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>
23 #include <asm/switch_to.h>
24
enter_vmx_usercopy(void)25 int enter_vmx_usercopy(void)
26 {
27 if (in_interrupt())
28 return 0;
29
30 preempt_disable();
31 /*
32 * We need to disable page faults as they can call schedule and
33 * thus make us lose the VMX context. So on page faults, we just
34 * fail which will cause 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 */
exit_vmx_usercopy(void)47 int exit_vmx_usercopy(void)
48 {
49 pagefault_enable();
50 preempt_enable();
51 return 0;
52 }
53
enter_vmx_copy(void)54 int enter_vmx_copy(void)
55 {
56 if (in_interrupt())
57 return 0;
58
59 preempt_disable();
60
61 enable_kernel_altivec();
62
63 return 1;
64 }
65
66 /*
67 * All calls to this function will be optimised into tail calls. We are
68 * passed a pointer to the destination which we return as required by a
69 * memcpy implementation.
70 */
exit_vmx_copy(void * dest)71 void *exit_vmx_copy(void *dest)
72 {
73 preempt_enable();
74 return dest;
75 }
76