NetBSD/sys/kern/subr_debug.c

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/* $NetBSD: subr_debug.c,v 1.7 2008/04/30 20:20:53 ad Exp $ */
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/*-
* Copyright (c) 2007, 2008 The NetBSD Foundation, Inc.
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* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Andrew Doran.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/*
* Shared support code for kernels built with the DEBUG option.
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: subr_debug.c,v 1.7 2008/04/30 20:20:53 ad Exp $");
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#include "opt_ddb.h"
#include <sys/param.h>
#include <sys/proc.h>
#include <sys/systm.h>
#include <sys/kmem.h>
#include <sys/debug.h>
#include <sys/atomic.h>
#include <sys/cpu.h>
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#include <uvm/uvm_extern.h>
#include <machine/lock.h>
/*
* Allocation/free validation by pointer address. Introduces
* significant overhead and is not enabled by default. Patch
* `debug_freecheck' to 1 at boot time to enable.
*/
#define FREECHECK_BYTES (8*1024*1024)
typedef struct fcitem {
void *i_addr;
struct fcitem *i_next;
} fcitem_t;
fcitem_t *freecheck_free;
__cpu_simple_lock_t freecheck_lock;
u_int debug_freecheck;
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void
debug_init(void)
{
size_t cnt;
fcitem_t *i;
__cpu_simple_lock_init(&freecheck_lock);
if (debug_freecheck) {
i = (fcitem_t *)uvm_km_alloc(kernel_map, FREECHECK_BYTES, 0,
UVM_KMF_WIRED);
if (i == NULL) {
printf("freecheck_init: unable to allocate memory");
return;
}
for (cnt = FREECHECK_BYTES / sizeof(*i); cnt != 0; cnt--) {
i->i_next = freecheck_free;
freecheck_free = i++;
}
}
}
void
freecheck_out(void **head, void *addr)
{
fcitem_t *i;
int s;
if (!debug_freecheck)
return;
s = splvm();
__cpu_simple_lock(&freecheck_lock);
for (i = *head; i != NULL; i = i->i_next) {
if (i->i_addr != addr)
continue;
__cpu_simple_unlock(&freecheck_lock);
splx(s);
panic("freecheck_out: %p already out", addr);
}
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if ((i = freecheck_free) != NULL) {
freecheck_free = i->i_next;
i->i_addr = addr;
i->i_next = *head;
*head = i;
}
__cpu_simple_unlock(&freecheck_lock);
splx(s);
if (i == NULL) {
if (atomic_swap_uint(&debug_freecheck, 1) == 0)
printf("freecheck_out: no more slots\n");
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}
}
void
freecheck_in(void **head, void *addr)
{
fcitem_t *i;
void *pp;
int s;
if (!debug_freecheck)
return;
s = splvm();
__cpu_simple_lock(&freecheck_lock);
for (i = *head, pp = head; i != NULL; pp = &i->i_next, i = i->i_next) {
if (i->i_addr == addr) {
*(fcitem_t **)pp = i->i_next;
i->i_next = freecheck_free;
freecheck_free = i;
break;
}
}
__cpu_simple_unlock(&freecheck_lock);
splx(s);
if (i != NULL)
return;
#ifdef DDB
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printf("freecheck_in: %p not out\n", addr);
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Debugger();
#else
panic("freecheck_in: %p not out", addr);
#endif
}