arch/powerpc/platforms/cell/spu_fault.c

   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/module.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  */
  35 int 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
  90 out_unlock:
  91         up_read(&mm->mmap_sem);
  92         return ret;
  93 }
  94 EXPORT_SYMBOL_GPL(spu_handle_mm_fault);