usr/src/lib/libc/amd64/unwind/thrp_unwind.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21
  22 /*
  23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26
  27 #pragma ident   "%Z%%M% %I%     %E% SMI"
  28
  29 #include "lint.h"
  30 #include "thr_uberdata.h"
  31 #include "stack_unwind.h"
  32 #include "reg_num.h"
  33 #include <dlfcn.h>
  34
  35 /*
  36  * Due to the subtle mysteries of the amd64 unwind interfaces, the
  37  * "Canonical Frame Address" is 16 bytes higher in memory than the
  38  * value of the frame pointer (%fp).
  39  */
  40 #define CFA_ADJUST      16
  41
  42 /* ARGSUSED */
  43 static _Unwind_Reason_Code
  44 posix_stop_func(
  45         int version,
  46         _Unwind_Action _Unwind_actions,
  47         uint64_t exceptionClass,
  48         struct _Unwind_Exception *exceptionObject,
  49         struct _Unwind_Context *context,
  50         void *func_arg)
  51 {
  52         __cleanup_t **headp = (__cleanup_t **)func_arg;
  53         __cleanup_t *head;
  54         uint64_t cfa;
  55
  56         /*
  57          * If we have reached the origin of the stack, exit now.
  58          */
  59         cfa = _Unwind_GetCFA(context);
  60         if (cfa == 0 || _Unwind_GetGR(context, RET_ADD) == 0) {
  61                 _Unwind_DeleteException(exceptionObject);
  62                 _thrp_exit();
  63                 thr_panic("posix_stop_func(): _thrp_exit() returned");
  64         }
  65
  66         /*
  67          * Call all Posix cleanup handlers for this frame.
  68          */
  69         while ((head = *headp) != NULL &&
  70             (caddr_t)cfa == head->fp + CFA_ADJUST) {
  71                 *headp = head->next;
  72                 (*head->func)(head->arg);
  73         }
  74
  75         return (_URC_NO_REASON);
  76 }
  77
  78 /*
  79  * _ex_unwind() is provided by libCrun to perform stack unwinding
  80  * and calling C++ destructors as needed, interleaved with calling
  81  * Posix cleanup handlers along the way.  If libCrun is not present
  82  * we just need to call the Posix cleanup handlers.
  83  */
  84
  85 /* ARGSUSED */
  86 void
  87 _thrp_unwind(void *dummy)
  88 {
  89         ulwp_t *self = curthread;
  90         __cleanup_t **headp = &self->ul_clnup_hdr;
  91         __cleanup_t *head;
  92         void (*fptr)(_Unwind_Stop_Fn, void *);
  93
  94         /* Do this once per thread exit, not once per unwind frame */
  95         if (self->ul_ex_unwind == NULL &&
  96             (self->ul_ex_unwind = dlsym(RTLD_PROBE, "_ex_unwind")) == NULL)
  97                 self->ul_ex_unwind = (void *)-1;
  98
  99         if (self->ul_ex_unwind == (void *)-1)
 100                 fptr = NULL;
 101         else
 102                 fptr = (void (*)())self->ul_ex_unwind;
 103
 104         /*
 105          * Call _ex_unwind() if it is present (C++ loaded),
 106          * else just call the Posix cleanup handlers.
 107          */
 108         if (fptr != NULL)
 109                 (*fptr)(posix_stop_func, headp);
 110
 111         /*
 112          * Call all remaining Posix cleanup handlers.
 113          */
 114         while ((head = *headp) != NULL) {
 115                 *headp = head->next;
 116                 (*head->func)(head->arg);
 117         }
 118
 119         _thrp_exit();
 120         thr_panic("_thrp_unwind(): _thrp_exit() returned");
 121 }