Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/teigland/dlm
[linux-2.6] / 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 0
43         if (!IS_VALID_EA(ea)) {
44                 return -EFAULT;
45         }
46 #endif /* XXX */
47         if (mm == NULL) {
48                 return -EFAULT;
49         }
50         if (mm->pgd == NULL) {
51                 return -EFAULT;
52         }
53
54         down_read(&mm->mmap_sem);
55         vma = find_vma(mm, ea);
56         if (!vma)
57                 goto bad_area;
58         if (vma->vm_start <= ea)
59                 goto good_area;
60         if (!(vma->vm_flags & VM_GROWSDOWN))
61                 goto bad_area;
62         if (expand_stack(vma, ea))
63                 goto bad_area;
64 good_area:
65         is_write = dsisr & MFC_DSISR_ACCESS_PUT;
66         if (is_write) {
67                 if (!(vma->vm_flags & VM_WRITE))
68                         goto bad_area;
69         } else {
70                 if (dsisr & MFC_DSISR_ACCESS_DENIED)
71                         goto bad_area;
72                 if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
73                         goto bad_area;
74         }
75         ret = 0;
76         *flt = handle_mm_fault(mm, vma, ea, is_write);
77         if (unlikely(*flt & VM_FAULT_ERROR)) {
78                 if (*flt & VM_FAULT_OOM) {
79                         ret = -ENOMEM;
80                         goto bad_area;
81                 } else if (*flt & VM_FAULT_SIGBUS) {
82                         ret = -EFAULT;
83                         goto bad_area;
84                 }
85                 BUG();
86         }
87         if (*flt & VM_FAULT_MAJOR)
88                 current->maj_flt++;
89         else
90                 current->min_flt++;
91         up_read(&mm->mmap_sem);
92         return ret;
93
94 bad_area:
95         up_read(&mm->mmap_sem);
96         return -EFAULT;
97 }
98 EXPORT_SYMBOL_GPL(spu_handle_mm_fault);