blob: a507e1174662e2bd0072a739d217a7480bcd60c2 [file] [log] [blame]
Adrian Bunk88278ca2008-05-19 16:53:02 -07001/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07002 * 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>
Linus Torvalds1da177e2005-04-16 15:20:36 -070021#include <linux/interrupt.h>
22#include <linux/module.h>
Christoph Hellwig1eeb66a2007-05-08 00:27:03 -070023#include <linux/kdebug.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070024
25#include <asm/system.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070026#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>
Linus Torvalds1da177e2005-04-16 15:20:36 -070033#include <asm/uaccess.h>
34
Linus Torvalds1da177e2005-04-16 15:20:36 -070035extern 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
41int num_segmaps, num_contexts;
42int invalid_segment;
43
44/* various Virtual Address Cache parameters we find at boot time... */
45
46int vac_size, vac_linesize, vac_do_hw_vac_flushes;
47int vac_entries_per_context, vac_entries_per_segment;
48int vac_entries_per_page;
49
David S. Miller9f2b2a52008-05-01 22:28:17 -070050/* Return how much physical memory we have. */
51unsigned long probe_memory(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -070052{
David S. Miller9f2b2a52008-05-01 22:28:17 -070053 unsigned long total = 0;
54 int i;
Linus Torvalds1da177e2005-04-16 15:20:36 -070055
David S. Miller9f2b2a52008-05-01 22:28:17 -070056 for (i = 0; sp_banks[i].num_bytes; i++)
57 total += sp_banks[i].num_bytes;
Linus Torvalds1da177e2005-04-16 15:20:36 -070058
Linus Torvalds1da177e2005-04-16 15:20:36 -070059 return total;
60}
61
62extern void sun4c_complete_all_stores(void);
63
64/* Whee, a level 15 NMI interrupt memory error. Let's have fun... */
65asmlinkage 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
82static void unhandled_fault(unsigned long, struct task_struct *,
83 struct pt_regs *) __attribute__ ((noreturn));
84
85static 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
103asmlinkage 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(&regs, 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, &regs);
146
147 /* Not reached */
148 return 0;
149}
150
151extern unsigned long safe_compute_effective_address(struct pt_regs *,
152 unsigned int);
153
154static 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
170asmlinkage 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);
Nick Piggin83c54072007-07-19 01:47:05 -0700180 int fault;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700181
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 */
Adrian Bunk5110bd22008-08-31 20:59:37 -0700194 if (!ARCH_SUN4C && address >= TASK_SIZE)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700195 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 */
228good_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 */
Nick Piggin83c54072007-07-19 01:47:05 -0700244 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();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700251 }
Nick Piggin83c54072007-07-19 01:47:05 -0700252 if (fault & VM_FAULT_MAJOR)
253 current->maj_flt++;
254 else
255 current->min_flt++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256 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 */
263bad_area:
264 up_read(&mm->mmap_sem);
265
266bad_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? */
284no_context:
285 g2 = regs->u_regs[UREG_G2];
286 if (!from_user && (fixup = search_extables_range(regs->pc, &g2))) {
287 if (fixup > 10) { /* Values below are reserved for other things */
288 extern const unsigned __memset_start[];
289 extern const unsigned __memset_end[];
290 extern const unsigned __csum_partial_copy_start[];
291 extern const unsigned __csum_partial_copy_end[];
292
293#ifdef DEBUG_EXCEPTIONS
294 printk("Exception: PC<%08lx> faddr<%08lx>\n", regs->pc, address);
295 printk("EX_TABLE: insn<%08lx> fixup<%08x> g2<%08lx>\n",
296 regs->pc, fixup, g2);
297#endif
298 if ((regs->pc >= (unsigned long)__memset_start &&
299 regs->pc < (unsigned long)__memset_end) ||
300 (regs->pc >= (unsigned long)__csum_partial_copy_start &&
301 regs->pc < (unsigned long)__csum_partial_copy_end)) {
302 regs->u_regs[UREG_I4] = address;
303 regs->u_regs[UREG_I5] = regs->pc;
304 }
305 regs->u_regs[UREG_G2] = g2;
306 regs->pc = fixup;
307 regs->npc = regs->pc + 4;
308 return;
309 }
310 }
311
312 unhandled_fault (address, tsk, regs);
313 do_exit(SIGKILL);
314
315/*
316 * We ran out of memory, or some other thing happened to us that made
317 * us unable to handle the page fault gracefully.
318 */
319out_of_memory:
320 up_read(&mm->mmap_sem);
321 printk("VM: killing process %s\n", tsk->comm);
322 if (from_user)
Will Schmidtdcca2bd2007-10-16 01:24:18 -0700323 do_group_exit(SIGKILL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700324 goto no_context;
325
326do_sigbus:
327 up_read(&mm->mmap_sem);
328 info.si_signo = SIGBUS;
329 info.si_errno = 0;
330 info.si_code = BUS_ADRERR;
331 info.si_addr = (void __user *) compute_si_addr(regs, text_fault);
332 info.si_trapno = 0;
333 force_sig_info (SIGBUS, &info, tsk);
334 if (!from_user)
335 goto no_context;
336
337vmalloc_fault:
338 {
339 /*
340 * Synchronize this task's top level page-table
341 * with the 'reference' page table.
342 */
343 int offset = pgd_index(address);
344 pgd_t *pgd, *pgd_k;
345 pmd_t *pmd, *pmd_k;
346
347 pgd = tsk->active_mm->pgd + offset;
348 pgd_k = init_mm.pgd + offset;
349
350 if (!pgd_present(*pgd)) {
351 if (!pgd_present(*pgd_k))
352 goto bad_area_nosemaphore;
353 pgd_val(*pgd) = pgd_val(*pgd_k);
354 return;
355 }
356
357 pmd = pmd_offset(pgd, address);
358 pmd_k = pmd_offset(pgd_k, address);
359
360 if (pmd_present(*pmd) || !pmd_present(*pmd_k))
361 goto bad_area_nosemaphore;
362 *pmd = *pmd_k;
363 return;
364 }
365}
366
367asmlinkage void do_sun4c_fault(struct pt_regs *regs, int text_fault, int write,
368 unsigned long address)
369{
370 extern void sun4c_update_mmu_cache(struct vm_area_struct *,
371 unsigned long,pte_t);
372 extern pte_t *sun4c_pte_offset_kernel(pmd_t *,unsigned long);
373 struct task_struct *tsk = current;
374 struct mm_struct *mm = tsk->mm;
375 pgd_t *pgdp;
376 pte_t *ptep;
377
378 if (text_fault) {
379 address = regs->pc;
380 } else if (!write &&
381 !(regs->psr & PSR_PS)) {
382 unsigned int insn, __user *ip;
383
384 ip = (unsigned int __user *)regs->pc;
385 if (!get_user(insn, ip)) {
386 if ((insn & 0xc1680000) == 0xc0680000)
387 write = 1;
388 }
389 }
390
391 if (!mm) {
392 /* We are oopsing. */
393 do_sparc_fault(regs, text_fault, write, address);
394 BUG(); /* P3 Oops already, you bitch */
395 }
396
397 pgdp = pgd_offset(mm, address);
398 ptep = sun4c_pte_offset_kernel((pmd_t *) pgdp, address);
399
400 if (pgd_val(*pgdp)) {
401 if (write) {
402 if ((pte_val(*ptep) & (_SUN4C_PAGE_WRITE|_SUN4C_PAGE_PRESENT))
403 == (_SUN4C_PAGE_WRITE|_SUN4C_PAGE_PRESENT)) {
404 unsigned long flags;
405
406 *ptep = __pte(pte_val(*ptep) | _SUN4C_PAGE_ACCESSED |
407 _SUN4C_PAGE_MODIFIED |
408 _SUN4C_PAGE_VALID |
409 _SUN4C_PAGE_DIRTY);
410
411 local_irq_save(flags);
412 if (sun4c_get_segmap(address) != invalid_segment) {
413 sun4c_put_pte(address, pte_val(*ptep));
414 local_irq_restore(flags);
415 return;
416 }
417 local_irq_restore(flags);
418 }
419 } else {
420 if ((pte_val(*ptep) & (_SUN4C_PAGE_READ|_SUN4C_PAGE_PRESENT))
421 == (_SUN4C_PAGE_READ|_SUN4C_PAGE_PRESENT)) {
422 unsigned long flags;
423
424 *ptep = __pte(pte_val(*ptep) | _SUN4C_PAGE_ACCESSED |
425 _SUN4C_PAGE_VALID);
426
427 local_irq_save(flags);
428 if (sun4c_get_segmap(address) != invalid_segment) {
429 sun4c_put_pte(address, pte_val(*ptep));
430 local_irq_restore(flags);
431 return;
432 }
433 local_irq_restore(flags);
434 }
435 }
436 }
437
438 /* This conditional is 'interesting'. */
439 if (pgd_val(*pgdp) && !(write && !(pte_val(*ptep) & _SUN4C_PAGE_WRITE))
440 && (pte_val(*ptep) & _SUN4C_PAGE_VALID))
441 /* Note: It is safe to not grab the MMAP semaphore here because
442 * we know that update_mmu_cache() will not sleep for
443 * any reason (at least not in the current implementation)
444 * and therefore there is no danger of another thread getting
445 * on the CPU and doing a shrink_mmap() on this vma.
446 */
447 sun4c_update_mmu_cache (find_vma(current->mm, address), address,
448 *ptep);
449 else
450 do_sparc_fault(regs, text_fault, write, address);
451}
452
453/* This always deals with user addresses. */
Adrian Bunk50215d62008-06-05 11:41:51 -0700454static void force_user_fault(unsigned long address, int write)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700455{
456 struct vm_area_struct *vma;
457 struct task_struct *tsk = current;
458 struct mm_struct *mm = tsk->mm;
459 siginfo_t info;
460
461 info.si_code = SEGV_MAPERR;
462
463#if 0
464 printk("wf<pid=%d,wr=%d,addr=%08lx>\n",
465 tsk->pid, write, address);
466#endif
467 down_read(&mm->mmap_sem);
468 vma = find_vma(mm, address);
469 if(!vma)
470 goto bad_area;
471 if(vma->vm_start <= address)
472 goto good_area;
473 if(!(vma->vm_flags & VM_GROWSDOWN))
474 goto bad_area;
475 if(expand_stack(vma, address))
476 goto bad_area;
477good_area:
478 info.si_code = SEGV_ACCERR;
479 if(write) {
480 if(!(vma->vm_flags & VM_WRITE))
481 goto bad_area;
482 } else {
483 if(!(vma->vm_flags & (VM_READ | VM_EXEC)))
484 goto bad_area;
485 }
486 switch (handle_mm_fault(mm, vma, address, write)) {
487 case VM_FAULT_SIGBUS:
488 case VM_FAULT_OOM:
489 goto do_sigbus;
490 }
491 up_read(&mm->mmap_sem);
492 return;
493bad_area:
494 up_read(&mm->mmap_sem);
495#if 0
496 printk("Window whee %s [%d]: segfaults at %08lx\n",
497 tsk->comm, tsk->pid, address);
498#endif
499 info.si_signo = SIGSEGV;
500 info.si_errno = 0;
501 /* info.si_code set above to make clear whether
502 this was a SEGV_MAPERR or SEGV_ACCERR fault. */
503 info.si_addr = (void __user *) address;
504 info.si_trapno = 0;
505 force_sig_info (SIGSEGV, &info, tsk);
506 return;
507
508do_sigbus:
509 up_read(&mm->mmap_sem);
510 info.si_signo = SIGBUS;
511 info.si_errno = 0;
512 info.si_code = BUS_ADRERR;
513 info.si_addr = (void __user *) address;
514 info.si_trapno = 0;
515 force_sig_info (SIGBUS, &info, tsk);
516}
517
518void window_overflow_fault(void)
519{
520 unsigned long sp;
521
522 sp = current_thread_info()->rwbuf_stkptrs[0];
523 if(((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK))
524 force_user_fault(sp + 0x38, 1);
525 force_user_fault(sp, 1);
526}
527
528void window_underflow_fault(unsigned long sp)
529{
530 if(((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK))
531 force_user_fault(sp + 0x38, 0);
532 force_user_fault(sp, 0);
533}
534
535void window_ret_fault(struct pt_regs *regs)
536{
537 unsigned long sp;
538
539 sp = regs->u_regs[UREG_FP];
540 if(((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK))
541 force_user_fault(sp + 0x38, 0);
542 force_user_fault(sp, 0);
543}