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 } 67