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https://github.com/freebsd/freebsd-src
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6b35310173
A commit from 2012 (5d7380f8e3
, r228424) introduced
'td_stopsched', on the ground that a global variable would cause all
CPUs to have a copy of it in their cache, and consequently of all other
variables sharing the same cache line.
This is really a problem only if that cache line sees relatively
frequent modifications. This was unlikely to be the case back then
because nearby variables are almost never modified as well. In any
case, today we have a new tool at our disposal to ensure that this
variable goes into a read-mostly section containing frequently-accessed
variables ('__read_frequently'). Most of the cache lines covering this
section are likely to always be in every CPU cache. This makes the
second reason stated in the commit message (ensuring the field is in the
same cache line as some lock-related fields, since these are accessed in
close proximity) moot, as well as the second order effect of requiring
an additional line to be present in the cache (the one containing the
new 'scheduler_stopped' boolean, see below).
From a pure logical point of view, whether the scheduler is stopped is
a global state and is certainly not a per-thread quality.
Consequently, remove 'td_stopsched', which immediately frees a byte in
'struct thread'. Currently, the latter's size (and layout) stays
unchanged, but some of the later re-orderings will probably benefit from
this removal. Available bytes at the original position for
'td_stopsched' have been made explicit with the addition of the
'_td_pad0' member.
Store the global state in the new 'scheduler_stopped' boolean, which is
annotated with '__read_frequently'.
Replace uses of SCHEDULER_STOPPED_TD() with SCHEDULER_STOPPER() and
remove the former as it is now unnecessary.
Reviewed by: markj, kib
Approved by: markj (mentor)
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D43572
815 lines
18 KiB
C
815 lines
18 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause
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*
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* Copyright (c) 2004 The FreeBSD Project
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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#include "opt_kdb.h"
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#include "opt_stack.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/cons.h>
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#include <sys/kdb.h>
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#include <sys/kernel.h>
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#include <sys/malloc.h>
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#include <sys/lock.h>
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#include <sys/pcpu.h>
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#include <sys/priv.h>
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#include <sys/proc.h>
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#include <sys/sbuf.h>
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#include <sys/smp.h>
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#include <sys/stack.h>
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#include <sys/sysctl.h>
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#include <sys/tslog.h>
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#include <machine/kdb.h>
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#include <machine/pcb.h>
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#ifdef SMP
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#include <machine/smp.h>
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#endif
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#include <security/mac/mac_framework.h>
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u_char __read_frequently kdb_active = 0;
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static void *kdb_jmpbufp = NULL;
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struct kdb_dbbe *kdb_dbbe = NULL;
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static struct pcb kdb_pcb;
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struct pcb *kdb_thrctx = NULL;
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struct thread *kdb_thread = NULL;
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struct trapframe *kdb_frame = NULL;
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#ifdef BREAK_TO_DEBUGGER
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#define KDB_BREAK_TO_DEBUGGER 1
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#else
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#define KDB_BREAK_TO_DEBUGGER 0
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#endif
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#ifdef ALT_BREAK_TO_DEBUGGER
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#define KDB_ALT_BREAK_TO_DEBUGGER 1
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#else
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#define KDB_ALT_BREAK_TO_DEBUGGER 0
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#endif
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static int kdb_break_to_debugger = KDB_BREAK_TO_DEBUGGER;
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static int kdb_alt_break_to_debugger = KDB_ALT_BREAK_TO_DEBUGGER;
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static int kdb_enter_securelevel = 0;
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KDB_BACKEND(null, NULL, NULL, NULL, NULL);
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static int kdb_sysctl_available(SYSCTL_HANDLER_ARGS);
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static int kdb_sysctl_current(SYSCTL_HANDLER_ARGS);
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static int kdb_sysctl_enter(SYSCTL_HANDLER_ARGS);
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static int kdb_sysctl_panic(SYSCTL_HANDLER_ARGS);
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static int kdb_sysctl_panic_str(SYSCTL_HANDLER_ARGS);
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static int kdb_sysctl_trap(SYSCTL_HANDLER_ARGS);
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static int kdb_sysctl_trap_code(SYSCTL_HANDLER_ARGS);
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static int kdb_sysctl_stack_overflow(SYSCTL_HANDLER_ARGS);
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static SYSCTL_NODE(_debug, OID_AUTO, kdb, CTLFLAG_RW | CTLFLAG_MPSAFE, NULL,
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"KDB nodes");
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SYSCTL_PROC(_debug_kdb, OID_AUTO, available,
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CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0,
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kdb_sysctl_available, "A",
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"list of available KDB backends");
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SYSCTL_PROC(_debug_kdb, OID_AUTO, current,
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CTLTYPE_STRING | CTLFLAG_RW | CTLFLAG_MPSAFE, NULL, 0,
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kdb_sysctl_current, "A",
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"currently selected KDB backend");
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SYSCTL_PROC(_debug_kdb, OID_AUTO, enter,
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CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, NULL, 0,
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kdb_sysctl_enter, "I",
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"set to enter the debugger");
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SYSCTL_PROC(_debug_kdb, OID_AUTO, panic,
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CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SECURE | CTLFLAG_MPSAFE, NULL, 0,
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kdb_sysctl_panic, "I",
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"set to panic the kernel");
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SYSCTL_PROC(_debug_kdb, OID_AUTO, panic_str,
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CTLTYPE_STRING | CTLFLAG_RW | CTLFLAG_SECURE | CTLFLAG_MPSAFE, NULL, 0,
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kdb_sysctl_panic_str, "A",
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"trigger a kernel panic, using the provided string as the panic message");
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SYSCTL_PROC(_debug_kdb, OID_AUTO, trap,
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CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SECURE | CTLFLAG_MPSAFE, NULL, 0,
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kdb_sysctl_trap, "I",
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"set to cause a page fault via data access");
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SYSCTL_PROC(_debug_kdb, OID_AUTO, trap_code,
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CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SECURE | CTLFLAG_MPSAFE, NULL, 0,
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kdb_sysctl_trap_code, "I",
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"set to cause a page fault via code access");
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SYSCTL_PROC(_debug_kdb, OID_AUTO, stack_overflow,
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CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SECURE | CTLFLAG_MPSAFE, NULL, 0,
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kdb_sysctl_stack_overflow, "I",
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"set to cause a stack overflow");
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SYSCTL_INT(_debug_kdb, OID_AUTO, break_to_debugger,
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CTLFLAG_RWTUN,
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&kdb_break_to_debugger, 0, "Enable break to debugger");
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SYSCTL_INT(_debug_kdb, OID_AUTO, alt_break_to_debugger,
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CTLFLAG_RWTUN,
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&kdb_alt_break_to_debugger, 0, "Enable alternative break to debugger");
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SYSCTL_INT(_debug_kdb, OID_AUTO, enter_securelevel,
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CTLFLAG_RWTUN | CTLFLAG_SECURE,
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&kdb_enter_securelevel, 0,
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"Maximum securelevel to enter a KDB backend");
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/*
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* Flag to indicate to debuggers why the debugger was entered.
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*/
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const char * volatile kdb_why = KDB_WHY_UNSET;
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static int
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kdb_sysctl_available(SYSCTL_HANDLER_ARGS)
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{
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struct kdb_dbbe **iter;
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struct sbuf sbuf;
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int error;
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sbuf_new_for_sysctl(&sbuf, NULL, 64, req);
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SET_FOREACH(iter, kdb_dbbe_set) {
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if ((*iter)->dbbe_active == 0)
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sbuf_printf(&sbuf, "%s ", (*iter)->dbbe_name);
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}
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error = sbuf_finish(&sbuf);
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sbuf_delete(&sbuf);
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return (error);
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}
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static int
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kdb_sysctl_current(SYSCTL_HANDLER_ARGS)
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{
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char buf[16];
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int error;
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if (kdb_dbbe != NULL)
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strlcpy(buf, kdb_dbbe->dbbe_name, sizeof(buf));
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else
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*buf = '\0';
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error = sysctl_handle_string(oidp, buf, sizeof(buf), req);
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if (error != 0 || req->newptr == NULL)
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return (error);
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if (kdb_active)
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return (EBUSY);
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return (kdb_dbbe_select(buf));
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}
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static int
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kdb_sysctl_enter(SYSCTL_HANDLER_ARGS)
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{
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int error, i;
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error = sysctl_wire_old_buffer(req, sizeof(int));
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if (error == 0) {
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i = 0;
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error = sysctl_handle_int(oidp, &i, 0, req);
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}
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if (error != 0 || req->newptr == NULL)
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return (error);
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if (kdb_active)
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return (EBUSY);
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kdb_enter(KDB_WHY_SYSCTL, "sysctl debug.kdb.enter");
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return (0);
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}
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static int
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kdb_sysctl_panic(SYSCTL_HANDLER_ARGS)
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{
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int error, i;
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error = sysctl_wire_old_buffer(req, sizeof(int));
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if (error == 0) {
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i = 0;
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error = sysctl_handle_int(oidp, &i, 0, req);
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}
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if (error != 0 || req->newptr == NULL)
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return (error);
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panic("kdb_sysctl_panic");
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return (0);
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}
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static int
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kdb_sysctl_panic_str(SYSCTL_HANDLER_ARGS)
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{
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int error;
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static char buf[256]; /* static buffer to limit mallocs when panicing */
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*buf = '\0';
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error = sysctl_handle_string(oidp, buf, sizeof(buf), req);
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if (error != 0 || req->newptr == NULL)
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return (error);
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panic("kdb_sysctl_panic: %s", buf);
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return (0);
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}
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static int
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kdb_sysctl_trap(SYSCTL_HANDLER_ARGS)
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{
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int error, i;
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int *addr = (int *)0x10;
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error = sysctl_wire_old_buffer(req, sizeof(int));
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if (error == 0) {
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i = 0;
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error = sysctl_handle_int(oidp, &i, 0, req);
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}
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if (error != 0 || req->newptr == NULL)
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return (error);
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return (*addr);
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}
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static int
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kdb_sysctl_trap_code(SYSCTL_HANDLER_ARGS)
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{
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int error, i;
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void (*fp)(u_int, u_int, u_int) = (void *)0xdeadc0de;
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error = sysctl_wire_old_buffer(req, sizeof(int));
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if (error == 0) {
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i = 0;
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error = sysctl_handle_int(oidp, &i, 0, req);
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}
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if (error != 0 || req->newptr == NULL)
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return (error);
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(*fp)(0x11111111, 0x22222222, 0x33333333);
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return (0);
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}
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static void kdb_stack_overflow(volatile int *x) __noinline;
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static void
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kdb_stack_overflow(volatile int *x)
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{
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if (*x > 10000000)
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return;
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kdb_stack_overflow(x);
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*x += PCPU_GET(cpuid) / 1000000;
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}
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static int
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kdb_sysctl_stack_overflow(SYSCTL_HANDLER_ARGS)
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{
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int error, i;
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volatile int x;
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error = sysctl_wire_old_buffer(req, sizeof(int));
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if (error == 0) {
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i = 0;
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error = sysctl_handle_int(oidp, &i, 0, req);
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}
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if (error != 0 || req->newptr == NULL)
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return (error);
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x = 0;
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kdb_stack_overflow(&x);
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return (0);
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}
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void
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kdb_panic(const char *msg)
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{
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kdb_why = KDB_WHY_PANIC;
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printf("KDB: panic\n");
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panic("%s", msg);
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}
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void
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kdb_reboot(void)
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{
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kdb_why = KDB_WHY_REBOOT;
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printf("KDB: reboot requested\n");
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shutdown_nice(0);
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}
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|
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/*
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* Solaris implements a new BREAK which is initiated by a character sequence
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* CR ~ ^b which is similar to a familiar pattern used on Sun servers by the
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* Remote Console.
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*
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* Note that this function may be called from almost anywhere, with interrupts
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* disabled and with unknown locks held, so it must not access data other than
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* its arguments. Its up to the caller to ensure that the state variable is
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* consistent.
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*/
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#define KEY_CR 13 /* CR '\r' */
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#define KEY_TILDE 126 /* ~ */
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#define KEY_CRTLB 2 /* ^B */
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#define KEY_CRTLP 16 /* ^P */
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#define KEY_CRTLR 18 /* ^R */
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|
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/* States of th KDB "alternate break sequence" detecting state machine. */
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enum {
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KDB_ALT_BREAK_SEEN_NONE,
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KDB_ALT_BREAK_SEEN_CR,
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KDB_ALT_BREAK_SEEN_CR_TILDE,
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};
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int
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kdb_break(void)
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{
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|
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if (!kdb_break_to_debugger)
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return (0);
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kdb_enter(KDB_WHY_BREAK, "Break to debugger");
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return (KDB_REQ_DEBUGGER);
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}
|
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|
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static int
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kdb_alt_break_state(int key, int *state)
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{
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int brk;
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/* All states transition to KDB_ALT_BREAK_SEEN_CR on a CR. */
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if (key == KEY_CR) {
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*state = KDB_ALT_BREAK_SEEN_CR;
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return (0);
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}
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brk = 0;
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switch (*state) {
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case KDB_ALT_BREAK_SEEN_CR:
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*state = KDB_ALT_BREAK_SEEN_NONE;
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if (key == KEY_TILDE)
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*state = KDB_ALT_BREAK_SEEN_CR_TILDE;
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break;
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case KDB_ALT_BREAK_SEEN_CR_TILDE:
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*state = KDB_ALT_BREAK_SEEN_NONE;
|
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if (key == KEY_CRTLB)
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brk = KDB_REQ_DEBUGGER;
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else if (key == KEY_CRTLP)
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brk = KDB_REQ_PANIC;
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else if (key == KEY_CRTLR)
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brk = KDB_REQ_REBOOT;
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break;
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case KDB_ALT_BREAK_SEEN_NONE:
|
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default:
|
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*state = KDB_ALT_BREAK_SEEN_NONE;
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break;
|
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}
|
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return (brk);
|
|
}
|
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|
|
static int
|
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kdb_alt_break_internal(int key, int *state, int force_gdb)
|
|
{
|
|
int brk;
|
|
|
|
if (!kdb_alt_break_to_debugger)
|
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return (0);
|
|
brk = kdb_alt_break_state(key, state);
|
|
switch (brk) {
|
|
case KDB_REQ_DEBUGGER:
|
|
if (force_gdb)
|
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kdb_dbbe_select("gdb");
|
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kdb_enter(KDB_WHY_BREAK, "Break to debugger");
|
|
break;
|
|
|
|
case KDB_REQ_PANIC:
|
|
if (force_gdb)
|
|
kdb_dbbe_select("gdb");
|
|
kdb_panic("Panic sequence on console");
|
|
break;
|
|
|
|
case KDB_REQ_REBOOT:
|
|
kdb_reboot();
|
|
break;
|
|
}
|
|
return (0);
|
|
}
|
|
|
|
int
|
|
kdb_alt_break(int key, int *state)
|
|
{
|
|
|
|
return (kdb_alt_break_internal(key, state, 0));
|
|
}
|
|
|
|
/*
|
|
* This variation on kdb_alt_break() is used only by dcons, which has its own
|
|
* configuration flag to force GDB use regardless of the global KDB
|
|
* configuration.
|
|
*/
|
|
int
|
|
kdb_alt_break_gdb(int key, int *state)
|
|
{
|
|
|
|
return (kdb_alt_break_internal(key, state, 1));
|
|
}
|
|
|
|
/*
|
|
* Print a backtrace of the calling thread. The backtrace is generated by
|
|
* the selected debugger, provided it supports backtraces. If no debugger
|
|
* is selected or the current debugger does not support backtraces, this
|
|
* function silently returns.
|
|
*/
|
|
void
|
|
kdb_backtrace(void)
|
|
{
|
|
|
|
if (kdb_dbbe != NULL && kdb_dbbe->dbbe_trace != NULL) {
|
|
printf("KDB: stack backtrace:\n");
|
|
kdb_dbbe->dbbe_trace();
|
|
}
|
|
#ifdef STACK
|
|
else {
|
|
struct stack st;
|
|
|
|
printf("KDB: stack backtrace:\n");
|
|
stack_save(&st);
|
|
stack_print_ddb(&st);
|
|
}
|
|
#endif
|
|
}
|
|
|
|
/*
|
|
* Similar to kdb_backtrace() except that it prints a backtrace of an
|
|
* arbitrary thread rather than the calling thread.
|
|
*/
|
|
void
|
|
kdb_backtrace_thread(struct thread *td)
|
|
{
|
|
|
|
if (kdb_dbbe != NULL && kdb_dbbe->dbbe_trace_thread != NULL) {
|
|
printf("KDB: stack backtrace of thread %d:\n", td->td_tid);
|
|
kdb_dbbe->dbbe_trace_thread(td);
|
|
}
|
|
#ifdef STACK
|
|
else {
|
|
struct stack st;
|
|
|
|
printf("KDB: stack backtrace of thread %d:\n", td->td_tid);
|
|
if (stack_save_td(&st, td) == 0)
|
|
stack_print_ddb(&st);
|
|
}
|
|
#endif
|
|
}
|
|
|
|
/*
|
|
* Set/change the current backend.
|
|
*/
|
|
int
|
|
kdb_dbbe_select(const char *name)
|
|
{
|
|
struct kdb_dbbe *be, **iter;
|
|
int error;
|
|
|
|
error = priv_check(curthread, PRIV_KDB_SET_BACKEND);
|
|
if (error)
|
|
return (error);
|
|
|
|
SET_FOREACH(iter, kdb_dbbe_set) {
|
|
be = *iter;
|
|
if (be->dbbe_active == 0 && strcmp(be->dbbe_name, name) == 0) {
|
|
kdb_dbbe = be;
|
|
return (0);
|
|
}
|
|
}
|
|
return (EINVAL);
|
|
}
|
|
|
|
static bool
|
|
kdb_backend_permitted(struct kdb_dbbe *be, struct thread *td)
|
|
{
|
|
struct ucred *cred;
|
|
int error;
|
|
|
|
cred = td->td_ucred;
|
|
if (cred == NULL) {
|
|
KASSERT(td == &thread0 && cold,
|
|
("%s: missing cred for %p", __func__, td));
|
|
error = 0;
|
|
} else {
|
|
error = securelevel_gt(cred, kdb_enter_securelevel);
|
|
}
|
|
#ifdef MAC
|
|
/*
|
|
* Give MAC a chance to weigh in on the policy: if the securelevel is
|
|
* not raised, then MAC may veto the backend, otherwise MAC may
|
|
* explicitly grant access.
|
|
*/
|
|
if (error == 0) {
|
|
error = mac_kdb_check_backend(be);
|
|
if (error != 0) {
|
|
printf("MAC prevented execution of KDB backend: %s\n",
|
|
be->dbbe_name);
|
|
return (false);
|
|
}
|
|
} else if (mac_kdb_grant_backend(be) == 0) {
|
|
error = 0;
|
|
}
|
|
#endif
|
|
if (error != 0)
|
|
printf("refusing to enter KDB with elevated securelevel\n");
|
|
return (error == 0);
|
|
}
|
|
|
|
/*
|
|
* Enter the currently selected debugger. If a message has been provided,
|
|
* it is printed first. If the debugger does not support the enter method,
|
|
* it is entered by using breakpoint(), which enters the debugger through
|
|
* kdb_trap(). The 'why' argument will contain a more mechanically usable
|
|
* string than 'msg', and is relied upon by DDB scripting to identify the
|
|
* reason for entering the debugger so that the right script can be run.
|
|
*/
|
|
void
|
|
kdb_enter(const char *why, const char *msg)
|
|
{
|
|
|
|
if (kdb_dbbe != NULL && kdb_active == 0) {
|
|
kdb_why = why;
|
|
if (msg != NULL)
|
|
printf("KDB: enter: %s\n", msg);
|
|
breakpoint();
|
|
kdb_why = KDB_WHY_UNSET;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Initialize the kernel debugger interface.
|
|
*/
|
|
void
|
|
kdb_init(void)
|
|
{
|
|
struct kdb_dbbe *be, **iter;
|
|
int cur_pri, pri;
|
|
|
|
TSENTER();
|
|
kdb_active = 0;
|
|
kdb_dbbe = NULL;
|
|
cur_pri = -1;
|
|
SET_FOREACH(iter, kdb_dbbe_set) {
|
|
be = *iter;
|
|
pri = (be->dbbe_init != NULL) ? be->dbbe_init() : -1;
|
|
be->dbbe_active = (pri >= 0) ? 0 : -1;
|
|
if (pri > cur_pri) {
|
|
cur_pri = pri;
|
|
kdb_dbbe = be;
|
|
}
|
|
}
|
|
if (kdb_dbbe != NULL) {
|
|
printf("KDB: debugger backends:");
|
|
SET_FOREACH(iter, kdb_dbbe_set) {
|
|
be = *iter;
|
|
if (be->dbbe_active == 0)
|
|
printf(" %s", be->dbbe_name);
|
|
}
|
|
printf("\n");
|
|
printf("KDB: current backend: %s\n",
|
|
kdb_dbbe->dbbe_name);
|
|
}
|
|
TSEXIT();
|
|
}
|
|
|
|
/*
|
|
* Handle contexts.
|
|
*/
|
|
void *
|
|
kdb_jmpbuf(jmp_buf new)
|
|
{
|
|
void *old;
|
|
|
|
old = kdb_jmpbufp;
|
|
kdb_jmpbufp = new;
|
|
return (old);
|
|
}
|
|
|
|
void
|
|
kdb_reenter(void)
|
|
{
|
|
|
|
if (!kdb_active || kdb_jmpbufp == NULL)
|
|
return;
|
|
|
|
printf("KDB: reentering\n");
|
|
kdb_backtrace();
|
|
longjmp(kdb_jmpbufp, 1);
|
|
/* NOTREACHED */
|
|
}
|
|
|
|
void
|
|
kdb_reenter_silent(void)
|
|
{
|
|
|
|
if (!kdb_active || kdb_jmpbufp == NULL)
|
|
return;
|
|
|
|
longjmp(kdb_jmpbufp, 1);
|
|
/* NOTREACHED */
|
|
}
|
|
|
|
/*
|
|
* Thread-related support functions.
|
|
*/
|
|
struct pcb *
|
|
kdb_thr_ctx(struct thread *thr)
|
|
{
|
|
#ifdef SMP
|
|
struct pcpu *pc;
|
|
#endif
|
|
|
|
if (thr == curthread)
|
|
return (&kdb_pcb);
|
|
|
|
#ifdef SMP
|
|
STAILQ_FOREACH(pc, &cpuhead, pc_allcpu) {
|
|
if (pc->pc_curthread == thr &&
|
|
CPU_ISSET(pc->pc_cpuid, &stopped_cpus))
|
|
return (&stoppcbs[pc->pc_cpuid]);
|
|
}
|
|
#endif
|
|
return (thr->td_pcb);
|
|
}
|
|
|
|
struct thread *
|
|
kdb_thr_first(void)
|
|
{
|
|
struct proc *p;
|
|
struct thread *thr;
|
|
u_int i;
|
|
|
|
/* This function may be called early. */
|
|
if (pidhashtbl == NULL)
|
|
return (&thread0);
|
|
|
|
for (i = 0; i <= pidhash; i++) {
|
|
LIST_FOREACH(p, &pidhashtbl[i], p_hash) {
|
|
thr = FIRST_THREAD_IN_PROC(p);
|
|
if (thr != NULL)
|
|
return (thr);
|
|
}
|
|
}
|
|
return (NULL);
|
|
}
|
|
|
|
struct thread *
|
|
kdb_thr_from_pid(pid_t pid)
|
|
{
|
|
struct proc *p;
|
|
|
|
LIST_FOREACH(p, PIDHASH(pid), p_hash) {
|
|
if (p->p_pid == pid)
|
|
return (FIRST_THREAD_IN_PROC(p));
|
|
}
|
|
return (NULL);
|
|
}
|
|
|
|
struct thread *
|
|
kdb_thr_lookup(lwpid_t tid)
|
|
{
|
|
struct thread *thr;
|
|
|
|
thr = kdb_thr_first();
|
|
while (thr != NULL && thr->td_tid != tid)
|
|
thr = kdb_thr_next(thr);
|
|
return (thr);
|
|
}
|
|
|
|
struct thread *
|
|
kdb_thr_next(struct thread *thr)
|
|
{
|
|
struct proc *p;
|
|
u_int hash;
|
|
|
|
p = thr->td_proc;
|
|
thr = TAILQ_NEXT(thr, td_plist);
|
|
if (thr != NULL)
|
|
return (thr);
|
|
if (pidhashtbl == NULL)
|
|
return (NULL);
|
|
hash = p->p_pid & pidhash;
|
|
for (;;) {
|
|
p = LIST_NEXT(p, p_hash);
|
|
while (p == NULL) {
|
|
if (++hash > pidhash)
|
|
return (NULL);
|
|
p = LIST_FIRST(&pidhashtbl[hash]);
|
|
}
|
|
thr = FIRST_THREAD_IN_PROC(p);
|
|
if (thr != NULL)
|
|
return (thr);
|
|
}
|
|
}
|
|
|
|
int
|
|
kdb_thr_select(struct thread *thr)
|
|
{
|
|
if (thr == NULL)
|
|
return (EINVAL);
|
|
kdb_thread = thr;
|
|
kdb_thrctx = kdb_thr_ctx(thr);
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Enter the debugger due to a trap.
|
|
*/
|
|
int
|
|
kdb_trap(int type, int code, struct trapframe *tf)
|
|
{
|
|
#ifdef SMP
|
|
cpuset_t other_cpus;
|
|
#endif
|
|
struct kdb_dbbe *be;
|
|
register_t intr;
|
|
int handled;
|
|
int did_stop_cpus;
|
|
|
|
be = kdb_dbbe;
|
|
if (be == NULL || be->dbbe_trap == NULL)
|
|
return (0);
|
|
|
|
/* We reenter the debugger through kdb_reenter(). */
|
|
if (kdb_active)
|
|
return (0);
|
|
|
|
intr = intr_disable();
|
|
|
|
if (!SCHEDULER_STOPPED()) {
|
|
#ifdef SMP
|
|
other_cpus = all_cpus;
|
|
CPU_ANDNOT(&other_cpus, &other_cpus, &stopped_cpus);
|
|
CPU_CLR(PCPU_GET(cpuid), &other_cpus);
|
|
stop_cpus_hard(other_cpus);
|
|
#endif
|
|
scheduler_stopped = true;
|
|
did_stop_cpus = 1;
|
|
} else
|
|
did_stop_cpus = 0;
|
|
|
|
kdb_active++;
|
|
|
|
kdb_frame = tf;
|
|
|
|
/* Let MD code do its thing first... */
|
|
kdb_cpu_trap(type, code);
|
|
|
|
makectx(tf, &kdb_pcb);
|
|
kdb_thr_select(curthread);
|
|
|
|
cngrab();
|
|
|
|
for (;;) {
|
|
if (!kdb_backend_permitted(be, curthread)) {
|
|
/* Unhandled breakpoint traps are fatal. */
|
|
handled = 1;
|
|
break;
|
|
}
|
|
handled = be->dbbe_trap(type, code);
|
|
if (be == kdb_dbbe)
|
|
break;
|
|
be = kdb_dbbe;
|
|
if (be == NULL || be->dbbe_trap == NULL)
|
|
break;
|
|
printf("Switching to %s back-end\n", be->dbbe_name);
|
|
}
|
|
|
|
cnungrab();
|
|
|
|
kdb_active--;
|
|
|
|
if (did_stop_cpus) {
|
|
scheduler_stopped = false;
|
|
#ifdef SMP
|
|
CPU_AND(&other_cpus, &other_cpus, &stopped_cpus);
|
|
restart_cpus(other_cpus);
|
|
#endif
|
|
}
|
|
|
|
intr_restore(intr);
|
|
|
|
return (handled);
|
|
}
|