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