3092
+ − 1 /* Virtual diry bit implementation for XEmacs.
+ − 2 Copyright (C) 2005 Marcus Crestani.
+ − 3
+ − 4 This file is part of XEmacs.
+ − 5
+ − 6 XEmacs is free software; you can redistribute it and/or modify it
+ − 7 under the terms of the GNU General Public License as published by the
+ − 8 Free Software Foundation; either version 2, or (at your option) any
+ − 9 later version.
+ − 10
+ − 11 XEmacs is distributed in the hope that it will be useful, but WITHOUT
+ − 12 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ − 13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ − 14 for more details.
+ − 15
+ − 16 You should have received a copy of the GNU General Public License
+ − 17 along with XEmacs; see the file COPYING. If not, write to
+ − 18 the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ − 19 Boston, MA 02111-1307, USA. */
+ − 20
+ − 21 /* Synched up with: Not in FSF. */
+ − 22
+ − 23 #include <config.h>
+ − 24 #include "lisp.h"
+ − 25 #include "gc.h"
+ − 26 #include "mc-alloc.h"
+ − 27 #include "vdb.h"
+ − 28
+ − 29 #include <errno.h>
+ − 30 #include <signal.h>
+ − 31 #include <sys/mman.h>
+ − 32 #include <sys/time.h>
+ − 33 #include <sys/resource.h>
+ − 34 #include <unistd.h>
+ − 35 #include <mach/mach.h>
+ − 36 #include <mach/mach_error.h>
+ − 37 #include <architecture/ppc/cframe.h>
+ − 38
+ − 39
+ − 40 /* the structure of an exception msg and its reply */
+ − 41 typedef struct rep_msg {
+ − 42 mach_msg_header_t head;
+ − 43 NDR_record_t NDR;
+ − 44 kern_return_t ret_code;
+ − 45 } mach_reply_msg_t;
+ − 46
+ − 47 typedef struct exc_msg {
+ − 48 mach_msg_header_t head;
+ − 49 /* start of the kernel processed data */
+ − 50 mach_msg_body_t msgh_body;
+ − 51 mach_msg_port_descriptor_t thread;
+ − 52 mach_msg_port_descriptor_t task;
+ − 53 /* end of the kernel processed data */
+ − 54 NDR_record_t NDR;
+ − 55 exception_type_t exception;
+ − 56 mach_msg_type_number_t code_cnt;
+ − 57 exception_data_t code;
+ − 58 /* some padding */
+ − 59 char pad[512];
+ − 60 } mach_exc_msg_t;
+ − 61
+ − 62 /* this is a neat little mach callback */
+ − 63 extern boolean_t exc_server(mach_msg_header_t *in, mach_msg_header_t *out);
+ − 64
+ − 65 /* these are the globals everyone needs */
+ − 66 static size_t page_size = 16384;
+ − 67 static mach_port_t task_self = NULL;
+ − 68 static mach_port_t exc_port = NULL;
+ − 69
+ − 70 /* these are some less neat mach callbacks */
+ − 71 kern_return_t
+ − 72 catch_exception_raise_state
+ − 73 (mach_port_t UNUSED (port),
+ − 74 exception_type_t UNUSED (exception_type),
+ − 75 exception_data_t UNUSED (exception_data),
+ − 76 mach_msg_type_number_t UNUSED (data_cnt),
+ − 77 thread_state_flavor_t *UNUSED (flavor),
+ − 78 thread_state_t UNUSED (in_state),
+ − 79 mach_msg_type_number_t UNUSED (is_cnt),
+ − 80 thread_state_t UNUSED (out_state),
+ − 81 mach_msg_type_number_t UNUSED (os_cnt))
+ − 82 {
+ − 83 return KERN_FAILURE;
+ − 84 }
+ − 85
+ − 86 kern_return_t
+ − 87 catch_exception_raise_state_identitity
+ − 88 (mach_port_t UNUSED (port),
+ − 89 mach_port_t UNUSED (thread_port),
+ − 90 mach_port_t UNUSED (task_port),
+ − 91 exception_type_t UNUSED (exception_type),
+ − 92 exception_data_t UNUSED (exception_data),
+ − 93 mach_msg_type_number_t UNUSED (data_count),
+ − 94 thread_state_flavor_t *UNUSED (state_flavor),
+ − 95 thread_state_t UNUSED (in_state),
+ − 96 mach_msg_type_number_t UNUSED (in_state_count),
+ − 97 thread_state_t UNUSED (out_state),
+ − 98 mach_msg_type_number_t UNUSED (out_state_count))
+ − 99 {
+ − 100 return KERN_FAILURE;
+ − 101 }
+ − 102
+ − 103 kern_return_t
+ − 104 catch_exception_raise
+ − 105 (mach_port_t UNUSED (port),
+ − 106 mach_port_t UNUSED (thread_port),
+ − 107 mach_port_t UNUSED (task_port),
+ − 108 exception_type_t UNUSED (exception_type),
+ − 109 exception_data_t exception_data,
+ − 110 mach_msg_type_number_t UNUSED (data_count))
+ − 111 {
+ − 112 /* kernel return value is in exception_data[0], faulting address in
+ − 113 exception_data[1] */
+ − 114 if (write_barrier_enabled
+ − 115 && (fault_on_protected_page ((void *) exception_data[1]))
+ − 116 && exception_data[0] == KERN_PROTECTION_FAILURE)
+ − 117 {
+ − 118 vdb_designate_modified ((void *) exception_data[1]);
+ − 119 unprotect_page_and_mark_dirty ((void *) exception_data[1]);
+ − 120 return KERN_SUCCESS;
+ − 121 }
+ − 122 else /* default sigsegv handler */
+ − 123 {
+ − 124 fprintf (stderr, "\n\nFatal Error: Received %s (%d) for address 0x%x\n",
+ − 125 "EXC_BAD_ACCESS", exception_data[0], (int) exception_data[1]);
+ − 126 return KERN_FAILURE;
+ − 127 }
+ − 128 }
+ − 129
+ − 130 /* this is the thread which forwards of exceptions read from the exception
+ − 131 server off to our exception catchers and then back out to the other
+ − 132 thread */
+ − 133 void
+ − 134 exception_thread(void)
+ − 135 {
+ − 136 mach_msg_header_t *message;
+ − 137 mach_msg_header_t *reply;
+ − 138 kern_return_t retval;
+ − 139
+ − 140 /* allocate the space for the message and reply */
+ − 141 message = (mach_msg_header_t *) malloc (sizeof (mach_exc_msg_t));
+ − 142 reply = (mach_msg_header_t *) malloc (sizeof (mach_reply_msg_t));
+ − 143 /* do this loop forever */
+ − 144 while (1)
+ − 145 {
+ − 146 /* block until we get an exception message */
+ − 147 retval = mach_msg (message, MACH_RCV_MSG, 0, sizeof (mach_exc_msg_t),
+ − 148 exc_port, MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL);
+ − 149 /* forward off the handling of this message */
+ − 150 if (!exc_server (message, reply))
+ − 151 {
+ − 152 fprintf (stderr, "INTERNAL ERROR: exc_server() failed.\n");
+ − 153 ABORT ();
+ − 154 }
+ − 155 /* send the message back out to the thread */
+ − 156 retval = mach_msg (reply, MACH_SEND_MSG, sizeof (mach_reply_msg_t), 0,
+ − 157 MACH_PORT_NULL, MACH_MSG_TIMEOUT_NONE,
+ − 158 MACH_PORT_NULL);
+ − 159 }
+ − 160 }
+ − 161
+ − 162 /* this initializes the subsystem (sets the exception port, starts the
+ − 163 exception handling thread, etc) */
+ − 164 void
+ − 165 vdb_install_signal_handler (void)
+ − 166 {
+ − 167 mach_port_t thread_self, exc_port_s, exc_thread;
+ − 168 ppc_thread_state_t *exc_thread_state;
+ − 169 mach_msg_type_name_t type;
+ − 170 void *subthread_stack;
+ − 171 kern_return_t retval;
+ − 172
+ − 173 /* get ids for ourself */
+ − 174 if (!task_self)
+ − 175 task_self = mach_task_self ();
+ − 176 thread_self = mach_thread_self ();
+ − 177
+ − 178 /* allocate the port we're going to get exceptions on */
+ − 179 retval = mach_port_allocate (task_self, MACH_PORT_RIGHT_RECEIVE, &exc_port);
+ − 180 if (retval != KERN_SUCCESS)
+ − 181 {
+ − 182 fprintf (stderr, "Couldn't allocate exception port: %s\n",
+ − 183 mach_error_string (retval));
+ − 184 ABORT ();
+ − 185 }
+ − 186
+ − 187 /* extract out the send rights for that port, which the OS needs */
+ − 188 retval = mach_port_extract_right (task_self, exc_port,
+ − 189 MACH_MSG_TYPE_MAKE_SEND,
+ − 190 &exc_port_s, &type);
+ − 191 if(retval != KERN_SUCCESS)
+ − 192 {
+ − 193 fprintf (stderr, "Couldn't extract send rights: %s\n",
+ − 194 mach_error_string (retval));
+ − 195 ABORT ();
+ − 196 }
+ − 197
+ − 198 /* set the exception ports for this thread to the above */
+ − 199 retval = thread_set_exception_ports(thread_self, EXC_MASK_BAD_ACCESS,
+ − 200 exc_port_s, EXCEPTION_DEFAULT,
+ − 201 PPC_THREAD_STATE);
+ − 202 if(retval != KERN_SUCCESS)
+ − 203 {
+ − 204 fprintf (stderr, "Couldn't set exception ports: %s\n",
+ − 205 mach_error_string (retval));
+ − 206 ABORT ();
+ − 207 }
+ − 208
+ − 209 /* set up the subthread */
+ − 210 retval = thread_create(task_self, &exc_thread);
+ − 211 if(retval != KERN_SUCCESS)
+ − 212 {
+ − 213 fprintf (stderr , "Couldn't create exception thread: %s\n",
+ − 214 mach_error_string (retval));
+ − 215 ABORT ();
+ − 216 }
+ − 217 subthread_stack = (void *) malloc (page_size);
+ − 218 subthread_stack =
+ − 219 (char *) subthread_stack + (page_size - C_ARGSAVE_LEN - C_RED_ZONE);
+ − 220 exc_thread_state =
+ − 221 (ppc_thread_state_t *) malloc (sizeof (ppc_thread_state_t));
+ − 222 exc_thread_state->srr0 = (unsigned int) exception_thread;
+ − 223 exc_thread_state->r1 = (unsigned int) subthread_stack;
+ − 224 retval = thread_set_state (exc_thread, PPC_THREAD_STATE,
+ − 225 (thread_state_t) exc_thread_state,
+ − 226 PPC_THREAD_STATE_COUNT);
+ − 227 if (retval != KERN_SUCCESS)
+ − 228 {
+ − 229 fprintf (stderr, "Couldn't set subthread state: %s\n",
+ − 230 mach_error_string (retval));
+ − 231 ABORT ();
+ − 232 }
+ − 233 retval = thread_resume (exc_thread);
+ − 234 if (retval != KERN_SUCCESS)
+ − 235 {
+ − 236 fprintf (stderr, "Couldn't resume subthread: %s\n",
+ − 237 mach_error_string (retval));
+ − 238 ABORT ();
+ − 239 }
+ − 240 allow_incremental_gc = 1;
+ − 241 }
+ − 242
+ − 243 void
+ − 244 vdb_protect (void *ptr, EMACS_INT len)
+ − 245 {
+ − 246 if (mprotect (ptr, len, PROT_READ))
+ − 247 {
+ − 248 perror ("Couldn't mprotect");
+ − 249 ABORT ();
+ − 250 }
+ − 251 }
+ − 252
+ − 253 void
+ − 254 vdb_unprotect (void *ptr, EMACS_INT len)
+ − 255 {
+ − 256 if (mprotect (ptr, len, PROT_READ | PROT_WRITE))
+ − 257 {
+ − 258 perror ("Couldn't mprotect");
+ − 259 ABORT ();
+ − 260 }
+ − 261 }