x86/xen: resume timer irqs early
[linux/fpc-iii.git] / arch / tile / mm / fault.c
blob6c0571216a9d67f81a09ff331a601d22ae881566
1 /*
2 * Copyright 2010 Tilera Corporation. All Rights Reserved.
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation, version 2.
8 * This program is distributed in the hope that it will be useful, but
9 * WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
11 * NON INFRINGEMENT. See the GNU General Public License for
12 * more details.
14 * From i386 code copyright (C) 1995 Linus Torvalds
17 #include <linux/signal.h>
18 #include <linux/sched.h>
19 #include <linux/kernel.h>
20 #include <linux/errno.h>
21 #include <linux/string.h>
22 #include <linux/types.h>
23 #include <linux/ptrace.h>
24 #include <linux/mman.h>
25 #include <linux/mm.h>
26 #include <linux/smp.h>
27 #include <linux/interrupt.h>
28 #include <linux/init.h>
29 #include <linux/tty.h>
30 #include <linux/vt_kern.h> /* For unblank_screen() */
31 #include <linux/highmem.h>
32 #include <linux/module.h>
33 #include <linux/kprobes.h>
34 #include <linux/hugetlb.h>
35 #include <linux/syscalls.h>
36 #include <linux/uaccess.h>
37 #include <linux/kdebug.h>
39 #include <asm/pgalloc.h>
40 #include <asm/sections.h>
41 #include <asm/traps.h>
42 #include <asm/syscalls.h>
44 #include <arch/interrupts.h>
46 static noinline void force_sig_info_fault(const char *type, int si_signo,
47 int si_code, unsigned long address,
48 int fault_num,
49 struct task_struct *tsk,
50 struct pt_regs *regs)
52 siginfo_t info;
54 if (unlikely(tsk->pid < 2)) {
55 panic("Signal %d (code %d) at %#lx sent to %s!",
56 si_signo, si_code & 0xffff, address,
57 is_idle_task(tsk) ? "the idle task" : "init");
60 info.si_signo = si_signo;
61 info.si_errno = 0;
62 info.si_code = si_code;
63 info.si_addr = (void __user *)address;
64 info.si_trapno = fault_num;
65 trace_unhandled_signal(type, regs, address, si_signo);
66 force_sig_info(si_signo, &info, tsk);
69 #ifndef __tilegx__
71 * Synthesize the fault a PL0 process would get by doing a word-load of
72 * an unaligned address or a high kernel address.
74 SYSCALL_DEFINE1(cmpxchg_badaddr, unsigned long, address)
76 struct pt_regs *regs = current_pt_regs();
78 if (address >= PAGE_OFFSET)
79 force_sig_info_fault("atomic segfault", SIGSEGV, SEGV_MAPERR,
80 address, INT_DTLB_MISS, current, regs);
81 else
82 force_sig_info_fault("atomic alignment fault", SIGBUS,
83 BUS_ADRALN, address,
84 INT_UNALIGN_DATA, current, regs);
87 * Adjust pc to point at the actual instruction, which is unusual
88 * for syscalls normally, but is appropriate when we are claiming
89 * that a syscall swint1 caused a page fault or bus error.
91 regs->pc -= 8;
94 * Mark this as a caller-save interrupt, like a normal page fault,
95 * so that when we go through the signal handler path we will
96 * properly restore r0, r1, and r2 for the signal handler arguments.
98 regs->flags |= PT_FLAGS_CALLER_SAVES;
100 return 0;
102 #endif
104 static inline pmd_t *vmalloc_sync_one(pgd_t *pgd, unsigned long address)
106 unsigned index = pgd_index(address);
107 pgd_t *pgd_k;
108 pud_t *pud, *pud_k;
109 pmd_t *pmd, *pmd_k;
111 pgd += index;
112 pgd_k = init_mm.pgd + index;
114 if (!pgd_present(*pgd_k))
115 return NULL;
117 pud = pud_offset(pgd, address);
118 pud_k = pud_offset(pgd_k, address);
119 if (!pud_present(*pud_k))
120 return NULL;
122 pmd = pmd_offset(pud, address);
123 pmd_k = pmd_offset(pud_k, address);
124 if (!pmd_present(*pmd_k))
125 return NULL;
126 if (!pmd_present(*pmd))
127 set_pmd(pmd, *pmd_k);
128 else
129 BUG_ON(pmd_ptfn(*pmd) != pmd_ptfn(*pmd_k));
130 return pmd_k;
134 * Handle a fault on the vmalloc area.
136 static inline int vmalloc_fault(pgd_t *pgd, unsigned long address)
138 pmd_t *pmd_k;
139 pte_t *pte_k;
141 /* Make sure we are in vmalloc area */
142 if (!(address >= VMALLOC_START && address < VMALLOC_END))
143 return -1;
146 * Synchronize this task's top level page-table
147 * with the 'reference' page table.
149 pmd_k = vmalloc_sync_one(pgd, address);
150 if (!pmd_k)
151 return -1;
152 pte_k = pte_offset_kernel(pmd_k, address);
153 if (!pte_present(*pte_k))
154 return -1;
155 return 0;
158 /* Wait until this PTE has completed migration. */
159 static void wait_for_migration(pte_t *pte)
161 if (pte_migrating(*pte)) {
163 * Wait until the migrater fixes up this pte.
164 * We scale the loop count by the clock rate so we'll wait for
165 * a few seconds here.
167 int retries = 0;
168 int bound = get_clock_rate();
169 while (pte_migrating(*pte)) {
170 barrier();
171 if (++retries > bound)
172 panic("Hit migrating PTE (%#llx) and"
173 " page PFN %#lx still migrating",
174 pte->val, pte_pfn(*pte));
180 * It's not generally safe to use "current" to get the page table pointer,
181 * since we might be running an oprofile interrupt in the middle of a
182 * task switch.
184 static pgd_t *get_current_pgd(void)
186 HV_Context ctx = hv_inquire_context();
187 unsigned long pgd_pfn = ctx.page_table >> PAGE_SHIFT;
188 struct page *pgd_page = pfn_to_page(pgd_pfn);
189 BUG_ON(PageHighMem(pgd_page));
190 return (pgd_t *) __va(ctx.page_table);
194 * We can receive a page fault from a migrating PTE at any time.
195 * Handle it by just waiting until the fault resolves.
197 * It's also possible to get a migrating kernel PTE that resolves
198 * itself during the downcall from hypervisor to Linux. We just check
199 * here to see if the PTE seems valid, and if so we retry it.
201 * NOTE! We MUST NOT take any locks for this case. We may be in an
202 * interrupt or a critical region, and must do as little as possible.
203 * Similarly, we can't use atomic ops here, since we may be handling a
204 * fault caused by an atomic op access.
206 * If we find a migrating PTE while we're in an NMI context, and we're
207 * at a PC that has a registered exception handler, we don't wait,
208 * since this thread may (e.g.) have been interrupted while migrating
209 * its own stack, which would then cause us to self-deadlock.
211 static int handle_migrating_pte(pgd_t *pgd, int fault_num,
212 unsigned long address, unsigned long pc,
213 int is_kernel_mode, int write)
215 pud_t *pud;
216 pmd_t *pmd;
217 pte_t *pte;
218 pte_t pteval;
220 if (pgd_addr_invalid(address))
221 return 0;
223 pgd += pgd_index(address);
224 pud = pud_offset(pgd, address);
225 if (!pud || !pud_present(*pud))
226 return 0;
227 pmd = pmd_offset(pud, address);
228 if (!pmd || !pmd_present(*pmd))
229 return 0;
230 pte = pmd_huge_page(*pmd) ? ((pte_t *)pmd) :
231 pte_offset_kernel(pmd, address);
232 pteval = *pte;
233 if (pte_migrating(pteval)) {
234 if (in_nmi() && search_exception_tables(pc))
235 return 0;
236 wait_for_migration(pte);
237 return 1;
240 if (!is_kernel_mode || !pte_present(pteval))
241 return 0;
242 if (fault_num == INT_ITLB_MISS) {
243 if (pte_exec(pteval))
244 return 1;
245 } else if (write) {
246 if (pte_write(pteval))
247 return 1;
248 } else {
249 if (pte_read(pteval))
250 return 1;
253 return 0;
257 * This routine is responsible for faulting in user pages.
258 * It passes the work off to one of the appropriate routines.
259 * It returns true if the fault was successfully handled.
261 static int handle_page_fault(struct pt_regs *regs,
262 int fault_num,
263 int is_page_fault,
264 unsigned long address,
265 int write)
267 struct task_struct *tsk;
268 struct mm_struct *mm;
269 struct vm_area_struct *vma;
270 unsigned long stack_offset;
271 int fault;
272 int si_code;
273 int is_kernel_mode;
274 pgd_t *pgd;
275 unsigned int flags;
277 /* on TILE, protection faults are always writes */
278 if (!is_page_fault)
279 write = 1;
281 flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
283 is_kernel_mode = !user_mode(regs);
285 tsk = validate_current();
288 * Check to see if we might be overwriting the stack, and bail
289 * out if so. The page fault code is a relatively likely
290 * place to get trapped in an infinite regress, and once we
291 * overwrite the whole stack, it becomes very hard to recover.
293 stack_offset = stack_pointer & (THREAD_SIZE-1);
294 if (stack_offset < THREAD_SIZE / 8) {
295 pr_alert("Potential stack overrun: sp %#lx\n",
296 stack_pointer);
297 show_regs(regs);
298 pr_alert("Killing current process %d/%s\n",
299 tsk->pid, tsk->comm);
300 do_group_exit(SIGKILL);
304 * Early on, we need to check for migrating PTE entries;
305 * see homecache.c. If we find a migrating PTE, we wait until
306 * the backing page claims to be done migrating, then we proceed.
307 * For kernel PTEs, we rewrite the PTE and return and retry.
308 * Otherwise, we treat the fault like a normal "no PTE" fault,
309 * rather than trying to patch up the existing PTE.
311 pgd = get_current_pgd();
312 if (handle_migrating_pte(pgd, fault_num, address, regs->pc,
313 is_kernel_mode, write))
314 return 1;
316 si_code = SEGV_MAPERR;
319 * We fault-in kernel-space virtual memory on-demand. The
320 * 'reference' page table is init_mm.pgd.
322 * NOTE! We MUST NOT take any locks for this case. We may
323 * be in an interrupt or a critical region, and should
324 * only copy the information from the master page table,
325 * nothing more.
327 * This verifies that the fault happens in kernel space
328 * and that the fault was not a protection fault.
330 if (unlikely(address >= TASK_SIZE &&
331 !is_arch_mappable_range(address, 0))) {
332 if (is_kernel_mode && is_page_fault &&
333 vmalloc_fault(pgd, address) >= 0)
334 return 1;
336 * Don't take the mm semaphore here. If we fixup a prefetch
337 * fault we could otherwise deadlock.
339 mm = NULL; /* happy compiler */
340 vma = NULL;
341 goto bad_area_nosemaphore;
345 * If we're trying to touch user-space addresses, we must
346 * be either at PL0, or else with interrupts enabled in the
347 * kernel, so either way we can re-enable interrupts here
348 * unless we are doing atomic access to user space with
349 * interrupts disabled.
351 if (!(regs->flags & PT_FLAGS_DISABLE_IRQ))
352 local_irq_enable();
354 mm = tsk->mm;
357 * If we're in an interrupt, have no user context or are running in an
358 * atomic region then we must not take the fault.
360 if (in_atomic() || !mm) {
361 vma = NULL; /* happy compiler */
362 goto bad_area_nosemaphore;
365 if (!is_kernel_mode)
366 flags |= FAULT_FLAG_USER;
369 * When running in the kernel we expect faults to occur only to
370 * addresses in user space. All other faults represent errors in the
371 * kernel and should generate an OOPS. Unfortunately, in the case of an
372 * erroneous fault occurring in a code path which already holds mmap_sem
373 * we will deadlock attempting to validate the fault against the
374 * address space. Luckily the kernel only validly references user
375 * space from well defined areas of code, which are listed in the
376 * exceptions table.
378 * As the vast majority of faults will be valid we will only perform
379 * the source reference check when there is a possibility of a deadlock.
380 * Attempt to lock the address space, if we cannot we then validate the
381 * source. If this is invalid we can skip the address space check,
382 * thus avoiding the deadlock.
384 if (!down_read_trylock(&mm->mmap_sem)) {
385 if (is_kernel_mode &&
386 !search_exception_tables(regs->pc)) {
387 vma = NULL; /* happy compiler */
388 goto bad_area_nosemaphore;
391 retry:
392 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 (regs->sp < PAGE_OFFSET) {
404 * accessing the stack below sp is always a bug.
406 if (address < regs->sp)
407 goto bad_area;
409 if (expand_stack(vma, address))
410 goto bad_area;
413 * Ok, we have a good vm_area for this memory access, so
414 * we can handle it..
416 good_area:
417 si_code = SEGV_ACCERR;
418 if (fault_num == INT_ITLB_MISS) {
419 if (!(vma->vm_flags & VM_EXEC))
420 goto bad_area;
421 } else if (write) {
422 #ifdef TEST_VERIFY_AREA
423 if (!is_page_fault && regs->cs == KERNEL_CS)
424 pr_err("WP fault at "REGFMT"\n", regs->eip);
425 #endif
426 if (!(vma->vm_flags & VM_WRITE))
427 goto bad_area;
428 flags |= FAULT_FLAG_WRITE;
429 } else {
430 if (!is_page_fault || !(vma->vm_flags & VM_READ))
431 goto bad_area;
435 * If for any reason at all we couldn't handle the fault,
436 * make sure we exit gracefully rather than endlessly redo
437 * the fault.
439 fault = handle_mm_fault(mm, vma, address, flags);
441 if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
442 return 0;
444 if (unlikely(fault & VM_FAULT_ERROR)) {
445 if (fault & VM_FAULT_OOM)
446 goto out_of_memory;
447 else if (fault & VM_FAULT_SIGBUS)
448 goto do_sigbus;
449 BUG();
451 if (flags & FAULT_FLAG_ALLOW_RETRY) {
452 if (fault & VM_FAULT_MAJOR)
453 tsk->maj_flt++;
454 else
455 tsk->min_flt++;
456 if (fault & VM_FAULT_RETRY) {
457 flags &= ~FAULT_FLAG_ALLOW_RETRY;
458 flags |= FAULT_FLAG_TRIED;
461 * No need to up_read(&mm->mmap_sem) as we would
462 * have already released it in __lock_page_or_retry
463 * in mm/filemap.c.
465 goto retry;
469 #if CHIP_HAS_TILE_DMA()
470 /* If this was a DMA TLB fault, restart the DMA engine. */
471 switch (fault_num) {
472 case INT_DMATLB_MISS:
473 case INT_DMATLB_MISS_DWNCL:
474 case INT_DMATLB_ACCESS:
475 case INT_DMATLB_ACCESS_DWNCL:
476 __insn_mtspr(SPR_DMA_CTR, SPR_DMA_CTR__REQUEST_MASK);
477 break;
479 #endif
481 up_read(&mm->mmap_sem);
482 return 1;
485 * Something tried to access memory that isn't in our memory map..
486 * Fix it, but check if it's kernel or user first..
488 bad_area:
489 up_read(&mm->mmap_sem);
491 bad_area_nosemaphore:
492 /* User mode accesses just cause a SIGSEGV */
493 if (!is_kernel_mode) {
495 * It's possible to have interrupts off here.
497 local_irq_enable();
499 force_sig_info_fault("segfault", SIGSEGV, si_code, address,
500 fault_num, tsk, regs);
501 return 0;
504 no_context:
505 /* Are we prepared to handle this kernel fault? */
506 if (fixup_exception(regs))
507 return 0;
510 * Oops. The kernel tried to access some bad page. We'll have to
511 * terminate things with extreme prejudice.
514 bust_spinlocks(1);
516 /* FIXME: no lookup_address() yet */
517 #ifdef SUPPORT_LOOKUP_ADDRESS
518 if (fault_num == INT_ITLB_MISS) {
519 pte_t *pte = lookup_address(address);
521 if (pte && pte_present(*pte) && !pte_exec_kernel(*pte))
522 pr_crit("kernel tried to execute"
523 " non-executable page - exploit attempt?"
524 " (uid: %d)\n", current->uid);
526 #endif
527 if (address < PAGE_SIZE)
528 pr_alert("Unable to handle kernel NULL pointer dereference\n");
529 else
530 pr_alert("Unable to handle kernel paging request\n");
531 pr_alert(" at virtual address "REGFMT", pc "REGFMT"\n",
532 address, regs->pc);
534 show_regs(regs);
536 if (unlikely(tsk->pid < 2)) {
537 panic("Kernel page fault running %s!",
538 is_idle_task(tsk) ? "the idle task" : "init");
542 * More FIXME: we should probably copy the i386 here and
543 * implement a generic die() routine. Not today.
545 #ifdef SUPPORT_DIE
546 die("Oops", regs);
547 #endif
548 bust_spinlocks(1);
550 do_group_exit(SIGKILL);
553 * We ran out of memory, or some other thing happened to us that made
554 * us unable to handle the page fault gracefully.
556 out_of_memory:
557 up_read(&mm->mmap_sem);
558 if (is_kernel_mode)
559 goto no_context;
560 pagefault_out_of_memory();
561 return 0;
563 do_sigbus:
564 up_read(&mm->mmap_sem);
566 /* Kernel mode? Handle exceptions or die */
567 if (is_kernel_mode)
568 goto no_context;
570 force_sig_info_fault("bus error", SIGBUS, BUS_ADRERR, address,
571 fault_num, tsk, regs);
572 return 0;
575 #ifndef __tilegx__
577 /* We must release ICS before panicking or we won't get anywhere. */
578 #define ics_panic(fmt, ...) do { \
579 __insn_mtspr(SPR_INTERRUPT_CRITICAL_SECTION, 0); \
580 panic(fmt, __VA_ARGS__); \
581 } while (0)
584 * When we take an ITLB or DTLB fault or access violation in the
585 * supervisor while the critical section bit is set, the hypervisor is
586 * reluctant to write new values into the EX_CONTEXT_K_x registers,
587 * since that might indicate we have not yet squirreled the SPR
588 * contents away and can thus safely take a recursive interrupt.
589 * Accordingly, the hypervisor passes us the PC via SYSTEM_SAVE_K_2.
591 * Note that this routine is called before homecache_tlb_defer_enter(),
592 * which means that we can properly unlock any atomics that might
593 * be used there (good), but also means we must be very sensitive
594 * to not touch any data structures that might be located in memory
595 * that could migrate, as we could be entering the kernel on a dataplane
596 * cpu that has been deferring kernel TLB updates. This means, for
597 * example, that we can't migrate init_mm or its pgd.
599 struct intvec_state do_page_fault_ics(struct pt_regs *regs, int fault_num,
600 unsigned long address,
601 unsigned long info)
603 unsigned long pc = info & ~1;
604 int write = info & 1;
605 pgd_t *pgd = get_current_pgd();
607 /* Retval is 1 at first since we will handle the fault fully. */
608 struct intvec_state state = {
609 do_page_fault, fault_num, address, write, 1
612 /* Validate that we are plausibly in the right routine. */
613 if ((pc & 0x7) != 0 || pc < PAGE_OFFSET ||
614 (fault_num != INT_DTLB_MISS &&
615 fault_num != INT_DTLB_ACCESS)) {
616 unsigned long old_pc = regs->pc;
617 regs->pc = pc;
618 ics_panic("Bad ICS page fault args:"
619 " old PC %#lx, fault %d/%d at %#lx\n",
620 old_pc, fault_num, write, address);
623 /* We might be faulting on a vmalloc page, so check that first. */
624 if (fault_num != INT_DTLB_ACCESS && vmalloc_fault(pgd, address) >= 0)
625 return state;
628 * If we faulted with ICS set in sys_cmpxchg, we are providing
629 * a user syscall service that should generate a signal on
630 * fault. We didn't set up a kernel stack on initial entry to
631 * sys_cmpxchg, but instead had one set up by the fault, which
632 * (because sys_cmpxchg never releases ICS) came to us via the
633 * SYSTEM_SAVE_K_2 mechanism, and thus EX_CONTEXT_K_[01] are
634 * still referencing the original user code. We release the
635 * atomic lock and rewrite pt_regs so that it appears that we
636 * came from user-space directly, and after we finish the
637 * fault we'll go back to user space and re-issue the swint.
638 * This way the backtrace information is correct if we need to
639 * emit a stack dump at any point while handling this.
641 * Must match register use in sys_cmpxchg().
643 if (pc >= (unsigned long) sys_cmpxchg &&
644 pc < (unsigned long) __sys_cmpxchg_end) {
645 #ifdef CONFIG_SMP
646 /* Don't unlock before we could have locked. */
647 if (pc >= (unsigned long)__sys_cmpxchg_grab_lock) {
648 int *lock_ptr = (int *)(regs->regs[ATOMIC_LOCK_REG]);
649 __atomic_fault_unlock(lock_ptr);
651 #endif
652 regs->sp = regs->regs[27];
656 * We can also fault in the atomic assembly, in which
657 * case we use the exception table to do the first-level fixup.
658 * We may re-fixup again in the real fault handler if it
659 * turns out the faulting address is just bad, and not,
660 * for example, migrating.
662 else if (pc >= (unsigned long) __start_atomic_asm_code &&
663 pc < (unsigned long) __end_atomic_asm_code) {
664 const struct exception_table_entry *fixup;
665 #ifdef CONFIG_SMP
666 /* Unlock the atomic lock. */
667 int *lock_ptr = (int *)(regs->regs[ATOMIC_LOCK_REG]);
668 __atomic_fault_unlock(lock_ptr);
669 #endif
670 fixup = search_exception_tables(pc);
671 if (!fixup)
672 ics_panic("ICS atomic fault not in table:"
673 " PC %#lx, fault %d", pc, fault_num);
674 regs->pc = fixup->fixup;
675 regs->ex1 = PL_ICS_EX1(KERNEL_PL, 0);
679 * Now that we have released the atomic lock (if necessary),
680 * it's safe to spin if the PTE that caused the fault was migrating.
682 if (fault_num == INT_DTLB_ACCESS)
683 write = 1;
684 if (handle_migrating_pte(pgd, fault_num, address, pc, 1, write))
685 return state;
687 /* Return zero so that we continue on with normal fault handling. */
688 state.retval = 0;
689 return state;
692 #endif /* !__tilegx__ */
695 * This routine handles page faults. It determines the address, and the
696 * problem, and then passes it handle_page_fault() for normal DTLB and
697 * ITLB issues, and for DMA or SN processor faults when we are in user
698 * space. For the latter, if we're in kernel mode, we just save the
699 * interrupt away appropriately and return immediately. We can't do
700 * page faults for user code while in kernel mode.
702 void do_page_fault(struct pt_regs *regs, int fault_num,
703 unsigned long address, unsigned long write)
705 int is_page_fault;
707 #ifdef CONFIG_KPROBES
709 * This is to notify the fault handler of the kprobes. The
710 * exception code is redundant as it is also carried in REGS,
711 * but we pass it anyhow.
713 if (notify_die(DIE_PAGE_FAULT, "page fault", regs, -1,
714 regs->faultnum, SIGSEGV) == NOTIFY_STOP)
715 return;
716 #endif
718 #ifdef __tilegx__
720 * We don't need early do_page_fault_ics() support, since unlike
721 * Pro we don't need to worry about unlocking the atomic locks.
722 * There is only one current case in GX where we touch any memory
723 * under ICS other than our own kernel stack, and we handle that
724 * here. (If we crash due to trying to touch our own stack,
725 * we're in too much trouble for C code to help out anyway.)
727 if (write & ~1) {
728 unsigned long pc = write & ~1;
729 if (pc >= (unsigned long) __start_unalign_asm_code &&
730 pc < (unsigned long) __end_unalign_asm_code) {
731 struct thread_info *ti = current_thread_info();
733 * Our EX_CONTEXT is still what it was from the
734 * initial unalign exception, but now we've faulted
735 * on the JIT page. We would like to complete the
736 * page fault however is appropriate, and then retry
737 * the instruction that caused the unalign exception.
738 * Our state has been "corrupted" by setting the low
739 * bit in "sp", and stashing r0..r3 in the
740 * thread_info area, so we revert all of that, then
741 * continue as if this were a normal page fault.
743 regs->sp &= ~1UL;
744 regs->regs[0] = ti->unalign_jit_tmp[0];
745 regs->regs[1] = ti->unalign_jit_tmp[1];
746 regs->regs[2] = ti->unalign_jit_tmp[2];
747 regs->regs[3] = ti->unalign_jit_tmp[3];
748 write &= 1;
749 } else {
750 pr_alert("%s/%d: ICS set at page fault at %#lx: %#lx\n",
751 current->comm, current->pid, pc, address);
752 show_regs(regs);
753 do_group_exit(SIGKILL);
754 return;
757 #else
758 /* This case should have been handled by do_page_fault_ics(). */
759 BUG_ON(write & ~1);
760 #endif
762 #if CHIP_HAS_TILE_DMA()
764 * If it's a DMA fault, suspend the transfer while we're
765 * handling the miss; we'll restart after it's handled. If we
766 * don't suspend, it's possible that this process could swap
767 * out and back in, and restart the engine since the DMA is
768 * still 'running'.
770 if (fault_num == INT_DMATLB_MISS ||
771 fault_num == INT_DMATLB_ACCESS ||
772 fault_num == INT_DMATLB_MISS_DWNCL ||
773 fault_num == INT_DMATLB_ACCESS_DWNCL) {
774 __insn_mtspr(SPR_DMA_CTR, SPR_DMA_CTR__SUSPEND_MASK);
775 while (__insn_mfspr(SPR_DMA_USER_STATUS) &
776 SPR_DMA_STATUS__BUSY_MASK)
779 #endif
781 /* Validate fault num and decide if this is a first-time page fault. */
782 switch (fault_num) {
783 case INT_ITLB_MISS:
784 case INT_DTLB_MISS:
785 #if CHIP_HAS_TILE_DMA()
786 case INT_DMATLB_MISS:
787 case INT_DMATLB_MISS_DWNCL:
788 #endif
789 is_page_fault = 1;
790 break;
792 case INT_DTLB_ACCESS:
793 #if CHIP_HAS_TILE_DMA()
794 case INT_DMATLB_ACCESS:
795 case INT_DMATLB_ACCESS_DWNCL:
796 #endif
797 is_page_fault = 0;
798 break;
800 default:
801 panic("Bad fault number %d in do_page_fault", fault_num);
804 #if CHIP_HAS_TILE_DMA()
805 if (!user_mode(regs)) {
806 struct async_tlb *async;
807 switch (fault_num) {
808 #if CHIP_HAS_TILE_DMA()
809 case INT_DMATLB_MISS:
810 case INT_DMATLB_ACCESS:
811 case INT_DMATLB_MISS_DWNCL:
812 case INT_DMATLB_ACCESS_DWNCL:
813 async = &current->thread.dma_async_tlb;
814 break;
815 #endif
816 default:
817 async = NULL;
819 if (async) {
822 * No vmalloc check required, so we can allow
823 * interrupts immediately at this point.
825 local_irq_enable();
827 set_thread_flag(TIF_ASYNC_TLB);
828 if (async->fault_num != 0) {
829 panic("Second async fault %d;"
830 " old fault was %d (%#lx/%ld)",
831 fault_num, async->fault_num,
832 address, write);
834 BUG_ON(fault_num == 0);
835 async->fault_num = fault_num;
836 async->is_fault = is_page_fault;
837 async->is_write = write;
838 async->address = address;
839 return;
842 #endif
844 handle_page_fault(regs, fault_num, is_page_fault, address, write);
848 #if CHIP_HAS_TILE_DMA()
850 * This routine effectively re-issues asynchronous page faults
851 * when we are returning to user space.
853 void do_async_page_fault(struct pt_regs *regs)
855 struct async_tlb *async = &current->thread.dma_async_tlb;
858 * Clear thread flag early. If we re-interrupt while processing
859 * code here, we will reset it and recall this routine before
860 * returning to user space.
862 clear_thread_flag(TIF_ASYNC_TLB);
864 if (async->fault_num) {
866 * Clear async->fault_num before calling the page-fault
867 * handler so that if we re-interrupt before returning
868 * from the function we have somewhere to put the
869 * information from the new interrupt.
871 int fault_num = async->fault_num;
872 async->fault_num = 0;
873 handle_page_fault(regs, fault_num, async->is_fault,
874 async->address, async->is_write);
877 #endif /* CHIP_HAS_TILE_DMA() */
880 void vmalloc_sync_all(void)
882 #ifdef __tilegx__
883 /* Currently all L1 kernel pmd's are static and shared. */
884 BUILD_BUG_ON(pgd_index(VMALLOC_END - PAGE_SIZE) !=
885 pgd_index(VMALLOC_START));
886 #else
888 * Note that races in the updates of insync and start aren't
889 * problematic: insync can only get set bits added, and updates to
890 * start are only improving performance (without affecting correctness
891 * if undone).
893 static DECLARE_BITMAP(insync, PTRS_PER_PGD);
894 static unsigned long start = PAGE_OFFSET;
895 unsigned long address;
897 BUILD_BUG_ON(PAGE_OFFSET & ~PGDIR_MASK);
898 for (address = start; address >= PAGE_OFFSET; address += PGDIR_SIZE) {
899 if (!test_bit(pgd_index(address), insync)) {
900 unsigned long flags;
901 struct list_head *pos;
903 spin_lock_irqsave(&pgd_lock, flags);
904 list_for_each(pos, &pgd_list)
905 if (!vmalloc_sync_one(list_to_pgd(pos),
906 address)) {
907 /* Must be at first entry in list. */
908 BUG_ON(pos != pgd_list.next);
909 break;
911 spin_unlock_irqrestore(&pgd_lock, flags);
912 if (pos != pgd_list.next)
913 set_bit(pgd_index(address), insync);
915 if (address == start && test_bit(pgd_index(address), insync))
916 start = address + PGDIR_SIZE;
918 #endif