| Andrew Scull | b4b6d4a | 2019-01-02 15:54:55 +0000 | [diff] [blame] | 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 | #include <asm/asm-prototypes.h> |
| 25 | |
| 26 | int enter_vmx_usercopy(void) |
| 27 | { |
| 28 | if (in_interrupt()) |
| 29 | return 0; |
| 30 | |
| 31 | preempt_disable(); |
| 32 | /* |
| 33 | * We need to disable page faults as they can call schedule and |
| 34 | * thus make us lose the VMX context. So on page faults, we just |
| 35 | * fail which will cause a fallback to the normal non-vmx copy. |
| 36 | */ |
| 37 | pagefault_disable(); |
| 38 | |
| 39 | enable_kernel_altivec(); |
| 40 | |
| 41 | return 1; |
| 42 | } |
| 43 | |
| 44 | /* |
| 45 | * This function must return 0 because we tail call optimise when calling |
| 46 | * from __copy_tofrom_user_power7 which returns 0 on success. |
| 47 | */ |
| 48 | int exit_vmx_usercopy(void) |
| 49 | { |
| 50 | disable_kernel_altivec(); |
| 51 | pagefault_enable(); |
| 52 | preempt_enable(); |
| 53 | return 0; |
| 54 | } |
| 55 | |
| 56 | int enter_vmx_ops(void) |
| 57 | { |
| 58 | if (in_interrupt()) |
| 59 | return 0; |
| 60 | |
| 61 | preempt_disable(); |
| 62 | |
| 63 | enable_kernel_altivec(); |
| 64 | |
| 65 | return 1; |
| 66 | } |
| 67 | |
| 68 | /* |
| 69 | * All calls to this function will be optimised into tail calls. We are |
| 70 | * passed a pointer to the destination which we return as required by a |
| 71 | * memcpy implementation. |
| 72 | */ |
| 73 | void *exit_vmx_ops(void *dest) |
| 74 | { |
| 75 | disable_kernel_altivec(); |
| 76 | preempt_enable(); |
| 77 | return dest; |
| 78 | } |