Linux 4.13.16
[linux/fpc-iii.git] / arch / sh / mm / fault.c
blob6fd1bf7481c7d83674d76fe66dbdc1f89f74c2ee
1 /*
2 * Page fault handler for SH with an MMU.
4 * Copyright (C) 1999 Niibe Yutaka
5 * Copyright (C) 2003 - 2012 Paul Mundt
7 * Based on linux/arch/i386/mm/fault.c:
8 * Copyright (C) 1995 Linus Torvalds
10 * This file is subject to the terms and conditions of the GNU General Public
11 * License. See the file "COPYING" in the main directory of this archive
12 * for more details.
14 #include <linux/kernel.h>
15 #include <linux/mm.h>
16 #include <linux/sched/signal.h>
17 #include <linux/hardirq.h>
18 #include <linux/kprobes.h>
19 #include <linux/perf_event.h>
20 #include <linux/kdebug.h>
21 #include <linux/uaccess.h>
22 #include <asm/io_trapped.h>
23 #include <asm/mmu_context.h>
24 #include <asm/tlbflush.h>
25 #include <asm/traps.h>
27 static inline int notify_page_fault(struct pt_regs *regs, int trap)
29 int ret = 0;
31 if (kprobes_built_in() && !user_mode(regs)) {
32 preempt_disable();
33 if (kprobe_running() && kprobe_fault_handler(regs, trap))
34 ret = 1;
35 preempt_enable();
38 return ret;
41 static void
42 force_sig_info_fault(int si_signo, int si_code, unsigned long address,
43 struct task_struct *tsk)
45 siginfo_t info;
47 info.si_signo = si_signo;
48 info.si_errno = 0;
49 info.si_code = si_code;
50 info.si_addr = (void __user *)address;
52 force_sig_info(si_signo, &info, tsk);
56 * This is useful to dump out the page tables associated with
57 * 'addr' in mm 'mm'.
59 static void show_pte(struct mm_struct *mm, unsigned long addr)
61 pgd_t *pgd;
63 if (mm) {
64 pgd = mm->pgd;
65 } else {
66 pgd = get_TTB();
68 if (unlikely(!pgd))
69 pgd = swapper_pg_dir;
72 printk(KERN_ALERT "pgd = %p\n", pgd);
73 pgd += pgd_index(addr);
74 printk(KERN_ALERT "[%08lx] *pgd=%0*Lx", addr,
75 (u32)(sizeof(*pgd) * 2), (u64)pgd_val(*pgd));
77 do {
78 pud_t *pud;
79 pmd_t *pmd;
80 pte_t *pte;
82 if (pgd_none(*pgd))
83 break;
85 if (pgd_bad(*pgd)) {
86 printk("(bad)");
87 break;
90 pud = pud_offset(pgd, addr);
91 if (PTRS_PER_PUD != 1)
92 printk(", *pud=%0*Lx", (u32)(sizeof(*pud) * 2),
93 (u64)pud_val(*pud));
95 if (pud_none(*pud))
96 break;
98 if (pud_bad(*pud)) {
99 printk("(bad)");
100 break;
103 pmd = pmd_offset(pud, addr);
104 if (PTRS_PER_PMD != 1)
105 printk(", *pmd=%0*Lx", (u32)(sizeof(*pmd) * 2),
106 (u64)pmd_val(*pmd));
108 if (pmd_none(*pmd))
109 break;
111 if (pmd_bad(*pmd)) {
112 printk("(bad)");
113 break;
116 /* We must not map this if we have highmem enabled */
117 if (PageHighMem(pfn_to_page(pmd_val(*pmd) >> PAGE_SHIFT)))
118 break;
120 pte = pte_offset_kernel(pmd, addr);
121 printk(", *pte=%0*Lx", (u32)(sizeof(*pte) * 2),
122 (u64)pte_val(*pte));
123 } while (0);
125 printk("\n");
128 static inline pmd_t *vmalloc_sync_one(pgd_t *pgd, unsigned long address)
130 unsigned index = pgd_index(address);
131 pgd_t *pgd_k;
132 pud_t *pud, *pud_k;
133 pmd_t *pmd, *pmd_k;
135 pgd += index;
136 pgd_k = init_mm.pgd + index;
138 if (!pgd_present(*pgd_k))
139 return NULL;
141 pud = pud_offset(pgd, address);
142 pud_k = pud_offset(pgd_k, address);
143 if (!pud_present(*pud_k))
144 return NULL;
146 if (!pud_present(*pud))
147 set_pud(pud, *pud_k);
149 pmd = pmd_offset(pud, address);
150 pmd_k = pmd_offset(pud_k, address);
151 if (!pmd_present(*pmd_k))
152 return NULL;
154 if (!pmd_present(*pmd))
155 set_pmd(pmd, *pmd_k);
156 else {
158 * The page tables are fully synchronised so there must
159 * be another reason for the fault. Return NULL here to
160 * signal that we have not taken care of the fault.
162 BUG_ON(pmd_page(*pmd) != pmd_page(*pmd_k));
163 return NULL;
166 return pmd_k;
169 #ifdef CONFIG_SH_STORE_QUEUES
170 #define __FAULT_ADDR_LIMIT P3_ADDR_MAX
171 #else
172 #define __FAULT_ADDR_LIMIT VMALLOC_END
173 #endif
176 * Handle a fault on the vmalloc or module mapping area
178 static noinline int vmalloc_fault(unsigned long address)
180 pgd_t *pgd_k;
181 pmd_t *pmd_k;
182 pte_t *pte_k;
184 /* Make sure we are in vmalloc/module/P3 area: */
185 if (!(address >= VMALLOC_START && address < __FAULT_ADDR_LIMIT))
186 return -1;
189 * Synchronize this task's top level page-table
190 * with the 'reference' page table.
192 * Do _not_ use "current" here. We might be inside
193 * an interrupt in the middle of a task switch..
195 pgd_k = get_TTB();
196 pmd_k = vmalloc_sync_one(pgd_k, address);
197 if (!pmd_k)
198 return -1;
200 pte_k = pte_offset_kernel(pmd_k, address);
201 if (!pte_present(*pte_k))
202 return -1;
204 return 0;
207 static void
208 show_fault_oops(struct pt_regs *regs, unsigned long address)
210 if (!oops_may_print())
211 return;
213 printk(KERN_ALERT "BUG: unable to handle kernel ");
214 if (address < PAGE_SIZE)
215 printk(KERN_CONT "NULL pointer dereference");
216 else
217 printk(KERN_CONT "paging request");
219 printk(KERN_CONT " at %08lx\n", address);
220 printk(KERN_ALERT "PC:");
221 printk_address(regs->pc, 1);
223 show_pte(NULL, address);
226 static noinline void
227 no_context(struct pt_regs *regs, unsigned long error_code,
228 unsigned long address)
230 /* Are we prepared to handle this kernel fault? */
231 if (fixup_exception(regs))
232 return;
234 if (handle_trapped_io(regs, address))
235 return;
238 * Oops. The kernel tried to access some bad page. We'll have to
239 * terminate things with extreme prejudice.
241 bust_spinlocks(1);
243 show_fault_oops(regs, address);
245 die("Oops", regs, error_code);
246 bust_spinlocks(0);
247 do_exit(SIGKILL);
250 static void
251 __bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
252 unsigned long address, int si_code)
254 struct task_struct *tsk = current;
256 /* User mode accesses just cause a SIGSEGV */
257 if (user_mode(regs)) {
259 * It's possible to have interrupts off here:
261 local_irq_enable();
263 force_sig_info_fault(SIGSEGV, si_code, address, tsk);
265 return;
268 no_context(regs, error_code, address);
271 static noinline void
272 bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
273 unsigned long address)
275 __bad_area_nosemaphore(regs, error_code, address, SEGV_MAPERR);
278 static void
279 __bad_area(struct pt_regs *regs, unsigned long error_code,
280 unsigned long address, int si_code)
282 struct mm_struct *mm = current->mm;
285 * Something tried to access memory that isn't in our memory map..
286 * Fix it, but check if it's kernel or user first..
288 up_read(&mm->mmap_sem);
290 __bad_area_nosemaphore(regs, error_code, address, si_code);
293 static noinline void
294 bad_area(struct pt_regs *regs, unsigned long error_code, unsigned long address)
296 __bad_area(regs, error_code, address, SEGV_MAPERR);
299 static noinline void
300 bad_area_access_error(struct pt_regs *regs, unsigned long error_code,
301 unsigned long address)
303 __bad_area(regs, error_code, address, SEGV_ACCERR);
306 static void
307 do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address)
309 struct task_struct *tsk = current;
310 struct mm_struct *mm = tsk->mm;
312 up_read(&mm->mmap_sem);
314 /* Kernel mode? Handle exceptions or die: */
315 if (!user_mode(regs))
316 no_context(regs, error_code, address);
318 force_sig_info_fault(SIGBUS, BUS_ADRERR, address, tsk);
321 static noinline int
322 mm_fault_error(struct pt_regs *regs, unsigned long error_code,
323 unsigned long address, unsigned int fault)
326 * Pagefault was interrupted by SIGKILL. We have no reason to
327 * continue pagefault.
329 if (fatal_signal_pending(current)) {
330 if (!(fault & VM_FAULT_RETRY))
331 up_read(&current->mm->mmap_sem);
332 if (!user_mode(regs))
333 no_context(regs, error_code, address);
334 return 1;
337 if (!(fault & VM_FAULT_ERROR))
338 return 0;
340 if (fault & VM_FAULT_OOM) {
341 /* Kernel mode? Handle exceptions or die: */
342 if (!user_mode(regs)) {
343 up_read(&current->mm->mmap_sem);
344 no_context(regs, error_code, address);
345 return 1;
347 up_read(&current->mm->mmap_sem);
350 * We ran out of memory, call the OOM killer, and return the
351 * userspace (which will retry the fault, or kill us if we got
352 * oom-killed):
354 pagefault_out_of_memory();
355 } else {
356 if (fault & VM_FAULT_SIGBUS)
357 do_sigbus(regs, error_code, address);
358 else if (fault & VM_FAULT_SIGSEGV)
359 bad_area(regs, error_code, address);
360 else
361 BUG();
364 return 1;
367 static inline int access_error(int error_code, struct vm_area_struct *vma)
369 if (error_code & FAULT_CODE_WRITE) {
370 /* write, present and write, not present: */
371 if (unlikely(!(vma->vm_flags & VM_WRITE)))
372 return 1;
373 return 0;
376 /* ITLB miss on NX page */
377 if (unlikely((error_code & FAULT_CODE_ITLB) &&
378 !(vma->vm_flags & VM_EXEC)))
379 return 1;
381 /* read, not present: */
382 if (unlikely(!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE))))
383 return 1;
385 return 0;
388 static int fault_in_kernel_space(unsigned long address)
390 return address >= TASK_SIZE;
394 * This routine handles page faults. It determines the address,
395 * and the problem, and then passes it off to one of the appropriate
396 * routines.
398 asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
399 unsigned long error_code,
400 unsigned long address)
402 unsigned long vec;
403 struct task_struct *tsk;
404 struct mm_struct *mm;
405 struct vm_area_struct * vma;
406 int fault;
407 unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
409 tsk = current;
410 mm = tsk->mm;
411 vec = lookup_exception_vector();
414 * We fault-in kernel-space virtual memory on-demand. The
415 * 'reference' page table is init_mm.pgd.
417 * NOTE! We MUST NOT take any locks for this case. We may
418 * be in an interrupt or a critical region, and should
419 * only copy the information from the master page table,
420 * nothing more.
422 if (unlikely(fault_in_kernel_space(address))) {
423 if (vmalloc_fault(address) >= 0)
424 return;
425 if (notify_page_fault(regs, vec))
426 return;
428 bad_area_nosemaphore(regs, error_code, address);
429 return;
432 if (unlikely(notify_page_fault(regs, vec)))
433 return;
435 /* Only enable interrupts if they were on before the fault */
436 if ((regs->sr & SR_IMASK) != SR_IMASK)
437 local_irq_enable();
439 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
442 * If we're in an interrupt, have no user context or are running
443 * with pagefaults disabled then we must not take the fault:
445 if (unlikely(faulthandler_disabled() || !mm)) {
446 bad_area_nosemaphore(regs, error_code, address);
447 return;
450 retry:
451 down_read(&mm->mmap_sem);
453 vma = find_vma(mm, address);
454 if (unlikely(!vma)) {
455 bad_area(regs, error_code, address);
456 return;
458 if (likely(vma->vm_start <= address))
459 goto good_area;
460 if (unlikely(!(vma->vm_flags & VM_GROWSDOWN))) {
461 bad_area(regs, error_code, address);
462 return;
464 if (unlikely(expand_stack(vma, address))) {
465 bad_area(regs, error_code, address);
466 return;
470 * Ok, we have a good vm_area for this memory access, so
471 * we can handle it..
473 good_area:
474 if (unlikely(access_error(error_code, vma))) {
475 bad_area_access_error(regs, error_code, address);
476 return;
479 set_thread_fault_code(error_code);
481 if (user_mode(regs))
482 flags |= FAULT_FLAG_USER;
483 if (error_code & FAULT_CODE_WRITE)
484 flags |= FAULT_FLAG_WRITE;
487 * If for any reason at all we couldn't handle the fault,
488 * make sure we exit gracefully rather than endlessly redo
489 * the fault.
491 fault = handle_mm_fault(vma, address, flags);
493 if (unlikely(fault & (VM_FAULT_RETRY | VM_FAULT_ERROR)))
494 if (mm_fault_error(regs, error_code, address, fault))
495 return;
497 if (flags & FAULT_FLAG_ALLOW_RETRY) {
498 if (fault & VM_FAULT_MAJOR) {
499 tsk->maj_flt++;
500 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1,
501 regs, address);
502 } else {
503 tsk->min_flt++;
504 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1,
505 regs, address);
507 if (fault & VM_FAULT_RETRY) {
508 flags &= ~FAULT_FLAG_ALLOW_RETRY;
509 flags |= FAULT_FLAG_TRIED;
512 * No need to up_read(&mm->mmap_sem) as we would
513 * have already released it in __lock_page_or_retry
514 * in mm/filemap.c.
516 goto retry;
520 up_read(&mm->mmap_sem);