176 lines
4.3 KiB
C
176 lines
4.3 KiB
C
/*-
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* Copyright (c) 2006 Sam Leffler
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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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/*
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* Support for redirecting console msgs to gdb. We register
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* a pseudo console to hook cnputc and send stuff to the gdb
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* port. The only trickiness here is buffering output so this
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* isn't dog slow.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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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/reboot.h>
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#include <sys/sysctl.h>
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#include <machine/gdb_machdep.h>
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#include <machine/kdb.h>
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#include <gdb/gdb.h>
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#include <gdb/gdb_int.h>
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struct gdbcons {
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int npending;
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/* /2 for hex conversion, -6 for protocol glue */
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char buf[GDB_BUFSZ/2 - 6];
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struct callout flush;
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};
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static struct gdbcons state = { -1 };
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static int gdbcons_enable = 0;
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SYSCTL_INT(_debug, OID_AUTO, gdbcons, CTLFLAG_RW, &gdbcons_enable,
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0, "copy console messages to gdb");
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TUNABLE_INT("debug.gdbcons", &gdbcons_enable);
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static void
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gdb_cnprobe(struct consdev *cp)
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{
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sprintf(cp->cn_name, "gdb");
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cp->cn_pri = CN_LOW; /* XXX no way to say "write only" */
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}
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static void
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gdb_cninit(struct consdev *cp)
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{
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struct gdbcons *c = &state;
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/* setup tx buffer and callout */
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if (c->npending == -1) {
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c->npending = 0;
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callout_init(&c->flush, CALLOUT_MPSAFE);
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cp->cn_arg = c;
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}
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}
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static void
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gdb_cnterm(struct consdev *cp)
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{
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}
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static int
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gdb_cngetc(struct consdev *cp)
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{
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return -1;
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}
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static void
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gdb_tx_puthex(int c)
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{
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const char *hex = "0123456789abcdef";
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gdb_tx_char(hex[(c>>4)&0xf]);
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gdb_tx_char(hex[(c>>0)&0xf]);
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}
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static void
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gdb_cnflush(void *arg)
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{
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struct gdbcons *gc = arg;
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int i;
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gdb_tx_begin('O');
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for (i = 0; i < gc->npending; i++)
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gdb_tx_puthex(gc->buf[i]);
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gdb_tx_end();
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gc->npending = 0;
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}
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/*
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* This glop is to figure out when it's safe to use callouts
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* to defer buffer flushing. There's probably a better way
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* and/or an earlier point in the boot process when it's ok.
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*/
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static int calloutok = 0;
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static void
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oktousecallout(void *data __unused)
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{
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calloutok = 1;
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}
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SYSINIT(gdbhack, SI_SUB_RUN_SCHEDULER, SI_ORDER_ANY, oktousecallout, NULL)
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static void
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gdb_cnputc(struct consdev *cp, int c)
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{
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struct gdbcons *gc;
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if (gdbcons_enable && gdb_cur != NULL && gdb_listening) {
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gc = cp->cn_arg;
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if (gc->npending != 0) {
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/*
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* Cancel any pending callout and flush the
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* buffer if there's no space for this byte.
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*/
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if (calloutok)
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callout_stop(&gc->flush);
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if (gc->npending == sizeof(gc->buf))
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gdb_cnflush(gc);
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}
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gc->buf[gc->npending++] = c;
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/*
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* Flush on end of line; this is especially helpful
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* during boot when we don't have callouts to flush
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* the buffer. Otherwise we defer flushing; a 1/4
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* second is a guess.
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*/
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if (c == '\n')
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gdb_cnflush(gc);
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else if (calloutok)
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callout_reset(&gc->flush, hz/4, gdb_cnflush, gc);
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}
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}
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CONSOLE_DRIVER(gdb);
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/*
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* Our console device only gets attached if the system is booted
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* with RB_MULTIPLE set so gdb_init also calls us to attach the
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* console so we're setup regardless.
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*/
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void
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gdb_consinit(void)
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{
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gdb_cnprobe(&gdb_consdev);
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gdb_cninit(&gdb_consdev);
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cnadd(&gdb_consdev);
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}
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