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1/*
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>
21#include <linux/perf_event.h>
22#include <linux/interrupt.h>
23#include <linux/module.h>
24#include <linux/kdebug.h>
25
26#include <asm/system.h>
27#include <asm/page.h>
28#include <asm/pgtable.h>
29#include <asm/memreg.h>
30#include <asm/openprom.h>
31#include <asm/oplib.h>
32#include <asm/smp.h>
33#include <asm/traps.h>
34#include <asm/uaccess.h>
35
36extern int prom_node_root;
37
38int show_unhandled_signals = 1;
39
40/* At boot time we determine these two values necessary for setting
41 * up the segment maps and page table entries (pte's).
42 */
43
44int num_segmaps, num_contexts;
45int invalid_segment;
46
47/* various Virtual Address Cache parameters we find at boot time... */
48
49int vac_size, vac_linesize, vac_do_hw_vac_flushes;
50int vac_entries_per_context, vac_entries_per_segment;
51int vac_entries_per_page;
52
53/* Return how much physical memory we have. */
54unsigned long probe_memory(void)
55{
56 unsigned long total = 0;
57 int i;
58
59 for (i = 0; sp_banks[i].num_bytes; i++)
60 total += sp_banks[i].num_bytes;
61
62 return total;
63}
64
65extern void sun4c_complete_all_stores(void);
66
67/* Whee, a level 15 NMI interrupt memory error. Let's have fun... */
68asmlinkage void sparc_lvl15_nmi(struct pt_regs *regs, unsigned long serr,
69 unsigned long svaddr, unsigned long aerr,
70 unsigned long avaddr)
71{
72 sun4c_complete_all_stores();
73 printk("FAULT: NMI received\n");
74 printk("SREGS: Synchronous Error %08lx\n", serr);
75 printk(" Synchronous Vaddr %08lx\n", svaddr);
76 printk(" Asynchronous Error %08lx\n", aerr);
77 printk(" Asynchronous Vaddr %08lx\n", avaddr);
78 if (sun4c_memerr_reg)
79 printk(" Memory Parity Error %08lx\n", *sun4c_memerr_reg);
80 printk("REGISTER DUMP:\n");
81 show_regs(regs);
82 prom_halt();
83}
84
85static void unhandled_fault(unsigned long, struct task_struct *,
86 struct pt_regs *) __attribute__ ((noreturn));
87
88static void unhandled_fault(unsigned long address, struct task_struct *tsk,
89 struct pt_regs *regs)
90{
91 if((unsigned long) address < PAGE_SIZE) {
92 printk(KERN_ALERT
93 "Unable to handle kernel NULL pointer dereference\n");
94 } else {
95 printk(KERN_ALERT "Unable to handle kernel paging request "
96 "at virtual address %08lx\n", address);
97 }
98 printk(KERN_ALERT "tsk->{mm,active_mm}->context = %08lx\n",
99 (tsk->mm ? tsk->mm->context : tsk->active_mm->context));
100 printk(KERN_ALERT "tsk->{mm,active_mm}->pgd = %08lx\n",
101 (tsk->mm ? (unsigned long) tsk->mm->pgd :
102 (unsigned long) tsk->active_mm->pgd));
103 die_if_kernel("Oops", regs);
104}
105
106asmlinkage int lookup_fault(unsigned long pc, unsigned long ret_pc,
107 unsigned long address)
108{
109 struct pt_regs regs;
110 unsigned long g2;
111 unsigned int insn;
112 int i;
113
114 i = search_extables_range(ret_pc, &g2);
115 switch (i) {
116 case 3:
117 /* load & store will be handled by fixup */
118 return 3;
119
120 case 1:
121 /* store will be handled by fixup, load will bump out */
122 /* for _to_ macros */
123 insn = *((unsigned int *) pc);
124 if ((insn >> 21) & 1)
125 return 1;
126 break;
127
128 case 2:
129 /* load will be handled by fixup, store will bump out */
130 /* for _from_ macros */
131 insn = *((unsigned int *) pc);
132 if (!((insn >> 21) & 1) || ((insn>>19)&0x3f) == 15)
133 return 2;
134 break;
135
136 default:
137 break;
138 }
139
140 memset(®s, 0, sizeof (regs));
141 regs.pc = pc;
142 regs.npc = pc + 4;
143 __asm__ __volatile__(
144 "rd %%psr, %0\n\t"
145 "nop\n\t"
146 "nop\n\t"
147 "nop\n" : "=r" (regs.psr));
148 unhandled_fault(address, current, ®s);
149
150 /* Not reached */
151 return 0;
152}
153
154static inline void
155show_signal_msg(struct pt_regs *regs, int sig, int code,
156 unsigned long address, struct task_struct *tsk)
157{
158 if (!unhandled_signal(tsk, sig))
159 return;
160
161 if (!printk_ratelimit())
162 return;
163
164 printk("%s%s[%d]: segfault at %lx ip %p (rpc %p) sp %p error %x",
165 task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG,
166 tsk->comm, task_pid_nr(tsk), address,
167 (void *)regs->pc, (void *)regs->u_regs[UREG_I7],
168 (void *)regs->u_regs[UREG_FP], code);
169
170 print_vma_addr(KERN_CONT " in ", regs->pc);
171
172 printk(KERN_CONT "\n");
173}
174
175static void __do_fault_siginfo(int code, int sig, struct pt_regs *regs,
176 unsigned long addr)
177{
178 siginfo_t info;
179
180 info.si_signo = sig;
181 info.si_code = code;
182 info.si_errno = 0;
183 info.si_addr = (void __user *) addr;
184 info.si_trapno = 0;
185
186 if (unlikely(show_unhandled_signals))
187 show_signal_msg(regs, sig, info.si_code,
188 addr, current);
189
190 force_sig_info (sig, &info, current);
191}
192
193extern unsigned long safe_compute_effective_address(struct pt_regs *,
194 unsigned int);
195
196static unsigned long compute_si_addr(struct pt_regs *regs, int text_fault)
197{
198 unsigned int insn;
199
200 if (text_fault)
201 return regs->pc;
202
203 if (regs->psr & PSR_PS) {
204 insn = *(unsigned int *) regs->pc;
205 } else {
206 __get_user(insn, (unsigned int *) regs->pc);
207 }
208
209 return safe_compute_effective_address(regs, insn);
210}
211
212static noinline void do_fault_siginfo(int code, int sig, struct pt_regs *regs,
213 int text_fault)
214{
215 unsigned long addr = compute_si_addr(regs, text_fault);
216
217 __do_fault_siginfo(code, sig, regs, addr);
218}
219
220asmlinkage void do_sparc_fault(struct pt_regs *regs, int text_fault, int write,
221 unsigned long address)
222{
223 struct vm_area_struct *vma;
224 struct task_struct *tsk = current;
225 struct mm_struct *mm = tsk->mm;
226 unsigned int fixup;
227 unsigned long g2;
228 int from_user = !(regs->psr & PSR_PS);
229 int fault, code;
230
231 if(text_fault)
232 address = regs->pc;
233
234 /*
235 * We fault-in kernel-space virtual memory on-demand. The
236 * 'reference' page table is init_mm.pgd.
237 *
238 * NOTE! We MUST NOT take any locks for this case. We may
239 * be in an interrupt or a critical region, and should
240 * only copy the information from the master page table,
241 * nothing more.
242 */
243 code = SEGV_MAPERR;
244 if (!ARCH_SUN4C && address >= TASK_SIZE)
245 goto vmalloc_fault;
246
247 /*
248 * If we're in an interrupt or have no user
249 * context, we must not take the fault..
250 */
251 if (in_atomic() || !mm)
252 goto no_context;
253
254 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
255
256 down_read(&mm->mmap_sem);
257
258 /*
259 * The kernel referencing a bad kernel pointer can lock up
260 * a sun4c machine completely, so we must attempt recovery.
261 */
262 if(!from_user && address >= PAGE_OFFSET)
263 goto bad_area;
264
265 vma = find_vma(mm, address);
266 if(!vma)
267 goto bad_area;
268 if(vma->vm_start <= address)
269 goto good_area;
270 if(!(vma->vm_flags & VM_GROWSDOWN))
271 goto bad_area;
272 if(expand_stack(vma, address))
273 goto bad_area;
274 /*
275 * Ok, we have a good vm_area for this memory access, so
276 * we can handle it..
277 */
278good_area:
279 code = SEGV_ACCERR;
280 if(write) {
281 if(!(vma->vm_flags & VM_WRITE))
282 goto bad_area;
283 } else {
284 /* Allow reads even for write-only mappings */
285 if(!(vma->vm_flags & (VM_READ | VM_EXEC)))
286 goto bad_area;
287 }
288
289 /*
290 * If for any reason at all we couldn't handle the fault,
291 * make sure we exit gracefully rather than endlessly redo
292 * the fault.
293 */
294 fault = handle_mm_fault(mm, vma, address, write ? FAULT_FLAG_WRITE : 0);
295 if (unlikely(fault & VM_FAULT_ERROR)) {
296 if (fault & VM_FAULT_OOM)
297 goto out_of_memory;
298 else if (fault & VM_FAULT_SIGBUS)
299 goto do_sigbus;
300 BUG();
301 }
302 if (fault & VM_FAULT_MAJOR) {
303 current->maj_flt++;
304 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, regs, address);
305 } else {
306 current->min_flt++;
307 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, regs, address);
308 }
309 up_read(&mm->mmap_sem);
310 return;
311
312 /*
313 * Something tried to access memory that isn't in our memory map..
314 * Fix it, but check if it's kernel or user first..
315 */
316bad_area:
317 up_read(&mm->mmap_sem);
318
319bad_area_nosemaphore:
320 /* User mode accesses just cause a SIGSEGV */
321 if (from_user) {
322 do_fault_siginfo(code, SIGSEGV, regs, text_fault);
323 return;
324 }
325
326 /* Is this in ex_table? */
327no_context:
328 g2 = regs->u_regs[UREG_G2];
329 if (!from_user) {
330 fixup = search_extables_range(regs->pc, &g2);
331 if (fixup > 10) { /* Values below are reserved for other things */
332 extern const unsigned __memset_start[];
333 extern const unsigned __memset_end[];
334 extern const unsigned __csum_partial_copy_start[];
335 extern const unsigned __csum_partial_copy_end[];
336
337#ifdef DEBUG_EXCEPTIONS
338 printk("Exception: PC<%08lx> faddr<%08lx>\n", regs->pc, address);
339 printk("EX_TABLE: insn<%08lx> fixup<%08x> g2<%08lx>\n",
340 regs->pc, fixup, g2);
341#endif
342 if ((regs->pc >= (unsigned long)__memset_start &&
343 regs->pc < (unsigned long)__memset_end) ||
344 (regs->pc >= (unsigned long)__csum_partial_copy_start &&
345 regs->pc < (unsigned long)__csum_partial_copy_end)) {
346 regs->u_regs[UREG_I4] = address;
347 regs->u_regs[UREG_I5] = regs->pc;
348 }
349 regs->u_regs[UREG_G2] = g2;
350 regs->pc = fixup;
351 regs->npc = regs->pc + 4;
352 return;
353 }
354 }
355
356 unhandled_fault (address, tsk, regs);
357 do_exit(SIGKILL);
358
359/*
360 * We ran out of memory, or some other thing happened to us that made
361 * us unable to handle the page fault gracefully.
362 */
363out_of_memory:
364 up_read(&mm->mmap_sem);
365 if (from_user) {
366 pagefault_out_of_memory();
367 return;
368 }
369 goto no_context;
370
371do_sigbus:
372 up_read(&mm->mmap_sem);
373 do_fault_siginfo(BUS_ADRERR, SIGBUS, regs, text_fault);
374 if (!from_user)
375 goto no_context;
376
377vmalloc_fault:
378 {
379 /*
380 * Synchronize this task's top level page-table
381 * with the 'reference' page table.
382 */
383 int offset = pgd_index(address);
384 pgd_t *pgd, *pgd_k;
385 pmd_t *pmd, *pmd_k;
386
387 pgd = tsk->active_mm->pgd + offset;
388 pgd_k = init_mm.pgd + offset;
389
390 if (!pgd_present(*pgd)) {
391 if (!pgd_present(*pgd_k))
392 goto bad_area_nosemaphore;
393 pgd_val(*pgd) = pgd_val(*pgd_k);
394 return;
395 }
396
397 pmd = pmd_offset(pgd, address);
398 pmd_k = pmd_offset(pgd_k, address);
399
400 if (pmd_present(*pmd) || !pmd_present(*pmd_k))
401 goto bad_area_nosemaphore;
402 *pmd = *pmd_k;
403 return;
404 }
405}
406
407asmlinkage void do_sun4c_fault(struct pt_regs *regs, int text_fault, int write,
408 unsigned long address)
409{
410 extern void sun4c_update_mmu_cache(struct vm_area_struct *,
411 unsigned long,pte_t *);
412 extern pte_t *sun4c_pte_offset_kernel(pmd_t *,unsigned long);
413 struct task_struct *tsk = current;
414 struct mm_struct *mm = tsk->mm;
415 pgd_t *pgdp;
416 pte_t *ptep;
417
418 if (text_fault) {
419 address = regs->pc;
420 } else if (!write &&
421 !(regs->psr & PSR_PS)) {
422 unsigned int insn, __user *ip;
423
424 ip = (unsigned int __user *)regs->pc;
425 if (!get_user(insn, ip)) {
426 if ((insn & 0xc1680000) == 0xc0680000)
427 write = 1;
428 }
429 }
430
431 if (!mm) {
432 /* We are oopsing. */
433 do_sparc_fault(regs, text_fault, write, address);
434 BUG(); /* P3 Oops already, you bitch */
435 }
436
437 pgdp = pgd_offset(mm, address);
438 ptep = sun4c_pte_offset_kernel((pmd_t *) pgdp, address);
439
440 if (pgd_val(*pgdp)) {
441 if (write) {
442 if ((pte_val(*ptep) & (_SUN4C_PAGE_WRITE|_SUN4C_PAGE_PRESENT))
443 == (_SUN4C_PAGE_WRITE|_SUN4C_PAGE_PRESENT)) {
444 unsigned long flags;
445
446 *ptep = __pte(pte_val(*ptep) | _SUN4C_PAGE_ACCESSED |
447 _SUN4C_PAGE_MODIFIED |
448 _SUN4C_PAGE_VALID |
449 _SUN4C_PAGE_DIRTY);
450
451 local_irq_save(flags);
452 if (sun4c_get_segmap(address) != invalid_segment) {
453 sun4c_put_pte(address, pte_val(*ptep));
454 local_irq_restore(flags);
455 return;
456 }
457 local_irq_restore(flags);
458 }
459 } else {
460 if ((pte_val(*ptep) & (_SUN4C_PAGE_READ|_SUN4C_PAGE_PRESENT))
461 == (_SUN4C_PAGE_READ|_SUN4C_PAGE_PRESENT)) {
462 unsigned long flags;
463
464 *ptep = __pte(pte_val(*ptep) | _SUN4C_PAGE_ACCESSED |
465 _SUN4C_PAGE_VALID);
466
467 local_irq_save(flags);
468 if (sun4c_get_segmap(address) != invalid_segment) {
469 sun4c_put_pte(address, pte_val(*ptep));
470 local_irq_restore(flags);
471 return;
472 }
473 local_irq_restore(flags);
474 }
475 }
476 }
477
478 /* This conditional is 'interesting'. */
479 if (pgd_val(*pgdp) && !(write && !(pte_val(*ptep) & _SUN4C_PAGE_WRITE))
480 && (pte_val(*ptep) & _SUN4C_PAGE_VALID))
481 /* Note: It is safe to not grab the MMAP semaphore here because
482 * we know that update_mmu_cache() will not sleep for
483 * any reason (at least not in the current implementation)
484 * and therefore there is no danger of another thread getting
485 * on the CPU and doing a shrink_mmap() on this vma.
486 */
487 sun4c_update_mmu_cache (find_vma(current->mm, address), address,
488 ptep);
489 else
490 do_sparc_fault(regs, text_fault, write, address);
491}
492
493/* This always deals with user addresses. */
494static void force_user_fault(unsigned long address, int write)
495{
496 struct vm_area_struct *vma;
497 struct task_struct *tsk = current;
498 struct mm_struct *mm = tsk->mm;
499 int code;
500
501 code = SEGV_MAPERR;
502
503 down_read(&mm->mmap_sem);
504 vma = find_vma(mm, address);
505 if(!vma)
506 goto bad_area;
507 if(vma->vm_start <= address)
508 goto good_area;
509 if(!(vma->vm_flags & VM_GROWSDOWN))
510 goto bad_area;
511 if(expand_stack(vma, address))
512 goto bad_area;
513good_area:
514 code = SEGV_ACCERR;
515 if(write) {
516 if(!(vma->vm_flags & VM_WRITE))
517 goto bad_area;
518 } else {
519 if(!(vma->vm_flags & (VM_READ | VM_EXEC)))
520 goto bad_area;
521 }
522 switch (handle_mm_fault(mm, vma, address, write ? FAULT_FLAG_WRITE : 0)) {
523 case VM_FAULT_SIGBUS:
524 case VM_FAULT_OOM:
525 goto do_sigbus;
526 }
527 up_read(&mm->mmap_sem);
528 return;
529bad_area:
530 up_read(&mm->mmap_sem);
531 __do_fault_siginfo(code, SIGSEGV, tsk->thread.kregs, address);
532 return;
533
534do_sigbus:
535 up_read(&mm->mmap_sem);
536 __do_fault_siginfo(BUS_ADRERR, SIGBUS, tsk->thread.kregs, address);
537}
538
539static void check_stack_aligned(unsigned long sp)
540{
541 if (sp & 0x7UL)
542 force_sig(SIGILL, current);
543}
544
545void window_overflow_fault(void)
546{
547 unsigned long sp;
548
549 sp = current_thread_info()->rwbuf_stkptrs[0];
550 if(((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK))
551 force_user_fault(sp + 0x38, 1);
552 force_user_fault(sp, 1);
553
554 check_stack_aligned(sp);
555}
556
557void window_underflow_fault(unsigned long sp)
558{
559 if(((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK))
560 force_user_fault(sp + 0x38, 0);
561 force_user_fault(sp, 0);
562
563 check_stack_aligned(sp);
564}
565
566void window_ret_fault(struct pt_regs *regs)
567{
568 unsigned long sp;
569
570 sp = regs->u_regs[UREG_FP];
571 if(((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK))
572 force_user_fault(sp + 0x38, 0);
573 force_user_fault(sp, 0);
574
575 check_stack_aligned(sp);
576}
1/*
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>
21#include <linux/perf_event.h>
22#include <linux/interrupt.h>
23#include <linux/kdebug.h>
24#include <linux/uaccess.h>
25
26#include <asm/page.h>
27#include <asm/pgtable.h>
28#include <asm/openprom.h>
29#include <asm/oplib.h>
30#include <asm/setup.h>
31#include <asm/smp.h>
32#include <asm/traps.h>
33
34#include "mm_32.h"
35
36int show_unhandled_signals = 1;
37
38static void __noreturn unhandled_fault(unsigned long address,
39 struct task_struct *tsk,
40 struct pt_regs *regs)
41{
42 if ((unsigned long) address < PAGE_SIZE) {
43 printk(KERN_ALERT
44 "Unable to handle kernel NULL pointer dereference\n");
45 } else {
46 printk(KERN_ALERT "Unable to handle kernel paging request at virtual address %08lx\n",
47 address);
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 :
53 (unsigned long) tsk->active_mm->pgd));
54 die_if_kernel("Oops", regs);
55}
56
57asmlinkage int lookup_fault(unsigned long pc, unsigned long ret_pc,
58 unsigned long address)
59{
60 struct pt_regs regs;
61 unsigned long g2;
62 unsigned int insn;
63 int i;
64
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)
84 return 2;
85 break;
86
87 default:
88 break;
89 }
90
91 memset(®s, 0, sizeof(regs));
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
105static inline void
106show_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
126static 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
144static 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
151 if (regs->psr & PSR_PS)
152 insn = *(unsigned int *) regs->pc;
153 else
154 __get_user(insn, (unsigned int *) regs->pc);
155
156 return safe_compute_effective_address(regs, insn);
157}
158
159static 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
167asmlinkage 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;
175 int from_user = !(regs->psr & PSR_PS);
176 int fault, code;
177 unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
178
179 if (text_fault)
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 */
191 code = SEGV_MAPERR;
192 if (address >= TASK_SIZE)
193 goto vmalloc_fault;
194
195 /*
196 * If we're in an interrupt or have no user
197 * context, we must not take the fault..
198 */
199 if (pagefault_disabled() || !mm)
200 goto no_context;
201
202 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
203
204retry:
205 down_read(&mm->mmap_sem);
206
207 if (!from_user && address >= PAGE_OFFSET)
208 goto bad_area;
209
210 vma = find_vma(mm, address);
211 if (!vma)
212 goto bad_area;
213 if (vma->vm_start <= address)
214 goto good_area;
215 if (!(vma->vm_flags & VM_GROWSDOWN))
216 goto bad_area;
217 if (expand_stack(vma, address))
218 goto bad_area;
219 /*
220 * Ok, we have a good vm_area for this memory access, so
221 * we can handle it..
222 */
223good_area:
224 code = SEGV_ACCERR;
225 if (write) {
226 if (!(vma->vm_flags & VM_WRITE))
227 goto bad_area;
228 } else {
229 /* Allow reads even for write-only mappings */
230 if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
231 goto bad_area;
232 }
233
234 if (from_user)
235 flags |= FAULT_FLAG_USER;
236 if (write)
237 flags |= FAULT_FLAG_WRITE;
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 */
244 fault = handle_mm_fault(vma, address, flags);
245
246 if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
247 return;
248
249 if (unlikely(fault & VM_FAULT_ERROR)) {
250 if (fault & VM_FAULT_OOM)
251 goto out_of_memory;
252 else if (fault & VM_FAULT_SIGSEGV)
253 goto bad_area;
254 else if (fault & VM_FAULT_SIGBUS)
255 goto do_sigbus;
256 BUG();
257 }
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;
271 flags |= FAULT_FLAG_TRIED;
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 }
280 }
281
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 */
289bad_area:
290 up_read(&mm->mmap_sem);
291
292bad_area_nosemaphore:
293 /* User mode accesses just cause a SIGSEGV */
294 if (from_user) {
295 do_fault_siginfo(code, SIGSEGV, regs, text_fault);
296 return;
297 }
298
299 /* Is this in ex_table? */
300no_context:
301 g2 = regs->u_regs[UREG_G2];
302 if (!from_user) {
303 fixup = search_extables_range(regs->pc, &g2);
304 /* Values below 10 are reserved for other things */
305 if (fixup > 10) {
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[];
310
311#ifdef DEBUG_EXCEPTIONS
312 printk("Exception: PC<%08lx> faddr<%08lx>\n",
313 regs->pc, address);
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)) {
321 regs->u_regs[UREG_I4] = address;
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 }
330
331 unhandled_fault(address, tsk, regs);
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 */
338out_of_memory:
339 up_read(&mm->mmap_sem);
340 if (from_user) {
341 pagefault_out_of_memory();
342 return;
343 }
344 goto no_context;
345
346do_sigbus:
347 up_read(&mm->mmap_sem);
348 do_fault_siginfo(BUS_ADRERR, SIGBUS, regs, text_fault);
349 if (!from_user)
350 goto no_context;
351
352vmalloc_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;
377
378 *pmd = *pmd_k;
379 return;
380 }
381}
382
383/* This always deals with user addresses. */
384static void force_user_fault(unsigned long address, int write)
385{
386 struct vm_area_struct *vma;
387 struct task_struct *tsk = current;
388 struct mm_struct *mm = tsk->mm;
389 unsigned int flags = FAULT_FLAG_USER;
390 int code;
391
392 code = SEGV_MAPERR;
393
394 down_read(&mm->mmap_sem);
395 vma = find_vma(mm, address);
396 if (!vma)
397 goto bad_area;
398 if (vma->vm_start <= address)
399 goto good_area;
400 if (!(vma->vm_flags & VM_GROWSDOWN))
401 goto bad_area;
402 if (expand_stack(vma, address))
403 goto bad_area;
404good_area:
405 code = SEGV_ACCERR;
406 if (write) {
407 if (!(vma->vm_flags & VM_WRITE))
408 goto bad_area;
409 flags |= FAULT_FLAG_WRITE;
410 } else {
411 if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
412 goto bad_area;
413 }
414 switch (handle_mm_fault(vma, address, flags)) {
415 case VM_FAULT_SIGBUS:
416 case VM_FAULT_OOM:
417 goto do_sigbus;
418 }
419 up_read(&mm->mmap_sem);
420 return;
421bad_area:
422 up_read(&mm->mmap_sem);
423 __do_fault_siginfo(code, SIGSEGV, tsk->thread.kregs, address);
424 return;
425
426do_sigbus:
427 up_read(&mm->mmap_sem);
428 __do_fault_siginfo(BUS_ADRERR, SIGBUS, tsk->thread.kregs, address);
429}
430
431static void check_stack_aligned(unsigned long sp)
432{
433 if (sp & 0x7UL)
434 force_sig(SIGILL, current);
435}
436
437void window_overflow_fault(void)
438{
439 unsigned long sp;
440
441 sp = current_thread_info()->rwbuf_stkptrs[0];
442 if (((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK))
443 force_user_fault(sp + 0x38, 1);
444 force_user_fault(sp, 1);
445
446 check_stack_aligned(sp);
447}
448
449void window_underflow_fault(unsigned long sp)
450{
451 if (((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK))
452 force_user_fault(sp + 0x38, 0);
453 force_user_fault(sp, 0);
454
455 check_stack_aligned(sp);
456}
457
458void window_ret_fault(struct pt_regs *regs)
459{
460 unsigned long sp;
461
462 sp = regs->u_regs[UREG_FP];
463 if (((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK))
464 force_user_fault(sp + 0x38, 0);
465 force_user_fault(sp, 0);
466
467 check_stack_aligned(sp);
468}