along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include "defs.h"
+#include "displaced-stepping.h"
#include "gdbsupport/common-defs.h"
#include "gdbsupport/common-utils.h"
#include "infrun.h"
#include "top.h"
#include "inf-loop.h"
#include "regcache.h"
+#include "utils.h"
#include "value.h"
#include "observable.h"
#include "language.h"
displaced step operation on it. See displaced_step_prepare and
displaced_step_fixup for details. */
-/* Default destructor for displaced_step_copy_insn_closure. */
-
-displaced_step_copy_insn_closure::~displaced_step_copy_insn_closure () = default;
-
-/* Get the displaced stepping state of process PID. */
+/* Get the displaced stepping state of inferior INF. */
static displaced_step_inferior_state *
get_displaced_stepping_state (inferior *inf)
return &inf->displaced_step_state;
}
-/* Returns true if any inferior has a thread doing a displaced
- step. */
+/* Get the displaced stepping state of thread THREAD. */
-static bool
-displaced_step_in_progress_any_inferior ()
+static displaced_step_thread_state *
+get_displaced_stepping_state (thread_info *thread)
{
- for (inferior *i : all_inferiors ())
- {
- if (i->displaced_step_state.step_thread != nullptr)
- return true;
- }
-
- return false;
+ return &thread->displaced_step_state;
}
-/* Return true if thread represented by PTID is doing a displaced
- step. */
+/* Return true if the given thread is doing a displaced step. */
-static int
-displaced_step_in_progress_thread (thread_info *thread)
+static bool
+displaced_step_in_progress (thread_info *thread)
{
gdb_assert (thread != NULL);
- return get_displaced_stepping_state (thread->inf)->step_thread == thread;
+ return get_displaced_stepping_state (thread)->in_progress ();
}
-/* Return true if process PID has a thread doing a displaced step. */
+/* Return true if any thread of this inferior is doing a displaced step. */
-static int
+static bool
displaced_step_in_progress (inferior *inf)
{
- return get_displaced_stepping_state (inf)->step_thread != nullptr;
+ for (thread_info *thread : inf->non_exited_threads ())
+ {
+ if (displaced_step_in_progress (thread))
+ return true;
+ }
+
+ return false;
+}
+
+/* Return true if any thread is doing a displaced step. */
+
+static bool
+displaced_step_in_progress_any_thread ()
+{
+ for (thread_info *thread : all_non_exited_threads ())
+ {
+ if (displaced_step_in_progress (thread))
+ return true;
+ }
+
+ return false;
}
/* If inferior is in displaced stepping, and ADDR equals to starting address
struct displaced_step_copy_insn_closure *
get_displaced_step_copy_insn_closure_by_addr (CORE_ADDR addr)
{
- displaced_step_inferior_state *displaced
- = get_displaced_stepping_state (current_inferior ());
-
- /* If checking the mode of displaced instruction in copy area. */
- if (displaced->step_thread != nullptr
- && displaced->step_copy == addr)
- return displaced->step_closure.get ();
-
+// FIXME: implement me (only needed on ARM).
+// displaced_step_inferior_state *displaced
+// = get_displaced_stepping_state (current_inferior ());
+//
+// /* If checking the mode of displaced instruction in copy area. */
+// if (displaced->step_thread != nullptr
+// && displaced->step_copy == addr)
+// return displaced->step_closure.get ();
+//
return NULL;
}
static bool
gdbarch_supports_displaced_stepping (gdbarch *arch)
{
- /* Only check for the presence of step_copy_insn. Other required methods
- are checked by the gdbarch validation. */
+ /* Only check for the presence of copy_insn. Other required methods
+ are checked by the gdbarch validation to be provided if copy_insn is
+ provided. */
return gdbarch_displaced_step_copy_insn_p (arch);
}
return true;
}
-/* Simple function wrapper around displaced_step_inferior_state::reset. */
+/* Simple function wrapper around displaced_step_thread_state::reset. */
static void
-displaced_step_reset (displaced_step_inferior_state *displaced)
+displaced_step_reset (displaced_step_thread_state *displaced)
{
displaced->reset ();
}
stepped now; 0 if displaced stepping this thread got queued; or -1
if this instruction can't be displaced stepped. */
-static int
+static displaced_step_prepare_status
displaced_step_prepare_throw (thread_info *tp)
{
regcache *regcache = get_thread_regcache (tp);
struct gdbarch *gdbarch = regcache->arch ();
- const address_space *aspace = regcache->aspace ();
- CORE_ADDR original, copy;
- ULONGEST len;
- int status;
+ displaced_step_thread_state *thread_disp_step_state
+ = get_displaced_stepping_state (tp);
/* We should never reach this function if the architecture does not
support displaced stepping. */
jump/branch). */
tp->control.may_range_step = 0;
- /* We have to displaced step one thread at a time, as we only have
- access to a single scratch space per inferior. */
+ /* We are about to start a displaced step for this thread, if one is already
+ in progress, we goofed up somewhere. */
+ gdb_assert (!thread_disp_step_state->in_progress ());
- displaced_step_inferior_state *displaced
- = get_displaced_stepping_state (tp->inf);
+ scoped_restore_current_thread restore_thread;
- if (displaced->step_thread != nullptr)
- {
- /* Already waiting for a displaced step to finish. Defer this
- request and place in queue. */
+ switch_to_thread (tp);
+
+ CORE_ADDR original_pc = regcache_read_pc (regcache);
+
+ displaced_step_prepare_status status =
+ gdbarch_displaced_step_prepare (gdbarch, tp);
+ if (status == DISPLACED_STEP_PREPARE_STATUS_ERROR)
+ {
if (debug_displaced)
fprintf_unfiltered (gdb_stdlog,
- "displaced: deferring step of %s\n",
+ "displaced: failed to prepare (%s)",
target_pid_to_str (tp->ptid).c_str ());
- global_thread_step_over_chain_enqueue (tp);
- return 0;
+ return DISPLACED_STEP_PREPARE_STATUS_ERROR;
}
- else
+ else if (status == DISPLACED_STEP_PREPARE_STATUS_UNAVAILABLE)
{
+ /* Not enough displaced stepping resources available, defer this
+ request by placing it the queue. */
+
if (debug_displaced)
fprintf_unfiltered (gdb_stdlog,
- "displaced: stepping %s now\n",
+ "displaced: not enough resources available, "
+ "deferring step of %s\n",
target_pid_to_str (tp->ptid).c_str ());
- }
- displaced_step_reset (displaced);
-
- scoped_restore_current_thread restore_thread;
-
- switch_to_thread (tp);
-
- original = regcache_read_pc (regcache);
-
- copy = gdbarch_displaced_step_location (gdbarch);
- len = gdbarch_max_insn_length (gdbarch);
-
- if (breakpoint_in_range_p (aspace, copy, len))
- {
- /* There's a breakpoint set in the scratch pad location range
- (which is usually around the entry point). We'd either
- install it before resuming, which would overwrite/corrupt the
- scratch pad, or if it was already inserted, this displaced
- step would overwrite it. The latter is OK in the sense that
- we already assume that no thread is going to execute the code
- in the scratch pad range (after initial startup) anyway, but
- the former is unacceptable. Simply punt and fallback to
- stepping over this breakpoint in-line. */
- if (debug_displaced)
- {
- fprintf_unfiltered (gdb_stdlog,
- "displaced: breakpoint set in scratch pad. "
- "Stepping over breakpoint in-line instead.\n");
- }
-
- return -1;
- }
-
- /* Save the original contents of the copy area. */
- displaced->step_saved_copy.resize (len);
- status = target_read_memory (copy, displaced->step_saved_copy.data (), len);
- if (status != 0)
- throw_error (MEMORY_ERROR,
- _("Error accessing memory address %s (%s) for "
- "displaced-stepping scratch space."),
- paddress (gdbarch, copy), safe_strerror (status));
- if (debug_displaced)
- {
- fprintf_unfiltered (gdb_stdlog, "displaced: saved %s: ",
- paddress (gdbarch, copy));
- displaced_step_dump_bytes (gdb_stdlog,
- displaced->step_saved_copy.data (),
- len);
- };
+ global_thread_step_over_chain_enqueue (tp);
- displaced->step_closure
- = gdbarch_displaced_step_copy_insn (gdbarch, original, copy, regcache);
- if (displaced->step_closure == NULL)
- {
- /* The architecture doesn't know how or want to displaced step
- this instruction or instruction sequence. Fallback to
- stepping over the breakpoint in-line. */
- return -1;
- }
+ return DISPLACED_STEP_PREPARE_STATUS_UNAVAILABLE;
+ }
+
+ gdb_assert (status == DISPLACED_STEP_PREPARE_STATUS_OK);
+
+// FIXME: Should probably replicated in the arch implementation now.
+//
+// if (breakpoint_in_range_p (aspace, copy, len))
+// {
+// /* There's a breakpoint set in the scratch pad location range
+// (which is usually around the entry point). We'd either
+// install it before resuming, which would overwrite/corrupt the
+// scratch pad, or if it was already inserted, this displaced
+// step would overwrite it. The latter is OK in the sense that
+// we already assume that no thread is going to execute the code
+// in the scratch pad range (after initial startup) anyway, but
+// the former is unacceptable. Simply punt and fallback to
+// stepping over this breakpoint in-line. */
+// if (debug_displaced)
+// {
+// fprintf_unfiltered (gdb_stdlog,
+// "displaced: breakpoint set in scratch pad. "
+// "Stepping over breakpoint in-line instead.\n");
+// }
+//
+// gdb_assert (false);
+// gdbarch_displaced_step_release_location (gdbarch, copy);
+//
+// return -1;
+// }
/* Save the information we need to fix things up if the step
succeeds. */
- displaced->step_thread = tp;
- displaced->step_gdbarch = gdbarch;
- displaced->step_original = original;
- displaced->step_copy = copy;
-
- {
- displaced_step_reset_cleanup cleanup (displaced);
-
- /* Resume execution at the copy. */
- regcache_write_pc (regcache, copy);
+ thread_disp_step_state->set (gdbarch);
- cleanup.release ();
- }
+ // FIXME: get it from _prepare?
+ CORE_ADDR displaced_pc = 0;
if (debug_displaced)
- fprintf_unfiltered (gdb_stdlog, "displaced: displaced pc to %s\n",
- paddress (gdbarch, copy));
+ fprintf_unfiltered (gdb_stdlog,
+ "displaced: prepared successfully thread=%s, "
+ "original_pc=%s, displaced_pc=%s\n",
+ target_pid_to_str (tp->ptid).c_str (),
+ paddress (gdbarch, original_pc),
+ paddress (gdbarch, displaced_pc));
- return 1;
+ return DISPLACED_STEP_PREPARE_STATUS_OK;
}
/* Wrapper for displaced_step_prepare_throw that disabled further
attempts at displaced stepping if we get a memory error. */
-static int
+static displaced_step_prepare_status
displaced_step_prepare (thread_info *thread)
{
- int prepared = -1;
+ displaced_step_prepare_status status
+ = DISPLACED_STEP_PREPARE_STATUS_ERROR;
try
{
- prepared = displaced_step_prepare_throw (thread);
+ status = displaced_step_prepare_throw (thread);
}
catch (const gdb_exception_error &ex)
{
displaced_state->failed_before = 1;
}
- return prepared;
-}
-
-static void
-write_memory_ptid (ptid_t ptid, CORE_ADDR memaddr,
- const gdb_byte *myaddr, int len)
-{
- scoped_restore save_inferior_ptid = make_scoped_restore (&inferior_ptid);
-
- inferior_ptid = ptid;
- write_memory (memaddr, myaddr, len);
-}
-
-/* Restore the contents of the copy area for thread PTID. */
-
-static void
-displaced_step_restore (struct displaced_step_inferior_state *displaced,
- ptid_t ptid)
-{
- ULONGEST len = gdbarch_max_insn_length (displaced->step_gdbarch);
-
- write_memory_ptid (ptid, displaced->step_copy,
- displaced->step_saved_copy.data (), len);
- if (debug_displaced)
- fprintf_unfiltered (gdb_stdlog, "displaced: restored %s %s\n",
- target_pid_to_str (ptid).c_str (),
- paddress (displaced->step_gdbarch,
- displaced->step_copy));
+ return status;
}
/* If we displaced stepped an instruction successfully, adjust
-1. If the thread wasn't displaced stepping, return 0. */
static int
-displaced_step_fixup (thread_info *event_thread, enum gdb_signal signal)
+displaced_step_finish (thread_info *event_thread, enum gdb_signal signal)
{
- struct displaced_step_inferior_state *displaced
- = get_displaced_stepping_state (event_thread->inf);
- int ret;
+ displaced_step_thread_state *displaced
+ = get_displaced_stepping_state (event_thread);
- /* Was this event for the thread we displaced? */
- if (displaced->step_thread != event_thread)
+ /* Was this thread performing a displaced step? */
+ if (!displaced->in_progress ())
return 0;
+ displaced_step_reset_cleanup cleanup (displaced);
+
/* Fixup may need to read memory/registers. Switch to the thread
that we're fixing up. Also, target_stopped_by_watchpoint checks
the current thread, and displaced_step_restore performs ptid-dependent
memory accesses using current_inferior() and current_top_target(). */
switch_to_thread (event_thread);
- displaced_step_reset_cleanup cleanup (displaced);
-
- displaced_step_restore (displaced, displaced->step_thread->ptid);
+ /* Do the fixup, and release the resources acquired to do the displaced
+ step. */
+ displaced_step_finish_status finish_status =
+ gdbarch_displaced_step_finish (displaced->get_original_gdbarch (),
+ event_thread, signal);
- /* Did the instruction complete successfully? */
- if (signal == GDB_SIGNAL_TRAP
- && !(target_stopped_by_watchpoint ()
- && (gdbarch_have_nonsteppable_watchpoint (displaced->step_gdbarch)
- || target_have_steppable_watchpoint)))
- {
- /* Fix up the resulting state. */
- gdbarch_displaced_step_fixup (displaced->step_gdbarch,
- displaced->step_closure.get (),
- displaced->step_original,
- displaced->step_copy,
- get_thread_regcache (displaced->step_thread));
- ret = 1;
- }
+ if (finish_status == DISPLACED_STEP_FINISH_STATUS_OK)
+ return 1;
else
- {
- /* Since the instruction didn't complete, all we can do is
- relocate the PC. */
- struct regcache *regcache = get_thread_regcache (event_thread);
- CORE_ADDR pc = regcache_read_pc (regcache);
-
- pc = displaced->step_original + (pc - displaced->step_copy);
- regcache_write_pc (regcache, pc);
- ret = -1;
- }
-
- return ret;
+ return -1;
}
/* Data to be passed around while handling an event. This data is
start_step_over (void)
{
struct thread_info *tp, *next;
+ int started = 0;
/* Don't start a new step-over if we already have an in-line
step-over operation ongoing. */
if (step_over_info_valid_p ())
- return 0;
+ return started;
+
+ /* Steal the global thread step over chain. */
+ thread_info *threads_to_step = global_thread_step_over_chain_head;
+ global_thread_step_over_chain_head = NULL;
+
+ if (debug_infrun)
+ fprintf_unfiltered (gdb_stdlog,
+ "infrun: stealing list of %d threads to step from global queue\n",
+ thread_step_over_chain_length (threads_to_step));
- for (tp = global_thread_step_over_chain_head; tp != NULL; tp = next)
+ for (tp = threads_to_step; tp != NULL; tp = next)
{
struct execution_control_state ecss;
struct execution_control_state *ecs = &ecss;
gdb_assert (!tp->stop_requested);
- next = global_thread_step_over_chain_next (tp);
-
- /* If this inferior already has a displaced step in process,
- don't start a new one. */
- if (displaced_step_in_progress (tp->inf))
- continue;
+ next = thread_step_over_chain_next (threads_to_step, tp);
step_what = thread_still_needs_step_over (tp);
must_be_in_line = ((step_what & STEP_OVER_WATCHPOINT)
/* We currently stop all threads of all processes to step-over
in-line. If we need to start a new in-line step-over, let
any pending displaced steps finish first. */
- if (must_be_in_line && displaced_step_in_progress_any_inferior ())
- return 0;
-
- global_thread_step_over_chain_remove (tp);
+ if (must_be_in_line && displaced_step_in_progress_any_thread ())
+ continue;
- if (global_thread_step_over_chain_head == NULL)
- infrun_log_debug ("step-over queue now empty");
+ thread_step_over_chain_remove (&threads_to_step, tp);
if (tp->control.trap_expected
|| tp->resumed
if (!ecs->wait_some_more)
error (_("Command aborted."));
- gdb_assert (tp->resumed);
+ /* If the thread's step over could not be initiated, it was re-added
+ to the global step over chain. */
+ if (tp->resumed)
+ {
+ infrun_log_debug ("start_step_over: [%s] was resumed.\n",
+ target_pid_to_str (tp->ptid).c_str ());
+ gdb_assert (!thread_is_in_step_over_chain (tp));
+ }
+ else
+ {
+ infrun_log_debug ("infrun: start_step_over: [%s] was NOT resumed.\n",
+ target_pid_to_str (tp->ptid).c_str ());
+ gdb_assert (thread_is_in_step_over_chain (tp));
+
+ }
/* If we started a new in-line step-over, we're done. */
if (step_over_info_valid_p ())
{
gdb_assert (tp->control.trap_expected);
- return 1;
+ started = 1;
+ break;
}
if (!target_is_non_stop_p ())
/* With remote targets (at least), in all-stop, we can't
issue any further remote commands until the program stops
again. */
- return 1;
+ started = 1;
+ break;
}
/* Either the thread no longer needed a step-over, or a new
displaced step on a thread of other process. */
}
- return 0;
+ /* If there are threads left in the THREADS_TO_STEP list, but we have
+ detected that we can't start anything more, put back these threads
+ in the global list. */
+ if (threads_to_step == NULL)
+ {
+ if (debug_infrun)
+ fprintf_unfiltered (gdb_stdlog,
+ "infrun: step-over queue now empty\n");
+ }
+ else
+ {
+ if (debug_infrun)
+ fprintf_unfiltered (gdb_stdlog,
+ "infrun: putting back %d threads to step in global queue\n",
+ thread_step_over_chain_length (threads_to_step));
+ while (threads_to_step != nullptr)
+ {
+ thread_info *thread = threads_to_step;
+
+ /* Remove from that list. */
+ thread_step_over_chain_remove (&threads_to_step, thread);
+
+ /* Add to global list. */
+ global_thread_step_over_chain_enqueue (thread);
+
+ }
+ }
+
+ return started;
}
/* Update global variables holding ptids to hold NEW_PTID if they were
&& sig == GDB_SIGNAL_0
&& !current_inferior ()->waiting_for_vfork_done)
{
- int prepared = displaced_step_prepare (tp);
+ displaced_step_prepare_status prepare_status
+ = displaced_step_prepare (tp);
- if (prepared == 0)
+ if (prepare_status == DISPLACED_STEP_PREPARE_STATUS_UNAVAILABLE)
{
infrun_log_debug ("Got placed in step-over queue");
tp->control.trap_expected = 0;
return;
}
- else if (prepared < 0)
+ else if (prepare_status == DISPLACED_STEP_PREPARE_STATUS_ERROR)
{
/* Fallback to stepping over the breakpoint in-line. */
insert_breakpoints ();
}
- else if (prepared > 0)
+ else if (prepare_status == DISPLACED_STEP_PREPARE_STATUS_OK)
{
- struct displaced_step_inferior_state *displaced;
-
- /* Update pc to reflect the new address from which we will
- execute instructions due to displaced stepping. */
- pc = regcache_read_pc (get_thread_regcache (tp));
-
- displaced = get_displaced_stepping_state (tp->inf);
- step = gdbarch_displaced_step_hw_singlestep
- (gdbarch, displaced->step_closure.get ());
+ step = gdbarch_displaced_step_hw_singlestep (gdbarch, NULL);
}
+ else
+ gdb_assert_not_reached ("invalid displaced_step_prepare_status value");
}
/* Do we need to do it the hard way, w/temp breakpoints? */
struct inferior *inf = current_inferior ();
ptid_t pid_ptid = ptid_t (inf->pid);
- displaced_step_inferior_state *displaced = get_displaced_stepping_state (inf);
+ // displaced_step_inferior_state *displaced = get_displaced_stepping_state (inf);
/* Is any thread of this process displaced stepping? If not,
there's nothing else to do. */
- if (displaced->step_thread == nullptr)
+ if (displaced_step_in_progress (inf))
return;
infrun_log_debug ("displaced-stepping in-process while detaching");
scoped_restore restore_detaching = make_scoped_restore (&inf->detaching, true);
- while (displaced->step_thread != nullptr)
+ // FIXME
+ while (false)
{
struct execution_control_state ecss;
struct execution_control_state *ecs;
t->suspend.waitstatus.kind = TARGET_WAITKIND_IGNORE;
t->suspend.waitstatus_pending_p = 0;
- if (displaced_step_fixup (t, GDB_SIGNAL_0) < 0)
+ if (displaced_step_finish (t, GDB_SIGNAL_0) < 0)
{
/* Add it back to the step-over queue. */
infrun_log_debug ("displaced-step of %s "
sig = (event.ws.kind == TARGET_WAITKIND_STOPPED
? event.ws.value.sig : GDB_SIGNAL_0);
- if (displaced_step_fixup (t, sig) < 0)
+ if (displaced_step_finish (t, sig) < 0)
{
/* Add it back to the step-over queue. */
t->control.trap_expected = 0;
/* If checking displaced stepping is supported, and thread
ecs->ptid is displaced stepping. */
- if (displaced_step_in_progress_thread (ecs->event_thread))
+ if (displaced_step_in_progress (ecs->event_thread))
{
struct inferior *parent_inf
= find_inferior_ptid (ecs->target, ecs->ptid);
if (ecs->ws.kind == TARGET_WAITKIND_FORKED)
{
- struct displaced_step_inferior_state *displaced
- = get_displaced_stepping_state (parent_inf);
+ // struct displaced_step_inferior_state *displaced
+ // = get_displaced_stepping_state (parent_inf);
/* Restore scratch pad for child process. */
- displaced_step_restore (displaced, ecs->ws.value.related_pid);
+ //displaced_step_restore (displaced, ecs->ws.value.related_pid);
+ // FIXME: we should restore all the buffers that were currently in use
}
/* GDB has got TARGET_WAITKIND_FORKED or TARGET_WAITKIND_VFORKED,
has been done. Perform cleanup for parent process here. Note
that this operation also cleans up the child process for vfork,
because their pages are shared. */
- displaced_step_fixup (ecs->event_thread, GDB_SIGNAL_TRAP);
+ displaced_step_finish (ecs->event_thread, GDB_SIGNAL_TRAP);
/* Start a new step-over in another thread if there's one
that needs it. */
start_step_over ();
{
int had_step_over_info;
- displaced_step_fixup (ecs->event_thread,
- ecs->event_thread->suspend.stop_signal);
+ displaced_step_finish (ecs->event_thread,
+ ecs->event_thread->suspend.stop_signal);
had_step_over_info = step_over_info_valid_p ();
projects / deliverable / binutils-gdb.git / blobdiff