/* $NetBSD: kgdb_stub.c,v 1.18 2009/11/27 03:23:15 rmind Exp $ */
/*
* Copyright (c) 1990, 1993
* The Regents of the University of California. All rights reserved.
*
* This software was developed by the Computer Systems Engineering group
* at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
* contributed to Berkeley.
*
* All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Lawrence Berkeley Laboratories.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)kgdb_stub.c 8.4 (Berkeley) 1/12/94
*/
/*
* "Stub" to allow remote CPU to debug over a serial line using gdb.
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: kgdb_stub.c,v 1.18 2009/11/27 03:23:15 rmind Exp $");
#include "opt_kgdb.h"
#ifdef KGDB
#ifndef lint
static char rcsid[] = "$NetBSD: kgdb_stub.c,v 1.18 2009/11/27 03:23:15 rmind Exp $";
#endif
#include <sys/param.h>
#include <sys/systm.h>
#include <machine/trap.h>
#include <machine/cpu.h>
#include <machine/psl.h>
#include <machine/reg.h>
#include <machine/frame.h>
#include <sys/buf.h>
#include <dev/cons.h>
#include <x68k/x68k/kgdb_proto.h>
#include <machine/remote-sl.h>
extern int kernacc();
extern void chgkprot();
#ifndef KGDB_DEV
#define KGDB_DEV NODEV
#endif
#ifndef KGDB_DEVRATE
#define KGDB_DEVRATE 9600
#endif
dev_t kgdb_dev = KGDB_DEV; /* remote debugging device (NODEV if none) */
int kgdb_rate = KGDB_DEVRATE; /* remote debugging baud rate */
int kgdb_active = 0; /* remote debugging active if != 0 */
int kgdb_debug_init = 0; /* != 0 waits for remote at system init */
int kgdb_debug_panic = 1; /* != 0 waits for remote on panic */
int kgdb_debug = 0;
#define GETC ((*kgdb_getc)(kgdb_dev))
#define PUTC(c) ((*kgdb_putc)(kgdb_dev, c))
#define PUTESC(c) { \
if (c == FRAME_END) { \
PUTC(FRAME_ESCAPE); \
c = TRANS_FRAME_END; \
} else if (c == FRAME_ESCAPE) { \
PUTC(FRAME_ESCAPE); \
c = TRANS_FRAME_ESCAPE; \
} else if (c == FRAME_START) { \
PUTC(FRAME_ESCAPE); \
c = TRANS_FRAME_START; \
} \
PUTC(c); \
}
static int (*kgdb_getc)();
static int (*kgdb_putc)();
/*
* Send a message. The host gets one chance to read it.
*/
static void
kgdb_send(u_char type, u_char *bp, int len)
{
u_char csum;
u_char *ep = bp + len;
PUTC(FRAME_START);
PUTESC(type);
csum = type;
while (bp < ep) {
type = *bp++;
csum += type;
PUTESC(type)
}
csum = -csum;
PUTESC(csum)
PUTC(FRAME_END);
}
static int
kgdb_recv(u_char *bp, int *lenp)
{
u_char c, csum;
int escape, len;
int type;
restart:
csum = len = escape = 0;
type = -1;
while (1) {
c = GETC;
switch (c) {
case FRAME_ESCAPE:
escape = 1;
continue;
case TRANS_FRAME_ESCAPE:
if (escape)
c = FRAME_ESCAPE;
break;
case TRANS_FRAME_END:
if (escape)
c = FRAME_END;
break;
case TRANS_FRAME_START:
if (escape)
c = FRAME_START;
break;
case FRAME_START:
goto restart;
case FRAME_END:
if (type < 0 || --len < 0) {
csum = len = escape = 0;
type = -1;
continue;
}
if (csum != 0) {
return (0);
}
*lenp = len;
return type;
}
csum += c;
if (type < 0) {
type = c;
escape = 0;
continue;
}
if (++len > SL_RPCSIZE) {
while (GETC != FRAME_END)
;
return (0);
}
*bp++ = c;
escape = 0;
}
}
/*
* Translate a trap number into a unix compatible signal value.
* (gdb only understands unix signal numbers).
*/
static int
computeSignal(int type)
{
int sigval;
switch (type) {
case T_BUSERR:
case T_ADDRERR:
sigval = SIGBUS;
break;
case T_ILLINST:
case T_PRIVINST:
sigval = SIGILL;
break;
case T_ZERODIV:
case T_CHKINST:
case T_TRAPVINST:
sigval = SIGFPE;
break;
case T_TRACE:
sigval = SIGTRAP;
break;
case T_MMUFLT:
sigval = SIGSEGV;
break;
case T_SSIR:
sigval = SIGSEGV;
break;
case T_FMTERR:
sigval = SIGILL;
break;
case T_FPERR:
case T_COPERR:
sigval = SIGFPE;
break;
case T_ASTFLT:
sigval = SIGINT;
break;
case T_TRAP15:
sigval = SIGTRAP;
break;
default:
sigval = SIGEMT;
break;
}
return (sigval);
}
/*
* Trap into kgdb to wait for debugger to connect,
* noting on the console why nothing else is going on.
*/
void
kgdb_connect(int verbose)
{
if (verbose)
printf("kgdb waiting...");
/* trap into kgdb */
__asm("trap #15;");
if (verbose)
printf("connected.\n");
}
/*
* Decide what to do on panic.
*/
void
kgdb_panic(void)
{
if (kgdb_active == 0 && kgdb_debug_panic && kgdb_dev != NODEV)
kgdb_connect(1);
}
/*
* Definitions exported from gdb.
*/
#define NUM_REGS 18
#define REGISTER_BYTES ((16+2)*4)
#define REGISTER_BYTE(N) ((N)*4)
#define GDB_SR 16
#define GDB_PC 17
static inline void
kgdb_copy(u_char *src, u_char *dst, u_int nbytes)
{
u_char *ep = src + nbytes;
while (src < ep)
*dst++ = *src++;
}
/*
* There is a short pad word between SP (A7) and SR which keeps the
* kernel stack long word aligned (note that this is in addition to
* the stack adjust short that we treat as the upper half of a longword
* SR). We must skip this when copying into and out of gdb.
*/
static inline void
regs_to_gdb(struct frame *fp, u_long *regs)
{
kgdb_copy((u_char *)fp->f_regs, (u_char *)regs, 16*4);
kgdb_copy((u_char *)&fp->f_stackadj, (u_char *)®s[GDB_SR], 2*4);
}
static inline void
gdb_to_regs(struct frame *fp, u_long *regs)
{
kgdb_copy((u_char *)regs, (u_char *)fp->f_regs, 16*4);
kgdb_copy((u_char *)®s[GDB_SR], (u_char *)&fp->f_stackadj, 2*4);
}
static u_long reg_cache[NUM_REGS];
static u_char inbuffer[SL_RPCSIZE+1];
static u_char outbuffer[SL_RPCSIZE];
/*
* This function does all command procesing for interfacing to
* a remote gdb.
*/
int
kgdb_trap(int type, struct frame *frame)
{
u_long len;
u_char *addr;
u_char *cp;
u_char out, in;
int outlen;
int inlen;
u_long gdb_regs[NUM_REGS];
if ((int)kgdb_dev < 0) {
/* not debugging */
return (0);
}
if (kgdb_active == 0) {
if (type != T_TRAP15) {
/* No debugger active -- let trap handle this. */
return (0);
}
kgdb_getc = 0;
for (inlen = 0; constab[inlen].cn_probe; inlen++)
if (major(constab[inlen].cn_dev) == major(kgdb_dev)) {
kgdb_getc = constab[inlen].cn_getc;
kgdb_putc = constab[inlen].cn_putc;
break;
}
if (kgdb_getc == 0 || kgdb_putc == 0)
return (0);
/*
* If the packet that woke us up isn't an exec packet,
* ignore it since there is no active debugger. Also,
* we check that it's not an ack to be sure that the
* remote side doesn't send back a response after the
* local gdb has exited. Otherwise, the local host
* could trap into gdb if it's running a gdb kernel too.
*/
in = GETC;
/*
* If we came in asynchronously through the serial line,
* the framing character is eaten by the receive interrupt,
* but if we come in through a synchronous trap (i.e., via
* kgdb_connect()), we will see the extra character.
*/
if (in == FRAME_START)
in = GETC;
/*
* Check that this is a debugger exec message. If so,
* slurp up the entire message then ack it, and fall
* through to the recv loop.
*/
if (KGDB_CMD(in) != KGDB_EXEC || (in & KGDB_ACK) != 0)
return (0);
while (GETC != FRAME_END)
;
/*
* Do the printf *before* we ack the message. This way
* we won't drop any inbound characters while we're
* doing the polling printf.
*/
printf("kgdb started from device %x\n", kgdb_dev);
kgdb_send(in | KGDB_ACK, (u_char *)0, 0);
kgdb_active = 1;
}
/*
* Stick frame regs into our reg cache then tell remote host
* that an exception has occurred.
*/
regs_to_gdb(frame, gdb_regs);
if (type != T_TRAP15) {
/*
* Only send an asynchronous SIGNAL message when we hit
* a breakpoint. Otherwise, we will drop the incoming
* packet while we output this one (and on entry the other
* side isn't interested in the SIGNAL type -- if it is,
* it will have used a signal packet.)
*/
outbuffer[0] = computeSignal(type);
kgdb_send(KGDB_SIGNAL, outbuffer, 1);
}
while (1) {
in = kgdb_recv(inbuffer, &inlen);
if (in == 0 || (in & KGDB_ACK))
/* Ignore inbound acks and error conditions. */
continue;
out = in | KGDB_ACK;
switch (KGDB_CMD(in)) {
case KGDB_SIGNAL:
/*
* if this command came from a running gdb,
* answer it -- the other guy has no way of
* knowing if we're in or out of this loop
* when he issues a "remote-signal". (Note
* that without the length check, we could
* loop here forever if the ourput line is
* looped back or the remote host is echoing.)
*/
if (inlen == 0) {
outbuffer[0] = computeSignal(type);
kgdb_send(KGDB_SIGNAL, outbuffer, 1);
}
continue;
case KGDB_REG_R:
case KGDB_REG_R | KGDB_DELTA:
cp = outbuffer;
outlen = 0;
for (len = inbuffer[0]; len < NUM_REGS; ++len) {
if (reg_cache[len] != gdb_regs[len] ||
(in & KGDB_DELTA) == 0) {
if (outlen + 5 > SL_MAXDATA) {
out |= KGDB_MORE;
break;
}
cp[outlen] = len;
kgdb_copy((u_char *)&gdb_regs[len],
&cp[outlen + 1], 4);
reg_cache[len] = gdb_regs[len];
outlen += 5;
}
}
break;
case KGDB_REG_W:
case KGDB_REG_W | KGDB_DELTA:
cp = inbuffer;
for (len = 0; len < inlen; len += 5) {
int j = cp[len];
kgdb_copy(&cp[len + 1],
(u_char *)&gdb_regs[j], 4);
reg_cache[j] = gdb_regs[j];
}
gdb_to_regs(frame, gdb_regs);
outlen = 0;
break;
case KGDB_MEM_R:
len = inbuffer[0];
kgdb_copy(&inbuffer[1], (u_char *)&addr, 4);
if (len > SL_MAXDATA) {
outlen = 1;
outbuffer[0] = E2BIG;
} else if (!kgdb_acc(addr, len, B_READ)) {
outlen = 1;
outbuffer[0] = EFAULT;
} else {
outlen = len + 1;
outbuffer[0] = 0;
kgdb_copy(addr, &outbuffer[1], len);
}
break;
case KGDB_MEM_W:
len = inlen - 4;
kgdb_copy(inbuffer, (u_char *)&addr, 4);
outlen = 1;
if (!kgdb_acc(addr, len, B_READ))
outbuffer[0] = EFAULT;
else {
outbuffer[0] = 0;
if (!kgdb_acc(addr, len, B_WRITE))
chgkprot(addr, len, B_WRITE);
kgdb_copy(&inbuffer[4], addr, len);
ICIA();
}
break;
case KGDB_KILL:
kgdb_active = 0;
printf("kgdb detached\n");
/* fall through */
case KGDB_CONT:
kgdb_send(out, 0, 0);
frame->f_sr &=~ PSL_T;
return (1);
case KGDB_STEP:
kgdb_send(out, 0, 0);
frame->f_sr |= PSL_T;
return (1);
case KGDB_EXEC:
default:
/* Unknown command. Ack with a null message. */
outlen = 0;
break;
}
/* Send the reply */
kgdb_send(out, outbuffer, outlen);
}
}
/*
* XXX do kernacc call if safe, otherwise attempt
* to simulate by simple bounds-checking.
*/
int
kgdb_acc(void *addr, int len, int rw)
{
extern char kstack[]; /* XXX */
extern char *kernel_map; /* XXX! */
if (kernel_map != NULL)
return (kernacc(addr, len, rw));
if (addr < uvm_lwp_getuarea(&lwp0) + USPACE ||
kstack <= addr && addr < kstack + USPACE)
return (1);
return (0);
}
#endif /* KGDB */