1/*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright 2000 Brian S. Dean <bsd@bsdhome.com> 5 * All Rights Reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY BRIAN S. DEAN ``AS IS'' AND ANY 18 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 20 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL BRIAN S. DEAN BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 22 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 23 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR 24 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 25 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE 27 * USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH 28 * DAMAGE. 29 */ 30 31#include <sys/cdefs.h> 32__FBSDID("$FreeBSD$"); 33 34#include <machine/reg.h> 35#include <machine/sysarch.h> 36 37int 38i386_set_watch(int watchnum, unsigned int watchaddr, int size, 39 int access, struct dbreg * d) 40{ 41 int i; 42 unsigned int mask; 43 44 if (watchnum == -1) { 45 for (i = 0, mask = 0x3; i < 4; i++, mask <<= 2) 46 if ((DBREG_DRX(d,7) & mask) == 0) 47 break; 48 if (i < 4) 49 watchnum = i; 50 else 51 return -1; 52 } 53 54 switch (access) { 55 case DBREG_DR7_EXEC: 56 size = 1; /* size must be 1 for an execution breakpoint */ 57 /* fall through */ 58 case DBREG_DR7_WRONLY: 59 case DBREG_DR7_RDWR: 60 break; 61 default : return -1; break; 62 } 63 64 /* 65 * we can watch a 1, 2, or 4 byte sized location 66 */ 67 switch (size) { 68 case 1 : mask = 0x00; break; 69 case 2 : mask = 0x01 << 2; break; 70 case 4 : mask = 0x03 << 2; break; 71 default : return -1; break; 72 } 73 74 mask |= access; 75 76 /* clear the bits we are about to affect */ 77 DBREG_DRX(d,7) &= ~((0x3 << (watchnum*2)) | (0x0f << (watchnum*4+16))); 78 79 /* set drN register to the address, N=watchnum */ 80 DBREG_DRX(d,watchnum) = watchaddr; 81 82 /* enable the watchpoint */ 83 DBREG_DRX(d,7) |= (0x2 << (watchnum*2)) | (mask << (watchnum*4+16)); 84 85 return watchnum; 86} 87