osfmk/kern/xpr.c

   1 /*
   2  * Copyright (c) 2000-2005 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 /*
  29  * @OSF_COPYRIGHT@
  30  */
  31 /*
  32  * Mach Operating System
  33  * Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
  34  * All Rights Reserved.
  35  *
  36  * Permission to use, copy, modify and distribute this software and its
  37  * documentation is hereby granted, provided that both the copyright
  38  * notice and this permission notice appear in all copies of the
  39  * software, derivative works or modified versions, and any portions
  40  * thereof, and that both notices appear in supporting documentation.
  41  *
  42  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  43  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  44  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  45  *
  46  * Carnegie Mellon requests users of this software to return to
  47  *
  48  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  49  *  School of Computer Science
  50  *  Carnegie Mellon University
  51  *  Pittsburgh PA 15213-3890
  52  *
  53  * any improvements or extensions that they make and grant Carnegie Mellon
  54  * the rights to redistribute these changes.
  55  */
  56 /*
  57  * xpr silent tracing circular buffer.
  58  */
  59
  60 #include <mach/machine/vm_types.h>
  61 #include <kern/xpr.h>
  62 #include <kern/lock.h>
  63 #include <kern/spl.h>
  64 #include <kern/cpu_number.h>
  65 #include <kern/misc_protos.h>
  66 #include <kern/thread.h>
  67 #include <vm/vm_kern.h>
  68 #include <string.h>
  69
  70 /*
  71  *      After a spontaneous reboot, it is desirable to look
  72  *      at the old xpr buffer.  Assuming xprbootstrap allocates
  73  *      the buffer in the same place in physical memory and
  74  *      the reboot doesn't clear memory, this should work.
  75  *      xprptr will be reset, but the saved value should be OK.
  76  *      Just set xprenable false so the buffer isn't overwritten.
  77  */
  78
  79 decl_simple_lock_data(,xprlock)
  80 boolean_t xprenable = TRUE;     /* Enable xpr tracing */
  81 int nxprbufs = 0;       /* Number of contiguous xprbufs allocated */
  82 int xprflags = 0;       /* Bit mask of xpr flags enabled */
  83 struct xprbuf *xprbase; /* Pointer to circular buffer nxprbufs*sizeof(xprbuf)*/
  84 struct xprbuf *xprptr;  /* Currently allocated xprbuf */
  85 struct xprbuf *xprlast; /* Pointer to end of circular buffer */
  86
  87 void
  88 xpr(
  89         const char      *msg,
  90         long            arg1,
  91         long            arg2,
  92         long            arg3,
  93         long            arg4,
  94         long            arg5)
  95 {
  96         spl_t s;
  97         register struct xprbuf *x;
  98
  99         /* If we aren't initialized, ignore trace request */
 100         if (!xprenable || (xprptr == 0))
 101                 return;
 102         /* Guard against all interrupts and allocate next buffer. */
 103
 104         s = splhigh();
 105         simple_lock(&xprlock);
 106         x = xprptr++;
 107         if (xprptr >= xprlast) {
 108                 /* wrap around */
 109                 xprptr = xprbase;
 110         }
 111         /* Save xprptr in allocated memory. */
 112         *(struct xprbuf **)xprlast = xprptr;
 113         simple_unlock(&xprlock);
 114         x->timestamp = XPR_TIMESTAMP;
 115         splx(s);
 116         x->msg = msg;
 117         x->arg1 = arg1;
 118         x->arg2 = arg2;
 119         x->arg3 = arg3;
 120         x->arg4 = arg4;
 121         x->arg5 = arg5;
 122         mp_disable_preemption();
 123         x->cpuinfo = cpu_number();
 124         mp_enable_preemption();
 125 }
 126