
292 | bad_area: | |
293 | up_read(&mm->mmap_sem); | |
294 | ||
295 | bad_area_nosemaphore: | |
296 | /* User mode accesses just cause a SIGSEGV */ | |
4b177647 DM |
297 | if (from_user) { |
298 | do_fault_siginfo(code, SIGSEGV, regs, text_fault); | |
1da177e4 LT |
299 | return; |
300 | } | |
301 | ||
302 | /* Is this in ex_table? */ | |
303 | no_context: | |
304 | g2 = regs->u_regs[UREG_G2]; | |
0157141a SR |
305 | if (!from_user) { |
306 | fixup = search_extables_range(regs->pc, &g2); | |
70168dfa SR |
307 | /* Values below 10 are reserved for other things */ |
308 | if (fixup > 10) { | |
1da177e4 LT |
309 | extern const unsigned __memset_start[]; |
310 | extern const unsigned __memset_end[]; | |
311 | extern const unsigned __csum_partial_copy_start[]; | |
312 | extern const unsigned __csum_partial_copy_end[]; | |
313 | ||
314 | #ifdef DEBUG_EXCEPTIONS | |
70168dfa SR |
315 | printk("Exception: PC<%08lx> faddr<%08lx>\n", |
316 | regs->pc, address); | |
1da177e4 LT |
317 | printk("EX_TABLE: insn<%08lx> fixup<%08x> g2<%08lx>\n", |
318 | regs->pc, fixup, g2); | |
319 | #endif | |
320 | if ((regs->pc >= (unsigned long)__memset_start && | |
321 | regs->pc < (unsigned long)__memset_end) || | |
322 | (regs->pc >= (unsigned long)__csum_partial_copy_start && | |
323 | regs->pc < (unsigned long)__csum_partial_copy_end)) { | |
70168dfa | 324 | regs->u_regs[UREG_I4] = address; |
1da177e4 LT |
325 | regs->u_regs[UREG_I5] = regs->pc; |
326 | } | |
327 | regs->u_regs[UREG_G2] = g2; | |
328 | regs->pc = fixup; | |
329 | regs->npc = regs->pc + 4; | |
330 | return; | |
331 | } | |
332 | } | |
70168dfa SR |
333 | |
334 | unhandled_fault(address, tsk, regs); | |
1da177e4 LT |
335 | do_exit(SIGKILL); |
336 | ||
337 | /* | |
338 | * We ran out of memory, or some other thing happened to us that made | |
339 | * us unable to handle the page fault gracefully. | |
340 | */ | |
341 | out_of_memory: | |
342 | up_read(&mm->mmap_sem); | |
a923c28f DM |
343 | if (from_user) { |
344 | pagefault_out_of_memory(); | |
345 | return; | |
346 | } | |
1da177e4 LT |
347 | goto no_context; |
348 | ||
349 | do_sigbus: | |
350 | up_read(&mm->mmap_sem); | |
4b177647 | 351 | do_fault_siginfo(BUS_ADRERR, SIGBUS, regs, text_fault); |
1da177e4 LT |
352 | if (!from_user) |
353 | goto no_context; | |
354 | ||
355 | vmalloc_fault: | |
356 | { | |
357 | /* | |
358 | * Synchronize this task's top level page-table | |
359 | * with the 'reference' page table. | |
360 | */ | |
361 | int offset = pgd_index(address); | |
362 | pgd_t *pgd, *pgd_k; | |
363 | pmd_t *pmd, *pmd_k; | |
364 | ||
365 | pgd = tsk->active_mm->pgd + offset; | |
366 | pgd_k = init_mm.pgd + offset; | |
367 | ||
368 | if (!pgd_present(*pgd)) { | |
369 | if (!pgd_present(*pgd_k)) | |
370 | goto bad_area_nosemaphore; | |
371 | pgd_val(*pgd) = pgd_val(*pgd_k); | |
372 | return; | |
373 | } | |
374 | ||
375 | pmd = pmd_offset(pgd, address); | |
376 | pmd_k = pmd_offset(pgd_k, address); | |
377 | ||
378 | if (pmd_present(*pmd) || !pmd_present(*pmd_k)) | |
379 | goto bad_area_nosemaphore; | |
70168dfa | 380 | |
1da177e4 LT |
381 | *pmd = *pmd_k; |
382 | return; | |
383 | } | |
384 | } | |
385 | ||
1da177e4 | 386 | /* This always deals with user addresses. */ |
50215d65 | 387 | static void force_user_fault(unsigned long address, int write) |
1da177e4 LT |
388 | { |
389 | struct vm_area_struct *vma; | |
390 | struct task_struct *tsk = current; | |
391 | struct mm_struct *mm = tsk->mm; | |
e2ec2c2b | 392 | unsigned int flags = FAULT_FLAG_USER; |
4b177647 | 393 | int code; |
1da177e4 | 394 | |
4b177647 | 395 | code = SEGV_MAPERR; |
1da177e4 | 396 | |
1da177e4 LT |
397 | down_read(&mm->mmap_sem); |
398 | vma = find_vma(mm, address); | |
70168dfa | 399 | if (!vma) |
1da177e4 | 400 | goto bad_area; |
70168dfa | 401 | if (vma->vm_start <= address) |
1da177e4 | 402 | goto good_area; |
70168dfa | 403 | if (!(vma->vm_flags & VM_GROWSDOWN)) |
1da177e4 | 404 | goto bad_area; |
70168dfa | 405 | if (expand_stack(vma, address)) |
1da177e4 LT |
406 | goto bad_area; |
407 | good_area: | |
4b177647 | 408 | code = SEGV_ACCERR; |
70168dfa SR |
409 | if (write) { |
410 | if (!(vma->vm_flags & VM_WRITE)) | |
1da177e4 | 411 | goto bad_area; |
e2ec2c2b | 412 | flags |= FAULT_FLAG_WRITE; |
1da177e4 | 413 | } else { |
70168dfa | 414 | if (!(vma->vm_flags & (VM_READ | VM_EXEC))) |
1da177e4 LT |
415 | goto bad_area; |
416 | } | |
e2ec2c2b | 417 | switch (handle_mm_fault(mm, vma, address, flags)) { |
1da177e4 LT |
418 | case VM_FAULT_SIGBUS: |
419 | case VM_FAULT_OOM: | |
420 | goto do_sigbus; | |
421 | } | |
422 | up_read(&mm->mmap_sem); | |
423 | return; | |
424 | bad_area: | |
425 | up_read(&mm->mmap_sem); | |
4b177647 | 426 | __do_fault_siginfo(code, SIGSEGV, tsk->thread.kregs, address); |
1da177e4 LT |
427 | return; |
428 | ||
429 | do_sigbus: | |
430 | up_read(&mm->mmap_sem); | |
4b177647 | 431 | __do_fault_siginfo(BUS_ADRERR, SIGBUS, tsk->thread.kregs, address); |
1da177e4 LT |
432 | } |
433 | ||
9088333e DM |
434 | static void check_stack_aligned(unsigned long sp) |
435 | { | |
436 | if (sp & 0x7UL) | |
437 | force_sig(SIGILL, current); | |
438 | } | |
439 | ||
1da177e4 LT |
440 | void window_overflow_fault(void) |
441 | { | |
442 | unsigned long sp; | |
443 | ||
444 | sp = current_thread_info()->rwbuf_stkptrs[0]; | |
70168dfa | 445 | if (((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK)) |
1da177e4 LT |
446 | force_user_fault(sp + 0x38, 1); |
447 | force_user_fault(sp, 1); | |
9088333e DM |
448 | |
449 | check_stack_aligned(sp); | |
1da177e4 LT |
450 | } |
451 | ||
452 | void window_underflow_fault(unsigned long sp) | |
453 | { | |
70168dfa | 454 | if (((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK)) |
1da177e4 LT |
455 | force_user_fault(sp + 0x38, 0); |
456 | force_user_fault(sp, 0); | |
9088333e DM |
457 | |
458 | check_stack_aligned(sp); | |
1da177e4 LT |
459 | } |
460 | ||
461 | void window_ret_fault(struct pt_regs *regs) | |
462 | { | |
463 | unsigned long sp; | |
464 | ||
465 | sp = regs->u_regs[UREG_FP]; | |
70168dfa | 466 | if (((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK)) |
1da177e4 LT |
467 | force_user_fault(sp + 0x38, 0); |
468 | force_user_fault(sp, 0); | |
9088333e DM |
469 | |
470 | check_stack_aligned(sp); | |
1da177e4 | 471 | } |