1 /* SPDX-License-Identifier: GPL-2.0+ */ 2 /* 3 * Copyright (c) 2012 The Chromium OS Authors. 4 * 5 * (C) Copyright 2008-2011 6 * Graeme Russ, <graeme.russ (at) gmail.com> 7 * 8 * (C) Copyright 2002 9 * Daniel Engstrm, Omicron Ceti AB, <daniel (at) omicron.se> 10 * 11 * Portions of this file are derived from the Linux kernel source 12 * Copyright (C) 1991, 1992 Linus Torvalds 13 */ 14 15 #ifndef __X86_CONTROL_REGS_H 16 #define __X86_CONTROL_REGS_H 17 18 /* 19 * The memory clobber prevents the GCC from reordering the read/write order 20 * of CR0 21 */ 22 static inline unsigned long read_cr0(void) 23 { 24 unsigned long val; 25 26 asm volatile ("movl %%cr0, %0" : "=r" (val) : : "memory"); 27 return val; 28 } 29 30 static inline void write_cr0(unsigned long val) 31 { 32 asm volatile ("movl %0, %%cr0" : : "r" (val) : "memory"); 33 } 34 35 static inline unsigned long read_cr2(void) 36 { 37 unsigned long val; 38 39 asm volatile("mov %%cr2,%0\n\t" : "=r" (val) : : "memory"); 40 return val; 41 } 42 43 static inline unsigned long read_cr3(void) 44 { 45 unsigned long val; 46 47 asm volatile("mov %%cr3,%0\n\t" : "=r" (val) : : "memory"); 48 return val; 49 } 50 51 static inline unsigned long read_cr4(void) 52 { 53 unsigned long val; 54 55 asm volatile("mov %%cr4,%0\n\t" : "=r" (val) : : "memory"); 56 return val; 57 } 58 59 static inline unsigned long get_debugreg(int regno) 60 { 61 unsigned long val = 0; /* Damn you, gcc! */ 62 63 switch (regno) { 64 case 0: 65 asm("mov %%db0, %0" : "=r" (val)); 66 break; 67 case 1: 68 asm("mov %%db1, %0" : "=r" (val)); 69 break; 70 case 2: 71 asm("mov %%db2, %0" : "=r" (val)); 72 break; 73 case 3: 74 asm("mov %%db3, %0" : "=r" (val)); 75 break; 76 case 6: 77 asm("mov %%db6, %0" : "=r" (val)); 78 break; 79 case 7: 80 asm("mov %%db7, %0" : "=r" (val)); 81 break; 82 default: 83 val = 0; 84 } 85 return val; 86 } 87 88 #endif 89
