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spu_fault.c

/*
 * SPU mm fault handler
 *
 * (C) Copyright IBM Deutschland Entwicklung GmbH 2007
 *
 * Author: Arnd Bergmann <arndb@de.ibm.com>
 * Author: Jeremy Kerr <jk@ozlabs.org>
 *
 * 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, 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, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/module.h>

#include <asm/spu.h>
#include <asm/spu_csa.h>

/*
 * This ought to be kept in sync with the powerpc specific do_page_fault
 * function. Currently, there are a few corner cases that we haven't had
 * to handle fortunately.
 */
int spu_handle_mm_fault(struct mm_struct *mm, unsigned long ea,
            unsigned long dsisr, unsigned *flt)
{
      struct vm_area_struct *vma;
      unsigned long is_write;
      int ret;

#if 0
      if (!IS_VALID_EA(ea)) {
            return -EFAULT;
      }
#endif /* XXX */
      if (mm == NULL) {
            return -EFAULT;
      }
      if (mm->pgd == NULL) {
            return -EFAULT;
      }

      down_read(&mm->mmap_sem);
      vma = find_vma(mm, ea);
      if (!vma)
            goto bad_area;
      if (vma->vm_start <= ea)
            goto good_area;
      if (!(vma->vm_flags & VM_GROWSDOWN))
            goto bad_area;
      if (expand_stack(vma, ea))
            goto bad_area;
good_area:
      is_write = dsisr & MFC_DSISR_ACCESS_PUT;
      if (is_write) {
            if (!(vma->vm_flags & VM_WRITE))
                  goto bad_area;
      } else {
            if (dsisr & MFC_DSISR_ACCESS_DENIED)
                  goto bad_area;
            if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
                  goto bad_area;
      }
      ret = 0;
      *flt = handle_mm_fault(mm, vma, ea, is_write);
      if (unlikely(*flt & VM_FAULT_ERROR)) {
            if (*flt & VM_FAULT_OOM) {
                  ret = -ENOMEM;
                  goto bad_area;
            } else if (*flt & VM_FAULT_SIGBUS) {
                  ret = -EFAULT;
                  goto bad_area;
            }
            BUG();
      }
      if (*flt & VM_FAULT_MAJOR)
            current->maj_flt++;
      else
            current->min_flt++;
      up_read(&mm->mmap_sem);
      return ret;

bad_area:
      up_read(&mm->mmap_sem);
      return -EFAULT;
}
EXPORT_SYMBOL_GPL(spu_handle_mm_fault);

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