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> | |
1da177e4 LT |
21 | #include <linux/interrupt.h> |
22 | #include <linux/module.h> | |
1eeb66a1 | 23 | #include <linux/kdebug.h> |
1da177e4 LT |
24 | |
25 | #include <asm/system.h> | |
1da177e4 LT |
26 | #include <asm/page.h> |
27 | #include <asm/pgtable.h> | |
28 | #include <asm/memreg.h> | |
29 | #include <asm/openprom.h> | |
30 | #include <asm/oplib.h> | |
31 | #include <asm/smp.h> | |
32 | #include <asm/traps.h> | |
1da177e4 LT |
33 | #include <asm/uaccess.h> |
34 | ||
1da177e4 LT |
35 | extern int prom_node_root; |
36 | ||
37 | /* At boot time we determine these two values necessary for setting | |
38 | * up the segment maps and page table entries (pte's). | |
39 | */ | |
40 | ||
41 | int num_segmaps, num_contexts; | |
42 | int invalid_segment; | |
43 | ||
44 | /* various Virtual Address Cache parameters we find at boot time... */ | |
45 | ||
46 | int vac_size, vac_linesize, vac_do_hw_vac_flushes; | |
47 | int vac_entries_per_context, vac_entries_per_segment; | |
48 | int vac_entries_per_page; | |
49 | ||
9f2b2a5f DM |
50 | /* Return how much physical memory we have. */ |
51 | unsigned long probe_memory(void) | |
1da177e4 | 52 | { |
9f2b2a5f DM |
53 | unsigned long total = 0; |
54 | int i; | |
1da177e4 | 55 | |
9f2b2a5f DM |
56 | for (i = 0; sp_banks[i].num_bytes; i++) |
57 | total += sp_banks[i].num_bytes; | |
1da177e4 | 58 | |
1da177e4 LT |
59 | return total; |
60 | } | |
61 | ||
62 | extern void sun4c_complete_all_stores(void); | |
63 | ||
64 | /* Whee, a level 15 NMI interrupt memory error. Let's have fun... */ | |
65 | asmlinkage void sparc_lvl15_nmi(struct pt_regs *regs, unsigned long serr, | |
66 | unsigned long svaddr, unsigned long aerr, | |
67 | unsigned long avaddr) | |
68 | { | |
69 | sun4c_complete_all_stores(); | |
70 | printk("FAULT: NMI received\n"); | |
71 | printk("SREGS: Synchronous Error %08lx\n", serr); | |
72 | printk(" Synchronous Vaddr %08lx\n", svaddr); | |
73 | printk(" Asynchronous Error %08lx\n", aerr); | |
74 | printk(" Asynchronous Vaddr %08lx\n", avaddr); | |
75 | if (sun4c_memerr_reg) | |
76 | printk(" Memory Parity Error %08lx\n", *sun4c_memerr_reg); | |
77 | printk("REGISTER DUMP:\n"); | |
78 | show_regs(regs); | |
79 | prom_halt(); | |
80 | } | |
81 | ||
82 | static void unhandled_fault(unsigned long, struct task_struct *, | |
83 | struct pt_regs *) __attribute__ ((noreturn)); | |
84 | ||
85 | static void unhandled_fault(unsigned long address, struct task_struct *tsk, | |
86 | struct pt_regs *regs) | |
87 | { | |
88 | if((unsigned long) address < PAGE_SIZE) { | |
89 | printk(KERN_ALERT | |
90 | "Unable to handle kernel NULL pointer dereference\n"); | |
91 | } else { | |
92 | printk(KERN_ALERT "Unable to handle kernel paging request " | |
93 | "at virtual address %08lx\n", address); | |
94 | } | |
95 | printk(KERN_ALERT "tsk->{mm,active_mm}->context = %08lx\n", | |
96 | (tsk->mm ? tsk->mm->context : tsk->active_mm->context)); | |
97 | printk(KERN_ALERT "tsk->{mm,active_mm}->pgd = %08lx\n", | |
98 | (tsk->mm ? (unsigned long) tsk->mm->pgd : | |
99 | (unsigned long) tsk->active_mm->pgd)); | |
100 | die_if_kernel("Oops", regs); | |
101 | } | |
102 | ||
103 | asmlinkage int lookup_fault(unsigned long pc, unsigned long ret_pc, | |
104 | unsigned long address) | |
105 | { | |
106 | struct pt_regs regs; | |
107 | unsigned long g2; | |
108 | unsigned int insn; | |
109 | int i; | |
110 | ||
111 | i = search_extables_range(ret_pc, &g2); | |
112 | switch (i) { | |
113 | case 3: | |
114 | /* load & store will be handled by fixup */ | |
115 | return 3; | |
116 | ||
117 | case 1: | |
118 | /* store will be handled by fixup, load will bump out */ | |
119 | /* for _to_ macros */ | |
120 | insn = *((unsigned int *) pc); | |
121 | if ((insn >> 21) & 1) | |
122 | return 1; | |
123 | break; | |
124 | ||
125 | case 2: | |
126 | /* load will be handled by fixup, store will bump out */ | |
127 | /* for _from_ macros */ | |
128 | insn = *((unsigned int *) pc); | |
129 | if (!((insn >> 21) & 1) || ((insn>>19)&0x3f) == 15) | |
130 | return 2; | |
131 | break; | |
132 | ||
133 | default: | |
134 | break; | |
135 | }; | |
136 | ||
137 | memset(®s, 0, sizeof (regs)); | |
138 | regs.pc = pc; | |
139 | regs.npc = pc + 4; | |
140 | __asm__ __volatile__( | |
141 | "rd %%psr, %0\n\t" | |
142 | "nop\n\t" | |
143 | "nop\n\t" | |
144 | "nop\n" : "=r" (regs.psr)); | |
145 | unhandled_fault(address, current, ®s); | |
146 | ||
147 | /* Not reached */ | |
148 | return 0; | |
149 | } | |
150 | ||
151 | extern unsigned long safe_compute_effective_address(struct pt_regs *, | |
152 | unsigned int); | |
153 | ||
154 | static unsigned long compute_si_addr(struct pt_regs *regs, int text_fault) | |
155 | { | |
156 | unsigned int insn; | |
157 | ||
158 | if (text_fault) | |
159 | return regs->pc; | |
160 | ||
161 | if (regs->psr & PSR_PS) { | |
162 | insn = *(unsigned int *) regs->pc; | |
163 | } else { | |
164 | __get_user(insn, (unsigned int *) regs->pc); | |
165 | } | |
166 | ||
167 | return safe_compute_effective_address(regs, insn); | |
168 | } | |
169 | ||
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; | |
178 | siginfo_t info; | |
179 | int from_user = !(regs->psr & PSR_PS); | |
83c54070 | 180 | int fault; |
1da177e4 LT |
181 | |
182 | if(text_fault) | |
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 | */ | |
5110bd21 | 194 | if (!ARCH_SUN4C && address >= TASK_SIZE) |
1da177e4 LT |
195 | goto vmalloc_fault; |
196 | ||
197 | info.si_code = SEGV_MAPERR; | |
198 | ||
199 | /* | |
200 | * If we're in an interrupt or have no user | |
201 | * context, we must not take the fault.. | |
202 | */ | |
203 | if (in_atomic() || !mm) | |
204 | goto no_context; | |
205 | ||
206 | down_read(&mm->mmap_sem); | |
207 | ||
208 | /* | |
209 | * The kernel referencing a bad kernel pointer can lock up | |
210 | * a sun4c machine completely, so we must attempt recovery. | |
211 | */ | |
212 | if(!from_user && address >= PAGE_OFFSET) | |
213 | goto bad_area; | |
214 | ||
215 | vma = find_vma(mm, address); | |
216 | if(!vma) | |
217 | goto bad_area; | |
218 | if(vma->vm_start <= address) | |
219 | goto good_area; | |
220 | if(!(vma->vm_flags & VM_GROWSDOWN)) | |
221 | goto bad_area; | |
222 | if(expand_stack(vma, address)) | |
223 | goto bad_area; | |
224 | /* | |
225 | * Ok, we have a good vm_area for this memory access, so | |
226 | * we can handle it.. | |
227 | */ | |
228 | good_area: | |
229 | info.si_code = SEGV_ACCERR; | |
230 | if(write) { | |
231 | if(!(vma->vm_flags & VM_WRITE)) | |
232 | goto bad_area; | |
233 | } else { | |
234 | /* Allow reads even for write-only mappings */ | |
235 | if(!(vma->vm_flags & (VM_READ | VM_EXEC))) | |
236 | goto bad_area; | |
237 | } | |
238 | ||
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 | */ | |
83c54070 NP |
244 | fault = handle_mm_fault(mm, vma, address, write); |
245 | if (unlikely(fault & VM_FAULT_ERROR)) { | |
246 | if (fault & VM_FAULT_OOM) | |
247 | goto out_of_memory; | |
248 | else if (fault & VM_FAULT_SIGBUS) | |
249 | goto do_sigbus; | |
250 | BUG(); | |
251 | } | |
252 | if (fault & VM_FAULT_MAJOR) | |
1da177e4 | 253 | current->maj_flt++; |
83c54070 | 254 | else |
1da177e4 | 255 | current->min_flt++; |
1da177e4 LT |
256 | up_read(&mm->mmap_sem); |
257 | return; | |
258 | ||
259 | /* | |
260 | * Something tried to access memory that isn't in our memory map.. | |
261 | * Fix it, but check if it's kernel or user first.. | |
262 | */ | |
263 | bad_area: | |
264 | up_read(&mm->mmap_sem); | |
265 | ||
266 | bad_area_nosemaphore: | |
267 | /* User mode accesses just cause a SIGSEGV */ | |
268 | if(from_user) { | |
269 | #if 0 | |
270 | printk("Fault whee %s [%d]: segfaults at %08lx pc=%08lx\n", | |
271 | tsk->comm, tsk->pid, address, regs->pc); | |
272 | #endif | |
273 | info.si_signo = SIGSEGV; | |
274 | info.si_errno = 0; | |
275 | /* info.si_code set above to make clear whether | |
276 | this was a SEGV_MAPERR or SEGV_ACCERR fault. */ | |
277 | info.si_addr = (void __user *)compute_si_addr(regs, text_fault); | |
278 | info.si_trapno = 0; | |
279 | force_sig_info (SIGSEGV, &info, tsk); | |
280 | return; | |
281 | } | |
282 | ||
283 | /* Is this in ex_table? */ | |
284 | no_context: | |
285 | g2 = regs->u_regs[UREG_G2]; | |
0157141a SR |
286 | if (!from_user) { |
287 | fixup = search_extables_range(regs->pc, &g2); | |
1da177e4 LT |
288 | if (fixup > 10) { /* Values below are reserved for other things */ |
289 | extern const unsigned __memset_start[]; | |
290 | extern const unsigned __memset_end[]; | |
291 | extern const unsigned __csum_partial_copy_start[]; | |
292 | extern const unsigned __csum_partial_copy_end[]; | |
293 | ||
294 | #ifdef DEBUG_EXCEPTIONS | |
295 | printk("Exception: PC<%08lx> faddr<%08lx>\n", regs->pc, address); | |
296 | printk("EX_TABLE: insn<%08lx> fixup<%08x> g2<%08lx>\n", | |
297 | regs->pc, fixup, g2); | |
298 | #endif | |
299 | if ((regs->pc >= (unsigned long)__memset_start && | |
300 | regs->pc < (unsigned long)__memset_end) || | |
301 | (regs->pc >= (unsigned long)__csum_partial_copy_start && | |
302 | regs->pc < (unsigned long)__csum_partial_copy_end)) { | |
303 | regs->u_regs[UREG_I4] = address; | |
304 | regs->u_regs[UREG_I5] = regs->pc; | |
305 | } | |
306 | regs->u_regs[UREG_G2] = g2; | |
307 | regs->pc = fixup; | |
308 | regs->npc = regs->pc + 4; | |
309 | return; | |
310 | } | |
311 | } | |
312 | ||
313 | unhandled_fault (address, tsk, regs); | |
314 | do_exit(SIGKILL); | |
315 | ||
316 | /* | |
317 | * We ran out of memory, or some other thing happened to us that made | |
318 | * us unable to handle the page fault gracefully. | |
319 | */ | |
320 | out_of_memory: | |
321 | up_read(&mm->mmap_sem); | |
322 | printk("VM: killing process %s\n", tsk->comm); | |
323 | if (from_user) | |
dcca2bde | 324 | do_group_exit(SIGKILL); |
1da177e4 LT |
325 | goto no_context; |
326 | ||
327 | do_sigbus: | |
328 | up_read(&mm->mmap_sem); | |
329 | info.si_signo = SIGBUS; | |
330 | info.si_errno = 0; | |
331 | info.si_code = BUS_ADRERR; | |
332 | info.si_addr = (void __user *) compute_si_addr(regs, text_fault); | |
333 | info.si_trapno = 0; | |
334 | force_sig_info (SIGBUS, &info, tsk); | |
335 | if (!from_user) | |
336 | goto no_context; | |
337 | ||
338 | vmalloc_fault: | |
339 | { | |
340 | /* | |
341 | * Synchronize this task's top level page-table | |
342 | * with the 'reference' page table. | |
343 | */ | |
344 | int offset = pgd_index(address); | |
345 | pgd_t *pgd, *pgd_k; | |
346 | pmd_t *pmd, *pmd_k; | |
347 | ||
348 | pgd = tsk->active_mm->pgd + offset; | |
349 | pgd_k = init_mm.pgd + offset; | |
350 | ||
351 | if (!pgd_present(*pgd)) { | |
352 | if (!pgd_present(*pgd_k)) | |
353 | goto bad_area_nosemaphore; | |
354 | pgd_val(*pgd) = pgd_val(*pgd_k); | |
355 | return; | |
356 | } | |
357 | ||
358 | pmd = pmd_offset(pgd, address); | |
359 | pmd_k = pmd_offset(pgd_k, address); | |
360 | ||
361 | if (pmd_present(*pmd) || !pmd_present(*pmd_k)) | |
362 | goto bad_area_nosemaphore; | |
363 | *pmd = *pmd_k; | |
364 | return; | |
365 | } | |
366 | } | |
367 | ||
368 | asmlinkage void do_sun4c_fault(struct pt_regs *regs, int text_fault, int write, | |
369 | unsigned long address) | |
370 | { | |
371 | extern void sun4c_update_mmu_cache(struct vm_area_struct *, | |
372 | unsigned long,pte_t); | |
373 | extern pte_t *sun4c_pte_offset_kernel(pmd_t *,unsigned long); | |
374 | struct task_struct *tsk = current; | |
375 | struct mm_struct *mm = tsk->mm; | |
376 | pgd_t *pgdp; | |
377 | pte_t *ptep; | |
378 | ||
379 | if (text_fault) { | |
380 | address = regs->pc; | |
381 | } else if (!write && | |
382 | !(regs->psr & PSR_PS)) { | |
383 | unsigned int insn, __user *ip; | |
384 | ||
385 | ip = (unsigned int __user *)regs->pc; | |
386 | if (!get_user(insn, ip)) { | |
387 | if ((insn & 0xc1680000) == 0xc0680000) | |
388 | write = 1; | |
389 | } | |
390 | } | |
391 | ||
392 | if (!mm) { | |
393 | /* We are oopsing. */ | |
394 | do_sparc_fault(regs, text_fault, write, address); | |
395 | BUG(); /* P3 Oops already, you bitch */ | |
396 | } | |
397 | ||
398 | pgdp = pgd_offset(mm, address); | |
399 | ptep = sun4c_pte_offset_kernel((pmd_t *) pgdp, address); | |
400 | ||
401 | if (pgd_val(*pgdp)) { | |
402 | if (write) { | |
403 | if ((pte_val(*ptep) & (_SUN4C_PAGE_WRITE|_SUN4C_PAGE_PRESENT)) | |
404 | == (_SUN4C_PAGE_WRITE|_SUN4C_PAGE_PRESENT)) { | |
405 | unsigned long flags; | |
406 | ||
407 | *ptep = __pte(pte_val(*ptep) | _SUN4C_PAGE_ACCESSED | | |
408 | _SUN4C_PAGE_MODIFIED | | |
409 | _SUN4C_PAGE_VALID | | |
410 | _SUN4C_PAGE_DIRTY); | |
411 | ||
412 | local_irq_save(flags); | |
413 | if (sun4c_get_segmap(address) != invalid_segment) { | |
414 | sun4c_put_pte(address, pte_val(*ptep)); | |
415 | local_irq_restore(flags); | |
416 | return; | |
417 | } | |
418 | local_irq_restore(flags); | |
419 | } | |
420 | } else { | |
421 | if ((pte_val(*ptep) & (_SUN4C_PAGE_READ|_SUN4C_PAGE_PRESENT)) | |
422 | == (_SUN4C_PAGE_READ|_SUN4C_PAGE_PRESENT)) { | |
423 | unsigned long flags; | |
424 | ||
425 | *ptep = __pte(pte_val(*ptep) | _SUN4C_PAGE_ACCESSED | | |
426 | _SUN4C_PAGE_VALID); | |
427 | ||
428 | local_irq_save(flags); | |
429 | if (sun4c_get_segmap(address) != invalid_segment) { | |
430 | sun4c_put_pte(address, pte_val(*ptep)); | |
431 | local_irq_restore(flags); | |
432 | return; | |
433 | } | |
434 | local_irq_restore(flags); | |
435 | } | |
436 | } | |
437 | } | |
438 | ||
439 | /* This conditional is 'interesting'. */ | |
440 | if (pgd_val(*pgdp) && !(write && !(pte_val(*ptep) & _SUN4C_PAGE_WRITE)) | |
441 | && (pte_val(*ptep) & _SUN4C_PAGE_VALID)) | |
442 | /* Note: It is safe to not grab the MMAP semaphore here because | |
443 | * we know that update_mmu_cache() will not sleep for | |
444 | * any reason (at least not in the current implementation) | |
445 | * and therefore there is no danger of another thread getting | |
446 | * on the CPU and doing a shrink_mmap() on this vma. | |
447 | */ | |
448 | sun4c_update_mmu_cache (find_vma(current->mm, address), address, | |
449 | *ptep); | |
450 | else | |
451 | do_sparc_fault(regs, text_fault, write, address); | |
452 | } | |
453 | ||
454 | /* This always deals with user addresses. */ | |
50215d65 | 455 | static void force_user_fault(unsigned long address, int write) |
1da177e4 LT |
456 | { |
457 | struct vm_area_struct *vma; | |
458 | struct task_struct *tsk = current; | |
459 | struct mm_struct *mm = tsk->mm; | |
460 | siginfo_t info; | |
461 | ||
462 | info.si_code = SEGV_MAPERR; | |
463 | ||
464 | #if 0 | |
465 | printk("wf<pid=%d,wr=%d,addr=%08lx>\n", | |
466 | tsk->pid, write, address); | |
467 | #endif | |
468 | down_read(&mm->mmap_sem); | |
469 | vma = find_vma(mm, address); | |
470 | if(!vma) | |
471 | goto bad_area; | |
472 | if(vma->vm_start <= address) | |
473 | goto good_area; | |
474 | if(!(vma->vm_flags & VM_GROWSDOWN)) | |
475 | goto bad_area; | |
476 | if(expand_stack(vma, address)) | |
477 | goto bad_area; | |
478 | good_area: | |
479 | info.si_code = SEGV_ACCERR; | |
480 | if(write) { | |
481 | if(!(vma->vm_flags & VM_WRITE)) | |
482 | goto bad_area; | |
483 | } else { | |
484 | if(!(vma->vm_flags & (VM_READ | VM_EXEC))) | |
485 | goto bad_area; | |
486 | } | |
487 | switch (handle_mm_fault(mm, vma, address, write)) { | |
488 | case VM_FAULT_SIGBUS: | |
489 | case VM_FAULT_OOM: | |
490 | goto do_sigbus; | |
491 | } | |
492 | up_read(&mm->mmap_sem); | |
493 | return; | |
494 | bad_area: | |
495 | up_read(&mm->mmap_sem); | |
496 | #if 0 | |
497 | printk("Window whee %s [%d]: segfaults at %08lx\n", | |
498 | tsk->comm, tsk->pid, address); | |
499 | #endif | |
500 | info.si_signo = SIGSEGV; | |
501 | info.si_errno = 0; | |
502 | /* info.si_code set above to make clear whether | |
503 | this was a SEGV_MAPERR or SEGV_ACCERR fault. */ | |
504 | info.si_addr = (void __user *) address; | |
505 | info.si_trapno = 0; | |
506 | force_sig_info (SIGSEGV, &info, tsk); | |
507 | return; | |
508 | ||
509 | do_sigbus: | |
510 | up_read(&mm->mmap_sem); | |
511 | info.si_signo = SIGBUS; | |
512 | info.si_errno = 0; | |
513 | info.si_code = BUS_ADRERR; | |
514 | info.si_addr = (void __user *) address; | |
515 | info.si_trapno = 0; | |
516 | force_sig_info (SIGBUS, &info, tsk); | |
517 | } | |
518 | ||
519 | void window_overflow_fault(void) | |
520 | { | |
521 | unsigned long sp; | |
522 | ||
523 | sp = current_thread_info()->rwbuf_stkptrs[0]; | |
524 | if(((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK)) | |
525 | force_user_fault(sp + 0x38, 1); | |
526 | force_user_fault(sp, 1); | |
527 | } | |
528 | ||
529 | void window_underflow_fault(unsigned long sp) | |
530 | { | |
531 | if(((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK)) | |
532 | force_user_fault(sp + 0x38, 0); | |
533 | force_user_fault(sp, 0); | |
534 | } | |
535 | ||
536 | void window_ret_fault(struct pt_regs *regs) | |
537 | { | |
538 | unsigned long sp; | |
539 | ||
540 | sp = regs->u_regs[UREG_FP]; | |
541 | if(((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK)) | |
542 | force_user_fault(sp + 0x38, 0); | |
543 | force_user_fault(sp, 0); | |
544 | } |