Linux Kernel  3.7.1
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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 <[email protected]>
7  * Author: Jeremy Kerr <[email protected]>
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  */
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 }