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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// SPDX-License-Identifier: GPL-2.0
2/*
3 * fault.c: Page fault handlers for the Sparc.
4 *
5 * Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
6 * Copyright (C) 1996 Eddie C. Dost (ecd@skynet.be)
7 * Copyright (C) 1997 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
8 */
9
10#include <asm/head.h>
11
12#include <linux/string.h>
13#include <linux/types.h>
14#include <linux/sched.h>
15#include <linux/ptrace.h>
16#include <linux/mman.h>
17#include <linux/threads.h>
18#include <linux/kernel.h>
19#include <linux/signal.h>
20#include <linux/mm.h>
21#include <linux/smp.h>
22#include <linux/perf_event.h>
23#include <linux/interrupt.h>
24#include <linux/kdebug.h>
25#include <linux/uaccess.h>
26
27#include <asm/page.h>
28#include <asm/pgtable.h>
29#include <asm/openprom.h>
30#include <asm/oplib.h>
31#include <asm/setup.h>
32#include <asm/smp.h>
33#include <asm/traps.h>
34
35#include "mm_32.h"
36
37int show_unhandled_signals = 1;
38
39static void __noreturn unhandled_fault(unsigned long address,
40 struct task_struct *tsk,
41 struct pt_regs *regs)
42{
43 if ((unsigned long) address < PAGE_SIZE) {
44 printk(KERN_ALERT
45 "Unable to handle kernel NULL pointer dereference\n");
46 } else {
47 printk(KERN_ALERT "Unable to handle kernel paging request at virtual address %08lx\n",
48 address);
49 }
50 printk(KERN_ALERT "tsk->{mm,active_mm}->context = %08lx\n",
51 (tsk->mm ? tsk->mm->context : tsk->active_mm->context));
52 printk(KERN_ALERT "tsk->{mm,active_mm}->pgd = %08lx\n",
53 (tsk->mm ? (unsigned long) tsk->mm->pgd :
54 (unsigned long) tsk->active_mm->pgd));
55 die_if_kernel("Oops", regs);
56}
57
58asmlinkage int lookup_fault(unsigned long pc, unsigned long ret_pc,
59 unsigned long address)
60{
61 struct pt_regs regs;
62 unsigned long g2;
63 unsigned int insn;
64 int i;
65
66 i = search_extables_range(ret_pc, &g2);
67 switch (i) {
68 case 3:
69 /* load & store will be handled by fixup */
70 return 3;
71
72 case 1:
73 /* store will be handled by fixup, load will bump out */
74 /* for _to_ macros */
75 insn = *((unsigned int *) pc);
76 if ((insn >> 21) & 1)
77 return 1;
78 break;
79
80 case 2:
81 /* load will be handled by fixup, store will bump out */
82 /* for _from_ macros */
83 insn = *((unsigned int *) pc);
84 if (!((insn >> 21) & 1) || ((insn>>19)&0x3f) == 15)
85 return 2;
86 break;
87
88 default:
89 break;
90 }
91
92 memset(®s, 0, sizeof(regs));
93 regs.pc = pc;
94 regs.npc = pc + 4;
95 __asm__ __volatile__(
96 "rd %%psr, %0\n\t"
97 "nop\n\t"
98 "nop\n\t"
99 "nop\n" : "=r" (regs.psr));
100 unhandled_fault(address, current, ®s);
101
102 /* Not reached */
103 return 0;
104}
105
106static inline void
107show_signal_msg(struct pt_regs *regs, int sig, int code,
108 unsigned long address, struct task_struct *tsk)
109{
110 if (!unhandled_signal(tsk, sig))
111 return;
112
113 if (!printk_ratelimit())
114 return;
115
116 printk("%s%s[%d]: segfault at %lx ip %px (rpc %px) sp %px error %x",
117 task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG,
118 tsk->comm, task_pid_nr(tsk), address,
119 (void *)regs->pc, (void *)regs->u_regs[UREG_I7],
120 (void *)regs->u_regs[UREG_FP], code);
121
122 print_vma_addr(KERN_CONT " in ", regs->pc);
123
124 printk(KERN_CONT "\n");
125}
126
127static void __do_fault_siginfo(int code, int sig, struct pt_regs *regs,
128 unsigned long addr)
129{
130 if (unlikely(show_unhandled_signals))
131 show_signal_msg(regs, sig, code,
132 addr, current);
133
134 force_sig_fault(sig, code, (void __user *) addr, 0);
135}
136
137static unsigned long compute_si_addr(struct pt_regs *regs, int text_fault)
138{
139 unsigned int insn;
140
141 if (text_fault)
142 return regs->pc;
143
144 if (regs->psr & PSR_PS)
145 insn = *(unsigned int *) regs->pc;
146 else
147 __get_user(insn, (unsigned int *) regs->pc);
148
149 return safe_compute_effective_address(regs, insn);
150}
151
152static noinline void do_fault_siginfo(int code, int sig, struct pt_regs *regs,
153 int text_fault)
154{
155 unsigned long addr = compute_si_addr(regs, text_fault);
156
157 __do_fault_siginfo(code, sig, regs, addr);
158}
159
160asmlinkage void do_sparc_fault(struct pt_regs *regs, int text_fault, int write,
161 unsigned long address)
162{
163 struct vm_area_struct *vma;
164 struct task_struct *tsk = current;
165 struct mm_struct *mm = tsk->mm;
166 unsigned int fixup;
167 unsigned long g2;
168 int from_user = !(regs->psr & PSR_PS);
169 int code;
170 vm_fault_t fault;
171 unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
172
173 if (text_fault)
174 address = regs->pc;
175
176 /*
177 * We fault-in kernel-space virtual memory on-demand. The
178 * 'reference' page table is init_mm.pgd.
179 *
180 * NOTE! We MUST NOT take any locks for this case. We may
181 * be in an interrupt or a critical region, and should
182 * only copy the information from the master page table,
183 * nothing more.
184 */
185 code = SEGV_MAPERR;
186 if (address >= TASK_SIZE)
187 goto vmalloc_fault;
188
189 /*
190 * If we're in an interrupt or have no user
191 * context, we must not take the fault..
192 */
193 if (pagefault_disabled() || !mm)
194 goto no_context;
195
196 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
197
198retry:
199 down_read(&mm->mmap_sem);
200
201 if (!from_user && address >= PAGE_OFFSET)
202 goto bad_area;
203
204 vma = find_vma(mm, address);
205 if (!vma)
206 goto bad_area;
207 if (vma->vm_start <= address)
208 goto good_area;
209 if (!(vma->vm_flags & VM_GROWSDOWN))
210 goto bad_area;
211 if (expand_stack(vma, address))
212 goto bad_area;
213 /*
214 * Ok, we have a good vm_area for this memory access, so
215 * we can handle it..
216 */
217good_area:
218 code = SEGV_ACCERR;
219 if (write) {
220 if (!(vma->vm_flags & VM_WRITE))
221 goto bad_area;
222 } else {
223 /* Allow reads even for write-only mappings */
224 if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
225 goto bad_area;
226 }
227
228 if (from_user)
229 flags |= FAULT_FLAG_USER;
230 if (write)
231 flags |= FAULT_FLAG_WRITE;
232
233 /*
234 * If for any reason at all we couldn't handle the fault,
235 * make sure we exit gracefully rather than endlessly redo
236 * the fault.
237 */
238 fault = handle_mm_fault(vma, address, flags);
239
240 if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
241 return;
242
243 if (unlikely(fault & VM_FAULT_ERROR)) {
244 if (fault & VM_FAULT_OOM)
245 goto out_of_memory;
246 else if (fault & VM_FAULT_SIGSEGV)
247 goto bad_area;
248 else if (fault & VM_FAULT_SIGBUS)
249 goto do_sigbus;
250 BUG();
251 }
252
253 if (flags & FAULT_FLAG_ALLOW_RETRY) {
254 if (fault & VM_FAULT_MAJOR) {
255 current->maj_flt++;
256 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ,
257 1, regs, address);
258 } else {
259 current->min_flt++;
260 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN,
261 1, regs, address);
262 }
263 if (fault & VM_FAULT_RETRY) {
264 flags &= ~FAULT_FLAG_ALLOW_RETRY;
265 flags |= FAULT_FLAG_TRIED;
266
267 /* No need to up_read(&mm->mmap_sem) as we would
268 * have already released it in __lock_page_or_retry
269 * in mm/filemap.c.
270 */
271
272 goto retry;
273 }
274 }
275
276 up_read(&mm->mmap_sem);
277 return;
278
279 /*
280 * Something tried to access memory that isn't in our memory map..
281 * Fix it, but check if it's kernel or user first..
282 */
283bad_area:
284 up_read(&mm->mmap_sem);
285
286bad_area_nosemaphore:
287 /* User mode accesses just cause a SIGSEGV */
288 if (from_user) {
289 do_fault_siginfo(code, SIGSEGV, regs, text_fault);
290 return;
291 }
292
293 /* Is this in ex_table? */
294no_context:
295 g2 = regs->u_regs[UREG_G2];
296 if (!from_user) {
297 fixup = search_extables_range(regs->pc, &g2);
298 /* Values below 10 are reserved for other things */
299 if (fixup > 10) {
300 extern const unsigned int __memset_start[];
301 extern const unsigned int __memset_end[];
302 extern const unsigned int __csum_partial_copy_start[];
303 extern const unsigned int __csum_partial_copy_end[];
304
305#ifdef DEBUG_EXCEPTIONS
306 printk("Exception: PC<%08lx> faddr<%08lx>\n",
307 regs->pc, address);
308 printk("EX_TABLE: insn<%08lx> fixup<%08x> g2<%08lx>\n",
309 regs->pc, fixup, g2);
310#endif
311 if ((regs->pc >= (unsigned long)__memset_start &&
312 regs->pc < (unsigned long)__memset_end) ||
313 (regs->pc >= (unsigned long)__csum_partial_copy_start &&
314 regs->pc < (unsigned long)__csum_partial_copy_end)) {
315 regs->u_regs[UREG_I4] = address;
316 regs->u_regs[UREG_I5] = regs->pc;
317 }
318 regs->u_regs[UREG_G2] = g2;
319 regs->pc = fixup;
320 regs->npc = regs->pc + 4;
321 return;
322 }
323 }
324
325 unhandled_fault(address, tsk, regs);
326 do_exit(SIGKILL);
327
328/*
329 * We ran out of memory, or some other thing happened to us that made
330 * us unable to handle the page fault gracefully.
331 */
332out_of_memory:
333 up_read(&mm->mmap_sem);
334 if (from_user) {
335 pagefault_out_of_memory();
336 return;
337 }
338 goto no_context;
339
340do_sigbus:
341 up_read(&mm->mmap_sem);
342 do_fault_siginfo(BUS_ADRERR, SIGBUS, regs, text_fault);
343 if (!from_user)
344 goto no_context;
345
346vmalloc_fault:
347 {
348 /*
349 * Synchronize this task's top level page-table
350 * with the 'reference' page table.
351 */
352 int offset = pgd_index(address);
353 pgd_t *pgd, *pgd_k;
354 pmd_t *pmd, *pmd_k;
355
356 pgd = tsk->active_mm->pgd + offset;
357 pgd_k = init_mm.pgd + offset;
358
359 if (!pgd_present(*pgd)) {
360 if (!pgd_present(*pgd_k))
361 goto bad_area_nosemaphore;
362 pgd_val(*pgd) = pgd_val(*pgd_k);
363 return;
364 }
365
366 pmd = pmd_offset(pgd, address);
367 pmd_k = pmd_offset(pgd_k, address);
368
369 if (pmd_present(*pmd) || !pmd_present(*pmd_k))
370 goto bad_area_nosemaphore;
371
372 *pmd = *pmd_k;
373 return;
374 }
375}
376
377/* This always deals with user addresses. */
378static void force_user_fault(unsigned long address, int write)
379{
380 struct vm_area_struct *vma;
381 struct task_struct *tsk = current;
382 struct mm_struct *mm = tsk->mm;
383 unsigned int flags = FAULT_FLAG_USER;
384 int code;
385
386 code = SEGV_MAPERR;
387
388 down_read(&mm->mmap_sem);
389 vma = find_vma(mm, address);
390 if (!vma)
391 goto bad_area;
392 if (vma->vm_start <= address)
393 goto good_area;
394 if (!(vma->vm_flags & VM_GROWSDOWN))
395 goto bad_area;
396 if (expand_stack(vma, address))
397 goto bad_area;
398good_area:
399 code = SEGV_ACCERR;
400 if (write) {
401 if (!(vma->vm_flags & VM_WRITE))
402 goto bad_area;
403 flags |= FAULT_FLAG_WRITE;
404 } else {
405 if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
406 goto bad_area;
407 }
408 switch (handle_mm_fault(vma, address, flags)) {
409 case VM_FAULT_SIGBUS:
410 case VM_FAULT_OOM:
411 goto do_sigbus;
412 }
413 up_read(&mm->mmap_sem);
414 return;
415bad_area:
416 up_read(&mm->mmap_sem);
417 __do_fault_siginfo(code, SIGSEGV, tsk->thread.kregs, address);
418 return;
419
420do_sigbus:
421 up_read(&mm->mmap_sem);
422 __do_fault_siginfo(BUS_ADRERR, SIGBUS, tsk->thread.kregs, address);
423}
424
425static void check_stack_aligned(unsigned long sp)
426{
427 if (sp & 0x7UL)
428 force_sig(SIGILL);
429}
430
431void window_overflow_fault(void)
432{
433 unsigned long sp;
434
435 sp = current_thread_info()->rwbuf_stkptrs[0];
436 if (((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK))
437 force_user_fault(sp + 0x38, 1);
438 force_user_fault(sp, 1);
439
440 check_stack_aligned(sp);
441}
442
443void window_underflow_fault(unsigned long sp)
444{
445 if (((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK))
446 force_user_fault(sp + 0x38, 0);
447 force_user_fault(sp, 0);
448
449 check_stack_aligned(sp);
450}
451
452void window_ret_fault(struct pt_regs *regs)
453{
454 unsigned long sp;
455
456 sp = regs->u_regs[UREG_FP];
457 if (((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK))
458 force_user_fault(sp + 0x38, 0);
459 force_user_fault(sp, 0);
460
461 check_stack_aligned(sp);
462}