From: Pedro Alves <pedro@palves.net>
To: gdb-patches@sourceware.org
Subject: [PATCH 10/34] Windows gdb+gdbserver: Move suspending thread to when returning event
Date: Wed, 8 May 2024 00:42:09 +0100 [thread overview]
Message-ID: <20240507234233.371123-11-pedro@palves.net> (raw)
In-Reply-To: <20240507234233.371123-1-pedro@palves.net>
The current code suspends a thread just before calling
GetThreadContext. You can only call GetThreadContext if the thread is
suspended. But, after WaitForDebugEvent, all threads are implicitly
suspended. So I don't think we even needed to call SuspendThread
explictly at all before our GetThreadContext calls.
However, suspending threads when we're about to present a stop to gdb
simplifies adding non-stop support later. This way, the windows
SuspendThread state corresponds to whether a thread is suspended or
resumed from the core's perspective. Curiously, I noticed that Wine's
winedbg does something similar:
https://github.com/wine-mirror/wine/blob/234943344f7495d1e072338f0e06fa2d5cbf0aa1/programs/winedbg/gdbproxy.c#L651
This makes it much easier to reason about a thread's suspend state,
and simplifies adding non-stop mode later on.
Change-Id: Ifd6889a8afc041fad33cd1c4500e38941da6781b
---
gdb/windows-nat.c | 13 +++++--------
gdbserver/win32-low.cc | 5 +++++
2 files changed, 10 insertions(+), 8 deletions(-)
diff --git a/gdb/windows-nat.c b/gdb/windows-nat.c
index 9730377d6fc..aa531c4208a 100644
--- a/gdb/windows-nat.c
+++ b/gdb/windows-nat.c
@@ -710,7 +710,6 @@ windows_nat_target::fetch_registers (struct regcache *regcache, int r)
{
if (th->wow64_context.ContextFlags == 0)
{
- th->suspend ();
th->wow64_context.ContextFlags = CONTEXT_DEBUGGER_DR;
CHECK (Wow64GetThreadContext (th->h, &th->wow64_context));
}
@@ -720,7 +719,6 @@ windows_nat_target::fetch_registers (struct regcache *regcache, int r)
{
if (th->context.ContextFlags == 0)
{
- th->suspend ();
th->context.ContextFlags = CONTEXT_DEBUGGER_DR;
CHECK (GetThreadContext (th->h, &th->context));
}
@@ -1320,12 +1318,6 @@ windows_nat_target::windows_continue (DWORD continue_status, int id,
}
th->resume ();
}
- else
- {
- /* When single-stepping a specific thread, other threads must
- be suspended. */
- th->suspend ();
- }
std::optional<unsigned> err;
do_synchronously ([&] ()
@@ -1816,6 +1808,11 @@ windows_nat_target::wait (ptid_t ptid, struct target_waitstatus *ourstatus,
th->stopped_at_software_breakpoint = true;
th->pc_adjusted = false;
}
+
+ /* All-stop, suspend all threads until they are
+ explicitly resumed. */
+ for (auto &thr : windows_process.thread_list)
+ thr->suspend ();
}
return result;
diff --git a/gdbserver/win32-low.cc b/gdbserver/win32-low.cc
index 0d67cd984e4..8dd8f21330d 100644
--- a/gdbserver/win32-low.cc
+++ b/gdbserver/win32-low.cc
@@ -1226,6 +1226,11 @@ win32_process_target::wait (ptid_t ptid, target_waitstatus *ourstatus,
OUTMSG2 (("Child Stopped with signal = %d \n",
ourstatus->sig ()));
maybe_adjust_pc ();
+
+ /* All-stop, suspend all threads until they are explicitly
+ resumed. */
+ for_each_thread (suspend_one_thread);
+
return debug_event_ptid (&windows_process.current_event);
}
default:
--
2.43.2
next prev parent reply other threads:[~2024-05-07 23:43 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-07 23:41 [PATCH 00/34] Windows non-stop mode Pedro Alves
2024-05-07 23:42 ` [PATCH 01/34] Windows gdb: Dead code in windows_nat_target::do_initial_windows_stuff Pedro Alves
2024-05-08 14:39 ` Tom Tromey
2024-05-07 23:42 ` [PATCH 02/34] Windows gdb: Eliminate global current_process.dr[8] global Pedro Alves
2024-05-08 15:02 ` Tom Tromey
2024-05-07 23:42 ` [PATCH 03/34] Windows gdb+gdbserver: New find_thread, replaces thread_rec(DONT_INVALIDATE_CONTEXT) Pedro Alves
2024-05-08 15:03 ` Tom Tromey
2024-05-07 23:42 ` [PATCH 04/34] Windows gdb: handle_output_debug_string return type Pedro Alves
2024-05-08 14:43 ` Tom Tromey
2024-05-07 23:42 ` [PATCH 05/34] Windows gdb: Eliminate reload_context Pedro Alves
2024-05-08 14:45 ` Tom Tromey
2024-05-07 23:42 ` [PATCH 06/34] Windows gdb+gdbserver: Eliminate thread_rec(INVALIDATE_CONTEXT) calls Pedro Alves
2024-05-08 15:08 ` Tom Tromey
2024-05-07 23:42 ` [PATCH 07/34] Windows gdb+gdbserver: Eliminate DONT_SUSPEND Pedro Alves
2024-05-08 15:12 ` Tom Tromey
2024-05-07 23:42 ` [PATCH 08/34] Windows gdb+gdbserver: Eliminate windows_process_info::thread_rec Pedro Alves
2024-05-08 15:12 ` Tom Tromey
2024-05-07 23:42 ` [PATCH 09/34] Windows gdb: Simplify windows_nat_target::wait Pedro Alves
2024-05-07 23:42 ` Pedro Alves [this message]
2024-05-07 23:42 ` [PATCH 11/34] Windows gdb: Introduce continue_last_debug_event_main_thread Pedro Alves
2024-05-08 14:53 ` Tom Tromey
2024-05-07 23:42 ` [PATCH 12/34] Windows gdb: Introduce windows_continue_flags Pedro Alves
2024-05-08 15:16 ` Tom Tromey
2024-05-07 23:42 ` [PATCH 13/34] Windows gdb: Factor code out of windows_nat_target::windows_continue Pedro Alves
2024-05-08 15:18 ` Tom Tromey
2024-05-07 23:42 ` [PATCH 14/34] Windows gdb: Pending stop and current_event Pedro Alves
2024-05-08 15:18 ` Tom Tromey
2024-05-07 23:42 ` [PATCH 15/34] Windows gdb+gdbserver: Elim desired_stop_thread_id / rework pending_stops Pedro Alves
2024-05-07 23:42 ` [PATCH 16/34] Windows gdb+gdbserver: Introduce get_last_debug_event_ptid Pedro Alves
2024-05-07 23:42 ` [PATCH 17/34] Windows gdb: Can't pass signal to thread other than last stopped thread Pedro Alves
2024-05-07 23:42 ` [PATCH 18/34] Windows gdbserver: Fix scheduler-locking Pedro Alves
2024-05-07 23:42 ` [PATCH 19/34] Windows gdb: Enable "set scheduler-locking on" Pedro Alves
2024-05-08 15:25 ` Tom Tromey
2024-05-07 23:42 ` [PATCH 20/34] Windows gdbserver: Eliminate soft-interrupt mechanism Pedro Alves
2024-05-08 15:26 ` Tom Tromey
2024-05-07 23:42 ` [PATCH 21/34] Windows gdb+gdbserver: Make current_event per-thread state Pedro Alves
2024-05-07 23:42 ` [PATCH 22/34] Windows gdb+gdbserver: Make last_sig " Pedro Alves
2024-05-07 23:42 ` [PATCH 23/34] Windows gdb+gdbserver: Make siginfo_er " Pedro Alves
2024-05-07 23:42 ` [PATCH 24/34] Add backpointer from windows_thread_info to windows_process_info Pedro Alves
2024-05-08 15:28 ` Tom Tromey
2024-05-07 23:42 ` [PATCH 25/34] Windows gdb+gdbserver: Share $_siginfo reading code Pedro Alves
2024-05-08 15:29 ` Tom Tromey
2024-05-07 23:42 ` [PATCH 26/34] Windows gdb+gdbserver: Eliminate struct pending_stop Pedro Alves
2024-05-07 23:42 ` [PATCH 27/34] Windows gdb: Change serial_event management Pedro Alves
2024-05-07 23:42 ` [PATCH 28/34] Windows gdb: cygwin_set_dr => windows_set_dr, etc Pedro Alves
2024-05-08 14:46 ` Tom Tromey
2024-05-07 23:42 ` [PATCH 29/34] windows_per_inferior::continue_one_thread, unify WoW64/non-WoW64 paths Pedro Alves
2024-05-07 23:42 ` [PATCH 30/34] windows-nat.c: Avoid writing debug registers if watchpoint hit pending Pedro Alves
2024-05-07 23:42 ` [PATCH 31/34] Windows gdb+gdbserver: Check whether DBG_REPLY_LATER is available Pedro Alves
2024-05-08 12:45 ` Eli Zaretskii
2024-05-08 21:33 ` [PATCH 31/34 v1.2] " Pedro Alves
2024-05-09 10:07 ` Hannes Domani
[not found] ` <86zfsz5kly.fsf@gnu.org>
2024-05-09 11:11 ` Pedro Alves
2024-05-09 11:47 ` [PATCH 31/34 v1.3] " Pedro Alves
2024-05-09 12:28 ` Eli Zaretskii
2024-05-09 14:17 ` Tom Tromey
[not found] ` <86r0eb5g2n.fsf@gnu.org>
2024-05-09 13:27 ` [PATCH 31/34 v1.2] " Pedro Alves
2024-05-07 23:42 ` [PATCH 32/34] Windows gdb: Add non-stop support Pedro Alves
2024-05-07 23:42 ` [PATCH 33/34] Windows gdb: Watchpoints while running (internal vs external stops) Pedro Alves
2024-05-07 23:42 ` [PATCH 34/34] Mention Windows non-stop support in NEWS Pedro Alves
2024-05-08 15:40 ` [PATCH 00/34] Windows non-stop mode Tom Tromey
2024-05-15 17:35 ` Tom Tromey
2024-05-15 20:39 ` Pedro Alves
2024-05-16 15:53 ` Tom Tromey
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