From 7984d53228ace0dd98b75f566e62f1a0bb2a4a99 Mon Sep 17 00:00:00 2001 From: Pedro Alves Date: Mon, 3 May 2010 04:02:20 +0000 Subject: [PATCH] * linux-low.c (linux_kill, linux_detach): Adjust. (status_pending_p_callback): Remove redundant statement. Check for !TARGET_WAITIKIND_IGNORE, instead of TARGET_WAITKIND_STOPPED. (handle_tracepoints): Make sure LWP is locked. Adjust. (linux_wait_for_event_1): Adjust. (linux_cancel_breakpoints): New. (unsuspend_one_lwp): New. (unsuspend_all_lwps): New. (linux_wait_1): If finishing a step-over, unsuspend all lwps. (send_sigstop_callback): Change return type to int, add new `except' parameter and handle it. (suspend_and_send_sigstop_callback): New. (stop_all_lwps): Add new `suspend' and `expect' parameters, and pass them down. If SUSPEND, also increment the lwp's suspend count. (linux_resume_one_lwp): Add notice about resuming a suspended LWP. (need_step_over_p): Don't consider suspended LWPs. (start_step_over): Adjust. (proceed_one_lwp): Change return type to int, add new `except' parameter and handle it. (unsuspend_and_proceed_one_lwp): New. (proceed_all_lwps): Use find_inferior instead of for_each_inferior. (unstop_all_lwps): Add `unsuspend' parameter. If UNSUSPEND, them also decrement the suspend count of LWPs. Pass `except' down, instead of hacking its suspend count. (linux_pause_all): Add `freeze' parameter. Adjust. (linux_unpause_all): New. (linux_target_ops): Install linux_unpause_all. * server.c (handle_status): Adjust. * target.h (struct target_ops): New fields `unpause_all' and `cancel_breakpoints'. Add new parameter to `pause_all'. (pause_all): Add new `freeze' parameter. (unpause_all): New. (cancel_breakpoints): New. * tracepoint.c (clear_installed_tracepoints): Pause threads, and cancel breakpoints. (cmd_qtstart): Pause threads. (stop_tracing): Pause threads, and cancel breakpoints. * win32-low.c (win32_target_ops): Adjust. --- gdb/gdbserver/ChangeLog | 44 ++++++++ gdb/gdbserver/linux-low.c | 204 +++++++++++++++++++++++++++++-------- gdb/gdbserver/server.c | 2 +- gdb/gdbserver/target.h | 42 ++++++-- gdb/gdbserver/tracepoint.c | 19 ++++ gdb/gdbserver/win32-low.c | 3 +- 6 files changed, 260 insertions(+), 54 deletions(-) diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog index e4058dc4637..2cb1ac010e4 100644 --- a/gdb/gdbserver/ChangeLog +++ b/gdb/gdbserver/ChangeLog @@ -1,3 +1,47 @@ +2010-05-03 Pedro Alves + + * linux-low.c (linux_kill, linux_detach): Adjust. + (status_pending_p_callback): Remove redundant statement. Check + for !TARGET_WAITIKIND_IGNORE, instead of + TARGET_WAITKIND_STOPPED. + (handle_tracepoints): Make sure LWP is locked. Adjust. + (linux_wait_for_event_1): Adjust. + (linux_cancel_breakpoints): New. + (unsuspend_one_lwp): New. + (unsuspend_all_lwps): New. + (linux_wait_1): If finishing a step-over, unsuspend all lwps. + (send_sigstop_callback): Change return type to int, add new + `except' parameter and handle it. + (suspend_and_send_sigstop_callback): New. + (stop_all_lwps): Add new `suspend' and `expect' parameters, and + pass them down. If SUSPEND, also increment the lwp's suspend + count. + (linux_resume_one_lwp): Add notice about resuming a suspended LWP. + (need_step_over_p): Don't consider suspended LWPs. + (start_step_over): Adjust. + (proceed_one_lwp): Change return type to int, add new `except' + parameter and handle it. + (unsuspend_and_proceed_one_lwp): New. + (proceed_all_lwps): Use find_inferior instead of + for_each_inferior. + (unstop_all_lwps): Add `unsuspend' parameter. If UNSUSPEND, them + also decrement the suspend count of LWPs. Pass `except' down, + instead of hacking its suspend count. + (linux_pause_all): Add `freeze' parameter. Adjust. + (linux_unpause_all): New. + (linux_target_ops): Install linux_unpause_all. + * server.c (handle_status): Adjust. + * target.h (struct target_ops): New fields `unpause_all' and + `cancel_breakpoints'. Add new parameter to `pause_all'. + (pause_all): Add new `freeze' parameter. + (unpause_all): New. + (cancel_breakpoints): New. + * tracepoint.c (clear_installed_tracepoints): Pause threads, and + cancel breakpoints. + (cmd_qtstart): Pause threads. + (stop_tracing): Pause threads, and cancel breakpoints. + * win32-low.c (win32_target_ops): Adjust. + 2010-05-03 Pedro Alves * linux-low.c (linux_wait_for_event_1): Move passing the signal to diff --git a/gdb/gdbserver/linux-low.c b/gdb/gdbserver/linux-low.c index 36930febd08..4a19db74008 100644 --- a/gdb/gdbserver/linux-low.c +++ b/gdb/gdbserver/linux-low.c @@ -139,14 +139,14 @@ static int new_inferior; static void linux_resume_one_lwp (struct lwp_info *lwp, int step, int signal, siginfo_t *info); static void linux_resume (struct thread_resume *resume_info, size_t n); -static void stop_all_lwps (void); +static void stop_all_lwps (int suspend, struct lwp_info *except); +static void unstop_all_lwps (int unsuspend, struct lwp_info *except); static int linux_wait_for_event (ptid_t ptid, int *wstat, int options); static void *add_lwp (ptid_t ptid); static int linux_stopped_by_watchpoint (void); static void mark_lwp_dead (struct lwp_info *lwp, int wstat); static int linux_core_of_thread (ptid_t ptid); static void proceed_all_lwps (void); -static void unstop_all_lwps (struct lwp_info *except); static int finish_step_over (struct lwp_info *lwp); static CORE_ADDR get_stop_pc (struct lwp_info *lwp); static int kill_lwp (unsigned long lwpid, int signo); @@ -765,7 +765,7 @@ linux_kill (int pid) /* If we're killing a running inferior, make sure it is stopped first, as PTRACE_KILL will not work otherwise. */ - stop_all_lwps (); + stop_all_lwps (0, NULL); find_inferior (&all_threads, linux_kill_one_lwp, &pid); @@ -790,7 +790,7 @@ linux_kill (int pid) /* Since we presently can only stop all lwps of all processes, we need to unstop lwps of other processes. */ - unstop_all_lwps (NULL); + unstop_all_lwps (0, NULL); return 0; } @@ -840,7 +840,7 @@ linux_detach (int pid) the thread is stopped to sucessfully detach. Second, thread_db may need to uninstall thread event breakpoints from memory, which only works with a stopped process anyway. */ - stop_all_lwps (); + stop_all_lwps (0, NULL); #ifdef USE_THREAD_DB thread_db_detach (process); @@ -852,7 +852,7 @@ linux_detach (int pid) /* Since we presently can only stop all lwps of all processes, we need to unstop lwps of other processes. */ - unstop_all_lwps (NULL); + unstop_all_lwps (0, NULL); return 0; } @@ -928,7 +928,7 @@ status_pending_p_callback (struct inferior_list_entry *entry, void *arg) { struct lwp_info *lwp = (struct lwp_info *) entry; ptid_t ptid = * (ptid_t *) arg; - struct thread_info *thread = get_lwp_thread (lwp); + struct thread_info *thread; /* Check if we're only interested in events from a specific process or its lwps. */ @@ -941,7 +941,7 @@ status_pending_p_callback (struct inferior_list_entry *entry, void *arg) /* If we got a `vCont;t', but we haven't reported a stop yet, do report any status pending the LWP may have. */ if (thread->last_resume_kind == resume_stop - && thread->last_status.kind == TARGET_WAITKIND_STOPPED) + && thread->last_status.kind != TARGET_WAITKIND_IGNORE) return 0; return lwp->status_pending_p; @@ -1113,6 +1113,12 @@ handle_tracepoints (struct lwp_info *lwp) struct thread_info *tinfo = get_lwp_thread (lwp); int tpoint_related_event = 0; + /* If this tracepoint hit causes a tracing stop, we'll immediately + uninsert tracepoints. To do this, we temporarily pause all + threads, unpatch away, and then unpause threads. We need to make + sure the unpausing doesn't resume LWP too. */ + lwp->suspended++; + /* And we need to be sure that any all-threads-stopping doesn't try to move threads out of the jump pads, as it could deadlock the inferior (LWP could be in the jump pad, maybe even holding the @@ -1125,6 +1131,10 @@ handle_tracepoints (struct lwp_info *lwp) actions. */ tpoint_related_event |= tracepoint_was_hit (tinfo, lwp->stop_pc); + lwp->suspended--; + + gdb_assert (lwp->suspended == 0); + if (tpoint_related_event) { if (debug_threads) @@ -1290,7 +1300,7 @@ linux_wait_for_event_1 (ptid_t ptid, int *wstat, int options) /* Cancel the step-over operation --- the thread that started it is gone. */ if (finish_step_over (event_child)) - unstop_all_lwps (event_child); + unstop_all_lwps (1, event_child); delete_lwp (event_child); return lwpid; } @@ -1484,6 +1494,12 @@ cancel_breakpoints_callback (struct inferior_list_entry *entry, void *data) return 0; } +static void +linux_cancel_breakpoints (void) +{ + find_inferior (&all_lwps, cancel_breakpoints_callback, NULL); +} + /* Select one LWP out of those that have events pending. */ static void @@ -1551,6 +1567,32 @@ gdb_wants_lwp_stopped (struct inferior_list_entry *entry) thread->last_resume_kind = resume_stop; } +/* Decrement the suspend count of an LWP. */ + +static int +unsuspend_one_lwp (struct inferior_list_entry *entry, void *except) +{ + struct lwp_info *lwp = (struct lwp_info *) entry; + + /* Ignore EXCEPT. */ + if (lwp == except) + return 0; + + lwp->suspended--; + + gdb_assert (lwp->suspended >= 0); + return 0; +} + +/* Decrement the suspend count of all LWPs, except EXCEPT, if non + NULL. */ + +static void +unsuspend_all_lwps (struct lwp_info *except) +{ + find_inferior (&all_lwps, unsuspend_one_lwp, except); +} + /* Set all LWP's states as "want-stopped". */ static void @@ -1806,12 +1848,17 @@ retry: (*the_low_target.set_pc) (regcache, event_child->stop_pc); } - /* We've finished stepping over a breakpoint. We've stopped all - LWPs momentarily except the stepping one. This is where we - resume them all again. We're going to keep waiting, so use - proceed, which handles stepping over the next breakpoint. */ + /* We may have finished stepping over a breakpoint. If so, + we've stopped and suspended all LWPs momentarily except the + stepping one. This is where we resume them all again. We're + going to keep waiting, so use proceed, which handles stepping + over the next breakpoint. */ if (debug_threads) fprintf (stderr, "proceeding all threads.\n"); + + if (step_over_finished) + unsuspend_all_lwps (event_child); + proceed_all_lwps (); goto retry; } @@ -1833,7 +1880,7 @@ retry: if (!non_stop) { /* In all-stop, stop all threads. */ - stop_all_lwps (); + stop_all_lwps (0, NULL); /* If we're not waiting for a specific LWP, choose an event LWP from among those that have had events. Giving equal priority @@ -1863,7 +1910,7 @@ retry: threads stopped by now anyway. In non-stop, we need to re-resume threads that GDB wanted to be running. */ if (step_over_finished) - unstop_all_lwps (event_child); + unstop_all_lwps (1, event_child); } ourstatus->kind = TARGET_WAITKIND_STOPPED; @@ -1912,7 +1959,8 @@ retry: ourstatus->kind, ourstatus->value.sig); - get_lwp_thread (event_child)->last_status = *ourstatus; + current_inferior->last_status = *ourstatus; + return ptid_of (event_child); } @@ -2021,15 +2069,37 @@ send_sigstop (struct lwp_info *lwp) kill_lwp (pid, SIGSTOP); } -static void -send_sigstop_callback (struct inferior_list_entry *entry) +static int +send_sigstop_callback (struct inferior_list_entry *entry, void *except) { struct lwp_info *lwp = (struct lwp_info *) entry; + /* Ignore EXCEPT. */ + if (lwp == except) + return 0; + if (lwp->stopped) - return; + return 0; send_sigstop (lwp); + return 0; +} + +/* Increment the suspend count of an LWP, and stop it, if not stopped + yet. */ +static int +suspend_and_send_sigstop_callback (struct inferior_list_entry *entry, + void *except) +{ + struct lwp_info *lwp = (struct lwp_info *) entry; + + /* Ignore EXCEPT. */ + if (lwp == except) + return 0; + + lwp->suspended++; + + return send_sigstop_callback (entry, except); } static void @@ -2140,11 +2210,19 @@ wait_for_sigstop (struct inferior_list_entry *entry) } } +/* Stop all lwps that aren't stopped yet, except EXCEPT, if not NULL. + If SUSPEND, then also increase the suspend count of every LWP, + except EXCEPT. */ + static void -stop_all_lwps (void) +stop_all_lwps (int suspend, struct lwp_info *except) { stopping_threads = 1; - for_each_inferior (&all_lwps, send_sigstop_callback); + + if (suspend) + find_inferior (&all_lwps, suspend_and_send_sigstop_callback, except); + else + find_inferior (&all_lwps, send_sigstop_callback, except); for_each_inferior (&all_lwps, wait_for_sigstop); stopping_threads = 0; } @@ -2227,6 +2305,9 @@ linux_resume_one_lwp (struct lwp_info *lwp, { if (step == 0) fprintf (stderr, "BAD - reinserting but not stepping.\n"); + if (lwp->suspended) + fprintf (stderr, "BAD - reinserting and suspended(%d).\n", + lwp->suspended); step = 1; } @@ -2423,6 +2504,17 @@ need_step_over_p (struct inferior_list_entry *entry, void *dummy) return 0; } + gdb_assert (lwp->suspended >= 0); + + if (lwp->suspended) + { + if (debug_threads) + fprintf (stderr, + "Need step over [LWP %ld]? Ignoring, suspended\n", + lwpid_of (lwp)); + return 0; + } + if (!lwp->need_step_over) { if (debug_threads) @@ -2536,7 +2628,8 @@ start_step_over (struct lwp_info *lwp) "Starting step-over on LWP %ld. Stopping all threads\n", lwpid_of (lwp)); - stop_all_lwps (); + stop_all_lwps (1, lwp); + gdb_assert (lwp->suspended == 0); if (debug_threads) fprintf (stderr, "Done stopping all threads for step-over.\n"); @@ -2785,14 +2878,15 @@ linux_resume (struct thread_resume *resume_info, size_t n) breakpoint that needs stepping over, we start a step-over operation on that particular thread, and leave all others stopped. */ -static void -proceed_one_lwp (struct inferior_list_entry *entry) +static int +proceed_one_lwp (struct inferior_list_entry *entry, void *except) { - struct lwp_info *lwp; + struct lwp_info *lwp = (struct lwp_info *) entry; struct thread_info *thread; int step; - lwp = (struct lwp_info *) entry; + if (lwp == except) + return 0; if (debug_threads) fprintf (stderr, @@ -2802,7 +2896,7 @@ proceed_one_lwp (struct inferior_list_entry *entry) { if (debug_threads) fprintf (stderr, " LWP %ld already running\n", lwpid_of (lwp)); - return; + return 0; } thread = get_lwp_thread (lwp); @@ -2813,7 +2907,7 @@ proceed_one_lwp (struct inferior_list_entry *entry) if (debug_threads) fprintf (stderr, " client wants LWP to remain %ld stopped\n", lwpid_of (lwp)); - return; + return 0; } if (lwp->status_pending_p) @@ -2821,14 +2915,16 @@ proceed_one_lwp (struct inferior_list_entry *entry) if (debug_threads) fprintf (stderr, " LWP %ld has pending status, leaving stopped\n", lwpid_of (lwp)); - return; + return 0; } + gdb_assert (lwp->suspended >= 0); + if (lwp->suspended) { if (debug_threads) fprintf (stderr, " LWP %ld is suspended\n", lwpid_of (lwp)); - return; + return 0; } if (thread->last_resume_kind == resume_stop) @@ -2854,6 +2950,21 @@ proceed_one_lwp (struct inferior_list_entry *entry) step = thread->last_resume_kind == resume_step; linux_resume_one_lwp (lwp, step, 0, NULL); + return 0; +} + +static int +unsuspend_and_proceed_one_lwp (struct inferior_list_entry *entry, void *except) +{ + struct lwp_info *lwp = (struct lwp_info *) entry; + + if (lwp == except) + return 0; + + lwp->suspended--; + gdb_assert (lwp->suspended >= 0); + + return proceed_one_lwp (entry, except); } /* When we finish a step-over, set threads running again. If there's @@ -2891,7 +3002,7 @@ proceed_all_lwps (void) if (debug_threads) fprintf (stderr, "Proceeding, no step-over needed\n"); - for_each_inferior (&all_lwps, proceed_one_lwp); + find_inferior (&all_lwps, proceed_one_lwp, NULL); } /* Stopped LWPs that the client wanted to be running, that don't have @@ -2899,7 +3010,7 @@ proceed_all_lwps (void) NULL. This undoes a stop_all_lwps call. */ static void -unstop_all_lwps (struct lwp_info *except) +unstop_all_lwps (int unsuspend, struct lwp_info *except) { if (debug_threads) { @@ -2911,14 +3022,10 @@ unstop_all_lwps (struct lwp_info *except) "unstopping all lwps\n"); } - /* Make sure proceed_one_lwp doesn't try to resume this thread. */ - if (except != NULL) - ++except->suspended; - - for_each_inferior (&all_lwps, proceed_one_lwp); - - if (except != NULL) - --except->suspended; + if (unsuspend) + find_inferior (&all_lwps, unsuspend_and_proceed_one_lwp, except); + else + find_inferior (&all_lwps, proceed_one_lwp, except); } #ifdef HAVE_LINUX_USRREGS @@ -4296,9 +4403,18 @@ linux_thread_stopped (struct thread_info *thread) /* This exposes stop-all-threads functionality to other modules. */ static void -linux_pause_all (void) +linux_pause_all (int freeze) { - stop_all_lwps (); + stop_all_lwps (freeze, NULL); +} + +/* This exposes unstop-all-threads functionality to other gdbserver + modules. */ + +static void +linux_unpause_all (int unfreeze) +{ + unstop_all_lwps (unfreeze, NULL); } static struct target_ops linux_target_ops = { @@ -4351,8 +4467,10 @@ static struct target_ops linux_target_ops = { linux_read_pc, linux_write_pc, linux_thread_stopped, + NULL, linux_pause_all, - NULL, /* get_tib_address (Windows OS specific). */ + linux_unpause_all, + linux_cancel_breakpoints }; static void diff --git a/gdb/gdbserver/server.c b/gdb/gdbserver/server.c index ffca3977f39..75b9d886774 100644 --- a/gdb/gdbserver/server.c +++ b/gdb/gdbserver/server.c @@ -2101,7 +2101,7 @@ handle_status (char *own_buf) } else { - pause_all (); + pause_all (0); gdb_wants_all_threads_stopped (); if (all_threads.head) diff --git a/gdb/gdbserver/target.h b/gdb/gdbserver/target.h index fbe191086d6..4ac55b3c7e2 100644 --- a/gdb/gdbserver/target.h +++ b/gdb/gdbserver/target.h @@ -307,11 +307,23 @@ struct target_ops /* Return true if THREAD is known to be stopped now. */ int (*thread_stopped) (struct thread_info *thread); - /* Pause all threads. */ - void (*pause_all) (void); - /* Read Thread Information Block address. */ int (*get_tib_address) (ptid_t ptid, CORE_ADDR *address); + + /* Pause all threads. If FREEZE, arrange for any resume attempt be + be ignored until an unpause_all call unfreezes threads again. + There can be nested calls to pause_all, so a freeze counter + should be maintained. */ + void (*pause_all) (int freeze); + + /* Unpause all threads. Threads that hadn't been resumed by the + client should be left stopped. Basically a pause/unpause call + pair should not end up resuming threads that were stopped before + the pause call. */ + void (*unpause_all) (int unfreeze); + + /* Cancel all pending breakpoints hits in all threads. */ + void (*cancel_breakpoints) (void); }; extern struct target_ops *the_target; @@ -369,11 +381,25 @@ void set_target_ops (struct target_ops *); #define thread_stopped(thread) \ (*the_target->thread_stopped) (thread) -#define pause_all() \ - do \ - { \ - if (the_target->pause_all) \ - (*the_target->pause_all) (); \ +#define pause_all(freeze) \ + do \ + { \ + if (the_target->pause_all) \ + (*the_target->pause_all) (freeze); \ + } while (0) + +#define unpause_all(unfreeze) \ + do \ + { \ + if (the_target->unpause_all) \ + (*the_target->unpause_all) (unfreeze); \ + } while (0) + +#define cancel_breakpoints() \ + do \ + { \ + if (the_target->cancel_breakpoints) \ + (*the_target->cancel_breakpoints) (); \ } while (0) /* Start non-stop mode, returns 0 on success, -1 on failure. */ diff --git a/gdb/gdbserver/tracepoint.c b/gdb/gdbserver/tracepoint.c index c7970e32ca8..1076530cdb0 100644 --- a/gdb/gdbserver/tracepoint.c +++ b/gdb/gdbserver/tracepoint.c @@ -1336,6 +1336,9 @@ clear_installed_tracepoints (void) struct tracepoint *tpoint; struct tracepoint *prev_stpoint; + pause_all (1); + cancel_breakpoints (); + prev_stpoint = NULL; /* Restore any bytes overwritten by tracepoints. */ @@ -1357,6 +1360,8 @@ clear_installed_tracepoints (void) delete_breakpoint (tpoint->handle); tpoint->handle = NULL; } + + unpause_all (1); } /* Parse a packet that defines a tracepoint. */ @@ -1656,6 +1661,9 @@ cmd_qtstart (char *packet) *packet = '\0'; + /* Pause all threads temporarily while we patch tracepoints. */ + pause_all (1); + /* Install tracepoints. */ for (tpoint = tracepoints; tpoint; tpoint = tpoint->next) { @@ -1686,6 +1694,7 @@ cmd_qtstart (char *packet) clear_installed_tracepoints (); if (*packet == '\0') write_enn (packet); + unpause_all (1); return; } @@ -1697,6 +1706,8 @@ cmd_qtstart (char *packet) /* Tracing is now active, hits will now start being logged. */ tracing = 1; + unpause_all (1); + write_ok (packet); } @@ -1714,6 +1725,12 @@ stop_tracing (void) trace_debug ("Stopping the trace"); + /* Pause all threads before removing breakpoints from memory. */ + pause_all (1); + /* Since we're removing breakpoints, cancel breakpoint hits, + possibly related to the breakpoints we're about to delete. */ + cancel_breakpoints (); + /* Stop logging. Tracepoints can still be hit, but they will not be recorded. */ tracing = 0; @@ -1756,6 +1773,8 @@ stop_tracing (void) /* Clear out the tracepoints. */ clear_installed_tracepoints (); + + unpause_all (1); } static void diff --git a/gdb/gdbserver/win32-low.c b/gdb/gdbserver/win32-low.c index 7fbefb52b7c..72184f304f3 100644 --- a/gdb/gdbserver/win32-low.c +++ b/gdb/gdbserver/win32-low.c @@ -1811,8 +1811,7 @@ static struct target_ops win32_target_ops = { NULL, /* read_pc */ NULL, /* write_pc */ NULL, /* thread_stopped */ - NULL, /* pause_all */ - win32_get_tib_address, + win32_get_tib_address }; /* Initialize the Win32 backend. */ -- 2.30.2