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a66086b8 AB |
1 | /* |
2 | * This program is free software; you can redistribute it and/or modify | |
3 | * it under the terms of the GNU General Public License as published by | |
4 | * the Free Software Foundation; either version 2 of the License, or | |
5 | * (at your option) any later version. | |
6 | * | |
7 | * This program is distributed in the hope that it will be useful, | |
8 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
9 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
10 | * GNU General Public License for more details. | |
11 | * | |
12 | * You should have received a copy of the GNU General Public License | |
13 | * along with this program; if not, write to the Free Software | |
14 | * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. | |
15 | * | |
16 | * Copyright (C) IBM Corporation, 2011 | |
17 | * | |
18 | * Authors: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> | |
19 | * Anton Blanchard <anton@au.ibm.com> | |
20 | */ | |
21 | #include <linux/uaccess.h> | |
22 | #include <linux/hardirq.h> | |
ae3a197e | 23 | #include <asm/switch_to.h> |
a66086b8 | 24 | |
6f7839e5 | 25 | int enter_vmx_usercopy(void) |
a66086b8 AB |
26 | { |
27 | if (in_interrupt()) | |
28 | return 0; | |
29 | ||
30 | /* This acts as preempt_disable() as well and will make | |
31 | * enable_kernel_altivec(). We need to disable page faults | |
32 | * as they can call schedule and thus make us lose the VMX | |
33 | * context. So on page faults, we just fail which will cause | |
34 | * a fallback to the normal non-vmx copy. | |
35 | */ | |
36 | pagefault_disable(); | |
37 | ||
38 | enable_kernel_altivec(); | |
39 | ||
40 | return 1; | |
41 | } | |
42 | ||
43 | /* | |
44 | * This function must return 0 because we tail call optimise when calling | |
45 | * from __copy_tofrom_user_power7 which returns 0 on success. | |
46 | */ | |
6f7839e5 | 47 | int exit_vmx_usercopy(void) |
a66086b8 AB |
48 | { |
49 | pagefault_enable(); | |
50 | return 0; | |
51 | } | |
fde69282 AB |
52 | |
53 | int enter_vmx_copy(void) | |
54 | { | |
55 | if (in_interrupt()) | |
56 | return 0; | |
57 | ||
58 | preempt_disable(); | |
59 | ||
60 | enable_kernel_altivec(); | |
61 | ||
62 | return 1; | |
63 | } | |
64 | ||
65 | /* | |
66 | * All calls to this function will be optimised into tail calls. We are | |
67 | * passed a pointer to the destination which we return as required by a | |
68 | * memcpy implementation. | |
69 | */ | |
70 | void *exit_vmx_copy(void *dest) | |
71 | { | |
72 | preempt_enable(); | |
73 | return dest; | |
74 | } |