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> |
70ffdb93 | 24 | #include <linux/uaccess.h> |
1da177e4 | 25 | |
1da177e4 LT |
26 | #include <asm/page.h> |
27 | #include <asm/pgtable.h> | |
1da177e4 LT |
28 | #include <asm/openprom.h> |
29 | #include <asm/oplib.h> | |
9edfae3f | 30 | #include <asm/setup.h> |
1da177e4 LT |
31 | #include <asm/smp.h> |
32 | #include <asm/traps.h> | |
1da177e4 | 33 | |
e1b2f134 | 34 | #include "mm_32.h" |
4b177647 | 35 | |
e1b2f134 | 36 | int show_unhandled_signals = 1; |
1da177e4 | 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 | static unsigned long compute_si_addr(struct pt_regs *regs, int text_fault) |
145 | { | |
146 | unsigned int insn; | |
147 | ||
148 | if (text_fault) | |
149 | return regs->pc; | |
150 | ||
70168dfa | 151 | if (regs->psr & PSR_PS) |
1da177e4 | 152 | insn = *(unsigned int *) regs->pc; |
70168dfa | 153 | else |
1da177e4 | 154 | __get_user(insn, (unsigned int *) regs->pc); |
1da177e4 LT |
155 | |
156 | return safe_compute_effective_address(regs, insn); | |
157 | } | |
158 | ||
4b177647 DM |
159 | static noinline void do_fault_siginfo(int code, int sig, struct pt_regs *regs, |
160 | int text_fault) | |
161 | { | |
162 | unsigned long addr = compute_si_addr(regs, text_fault); | |
163 | ||
164 | __do_fault_siginfo(code, sig, regs, addr); | |
165 | } | |
166 | ||
1da177e4 LT |
167 | asmlinkage void do_sparc_fault(struct pt_regs *regs, int text_fault, int write, |
168 | unsigned long address) | |
169 | { | |
170 | struct vm_area_struct *vma; | |
171 | struct task_struct *tsk = current; | |
172 | struct mm_struct *mm = tsk->mm; | |
173 | unsigned int fixup; | |
174 | unsigned long g2; | |
1da177e4 | 175 | int from_user = !(regs->psr & PSR_PS); |
4b177647 | 176 | int fault, code; |
759496ba | 177 | unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; |
1da177e4 | 178 | |
70168dfa | 179 | if (text_fault) |
1da177e4 LT |
180 | address = regs->pc; |
181 | ||
182 | /* | |
183 | * We fault-in kernel-space virtual memory on-demand. The | |
184 | * 'reference' page table is init_mm.pgd. | |
185 | * | |
186 | * NOTE! We MUST NOT take any locks for this case. We may | |
187 | * be in an interrupt or a critical region, and should | |
188 | * only copy the information from the master page table, | |
189 | * nothing more. | |
190 | */ | |
c816be7b | 191 | code = SEGV_MAPERR; |
582a0bae | 192 | if (address >= TASK_SIZE) |
1da177e4 LT |
193 | goto vmalloc_fault; |
194 | ||
1da177e4 LT |
195 | /* |
196 | * If we're in an interrupt or have no user | |
197 | * context, we must not take the fault.. | |
198 | */ | |
70ffdb93 | 199 | if (pagefault_disabled() || !mm) |
70168dfa | 200 | goto no_context; |
1da177e4 | 201 | |
a8b0ca17 | 202 | perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address); |
a084b667 | 203 | |
c29554f5 | 204 | retry: |
1da177e4 LT |
205 | down_read(&mm->mmap_sem); |
206 | ||
70168dfa | 207 | if (!from_user && address >= PAGE_OFFSET) |
1da177e4 LT |
208 | goto bad_area; |
209 | ||
210 | vma = find_vma(mm, address); | |
70168dfa | 211 | if (!vma) |
1da177e4 | 212 | goto bad_area; |
70168dfa | 213 | if (vma->vm_start <= address) |
1da177e4 | 214 | goto good_area; |
70168dfa | 215 | if (!(vma->vm_flags & VM_GROWSDOWN)) |
1da177e4 | 216 | goto bad_area; |
70168dfa | 217 | if (expand_stack(vma, address)) |
1da177e4 LT |
218 | goto bad_area; |
219 | /* | |
220 | * Ok, we have a good vm_area for this memory access, so | |
221 | * we can handle it.. | |
222 | */ | |
223 | good_area: | |
4b177647 | 224 | code = SEGV_ACCERR; |
70168dfa SR |
225 | if (write) { |
226 | if (!(vma->vm_flags & VM_WRITE)) | |
1da177e4 LT |
227 | goto bad_area; |
228 | } else { | |
229 | /* Allow reads even for write-only mappings */ | |
70168dfa | 230 | if (!(vma->vm_flags & (VM_READ | VM_EXEC))) |
1da177e4 LT |
231 | goto bad_area; |
232 | } | |
233 | ||
759496ba JW |
234 | if (from_user) |
235 | flags |= FAULT_FLAG_USER; | |
236 | if (write) | |
237 | flags |= FAULT_FLAG_WRITE; | |
238 | ||
1da177e4 LT |
239 | /* |
240 | * If for any reason at all we couldn't handle the fault, | |
241 | * make sure we exit gracefully rather than endlessly redo | |
242 | * the fault. | |
243 | */ | |
c29554f5 KC |
244 | fault = handle_mm_fault(mm, vma, address, flags); |
245 | ||
246 | if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) | |
247 | return; | |
248 | ||
83c54070 NP |
249 | if (unlikely(fault & VM_FAULT_ERROR)) { |
250 | if (fault & VM_FAULT_OOM) | |
251 | goto out_of_memory; | |
33692f27 LT |
252 | else if (fault & VM_FAULT_SIGSEGV) |
253 | goto bad_area; | |
83c54070 NP |
254 | else if (fault & VM_FAULT_SIGBUS) |
255 | goto do_sigbus; | |
256 | BUG(); | |
257 | } | |
c29554f5 KC |
258 | |
259 | if (flags & FAULT_FLAG_ALLOW_RETRY) { | |
260 | if (fault & VM_FAULT_MAJOR) { | |
261 | current->maj_flt++; | |
262 | perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, | |
263 | 1, regs, address); | |
264 | } else { | |
265 | current->min_flt++; | |
266 | perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, | |
267 | 1, regs, address); | |
268 | } | |
269 | if (fault & VM_FAULT_RETRY) { | |
270 | flags &= ~FAULT_FLAG_ALLOW_RETRY; | |
45cac65b | 271 | flags |= FAULT_FLAG_TRIED; |
c29554f5 KC |
272 | |
273 | /* No need to up_read(&mm->mmap_sem) as we would | |
274 | * have already released it in __lock_page_or_retry | |
275 | * in mm/filemap.c. | |
276 | */ | |
277 | ||
278 | goto retry; | |
279 | } | |
a084b667 | 280 | } |
c29554f5 | 281 | |
1da177e4 LT |
282 | up_read(&mm->mmap_sem); |
283 | return; | |
284 | ||
285 | /* | |
286 | * Something tried to access memory that isn't in our memory map.. | |
287 | * Fix it, but check if it's kernel or user first.. | |
288 | */ | |
289 | bad_area: | |
290 | up_read(&mm->mmap_sem); | |
291 | ||
292 | bad_area_nosemaphore: | |
293 | /* User mode accesses just cause a SIGSEGV */ | |
4b177647 DM |
294 | if (from_user) { |
295 | do_fault_siginfo(code, SIGSEGV, regs, text_fault); | |
1da177e4 LT |
296 | return; |
297 | } | |
298 | ||
299 | /* Is this in ex_table? */ | |
300 | no_context: | |
301 | g2 = regs->u_regs[UREG_G2]; | |
0157141a SR |
302 | if (!from_user) { |
303 | fixup = search_extables_range(regs->pc, &g2); | |
70168dfa SR |
304 | /* Values below 10 are reserved for other things */ |
305 | if (fixup > 10) { | |
9ef595d8 JP |
306 | extern const unsigned int __memset_start[]; |
307 | extern const unsigned int __memset_end[]; | |
308 | extern const unsigned int __csum_partial_copy_start[]; | |
309 | extern const unsigned int __csum_partial_copy_end[]; | |
1da177e4 LT |
310 | |
311 | #ifdef DEBUG_EXCEPTIONS | |
70168dfa SR |
312 | printk("Exception: PC<%08lx> faddr<%08lx>\n", |
313 | regs->pc, address); | |
1da177e4 LT |
314 | printk("EX_TABLE: insn<%08lx> fixup<%08x> g2<%08lx>\n", |
315 | regs->pc, fixup, g2); | |
316 | #endif | |
317 | if ((regs->pc >= (unsigned long)__memset_start && | |
318 | regs->pc < (unsigned long)__memset_end) || | |
319 | (regs->pc >= (unsigned long)__csum_partial_copy_start && | |
320 | regs->pc < (unsigned long)__csum_partial_copy_end)) { | |
70168dfa | 321 | regs->u_regs[UREG_I4] = address; |
1da177e4 LT |
322 | regs->u_regs[UREG_I5] = regs->pc; |
323 | } | |
324 | regs->u_regs[UREG_G2] = g2; | |
325 | regs->pc = fixup; | |
326 | regs->npc = regs->pc + 4; | |
327 | return; | |
328 | } | |
329 | } | |
70168dfa SR |
330 | |
331 | unhandled_fault(address, tsk, regs); | |
1da177e4 LT |
332 | do_exit(SIGKILL); |
333 | ||
334 | /* | |
335 | * We ran out of memory, or some other thing happened to us that made | |
336 | * us unable to handle the page fault gracefully. | |
337 | */ | |
338 | out_of_memory: | |
339 | up_read(&mm->mmap_sem); | |
a923c28f DM |
340 | if (from_user) { |
341 | pagefault_out_of_memory(); | |
342 | return; | |
343 | } | |
1da177e4 LT |
344 | goto no_context; |
345 | ||
346 | do_sigbus: | |
347 | up_read(&mm->mmap_sem); | |
4b177647 | 348 | do_fault_siginfo(BUS_ADRERR, SIGBUS, regs, text_fault); |
1da177e4 LT |
349 | if (!from_user) |
350 | goto no_context; | |
351 | ||
352 | vmalloc_fault: | |
353 | { | |
354 | /* | |
355 | * Synchronize this task's top level page-table | |
356 | * with the 'reference' page table. | |
357 | */ | |
358 | int offset = pgd_index(address); | |
359 | pgd_t *pgd, *pgd_k; | |
360 | pmd_t *pmd, *pmd_k; | |
361 | ||
362 | pgd = tsk->active_mm->pgd + offset; | |
363 | pgd_k = init_mm.pgd + offset; | |
364 | ||
365 | if (!pgd_present(*pgd)) { | |
366 | if (!pgd_present(*pgd_k)) | |
367 | goto bad_area_nosemaphore; | |
368 | pgd_val(*pgd) = pgd_val(*pgd_k); | |
369 | return; | |
370 | } | |
371 | ||
372 | pmd = pmd_offset(pgd, address); | |
373 | pmd_k = pmd_offset(pgd_k, address); | |
374 | ||
375 | if (pmd_present(*pmd) || !pmd_present(*pmd_k)) | |
376 | goto bad_area_nosemaphore; | |
70168dfa | 377 | |
1da177e4 LT |
378 | *pmd = *pmd_k; |
379 | return; | |
380 | } | |
381 | } | |
382 | ||
1da177e4 | 383 | /* This always deals with user addresses. */ |
50215d65 | 384 | static void force_user_fault(unsigned long address, int write) |
1da177e4 LT |
385 | { |
386 | struct vm_area_struct *vma; | |
387 | struct task_struct *tsk = current; | |
388 | struct mm_struct *mm = tsk->mm; | |
759496ba | 389 | unsigned int flags = FAULT_FLAG_USER; |
4b177647 | 390 | int code; |
1da177e4 | 391 | |
4b177647 | 392 | code = SEGV_MAPERR; |
1da177e4 | 393 | |
1da177e4 LT |
394 | down_read(&mm->mmap_sem); |
395 | vma = find_vma(mm, address); | |
70168dfa | 396 | if (!vma) |
1da177e4 | 397 | goto bad_area; |
70168dfa | 398 | if (vma->vm_start <= address) |
1da177e4 | 399 | goto good_area; |
70168dfa | 400 | if (!(vma->vm_flags & VM_GROWSDOWN)) |
1da177e4 | 401 | goto bad_area; |
70168dfa | 402 | if (expand_stack(vma, address)) |
1da177e4 LT |
403 | goto bad_area; |
404 | good_area: | |
4b177647 | 405 | code = SEGV_ACCERR; |
70168dfa SR |
406 | if (write) { |
407 | if (!(vma->vm_flags & VM_WRITE)) | |
1da177e4 | 408 | goto bad_area; |
759496ba | 409 | flags |= FAULT_FLAG_WRITE; |
1da177e4 | 410 | } else { |
70168dfa | 411 | if (!(vma->vm_flags & (VM_READ | VM_EXEC))) |
1da177e4 LT |
412 | goto bad_area; |
413 | } | |
759496ba | 414 | switch (handle_mm_fault(mm, vma, address, flags)) { |
1da177e4 LT |
415 | case VM_FAULT_SIGBUS: |
416 | case VM_FAULT_OOM: | |
417 | goto do_sigbus; | |
418 | } | |
419 | up_read(&mm->mmap_sem); | |
420 | return; | |
421 | bad_area: | |
422 | up_read(&mm->mmap_sem); | |
4b177647 | 423 | __do_fault_siginfo(code, SIGSEGV, tsk->thread.kregs, address); |
1da177e4 LT |
424 | return; |
425 | ||
426 | do_sigbus: | |
427 | up_read(&mm->mmap_sem); | |
4b177647 | 428 | __do_fault_siginfo(BUS_ADRERR, SIGBUS, tsk->thread.kregs, address); |
1da177e4 LT |
429 | } |
430 | ||
9088333e DM |
431 | static void check_stack_aligned(unsigned long sp) |
432 | { | |
433 | if (sp & 0x7UL) | |
434 | force_sig(SIGILL, current); | |
435 | } | |
436 | ||
1da177e4 LT |
437 | void window_overflow_fault(void) |
438 | { | |
439 | unsigned long sp; | |
440 | ||
441 | sp = current_thread_info()->rwbuf_stkptrs[0]; | |
70168dfa | 442 | if (((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK)) |
1da177e4 LT |
443 | force_user_fault(sp + 0x38, 1); |
444 | force_user_fault(sp, 1); | |
9088333e DM |
445 | |
446 | check_stack_aligned(sp); | |
1da177e4 LT |
447 | } |
448 | ||
449 | void window_underflow_fault(unsigned long sp) | |
450 | { | |
70168dfa | 451 | if (((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK)) |
1da177e4 LT |
452 | force_user_fault(sp + 0x38, 0); |
453 | force_user_fault(sp, 0); | |
9088333e DM |
454 | |
455 | check_stack_aligned(sp); | |
1da177e4 LT |
456 | } |
457 | ||
458 | void window_ret_fault(struct pt_regs *regs) | |
459 | { | |
460 | unsigned long sp; | |
461 | ||
462 | sp = regs->u_regs[UREG_FP]; | |
70168dfa | 463 | if (((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK)) |
1da177e4 LT |
464 | force_user_fault(sp + 0x38, 0); |
465 | force_user_fault(sp, 0); | |
9088333e DM |
466 | |
467 | check_stack_aligned(sp); | |
1da177e4 | 468 | } |