1 /* $NetBSD: subr_debug.c,v 1.7 2008/04/30 20:20:53 ad Exp $ */ 2 3 /*- 4 * Copyright (c) 2007, 2008 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Andrew Doran. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 /* 33 * Shared support code for kernels built with the DEBUG option. 34 */ 35 36 #include <sys/cdefs.h> 37 __KERNEL_RCSID(0, "$NetBSD: subr_debug.c,v 1.7 2008/04/30 20:20:53 ad Exp $"); 38 39 #include "opt_ddb.h" 40 41 #include <sys/param.h> 42 #include <sys/proc.h> 43 #include <sys/systm.h> 44 #include <sys/kmem.h> 45 #include <sys/debug.h> 46 #include <sys/atomic.h> 47 #include <sys/cpu.h> 48 49 #include <uvm/uvm_extern.h> 50 51 #include <machine/lock.h> 52 53 /* 54 * Allocation/free validation by pointer address. Introduces 55 * significant overhead and is not enabled by default. Patch 56 * `debug_freecheck' to 1 at boot time to enable. 57 */ 58 #define FREECHECK_BYTES (8*1024*1024) 59 60 typedef struct fcitem { 61 void *i_addr; 62 struct fcitem *i_next; 63 } fcitem_t; 64 65 fcitem_t *freecheck_free; 66 __cpu_simple_lock_t freecheck_lock; 67 u_int debug_freecheck; 68 69 void 70 debug_init(void) 71 { 72 size_t cnt; 73 fcitem_t *i; 74 75 __cpu_simple_lock_init(&freecheck_lock); 76 77 if (debug_freecheck) { 78 i = (fcitem_t *)uvm_km_alloc(kernel_map, FREECHECK_BYTES, 0, 79 UVM_KMF_WIRED); 80 if (i == NULL) { 81 printf("freecheck_init: unable to allocate memory"); 82 return; 83 } 84 85 for (cnt = FREECHECK_BYTES / sizeof(*i); cnt != 0; cnt--) { 86 i->i_next = freecheck_free; 87 freecheck_free = i++; 88 } 89 } 90 } 91 92 void 93 freecheck_out(void **head, void *addr) 94 { 95 fcitem_t *i; 96 int s; 97 98 if (!debug_freecheck) 99 return; 100 101 s = splvm(); 102 __cpu_simple_lock(&freecheck_lock); 103 for (i = *head; i != NULL; i = i->i_next) { 104 if (i->i_addr != addr) 105 continue; 106 __cpu_simple_unlock(&freecheck_lock); 107 splx(s); 108 panic("freecheck_out: %p already out", addr); 109 } 110 if ((i = freecheck_free) != NULL) { 111 freecheck_free = i->i_next; 112 i->i_addr = addr; 113 i->i_next = *head; 114 *head = i; 115 } 116 __cpu_simple_unlock(&freecheck_lock); 117 splx(s); 118 119 if (i == NULL) { 120 if (atomic_swap_uint(&debug_freecheck, 1) == 0) 121 printf("freecheck_out: no more slots\n"); 122 } 123 } 124 125 void 126 freecheck_in(void **head, void *addr) 127 { 128 fcitem_t *i; 129 void *pp; 130 int s; 131 132 if (!debug_freecheck) 133 return; 134 135 s = splvm(); 136 __cpu_simple_lock(&freecheck_lock); 137 for (i = *head, pp = head; i != NULL; pp = &i->i_next, i = i->i_next) { 138 if (i->i_addr == addr) { 139 *(fcitem_t **)pp = i->i_next; 140 i->i_next = freecheck_free; 141 freecheck_free = i; 142 break; 143 } 144 } 145 __cpu_simple_unlock(&freecheck_lock); 146 splx(s); 147 148 if (i != NULL) 149 return; 150 151 #ifdef DDB 152 printf("freecheck_in: %p not out\n", addr); 153 Debugger(); 154 #else 155 panic("freecheck_in: %p not out", addr); 156 #endif 157 } 158