+++ /dev/null
-/*
- * arch/score/mm/fault.c
- *
- * Score Processor version.
- *
- * Copyright (C) 2009 Sunplus Core Technology Co., Ltd.
- * Lennox Wu <lennox.wu@sunplusct.com>
- * Chen Liqin <liqin.chen@sunplusct.com>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, see the file COPYING, or write
- * to the Free Software Foundation, Inc.,
- * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
- */
-
-#include <linux/errno.h>
-#include <linux/interrupt.h>
-#include <linux/kernel.h>
-#include <linux/mm.h>
-#include <linux/mman.h>
-#include <linux/extable.h>
-#include <linux/signal.h>
-#include <linux/sched.h>
-#include <linux/string.h>
-#include <linux/types.h>
-#include <linux/ptrace.h>
-#include <linux/uaccess.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 do_page_fault(struct pt_regs *regs, unsigned long write,
- unsigned long address)
-{
- struct vm_area_struct *vma = NULL;
- struct task_struct *tsk = current;
- struct mm_struct *mm = tsk->mm;
- const int field = sizeof(unsigned long) * 2;
- unsigned long flags = 0;
- siginfo_t info;
- int fault;
-
- info.si_code = SEGV_MAPERR;
-
- /*
- * We fault-in kernel-space virtual memory on-demand. The
- * 'reference' page table is init_mm.pgd.
- *
- * NOTE! We MUST NOT take any locks for this case. We may
- * be in an interrupt or a critical region, and should
- * only copy the information from the master page table,
- * nothing more.
- */
- if (unlikely(address >= VMALLOC_START && address <= VMALLOC_END))
- goto vmalloc_fault;
-#ifdef MODULE_START
- if (unlikely(address >= MODULE_START && address < MODULE_END))
- goto vmalloc_fault;
-#endif
-
- /*
- * If we're in an interrupt or have no user
- * context, we must not take the fault..
- */
- if (pagefault_disabled() || !mm)
- goto bad_area_nosemaphore;
-
- if (user_mode(regs))
- flags |= FAULT_FLAG_USER;
-
- 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:
- info.si_code = SEGV_ACCERR;
-
- if (write) {
- if (!(vma->vm_flags & VM_WRITE))
- goto bad_area;
- flags |= FAULT_FLAG_WRITE;
- } else {
- if (!(vma->vm_flags & (VM_READ | VM_WRITE | VM_EXEC)))
- 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.
- */
- fault = handle_mm_fault(vma, address, flags);
- if (unlikely(fault & VM_FAULT_ERROR)) {
- if (fault & VM_FAULT_OOM)
- goto out_of_memory;
- else if (fault & VM_FAULT_SIGSEGV)
- goto bad_area;
- 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:
- /* User mode accesses just cause a SIGSEGV */
- if (user_mode(regs)) {
- tsk->thread.cp0_badvaddr = address;
- tsk->thread.error_code = write;
- info.si_signo = SIGSEGV;
- info.si_errno = 0;
- /* info.si_code has been set above */
- info.si_addr = (void __user *) address;
- force_sig_info(SIGSEGV, &info, tsk);
- return;
- }
-
-no_context:
- /* Are we prepared to handle this kernel fault? */
- if (fixup_exception(regs)) {
- current->thread.cp0_baduaddr = address;
- return;
- }
-
- /*
- * Oops. The kernel tried to access some bad page. We'll have to
- * terminate things with extreme prejudice.
- */
- bust_spinlocks(1);
-
- printk(KERN_ALERT "CPU %d Unable to handle kernel paging request at "
- "virtual address %0*lx, epc == %0*lx, ra == %0*lx\n",
- 0, field, address, field, regs->cp0_epc,
- field, regs->regs[3]);
- die("Oops", regs);
-
- /*
- * 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 (!user_mode(regs))
- goto no_context;
- pagefault_out_of_memory();
- return;
-
-do_sigbus:
- up_read(&mm->mmap_sem);
- /* Kernel mode? Handle exceptions or die */
- if (!user_mode(regs))
- goto no_context;
- else
- /*
- * Send a sigbus, regardless of whether we were in kernel
- * or user mode.
- */
- tsk->thread.cp0_badvaddr = address;
- info.si_signo = SIGBUS;
- info.si_errno = 0;
- info.si_code = BUS_ADRERR;
- info.si_addr = (void __user *) address;
- force_sig_info(SIGBUS, &info, tsk);
- return;
-vmalloc_fault:
- {
- /*
- * 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_offset(address);
- pgd_t *pgd, *pgd_k;
- pud_t *pud, *pud_k;
- pmd_t *pmd, *pmd_k;
- pte_t *pte_k;
-
- pgd = (pgd_t *) pgd_current + offset;
- pgd_k = init_mm.pgd + offset;
-
- if (!pgd_present(*pgd_k))
- goto no_context;
- set_pgd(pgd, *pgd_k);
-
- pud = pud_offset(pgd, address);
- pud_k = pud_offset(pgd_k, address);
- if (!pud_present(*pud_k))
- goto no_context;
-
- pmd = pmd_offset(pud, address);
- pmd_k = pmd_offset(pud_k, address);
- if (!pmd_present(*pmd_k))
- goto no_context;
- set_pmd(pmd, *pmd_k);
-
- pte_k = pte_offset_kernel(pmd_k, address);
- if (!pte_present(*pte_k))
- goto no_context;
- return;
- }
-}
git.samba.org / sfrench / cifs-2.6.git / blobdiff