linux/arch/powerpc/platforms/cell/spu_fault.c
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   1/*
   2 * SPU mm fault handler
   3 *
   4 * (C) Copyright IBM Deutschland Entwicklung GmbH 2007
   5 *
   6 * Author: Arnd Bergmann <arndb@de.ibm.com>
   7 * Author: Jeremy Kerr <jk@ozlabs.org>
   8 *
   9 * This program is free software; you can redistribute it and/or modify
  10 * it under the terms of the GNU General Public License as published by
  11 * the Free Software Foundation; either version 2, or (at your option)
  12 * any later version.
  13 *
  14 * This program is distributed in the hope that it will be useful,
  15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17 * GNU General Public License for more details.
  18 *
  19 * You should have received a copy of the GNU General Public License
  20 * along with this program; if not, write to the Free Software
  21 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  22 */
  23#include <linux/sched.h>
  24#include <linux/mm.h>
  25#include <linux/export.h>
  26
  27#include <asm/spu.h>
  28#include <asm/spu_csa.h>
  29
  30/*
  31 * This ought to be kept in sync with the powerpc specific do_page_fault
  32 * function. Currently, there are a few corner cases that we haven't had
  33 * to handle fortunately.
  34 */
  35int spu_handle_mm_fault(struct mm_struct *mm, unsigned long ea,
  36                unsigned long dsisr, unsigned *flt)
  37{
  38        struct vm_area_struct *vma;
  39        unsigned long is_write;
  40        int ret;
  41
  42        if (mm == NULL)
  43                return -EFAULT;
  44
  45        if (mm->pgd == NULL)
  46                return -EFAULT;
  47
  48        down_read(&mm->mmap_sem);
  49        ret = -EFAULT;
  50        vma = find_vma(mm, ea);
  51        if (!vma)
  52                goto out_unlock;
  53
  54        if (ea < vma->vm_start) {
  55                if (!(vma->vm_flags & VM_GROWSDOWN))
  56                        goto out_unlock;
  57                if (expand_stack(vma, ea))
  58                        goto out_unlock;
  59        }
  60
  61        is_write = dsisr & MFC_DSISR_ACCESS_PUT;
  62        if (is_write) {
  63                if (!(vma->vm_flags & VM_WRITE))
  64                        goto out_unlock;
  65        } else {
  66                if (dsisr & MFC_DSISR_ACCESS_DENIED)
  67                        goto out_unlock;
  68                if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
  69                        goto out_unlock;
  70        }
  71
  72        ret = 0;
  73        *flt = handle_mm_fault(mm, vma, ea, is_write ? FAULT_FLAG_WRITE : 0);
  74        if (unlikely(*flt & VM_FAULT_ERROR)) {
  75                if (*flt & VM_FAULT_OOM) {
  76                        ret = -ENOMEM;
  77                        goto out_unlock;
  78                } else if (*flt & VM_FAULT_SIGBUS) {
  79                        ret = -EFAULT;
  80                        goto out_unlock;
  81                }
  82                BUG();
  83        }
  84
  85        if (*flt & VM_FAULT_MAJOR)
  86                current->maj_flt++;
  87        else
  88                current->min_flt++;
  89
  90out_unlock:
  91        up_read(&mm->mmap_sem);
  92        return ret;
  93}
  94EXPORT_SYMBOL_GPL(spu_handle_mm_fault);
  95