1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 *
4 * Copyright (C) IBM Corporation, 2011
5 *
6 * Authors: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
7 * Anton Blanchard <anton@au.ibm.com>
8 */
9 #include <linux/uaccess.h>
10 #include <linux/hardirq.h>
11 #include <asm/switch_to.h>
12 #include <asm/asm-prototypes.h>
13
14 int enter_vmx_usercopy(void)
15 {
16 if (in_interrupt())
17 return 0;
18
19 preempt_disable();
20 /*
21 * We need to disable page faults as they can call schedule and
22 * thus make us lose the VMX context. So on page faults, we just
23 * fail which will cause a fallback to the normal non-vmx copy.
24 */
25 pagefault_disable();
26
27 enable_kernel_altivec();
28
29 return 1;
30 }
31
32 /*
33 * This function must return 0 because we tail call optimise when calling
34 * from __copy_tofrom_user_power7 which returns 0 on success.
35 */
36 int exit_vmx_usercopy(void)
37 {
38 disable_kernel_altivec();
39 pagefault_enable();
40 preempt_enable();
41 return 0;
42 }
43
44 int enter_vmx_ops(void)
45 {
46 if (in_interrupt())
47 return 0;
48
49 preempt_disable();
50
51 enable_kernel_altivec();
52
53 return 1;
54 }
55
56 /*
57 * All calls to this function will be optimised into tail calls. We are
58 * passed a pointer to the destination which we return as required by a
59 * memcpy implementation.
60 */
61 void *exit_vmx_ops(void *dest)
62 {
63 disable_kernel_altivec();
64 preempt_enable();
65 return dest;
66 }