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 */
spu_handle_mm_fault(struct mm_struct * mm,unsigned long ea,unsigned long dsisr,unsigned * flt)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);
99