#include "regcache.h"
#include "objfiles.h"
+/* This module provides support for "Ravenscar" tasks (Ada) when
+ debugging on bare-metal targets.
+
+ The typical situation is when debugging a bare-metal target over
+ the remote protocol. In that situation, the system does not know
+ about high-level comcepts such as threads, only about some code
+ running on one or more CPUs. And since the remote protocol does not
+ provide any handling for CPUs, the de facto standard for handling
+ them is to have one thread per CPU, where the thread's ptid has
+ its lwp field set to the CPU number (eg: 1 for the first CPU,
+ 2 for the second one, etc). This module will make that assumption.
+
+ This module then creates and maintains the list of threads based
+ on the list of Ada tasks, with one thread per Ada tasks. The convention
+ is that threads corresponding to the CPUs (see assumption above)
+ have a ptid_t of the form (PID, LWP, 0), which threads corresponding
+ to our Ada tasks have a ptid_t of the form (PID, 0, TID) where TID
+ is the Ada task's ID as extracted from Ada runtime information.
+
+ Switching to a given Ada tasks (or its underlying thread) is performed
+ by fetching the registers of that tasks from the memory area where
+ the registers were saved. For any of the other operations, the
+ operation is performed by first finding the CPU on which the task
+ is running, switching to its corresponding ptid, and then performing
+ the operation on that ptid using the target beneath us. */
+
/* If non-null, ravenscar task support is enabled. */
static int ravenscar_task_support = 1;
/* 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. */
+/* PTID of the last thread that received an event.
+ This can be useful to determine the associated task that received
+ the event, to make it the current task. */
static ptid_t base_ptid;
static const char running_thread_name[] = "__gnat_running_thread_table";
"system__bb__threads__initialize";
static void ravenscar_update_thread_list (struct target_ops *ops);
-static ptid_t ravenscar_running_thread (void);
+static ptid_t ravenscar_active_task (int cpu);
static const char *ravenscar_extra_thread_info (struct target_ops *self,
struct thread_info *tp);
static int ravenscar_thread_alive (struct target_ops *ops, ptid_t ptid);
static void ravenscar_inferior_created (struct target_ops *target,
int from_tty);
+/* Return nonzero iff PTID corresponds to a ravenscar task. */
+
+static int
+is_ravenscar_task (ptid_t ptid)
+{
+ /* By construction, ravenscar tasks have their LWP set to zero. */
+ return ptid_get_lwp (ptid) == 0;
+}
+
+/* Given PTID, which can be either a ravenscar task or a CPU thread,
+ return which CPU that ptid is running on.
+
+ This assume that PTID is a valid ptid_t. Otherwise, a gdb_assert
+ will be triggered. */
+
+static int
+ravenscar_get_thread_base_cpu (ptid_t ptid)
+{
+ int base_cpu;
+
+ if (is_ravenscar_task (ptid))
+ {
+ struct ada_task_info *task_info = ada_get_task_info_from_ptid (ptid);
+
+ gdb_assert (task_info != NULL);
+ base_cpu = task_info->base_cpu;
+ }
+ else
+ {
+ /* We assume that the LWP of the PTID is equal to the CPU number. */
+ base_cpu = ptid_get_lwp (ptid);
+ }
+
+ return base_cpu;
+}
+
+/* Given a ravenscar task (identified by its ptid_t PTID), return nonzero
+ if this task is the currently active task on the cpu that task is
+ running on.
+
+ In other words, this function determine which CPU this task is
+ currently running on, and then return nonzero if the CPU in question
+ is executing the code for that task. If that's the case, then
+ that task's registers are in the CPU bank. Otherwise, the task
+ is currently suspended, and its registers have been saved in memory. */
+
+static int
+ravenscar_task_is_currently_active (ptid_t ptid)
+{
+ ptid_t active_task_ptid
+ = ravenscar_active_task (ravenscar_get_thread_base_cpu (ptid));
+
+ return ptid_equal (ptid, active_task_ptid);
+}
+
+/* Return the CPU thread (as a ptid_t) on which the given ravenscar
+ task is running.
+
+ This is the thread that corresponds to the CPU on which the task
+ is running. */
+
+static ptid_t
+get_base_thread_from_ravenscar_task (ptid_t ptid)
+{
+ int base_cpu;
+
+ if (!is_ravenscar_task (ptid))
+ return ptid;
+
+ base_cpu = ravenscar_get_thread_base_cpu (ptid);
+ return ptid_build (ptid_get_pid (ptid), base_cpu, 0);
+}
+
/* Fetch the ravenscar running thread from target memory and
update inferior_ptid accordingly. */
static void
ravenscar_update_inferior_ptid (void)
{
+ int base_cpu;
+
base_ptid = inferior_ptid;
+ gdb_assert (!is_ravenscar_task (inferior_ptid));
+ base_cpu = ravenscar_get_thread_base_cpu (base_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
+ /* Make sure we set base_ptid before calling ravenscar_active_task
as the latter relies on it. */
- inferior_ptid = ravenscar_running_thread ();
+ inferior_ptid = ravenscar_active_task (base_cpu);
gdb_assert (!ptid_equal (inferior_ptid, null_ptid));
/* The running thread may not have been added to
static int
ravenscar_runtime_initialized (void)
{
- return (!(ptid_equal (ravenscar_running_thread (), null_ptid)));
+ return (!(ptid_equal (ravenscar_active_task (1), 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)
+get_running_thread_id (int cpu)
{
struct bound_minimal_symbol object_msym = get_running_thread_msymbol ();
int object_size;
if (!object_msym.minsym)
return 0;
- object_addr = BMSYMBOL_VALUE_ADDRESS (object_msym);
object_size = TYPE_LENGTH (builtin_type_void_data_ptr);
+ object_addr = (BMSYMBOL_VALUE_ADDRESS (object_msym)
+ + (cpu - 1) * object_size);
buf_size = object_size;
buf = (gdb_byte *) alloca (buf_size);
read_memory (object_addr, buf, buf_size);
}
static ptid_t
-ravenscar_running_thread (void)
+ravenscar_active_task (int cpu)
{
- CORE_ADDR tid = get_running_thread_id ();
+ CORE_ADDR tid = get_running_thread_id (cpu);
if (tid == 0)
return null_ptid;
struct target_ops *beneath = find_target_beneath (ops);
ptid_t ptid = regcache_get_ptid (regcache);
- if (!ravenscar_runtime_initialized ()
- || ptid_equal (ptid, base_magic_null_ptid)
- || ptid_equal (ptid, ravenscar_running_thread ()))
- beneath->to_fetch_registers (beneath, regcache, regnum);
- else
+ if (ravenscar_runtime_initialized ()
+ && is_ravenscar_task (ptid)
+ && !ravenscar_task_is_currently_active (ptid))
{
struct gdbarch *gdbarch = regcache->arch ();
struct ravenscar_arch_ops *arch_ops
arch_ops->to_fetch_registers (regcache, regnum);
}
+ else
+ beneath->to_fetch_registers (beneath, regcache, regnum);
}
static void
struct target_ops *beneath = find_target_beneath (ops);
ptid_t ptid = regcache_get_ptid (regcache);
- if (!ravenscar_runtime_initialized ()
- || ptid_equal (ptid, base_magic_null_ptid)
- || ptid_equal (ptid, ravenscar_running_thread ()))
- beneath->to_store_registers (beneath, regcache, regnum);
- else
+ if (ravenscar_runtime_initialized ()
+ && is_ravenscar_task (ptid)
+ && !ravenscar_task_is_currently_active (ptid))
{
struct gdbarch *gdbarch = regcache->arch ();
struct ravenscar_arch_ops *arch_ops
arch_ops->to_store_registers (regcache, regnum);
}
+ else
+ beneath->to_store_registers (beneath, regcache, regnum);
}
static void
struct target_ops *beneath = find_target_beneath (self);
ptid_t ptid = regcache_get_ptid (regcache);
- if (!ravenscar_runtime_initialized ()
- || ptid_equal (ptid, base_magic_null_ptid)
- || ptid_equal (ptid, ravenscar_running_thread ()))
- beneath->to_prepare_to_store (beneath, regcache);
- else
+ if (ravenscar_runtime_initialized ()
+ && is_ravenscar_task (ptid)
+ && !ravenscar_task_is_currently_active (ptid))
{
struct gdbarch *gdbarch = regcache->arch ();
struct ravenscar_arch_ops *arch_ops
arch_ops->to_prepare_to_store (regcache);
}
+ else
+ beneath->to_prepare_to_store (beneath, regcache);
}
/* Implement the to_stopped_by_sw_breakpoint target_ops "method". */
struct target_ops *beneath = find_target_beneath (ops);
int result;
- inferior_ptid = base_ptid;
+ inferior_ptid = get_base_thread_from_ravenscar_task (saved_ptid);
result = beneath->to_stopped_by_sw_breakpoint (beneath);
inferior_ptid = saved_ptid;
return result;
struct target_ops *beneath = find_target_beneath (ops);
int result;
- inferior_ptid = base_ptid;
+ inferior_ptid = get_base_thread_from_ravenscar_task (saved_ptid);
result = beneath->to_stopped_by_hw_breakpoint (beneath);
inferior_ptid = saved_ptid;
return result;
struct target_ops *beneath = find_target_beneath (ops);
int result;
- inferior_ptid = base_ptid;
+ inferior_ptid = get_base_thread_from_ravenscar_task (saved_ptid);
result = beneath->to_stopped_by_watchpoint (beneath);
inferior_ptid = saved_ptid;
return result;
struct target_ops *beneath = find_target_beneath (ops);
int result;
- inferior_ptid = base_ptid;
+ inferior_ptid = get_base_thread_from_ravenscar_task (saved_ptid);
result = beneath->to_stopped_data_address (beneath, addr_p);
inferior_ptid = saved_ptid;
return result;
struct target_ops *beneath = find_target_beneath (ops);
int result;
- inferior_ptid = base_ptid;
+ inferior_ptid = get_base_thread_from_ravenscar_task (saved_ptid);
result = beneath->to_core_of_thread (beneath, inferior_ptid);
inferior_ptid = saved_ptid;
return result;
|| !has_ravenscar_runtime ())
return;
- base_magic_null_ptid = inferior_ptid;
ravenscar_update_inferior_ptid ();
push_target (&ravenscar_ops);
}
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