sys/kern/subr_spldebug.c

   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 #define SPLRAISE_STACKLEN 32
  47
  48 void *splraise_retaddrs[MAXCPUS][SPLRAISE_STACKLEN][4];
  49 int splraise_depth[MAXCPUS] = {0};
  50 int spllowered_to[MAXCPUS] = {0};
  51 void *spllowered_from[MAXCPUS][2] = {{0}};
  52 bool spldebug = false;
  53
  54 void    spldebug_start(void);
  55 void    spldebug_stop(void);
  56
  57 void
  58 spldebug_start(void)
  59 {
  60         spldebug = true;
  61 }
  62
  63 void
  64 spldebug_stop(void)
  65 {
  66         spldebug = false;
  67 }
  68
  69 void
  70 spldebug_lower(int ipl)
  71 {
  72         u_int cidx;
  73
  74         if (!spldebug)
  75                 return;
  76
  77         if (ipl == IPL_HIGH)
  78                 return;
  79
  80         cidx = cpu_index(curcpu());
  81
  82         KASSERT(cidx < MAXCPUS);
  83
  84         splraise_depth[cidx] = 0;
  85         spllowered_to[cidx] = ipl;
  86 #if 0
  87         spllowered_from[cidx][0] = return_address(0);
  88         spllowered_from[cidx][1] = return_address(1);
  89 #endif
  90 }
  91
  92 void
  93 spldebug_raise(int ipl)
  94 {
  95         int i;
  96         u_int cidx;
  97         void **retaddrs;
  98
  99         if (!spldebug)
 100                 return;
 101
 102         if (ipl != IPL_HIGH)
 103                 return;
 104
 105         cidx = cpu_index(curcpu());
 106
 107         KASSERT(cidx < MAXCPUS);
 108
 109         if (splraise_depth[cidx] >= SPLRAISE_STACKLEN)
 110                 return;
 111
 112         retaddrs = &splraise_retaddrs[cidx][splraise_depth[cidx]++][0];
 113
 114         retaddrs[0] = retaddrs[1] = retaddrs[2] = retaddrs[3] = NULL;
 115
 116         for (i = 0; i < 4; i++) {
 117                 retaddrs[i] = return_address(i);
 118
 119                 if (retaddrs[i] == NULL)
 120                         break;
 121         }
 122 }