| 1 | /* Ada Ravenscar thread support. |
| 2 | |
| 3 | Copyright (C) 2004-2014 Free Software Foundation, Inc. |
| 4 | |
| 5 | This file is part of GDB. |
| 6 | |
| 7 | This program is free software; you can redistribute it and/or modify |
| 8 | it under the terms of the GNU General Public License as published by |
| 9 | the Free Software Foundation; either version 3 of the License, or |
| 10 | (at your option) any later version. |
| 11 | |
| 12 | This program is distributed in the hope that it will be useful, |
| 13 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 15 | GNU General Public License for more details. |
| 16 | |
| 17 | You should have received a copy of the GNU General Public License |
| 18 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| 19 | |
| 20 | #include "defs.h" |
| 21 | #include "gdbcore.h" |
| 22 | #include "gdbthread.h" |
| 23 | #include "ada-lang.h" |
| 24 | #include "target.h" |
| 25 | #include "inferior.h" |
| 26 | #include "command.h" |
| 27 | #include "ravenscar-thread.h" |
| 28 | #include "observer.h" |
| 29 | #include <string.h> |
| 30 | #include "gdbcmd.h" |
| 31 | #include "top.h" |
| 32 | #include "regcache.h" |
| 33 | #include "objfiles.h" |
| 34 | |
| 35 | /* If non-null, ravenscar task support is enabled. */ |
| 36 | static int ravenscar_task_support = 1; |
| 37 | |
| 38 | /* This module's target-specific operations. */ |
| 39 | static struct target_ops ravenscar_ops; |
| 40 | |
| 41 | /* Some base target uses a special value for the null PID (exempli gratia |
| 42 | remote). */ |
| 43 | static ptid_t base_magic_null_ptid; |
| 44 | |
| 45 | /* Ptid of the inferior as seen by the process stratum. */ |
| 46 | static ptid_t base_ptid; |
| 47 | |
| 48 | static const char running_thread_name[] = "__gnat_running_thread_table"; |
| 49 | |
| 50 | static const char known_tasks_name[] = "system__tasking__debug__known_tasks"; |
| 51 | static const char first_task_name[] = "system__tasking__debug__first_task"; |
| 52 | |
| 53 | static const char ravenscar_runtime_initializer[] = |
| 54 | "system__bb__threads__initialize"; |
| 55 | |
| 56 | static void ravenscar_find_new_threads (struct target_ops *ops); |
| 57 | static ptid_t ravenscar_running_thread (void); |
| 58 | static char *ravenscar_extra_thread_info (struct target_ops *self, |
| 59 | struct thread_info *tp); |
| 60 | static int ravenscar_thread_alive (struct target_ops *ops, ptid_t ptid); |
| 61 | static void ravenscar_fetch_registers (struct target_ops *ops, |
| 62 | struct regcache *regcache, int regnum); |
| 63 | static void ravenscar_store_registers (struct target_ops *ops, |
| 64 | struct regcache *regcache, int regnum); |
| 65 | static void ravenscar_prepare_to_store (struct target_ops *self, |
| 66 | struct regcache *regcache); |
| 67 | static void ravenscar_resume (struct target_ops *ops, ptid_t ptid, int step, |
| 68 | enum gdb_signal siggnal); |
| 69 | static void ravenscar_mourn_inferior (struct target_ops *ops); |
| 70 | static void ravenscar_update_inferior_ptid (void); |
| 71 | static int has_ravenscar_runtime (void); |
| 72 | static int ravenscar_runtime_initialized (void); |
| 73 | static void ravenscar_inferior_created (struct target_ops *target, |
| 74 | int from_tty); |
| 75 | |
| 76 | /* Fetch the ravenscar running thread from target memory and |
| 77 | update inferior_ptid accordingly. */ |
| 78 | |
| 79 | static void |
| 80 | ravenscar_update_inferior_ptid (void) |
| 81 | { |
| 82 | base_ptid = inferior_ptid; |
| 83 | |
| 84 | /* If the runtime has not been initialized yet, the inferior_ptid is |
| 85 | the only ptid that there is. */ |
| 86 | if (!ravenscar_runtime_initialized ()) |
| 87 | return; |
| 88 | |
| 89 | /* Make sure we set base_ptid before calling ravenscar_running_thread |
| 90 | as the latter relies on it. */ |
| 91 | inferior_ptid = ravenscar_running_thread (); |
| 92 | gdb_assert (!ptid_equal (inferior_ptid, null_ptid)); |
| 93 | |
| 94 | /* The running thread may not have been added to |
| 95 | system.tasking.debug's list yet; so ravenscar_find_new_threads |
| 96 | may not always add it to the thread list. Add it here. */ |
| 97 | if (!find_thread_ptid (inferior_ptid)) |
| 98 | add_thread (inferior_ptid); |
| 99 | } |
| 100 | |
| 101 | /* The Ravenscar Runtime exports a symbol which contains the ID of |
| 102 | the thread that is currently running. Try to locate that symbol |
| 103 | and return its associated minimal symbol. |
| 104 | Return NULL if not found. */ |
| 105 | |
| 106 | static struct bound_minimal_symbol |
| 107 | get_running_thread_msymbol (void) |
| 108 | { |
| 109 | struct bound_minimal_symbol msym; |
| 110 | |
| 111 | msym = lookup_minimal_symbol (running_thread_name, NULL, NULL); |
| 112 | if (!msym.minsym) |
| 113 | /* Older versions of the GNAT runtime were using a different |
| 114 | (less ideal) name for the symbol where the active thread ID |
| 115 | is stored. If we couldn't find the symbol using the latest |
| 116 | name, then try the old one. */ |
| 117 | msym = lookup_minimal_symbol ("running_thread", NULL, NULL); |
| 118 | |
| 119 | return msym; |
| 120 | } |
| 121 | |
| 122 | /* Return True if the Ada Ravenscar run-time can be found in the |
| 123 | application. */ |
| 124 | |
| 125 | static int |
| 126 | has_ravenscar_runtime (void) |
| 127 | { |
| 128 | struct bound_minimal_symbol msym_ravenscar_runtime_initializer = |
| 129 | lookup_minimal_symbol (ravenscar_runtime_initializer, NULL, NULL); |
| 130 | struct bound_minimal_symbol msym_known_tasks = |
| 131 | lookup_minimal_symbol (known_tasks_name, NULL, NULL); |
| 132 | struct bound_minimal_symbol msym_first_task = |
| 133 | lookup_minimal_symbol (first_task_name, NULL, NULL); |
| 134 | struct bound_minimal_symbol msym_running_thread |
| 135 | = get_running_thread_msymbol (); |
| 136 | |
| 137 | return (msym_ravenscar_runtime_initializer.minsym |
| 138 | && (msym_known_tasks.minsym || msym_first_task.minsym) |
| 139 | && msym_running_thread.minsym); |
| 140 | } |
| 141 | |
| 142 | /* Return True if the Ada Ravenscar run-time can be found in the |
| 143 | application, and if it has been initialized on target. */ |
| 144 | |
| 145 | static int |
| 146 | ravenscar_runtime_initialized (void) |
| 147 | { |
| 148 | return (!(ptid_equal (ravenscar_running_thread (), null_ptid))); |
| 149 | } |
| 150 | |
| 151 | /* Return the ID of the thread that is currently running. |
| 152 | Return 0 if the ID could not be determined. */ |
| 153 | |
| 154 | static CORE_ADDR |
| 155 | get_running_thread_id (void) |
| 156 | { |
| 157 | struct bound_minimal_symbol object_msym = get_running_thread_msymbol (); |
| 158 | int object_size; |
| 159 | int buf_size; |
| 160 | gdb_byte *buf; |
| 161 | CORE_ADDR object_addr; |
| 162 | struct type *builtin_type_void_data_ptr = |
| 163 | builtin_type (target_gdbarch ())->builtin_data_ptr; |
| 164 | |
| 165 | if (!object_msym.minsym) |
| 166 | return 0; |
| 167 | |
| 168 | object_addr = BMSYMBOL_VALUE_ADDRESS (object_msym); |
| 169 | object_size = TYPE_LENGTH (builtin_type_void_data_ptr); |
| 170 | buf_size = object_size; |
| 171 | buf = alloca (buf_size); |
| 172 | read_memory (object_addr, buf, buf_size); |
| 173 | return extract_typed_address (buf, builtin_type_void_data_ptr); |
| 174 | } |
| 175 | |
| 176 | static void |
| 177 | ravenscar_resume (struct target_ops *ops, ptid_t ptid, int step, |
| 178 | enum gdb_signal siggnal) |
| 179 | { |
| 180 | struct target_ops *beneath = find_target_beneath (ops); |
| 181 | |
| 182 | inferior_ptid = base_ptid; |
| 183 | beneath->to_resume (beneath, base_ptid, step, siggnal); |
| 184 | } |
| 185 | |
| 186 | static ptid_t |
| 187 | ravenscar_wait (struct target_ops *ops, ptid_t ptid, |
| 188 | struct target_waitstatus *status, |
| 189 | int options) |
| 190 | { |
| 191 | struct target_ops *beneath = find_target_beneath (ops); |
| 192 | |
| 193 | inferior_ptid = base_ptid; |
| 194 | beneath->to_wait (beneath, base_ptid, status, 0); |
| 195 | /* Find any new threads that might have been created, and update |
| 196 | inferior_ptid to the active thread. |
| 197 | |
| 198 | Only do it if the program is still alive, though. Otherwise, |
| 199 | this causes problems when debugging through the remote protocol, |
| 200 | because we might try switching threads (and thus sending packets) |
| 201 | after the remote has disconnected. */ |
| 202 | if (status->kind != TARGET_WAITKIND_EXITED |
| 203 | && status->kind != TARGET_WAITKIND_SIGNALLED) |
| 204 | { |
| 205 | ravenscar_find_new_threads (ops); |
| 206 | ravenscar_update_inferior_ptid (); |
| 207 | } |
| 208 | return inferior_ptid; |
| 209 | } |
| 210 | |
| 211 | /* Add the thread associated to the given TASK to the thread list |
| 212 | (if the thread has already been added, this is a no-op). */ |
| 213 | |
| 214 | static void |
| 215 | ravenscar_add_thread (struct ada_task_info *task) |
| 216 | { |
| 217 | if (find_thread_ptid (task->ptid) == NULL) |
| 218 | add_thread (task->ptid); |
| 219 | } |
| 220 | |
| 221 | static void |
| 222 | ravenscar_find_new_threads (struct target_ops *ops) |
| 223 | { |
| 224 | ada_build_task_list (); |
| 225 | |
| 226 | /* Do not clear the thread list before adding the Ada task, to keep |
| 227 | the thread that the process stratum has included into it |
| 228 | (base_ptid) and the running thread, that may not have been included |
| 229 | to system.tasking.debug's list yet. */ |
| 230 | |
| 231 | iterate_over_live_ada_tasks (ravenscar_add_thread); |
| 232 | } |
| 233 | |
| 234 | static ptid_t |
| 235 | ravenscar_running_thread (void) |
| 236 | { |
| 237 | CORE_ADDR tid = get_running_thread_id (); |
| 238 | |
| 239 | if (tid == 0) |
| 240 | return null_ptid; |
| 241 | else |
| 242 | return ptid_build (ptid_get_pid (base_ptid), 0, tid); |
| 243 | } |
| 244 | |
| 245 | static char * |
| 246 | ravenscar_extra_thread_info (struct target_ops *self, struct thread_info *tp) |
| 247 | { |
| 248 | return "Ravenscar task"; |
| 249 | } |
| 250 | |
| 251 | static int |
| 252 | ravenscar_thread_alive (struct target_ops *ops, ptid_t ptid) |
| 253 | { |
| 254 | /* Ravenscar tasks are non-terminating. */ |
| 255 | return 1; |
| 256 | } |
| 257 | |
| 258 | static char * |
| 259 | ravenscar_pid_to_str (struct target_ops *ops, ptid_t ptid) |
| 260 | { |
| 261 | static char buf[30]; |
| 262 | |
| 263 | snprintf (buf, sizeof (buf), "Thread %#x", (int) ptid_get_tid (ptid)); |
| 264 | return buf; |
| 265 | } |
| 266 | |
| 267 | static void |
| 268 | ravenscar_fetch_registers (struct target_ops *ops, |
| 269 | struct regcache *regcache, int regnum) |
| 270 | { |
| 271 | struct target_ops *beneath = find_target_beneath (ops); |
| 272 | |
| 273 | if (!ravenscar_runtime_initialized () |
| 274 | || ptid_equal (inferior_ptid, base_magic_null_ptid) |
| 275 | || ptid_equal (inferior_ptid, ravenscar_running_thread ())) |
| 276 | beneath->to_fetch_registers (beneath, regcache, regnum); |
| 277 | else |
| 278 | { |
| 279 | struct gdbarch *gdbarch = get_regcache_arch (regcache); |
| 280 | struct ravenscar_arch_ops *arch_ops |
| 281 | = gdbarch_ravenscar_ops (gdbarch); |
| 282 | |
| 283 | arch_ops->to_fetch_registers (regcache, regnum); |
| 284 | } |
| 285 | } |
| 286 | |
| 287 | static void |
| 288 | ravenscar_store_registers (struct target_ops *ops, |
| 289 | struct regcache *regcache, int regnum) |
| 290 | { |
| 291 | struct target_ops *beneath = find_target_beneath (ops); |
| 292 | |
| 293 | if (!ravenscar_runtime_initialized () |
| 294 | || ptid_equal (inferior_ptid, base_magic_null_ptid) |
| 295 | || ptid_equal (inferior_ptid, ravenscar_running_thread ())) |
| 296 | beneath->to_store_registers (beneath, regcache, regnum); |
| 297 | else |
| 298 | { |
| 299 | struct gdbarch *gdbarch = get_regcache_arch (regcache); |
| 300 | struct ravenscar_arch_ops *arch_ops |
| 301 | = gdbarch_ravenscar_ops (gdbarch); |
| 302 | |
| 303 | arch_ops->to_store_registers (regcache, regnum); |
| 304 | } |
| 305 | } |
| 306 | |
| 307 | static void |
| 308 | ravenscar_prepare_to_store (struct target_ops *self, |
| 309 | struct regcache *regcache) |
| 310 | { |
| 311 | struct target_ops *beneath = find_target_beneath (&ravenscar_ops); |
| 312 | |
| 313 | if (!ravenscar_runtime_initialized () |
| 314 | || ptid_equal (inferior_ptid, base_magic_null_ptid) |
| 315 | || ptid_equal (inferior_ptid, ravenscar_running_thread ())) |
| 316 | beneath->to_prepare_to_store (beneath, regcache); |
| 317 | else |
| 318 | { |
| 319 | struct gdbarch *gdbarch = get_regcache_arch (regcache); |
| 320 | struct ravenscar_arch_ops *arch_ops |
| 321 | = gdbarch_ravenscar_ops (gdbarch); |
| 322 | |
| 323 | arch_ops->to_prepare_to_store (regcache); |
| 324 | } |
| 325 | } |
| 326 | |
| 327 | static void |
| 328 | ravenscar_mourn_inferior (struct target_ops *ops) |
| 329 | { |
| 330 | struct target_ops *beneath = find_target_beneath (&ravenscar_ops); |
| 331 | |
| 332 | base_ptid = null_ptid; |
| 333 | beneath->to_mourn_inferior (beneath); |
| 334 | unpush_target (&ravenscar_ops); |
| 335 | } |
| 336 | |
| 337 | /* Observer on inferior_created: push ravenscar thread stratum if needed. */ |
| 338 | |
| 339 | static void |
| 340 | ravenscar_inferior_created (struct target_ops *target, int from_tty) |
| 341 | { |
| 342 | struct ravenscar_arch_ops *ops; |
| 343 | |
| 344 | if (!ravenscar_task_support |
| 345 | || gdbarch_ravenscar_ops (current_inferior ()->gdbarch) == NULL |
| 346 | || !has_ravenscar_runtime ()) |
| 347 | return; |
| 348 | |
| 349 | base_magic_null_ptid = inferior_ptid; |
| 350 | ravenscar_update_inferior_ptid (); |
| 351 | push_target (&ravenscar_ops); |
| 352 | } |
| 353 | |
| 354 | static ptid_t |
| 355 | ravenscar_get_ada_task_ptid (struct target_ops *self, long lwp, long thread) |
| 356 | { |
| 357 | return ptid_build (ptid_get_pid (base_ptid), 0, thread); |
| 358 | } |
| 359 | |
| 360 | static void |
| 361 | init_ravenscar_thread_ops (void) |
| 362 | { |
| 363 | ravenscar_ops.to_shortname = "ravenscar"; |
| 364 | ravenscar_ops.to_longname = "Ravenscar tasks."; |
| 365 | ravenscar_ops.to_doc = "Ravenscar tasks support."; |
| 366 | ravenscar_ops.to_resume = ravenscar_resume; |
| 367 | ravenscar_ops.to_wait = ravenscar_wait; |
| 368 | ravenscar_ops.to_fetch_registers = ravenscar_fetch_registers; |
| 369 | ravenscar_ops.to_store_registers = ravenscar_store_registers; |
| 370 | ravenscar_ops.to_prepare_to_store = ravenscar_prepare_to_store; |
| 371 | ravenscar_ops.to_thread_alive = ravenscar_thread_alive; |
| 372 | ravenscar_ops.to_find_new_threads = ravenscar_find_new_threads; |
| 373 | ravenscar_ops.to_pid_to_str = ravenscar_pid_to_str; |
| 374 | ravenscar_ops.to_extra_thread_info = ravenscar_extra_thread_info; |
| 375 | ravenscar_ops.to_get_ada_task_ptid = ravenscar_get_ada_task_ptid; |
| 376 | ravenscar_ops.to_mourn_inferior = ravenscar_mourn_inferior; |
| 377 | ravenscar_ops.to_has_all_memory = default_child_has_all_memory; |
| 378 | ravenscar_ops.to_has_memory = default_child_has_memory; |
| 379 | ravenscar_ops.to_has_stack = default_child_has_stack; |
| 380 | ravenscar_ops.to_has_registers = default_child_has_registers; |
| 381 | ravenscar_ops.to_has_execution = default_child_has_execution; |
| 382 | ravenscar_ops.to_stratum = thread_stratum; |
| 383 | ravenscar_ops.to_magic = OPS_MAGIC; |
| 384 | } |
| 385 | |
| 386 | /* Command-list for the "set/show ravenscar" prefix command. */ |
| 387 | static struct cmd_list_element *set_ravenscar_list; |
| 388 | static struct cmd_list_element *show_ravenscar_list; |
| 389 | |
| 390 | /* Implement the "set ravenscar" prefix command. */ |
| 391 | |
| 392 | static void |
| 393 | set_ravenscar_command (char *arg, int from_tty) |
| 394 | { |
| 395 | printf_unfiltered (_(\ |
| 396 | "\"set ravenscar\" must be followed by the name of a setting.\n")); |
| 397 | help_list (set_ravenscar_list, "set ravenscar ", -1, gdb_stdout); |
| 398 | } |
| 399 | |
| 400 | /* Implement the "show ravenscar" prefix command. */ |
| 401 | |
| 402 | static void |
| 403 | show_ravenscar_command (char *args, int from_tty) |
| 404 | { |
| 405 | cmd_show_list (show_ravenscar_list, from_tty, ""); |
| 406 | } |
| 407 | |
| 408 | /* Implement the "show ravenscar task-switching" command. */ |
| 409 | |
| 410 | static void |
| 411 | show_ravenscar_task_switching_command (struct ui_file *file, int from_tty, |
| 412 | struct cmd_list_element *c, |
| 413 | const char *value) |
| 414 | { |
| 415 | if (ravenscar_task_support) |
| 416 | fprintf_filtered (file, _("\ |
| 417 | Support for Ravenscar task/thread switching is enabled\n")); |
| 418 | else |
| 419 | fprintf_filtered (file, _("\ |
| 420 | Support for Ravenscar task/thread switching is disabled\n")); |
| 421 | } |
| 422 | |
| 423 | /* Provide a prototype to silence -Wmissing-prototypes. */ |
| 424 | extern void _initialize_ravenscar (void); |
| 425 | |
| 426 | /* Module startup initialization function, automagically called by |
| 427 | init.c. */ |
| 428 | |
| 429 | void |
| 430 | _initialize_ravenscar (void) |
| 431 | { |
| 432 | init_ravenscar_thread_ops (); |
| 433 | base_ptid = null_ptid; |
| 434 | |
| 435 | /* Notice when the inferior is created in order to push the |
| 436 | ravenscar ops if needed. */ |
| 437 | observer_attach_inferior_created (ravenscar_inferior_created); |
| 438 | |
| 439 | complete_target_initialization (&ravenscar_ops); |
| 440 | |
| 441 | add_prefix_cmd ("ravenscar", no_class, set_ravenscar_command, |
| 442 | _("Prefix command for changing Ravenscar-specific settings"), |
| 443 | &set_ravenscar_list, "set ravenscar ", 0, &setlist); |
| 444 | |
| 445 | add_prefix_cmd ("ravenscar", no_class, show_ravenscar_command, |
| 446 | _("Prefix command for showing Ravenscar-specific settings"), |
| 447 | &show_ravenscar_list, "show ravenscar ", 0, &showlist); |
| 448 | |
| 449 | add_setshow_boolean_cmd ("task-switching", class_obscure, |
| 450 | &ravenscar_task_support, _("\ |
| 451 | Enable or disable support for GNAT Ravenscar tasks"), _("\ |
| 452 | Show whether support for GNAT Ravenscar tasks is enabled"), |
| 453 | _("\ |
| 454 | Enable or disable support for task/thread switching with the GNAT\n\ |
| 455 | Ravenscar run-time library for bareboard configuration."), |
| 456 | NULL, show_ravenscar_task_switching_command, |
| 457 | &set_ravenscar_list, &show_ravenscar_list); |
| 458 | } |