tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
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linux
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
13int enter_vmx_usercopy(void)
14{
15 if (in_interrupt())
16 return 0;
17
18 preempt_disable();
19 /*
20 * We need to disable page faults as they can call schedule and
21 * thus make us lose the VMX context. So on page faults, we just
22 * fail which will cause a fallback to the normal non-vmx copy.
23 */
24 pagefault_disable();
25
26 enable_kernel_altivec();
27
28 return 1;
29}
30
31/*
32 * This function must return 0 because we tail call optimise when calling
33 * from __copy_tofrom_user_power7 which returns 0 on success.
34 */
35int exit_vmx_usercopy(void)
36{
37 disable_kernel_altivec();
38 pagefault_enable();
39 preempt_enable();
40 return 0;
41}
42
43int enter_vmx_ops(void)
44{
45 if (in_interrupt())
46 return 0;
47
48 preempt_disable();
49
50 enable_kernel_altivec();
51
52 return 1;
53}
54
55/*
56 * All calls to this function will be optimised into tail calls. We are
57 * passed a pointer to the destination which we return as required by a
58 * memcpy implementation.
59 */
60void *exit_vmx_ops(void *dest)
61{
62 disable_kernel_altivec();
63 preempt_enable();
64 return dest;
65}