+++ /dev/null
-/*
- * Page fault handler for SH with an MMU.
- *
- * Copyright (C) 1999 Niibe Yutaka
- * Copyright (C) 2003 - 2007 Paul Mundt
- *
- * Based on linux/arch/i386/mm/fault.c:
- * Copyright (C) 1995 Linus Torvalds
- *
- * This file is subject to the terms and conditions of the GNU General Public
- * License. See the file "COPYING" in the main directory of this archive
- * for more details.
- */
-#include <linux/kernel.h>
-#include <linux/mm.h>
-#include <linux/hardirq.h>
-#include <linux/kprobes.h>
-#include <asm/system.h>
-#include <asm/mmu_context.h>
-#include <asm/tlbflush.h>
-#include <asm/kgdb.h>
-
-/*
- * This routine handles page faults. It determines the address,
- * and the problem, and then passes it off to one of the appropriate
- * routines.
- */
-asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
- unsigned long writeaccess,
- unsigned long address)
-{
- struct task_struct *tsk;
- struct mm_struct *mm;
- struct vm_area_struct * vma;
- int si_code;
- int fault;
- siginfo_t info;
-
- trace_hardirqs_on();
- local_irq_enable();
-
-#ifdef CONFIG_SH_KGDB
- if (kgdb_nofault && kgdb_bus_err_hook)
- kgdb_bus_err_hook();
-#endif
-
- tsk = current;
- mm = tsk->mm;
- si_code = SEGV_MAPERR;
-
- if (unlikely(address >= TASK_SIZE)) {
- /*
- * Synchronize this task's top level page-table
- * with the 'reference' page table.
- *
- * Do _not_ use "tsk" here. We might be inside
- * an interrupt in the middle of a task switch..
- */
- int offset = pgd_index(address);
- pgd_t *pgd, *pgd_k;
- pud_t *pud, *pud_k;
- pmd_t *pmd, *pmd_k;
-
- pgd = get_TTB() + offset;
- pgd_k = swapper_pg_dir + offset;
-
- /* This will never happen with the folded page table. */
- if (!pgd_present(*pgd)) {
- if (!pgd_present(*pgd_k))
- goto bad_area_nosemaphore;
- set_pgd(pgd, *pgd_k);
- return;
- }
-
- pud = pud_offset(pgd, address);
- pud_k = pud_offset(pgd_k, address);
- if (pud_present(*pud) || !pud_present(*pud_k))
- goto bad_area_nosemaphore;
- set_pud(pud, *pud_k);
-
- pmd = pmd_offset(pud, address);
- pmd_k = pmd_offset(pud_k, address);
- if (pmd_present(*pmd) || !pmd_present(*pmd_k))
- goto bad_area_nosemaphore;
- set_pmd(pmd, *pmd_k);
-
- return;
- }
-
- /*
- * If we're in an interrupt or have no user
- * context, we must not take the fault..
- */
- if (in_atomic() || !mm)
- goto no_context;
-
- down_read(&mm->mmap_sem);
-
- vma = find_vma(mm, address);
- if (!vma)
- goto bad_area;
- if (vma->vm_start <= address)
- goto good_area;
- if (!(vma->vm_flags & VM_GROWSDOWN))
- goto bad_area;
- if (expand_stack(vma, address))
- goto bad_area;
-/*
- * Ok, we have a good vm_area for this memory access, so
- * we can handle it..
- */
-good_area:
- si_code = SEGV_ACCERR;
- if (writeaccess) {
- if (!(vma->vm_flags & VM_WRITE))
- goto bad_area;
- } else {
- if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)))
- goto bad_area;
- }
-
- /*
- * If for any reason at all we couldn't handle the fault,
- * make sure we exit gracefully rather than endlessly redo
- * the fault.
- */
-survive:
- fault = handle_mm_fault(mm, vma, address, writeaccess);
- if (unlikely(fault & VM_FAULT_ERROR)) {
- if (fault & VM_FAULT_OOM)
- goto out_of_memory;
- else if (fault & VM_FAULT_SIGBUS)
- goto do_sigbus;
- BUG();
- }
- if (fault & VM_FAULT_MAJOR)
- tsk->maj_flt++;
- else
- tsk->min_flt++;
-
- up_read(&mm->mmap_sem);
- return;
-
-/*
- * Something tried to access memory that isn't in our memory map..
- * Fix it, but check if it's kernel or user first..
- */
-bad_area:
- up_read(&mm->mmap_sem);
-
-bad_area_nosemaphore:
- if (user_mode(regs)) {
- info.si_signo = SIGSEGV;
- info.si_errno = 0;
- info.si_code = si_code;
- info.si_addr = (void *) address;
- force_sig_info(SIGSEGV, &info, tsk);
- return;
- }
-
-no_context:
- /* Are we prepared to handle this kernel fault? */
- if (fixup_exception(regs))
- return;
-
-/*
- * Oops. The kernel tried to access some bad page. We'll have to
- * terminate things with extreme prejudice.
- *
- */
-
- bust_spinlocks(1);
-
- if (oops_may_print()) {
- __typeof__(pte_val(__pte(0))) page;
-
- if (address < PAGE_SIZE)
- printk(KERN_ALERT "Unable to handle kernel NULL "
- "pointer dereference");
- else
- printk(KERN_ALERT "Unable to handle kernel paging "
- "request");
- printk(" at virtual address %08lx\n", address);
- printk(KERN_ALERT "pc = %08lx\n", regs->pc);
- page = (unsigned long)get_TTB();
- if (page) {
- page = ((__typeof__(page) *)page)[address >> PGDIR_SHIFT];
- printk(KERN_ALERT "*pde = %08lx\n", page);
- if (page & _PAGE_PRESENT) {
- page &= PAGE_MASK;
- address &= 0x003ff000;
- page = ((__typeof__(page) *)
- __va(page))[address >>
- PAGE_SHIFT];
- printk(KERN_ALERT "*pte = %08lx\n", page);
- }
- }
- }
-
- die("Oops", regs, writeaccess);
- bust_spinlocks(0);
- do_exit(SIGKILL);
-
-/*
- * We ran out of memory, or some other thing happened to us that made
- * us unable to handle the page fault gracefully.
- */
-out_of_memory:
- up_read(&mm->mmap_sem);
- if (is_global_init(current)) {
- yield();
- down_read(&mm->mmap_sem);
- goto survive;
- }
- printk("VM: killing process %s\n", tsk->comm);
- if (user_mode(regs))
- do_group_exit(SIGKILL);
- goto no_context;
-
-do_sigbus:
- up_read(&mm->mmap_sem);
-
- /*
- * Send a sigbus, regardless of whether we were in kernel
- * or user mode.
- */
- info.si_signo = SIGBUS;
- info.si_errno = 0;
- info.si_code = BUS_ADRERR;
- info.si_addr = (void *)address;
- force_sig_info(SIGBUS, &info, tsk);
-
- /* Kernel mode? Handle exceptions or die */
- if (!user_mode(regs))
- goto no_context;
-}
-
-#ifdef CONFIG_SH_STORE_QUEUES
-/*
- * This is a special case for the SH-4 store queues, as pages for this
- * space still need to be faulted in before it's possible to flush the
- * store queue cache for writeout to the remapped region.
- */
-#define P3_ADDR_MAX (P4SEG_STORE_QUE + 0x04000000)
-#else
-#define P3_ADDR_MAX P4SEG
-#endif
-
-/*
- * Called with interrupts disabled.
- */
-asmlinkage int __kprobes __do_page_fault(struct pt_regs *regs,
- unsigned long writeaccess,
- unsigned long address)
-{
- pgd_t *pgd;
- pud_t *pud;
- pmd_t *pmd;
- pte_t *pte;
- pte_t entry;
-
-#ifdef CONFIG_SH_KGDB
- if (kgdb_nofault && kgdb_bus_err_hook)
- kgdb_bus_err_hook();
-#endif
-
- /*
- * We don't take page faults for P1, P2, and parts of P4, these
- * are always mapped, whether it be due to legacy behaviour in
- * 29-bit mode, or due to PMB configuration in 32-bit mode.
- */
- if (address >= P3SEG && address < P3_ADDR_MAX) {
- pgd = pgd_offset_k(address);
- } else {
- if (unlikely(address >= TASK_SIZE || !current->mm))
- return 1;
-
- pgd = pgd_offset(current->mm, address);
- }
-
- pud = pud_offset(pgd, address);
- if (pud_none_or_clear_bad(pud))
- return 1;
- pmd = pmd_offset(pud, address);
- if (pmd_none_or_clear_bad(pmd))
- return 1;
-
- pte = pte_offset_kernel(pmd, address);
- entry = *pte;
- if (unlikely(pte_none(entry) || pte_not_present(entry)))
- return 1;
- if (unlikely(writeaccess && !pte_write(entry)))
- return 1;
-
- if (writeaccess)
- entry = pte_mkdirty(entry);
- entry = pte_mkyoung(entry);
-
- set_pte(pte, entry);
- update_mmu_cache(NULL, address, entry);
-
- return 0;
-}
git.openpandora.org / pandora-kernel.git / blobdiff