binutils-gdb/gdb/ravenscar-thread.c

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/* 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 target_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 target_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);
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);
}