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subr_spldebug.c revision 1.1 
      1 /*	$NetBSD: subr_spldebug.c,v 1.1 2009/11/03 05:23:28 dyoung Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2009 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by David Young.
      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  * Interrupt priority level debugging code.
     34  */
     35 
     36 #include <sys/cdefs.h>
     37 __KERNEL_RCSID(0, "$NetBSD: subr_spldebug.c,v 1.1 2009/11/03 05:23:28 dyoung Exp $");
     38 
     39 #include <sys/param.h>
     40 #include <sys/spldebug.h>
     41 #include <sys/systm.h>
     42 #include <sys/kernel.h>
     43 #include <sys/cpu.h>
     44 #include <machine/return.h>
     45 
     46 __strong_alias(spldebug_start, _spldebug_start);
     47 __strong_alias(spldebug_stop, _spldebug_stop);
     48 
     49 #define SPLRAISE_STACKLEN 32
     50 
     51 void *splraise_retaddrs[MAXCPUS][SPLRAISE_STACKLEN][4];
     52 int splraise_depth[MAXCPUS] = {0};
     53 int spllowered_to[MAXCPUS] = {0};
     54 void *spllowered_from[MAXCPUS][2] = {{0}};
     55 bool spldebug = false;
     56 
     57 void	_spldebug_start(void);
     58 void	_spldebug_stop(void);
     59 
     60 void
     61 _spldebug_start(void)
     62 {
     63 	spldebug = true;
     64 }
     65 
     66 void
     67 _spldebug_stop(void)
     68 {
     69 	spldebug = false;
     70 }
     71 
     72 void
     73 spldebug_lower(int ipl)
     74 {
     75 	struct cpu_info *ci;
     76 
     77 	if (!spldebug)
     78 		return;
     79 
     80 	if (ipl >= IPL_HIGH)
     81 		return;
     82 
     83 	if (cold)
     84 		ci = &cpu_info_primary;
     85 	else
     86 		ci = curcpu();
     87 
     88 	if (cpu_index(ci) > MAXCPUS)
     89 		return;
     90 
     91 	splraise_depth[cpu_index(ci)] = 0;
     92 	spllowered_to[cpu_index(ci)] = ipl;
     93 #if 0
     94 	spllowered_from[cpu_index(ci)][0] = return_address(0);
     95 	spllowered_from[cpu_index(ci)][1] = return_address(1);
     96 #endif
     97 }
     98 
     99 void
    100 spldebug_raise(int ipl)
    101 {
    102 	int i;
    103 	void **retaddrs;
    104 	struct cpu_info *ci;
    105 
    106 	if (!spldebug)
    107 		return;
    108 
    109 	if (ipl < IPL_HIGH)
    110 		return;
    111 
    112 	if (cold)
    113 		ci = &cpu_info_primary;
    114 	else
    115 		ci = curcpu();
    116 
    117 	if (cpu_index(ci) >= MAXCPUS)
    118 		return;
    119 
    120 	if (splraise_depth[cpu_index(ci)] >= SPLRAISE_STACKLEN)
    121 		return;
    122 
    123 	retaddrs = &splraise_retaddrs[cpu_index(ci)]
    124 	    [splraise_depth[cpu_index(ci)]++][0];
    125 
    126 	retaddrs[0] = retaddrs[1] = retaddrs[2] = retaddrs[3] = NULL;
    127 
    128 	for (i = 0; i < 4; i++) {
    129 		retaddrs[i] = return_address(i);
    130 
    131 		if (retaddrs[i] == NULL)
    132 			break;
    133 	}
    134 }
    135