/* Ada Ravenscar thread support. Copyright 2004, 2009-2012 Free Software Foundation, Inc. This file is part of GDB. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>. */ #include "defs.h" #include "gdbcore.h" #include "gdbthread.h" #include "ada-lang.h" #include "target.h" #include "inferior.h" #include "command.h" #include "ravenscar-thread.h" #include "observer.h" #include "gdb_string.h" #include "gdbcmd.h" #include "top.h" #include "regcache.h" /* If non-null, ravenscar task support is enabled. */ static int ravenscar_task_support = 1; /* Non-null if the ravenscar thread layer has been pushed on the target stack. */ static int ravenscar_is_open = 0; /* This module's target-specific operations. */ static struct target_ops ravenscar_ops; /* Some base target uses a special value for the null PID (exempli gratia remote). */ static ptid_t base_magic_null_ptid; /* Ptid of the inferior as seen by the process stratum. */ static ptid_t base_ptid; static const char running_thread_name[] = "__gnat_running_thread_table"; static const char known_tasks_name[] = "system__tasking__debug__known_tasks"; static const char first_task_name[] = "system__tasking__debug__first_task"; static const char ravenscar_runtime_initializer[] = "system__bb__threads__initialize"; static struct observer *update_target_observer = NULL; /* Architecture-specific hooks. */ static struct ravenscar_arch_ops* current_arch_ops; static void ravenscar_find_new_threads (struct target_ops *ops); static ptid_t ravenscar_running_thread (void); static char *ravenscar_extra_thread_info (struct thread_info *tp); static int ravenscar_thread_alive (struct target_ops *ops, ptid_t ptid); static void ravenscar_fetch_registers (struct target_ops *ops, struct regcache *regcache, int regnum); static void ravenscar_store_registers (struct target_ops *ops, struct regcache *regcache, int regnum); static void ravenscar_prepare_to_store (struct regcache *regcache); static void ravenscar_initialize (char *name, int from_tty); static void ravenscar_resume (struct target_ops *ops, ptid_t ptid, int step, enum gdb_signal siggnal); static void ravenscar_mourn_inferior (struct target_ops *ops); static void ravenscar_update_inferior_ptid (void); static int has_ravenscar_runtime (void); static int ravenscar_runtime_initialized (void); static void ravenscar_inferior_created (struct target_ops *target, int from_tty); /* Fetch the ravenscar running thread from target memory and update inferior_ptid accordingly. */ static void ravenscar_update_inferior_ptid (void) { base_ptid = inferior_ptid; /* If the runtime has not been initialized yet, the inferior_ptid is the only ptid that there is. */ if (!ravenscar_runtime_initialized ()) return; /* Make sure we set base_ptid before calling ravenscar_running_thread as the latter relies on it. */ inferior_ptid = ravenscar_running_thread (); gdb_assert (!ptid_equal (inferior_ptid, null_ptid)); /* The running thread may not have been added to system.tasking.debug's list yet; so ravenscar_find_new_threads may not always add it to the thread list. Add it here. */ if (!find_thread_ptid (inferior_ptid)) add_thread (inferior_ptid); } /* The Ravenscar Runtime exports a symbol which contains the ID of the thread that is currently running. Try to locate that symbol and return its associated minimal symbol. Return NULL if not found. */ static struct minimal_symbol * get_running_thread_msymbol (void) { struct minimal_symbol *msym; msym = lookup_minimal_symbol (running_thread_name, NULL, NULL); if (!msym) /* Older versions of the GNAT runtime were using a different (less ideal) name for the symbol where the active thread ID is stored. If we couldn't find the symbol using the latest name, then try the old one. */ msym = lookup_minimal_symbol ("running_thread", NULL, NULL); return msym; } /* Return True if the Ada Ravenscar run-time can be found in the application. */ static int has_ravenscar_runtime (void) { struct minimal_symbol *msym_ravenscar_runtime_initializer = lookup_minimal_symbol (ravenscar_runtime_initializer, NULL, NULL); struct minimal_symbol *msym_known_tasks = lookup_minimal_symbol (known_tasks_name, NULL, NULL); struct minimal_symbol *msym_first_task = lookup_minimal_symbol (first_task_name, NULL, NULL); struct minimal_symbol *msym_running_thread = get_running_thread_msymbol (); return (msym_ravenscar_runtime_initializer && (msym_known_tasks || msym_first_task) && msym_running_thread); } /* Return True if the Ada Ravenscar run-time can be found in the application, and if it has been initialized on target. */ static int ravenscar_runtime_initialized (void) { return (!(ptid_equal (ravenscar_running_thread (), null_ptid))); } /* Return the ID of the thread that is currently running. Return 0 if the ID could not be determined. */ static CORE_ADDR get_running_thread_id (void) { const struct minimal_symbol *object_msym = get_running_thread_msymbol (); int object_size; int buf_size; char *buf; CORE_ADDR object_addr; struct type *builtin_type_void_data_ptr = builtin_type (target_gdbarch ())->builtin_data_ptr; if (!object_msym) return 0; object_addr = SYMBOL_VALUE_ADDRESS (object_msym); object_size = TYPE_LENGTH (builtin_type_void_data_ptr); buf_size = object_size; buf = alloca (buf_size); read_memory (object_addr, buf, buf_size); return extract_typed_address (buf, builtin_type_void_data_ptr); } static void ravenscar_close (int quitting) { ravenscar_is_open = 0; } static void ravenscar_resume (struct target_ops *ops, ptid_t ptid, int step, enum gdb_signal siggnal) { struct target_ops *beneath = find_target_beneath (ops); inferior_ptid = base_ptid; beneath->to_resume (beneath, base_ptid, step, siggnal); } static ptid_t ravenscar_wait (struct target_ops *ops, ptid_t ptid, struct target_waitstatus *status, int options) { struct target_ops *beneath = find_target_beneath (ops); inferior_ptid = base_ptid; beneath->to_wait (beneath, base_ptid, status, 0); /* Find any new threads that might have been created, and update inferior_ptid to the active thread. Only do it if the program is still alive, though. Otherwise, this causes problems when debugging through the remote protocol, because we might try switching threads (and thus sending packets) after the remote has disconnected. */ if (status->kind != TARGET_WAITKIND_EXITED && status->kind != TARGET_WAITKIND_SIGNALLED) { ravenscar_find_new_threads (ops); ravenscar_update_inferior_ptid (); } return inferior_ptid; } /* Add the thread associated to the given TASK to the thread list (if the thread has already been added, this is a no-op). */ static void ravenscar_add_thread (struct ada_task_info *task) { if (find_thread_ptid (task->ptid) == NULL) add_thread (task->ptid); } static void ravenscar_find_new_threads (struct target_ops *ops) { ada_build_task_list (); /* Do not clear the thread list before adding the Ada task, to keep the thread that the process stratum has included into it (base_ptid) and the running thread, that may not have been included to system.tasking.debug's list yet. */ iterate_over_live_ada_tasks (ravenscar_add_thread); } static ptid_t ravenscar_running_thread (void) { CORE_ADDR tid = get_running_thread_id (); if (tid == 0) return null_ptid; else return ptid_build (ptid_get_pid (base_ptid), 0, tid); } static char * ravenscar_extra_thread_info (struct thread_info *tp) { return "Ravenscar task"; } static int ravenscar_thread_alive (struct target_ops *ops, ptid_t ptid) { /* Ravenscar tasks are non-terminating. */ return 1; } static char * ravenscar_pid_to_str (struct target_ops *ops, ptid_t ptid) { static char buf[30]; snprintf (buf, sizeof (buf), "Thread %#x", (int) ptid_get_tid (ptid)); return buf; } static void ravenscar_fetch_registers (struct target_ops *ops, struct regcache *regcache, int regnum) { struct target_ops *beneath = find_target_beneath (ops); if (!ravenscar_runtime_initialized () || ptid_equal (inferior_ptid, base_magic_null_ptid) || ptid_equal (inferior_ptid, ravenscar_running_thread ())) beneath->to_fetch_registers (beneath, regcache, regnum); else current_arch_ops->to_fetch_registers (regcache, regnum); } static void ravenscar_store_registers (struct target_ops *ops, struct regcache *regcache, int regnum) { struct target_ops *beneath = find_target_beneath (ops); if (!ravenscar_runtime_initialized () || ptid_equal (inferior_ptid, base_magic_null_ptid) || ptid_equal (inferior_ptid, ravenscar_running_thread ())) beneath->to_store_registers (beneath, regcache, regnum); else current_arch_ops->to_store_registers (regcache, regnum); } static void ravenscar_prepare_to_store (struct regcache *regcache) { struct target_ops *beneath = find_target_beneath (&ravenscar_ops); if (!ravenscar_runtime_initialized () || ptid_equal (inferior_ptid, base_magic_null_ptid) || ptid_equal (inferior_ptid, ravenscar_running_thread ())) beneath->to_prepare_to_store (regcache); else current_arch_ops->to_prepare_to_store (regcache); } static void ravenscar_mourn_inferior (struct target_ops *ops) { struct target_ops *beneath = find_target_beneath (&ravenscar_ops); base_ptid = null_ptid; beneath->to_mourn_inferior (beneath); unpush_target (&ravenscar_ops); } /* Observer on inferior_created: push ravenscar thread stratum if needed. */ static void ravenscar_inferior_created (struct target_ops *target, int from_tty) { if (ravenscar_task_support && has_ravenscar_runtime ()) ravenscar_initialize (NULL, 0); } void ravenscar_register_arch_ops (struct ravenscar_arch_ops *ops) { /* FIXME: To be clean, we would need to handle a list of architectures, just like in remote-wtx-hw.c. However, for now the only Ravenscar run-time for bare board that is implemented in GNAT is for only one architecture: erc32-elf. So no need to care about that for now... */ current_arch_ops = ops; } /* Initialize Ravenscar support. */ static void ravenscar_initialize (char *name, int from_tty) { if (ravenscar_is_open) return; base_magic_null_ptid = inferior_ptid; ravenscar_update_inferior_ptid (); push_target (&ravenscar_ops); ravenscar_is_open = 1; } static ptid_t ravenscar_get_ada_task_ptid (long lwp, long thread) { return ptid_build (ptid_get_pid (base_ptid), 0, thread); } static void init_ravenscar_thread_ops (void) { ravenscar_ops.to_shortname = "ravenscar"; ravenscar_ops.to_longname = "Ravenscar tasks."; ravenscar_ops.to_doc = "Ravenscar tasks support."; ravenscar_ops.to_close = ravenscar_close; ravenscar_ops.to_resume = ravenscar_resume; ravenscar_ops.to_wait = ravenscar_wait; ravenscar_ops.to_fetch_registers = ravenscar_fetch_registers; ravenscar_ops.to_store_registers = ravenscar_store_registers; ravenscar_ops.to_prepare_to_store = ravenscar_prepare_to_store; ravenscar_ops.to_thread_alive = ravenscar_thread_alive; ravenscar_ops.to_find_new_threads = ravenscar_find_new_threads; ravenscar_ops.to_pid_to_str = ravenscar_pid_to_str; ravenscar_ops.to_extra_thread_info = ravenscar_extra_thread_info; ravenscar_ops.to_get_ada_task_ptid = ravenscar_get_ada_task_ptid; ravenscar_ops.to_mourn_inferior = ravenscar_mourn_inferior; ravenscar_ops.to_has_all_memory = default_child_has_all_memory; ravenscar_ops.to_has_memory = default_child_has_memory; ravenscar_ops.to_has_stack = default_child_has_stack; ravenscar_ops.to_has_registers = default_child_has_registers; ravenscar_ops.to_has_execution = default_child_has_execution; ravenscar_ops.to_stratum = thread_stratum; ravenscar_ops.to_magic = OPS_MAGIC; } /* Command-list for the "set/show ravenscar" prefix command. */ static struct cmd_list_element *set_ravenscar_list; static struct cmd_list_element *show_ravenscar_list; /* Implement the "set ravenscar" prefix command. */ static void set_ravenscar_command (char *arg, int from_tty) { printf_unfiltered (_(\ "\"set ravenscar\" must be followed by the name of a setting.\n")); help_list (set_ravenscar_list, "set ravenscar ", -1, gdb_stdout); } /* Implement the "show ravenscar" prefix command. */ static void show_ravenscar_command (char *args, int from_tty) { cmd_show_list (show_ravenscar_list, from_tty, ""); } /* Implement the "show ravenscar task-switching" command. */ static void show_ravenscar_task_switching_command (struct ui_file *file, int from_tty, struct cmd_list_element *c, const char *value) { if (ravenscar_task_support) fprintf_filtered (file, _("\ Support for Ravenscar task/thread switching is enabled\n")); else fprintf_filtered (file, _("\ Support for Ravenscar task/thread switching is disabled\n")); } /* Provide a prototype to silence -Wmissing-prototypes. */ extern void _initialize_ravenscar (void); /* Module startup initialization function, automagically called by init.c. */ void _initialize_ravenscar (void) { init_ravenscar_thread_ops (); base_ptid = null_ptid; /* Notice when the inferior is created in order to push the ravenscar ops if needed. */ observer_attach_inferior_created (ravenscar_inferior_created); add_target (&ravenscar_ops); add_prefix_cmd ("ravenscar", no_class, set_ravenscar_command, _("Prefix command for changing Ravenscar-specific settings"), &set_ravenscar_list, "set ravenscar ", 0, &setlist); add_prefix_cmd ("ravenscar", no_class, show_ravenscar_command, _("Prefix command for showing Ravenscar-specific settings"), &show_ravenscar_list, "show ravenscar ", 0, &showlist); add_setshow_boolean_cmd ("task-switching", class_obscure, &ravenscar_task_support, _("\ Enable or disable support for GNAT Ravenscar tasks"), _("\ Show whether support for GNAT Ravenscar tasks is enabled"), _("\ Enable or disable support for task/thread switching with the GNAT\n\ Ravenscar run-time library for bareboard configuration."), NULL, show_ravenscar_task_switching_command, &set_ravenscar_list, &show_ravenscar_list); }