4.4BSD/usr/src/sys/sparc/sparc/kgdb_stub.c
/*
* Copyright (c) 1992, 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 Laboratory.
*
* 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. 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, Berkeley and its contributors.
* 4. 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 8.1 (Berkeley) 6/11/93
*
* from: $Header: kgdb_stub.c,v 1.13 92/11/26 03:04:55 torek Exp $
*/
/*
* "Stub" to allow remote cpu to debug over a serial line using gdb.
*/
#ifdef KGDB
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/buf.h>
#include <machine/ctlreg.h>
#include <machine/psl.h>
#include <machine/pte.h>
#include <machine/reg.h>
#include <machine/remote-sl.h>
#include <machine/trap.h>
#include <sparc/sparc/asm.h>
#include <sparc/sparc/kgdb_proto.h>
#ifndef KGDBDEV
#define KGDBDEV -1
#endif
#ifndef KGDBRATE
#define KGDBRATE 38400
#endif
int kgdb_dev = KGDBDEV; /* remote debugging device (-1 if none) */
int kgdb_rate = KGDBRATE; /* remote debugging baud rate */
int kgdb_active = 0; /* remote debugging active if != 0 */
int kgdb_debug_panic = 0; /* != 0 waits for remote on panic */
#define getpte(va) lda(va, ASI_PTE)
#define setpte(va, pte) sta(va, ASI_PTE, pte)
/*
* This little routine exists simply so that bcopy() can be debugged.
*/
kgdb_copy(src, dst, len)
register char *src, *dst;
register int len;
{
while (--len >= 0)
*dst++ = *src++;
}
static int (*kgdb_getc) __P((void *));
static void (*kgdb_putc) __P((void *, int));
static void *kgdb_ioarg;
#define GETC() ((*kgdb_getc)(kgdb_ioarg))
#define PUTC(c) ((*kgdb_putc)(kgdb_ioarg, 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); \
}
kgdb_attach(getfn, putfn, ioarg)
int (*getfn) __P((void *));
void (*putfn) __P((void *, int));
void *ioarg;
{
kgdb_getc = getfn;
kgdb_putc = putfn;
kgdb_ioarg = ioarg;
}
/*
* Send a message. The host gets one chance to read it.
*/
static void
kgdb_send(type, bp, len)
register u_char type;
register u_char *bp;
register int len;
{
register u_char csum;
register 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(bp, lenp)
u_char *bp;
int *lenp;
{
register u_char c, csum;
register int escape, len;
register 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)
continue;
return (0);
}
*bp++ = c;
escape = 0;
}
}
/*
* Translate a trap number into a unix compatible signal value.
* (gdb only understands unix signal numbers).
* ### should this be done at the other end?
*/
static int
computeSignal(type)
int type;
{
int sigval;
switch (type) {
case T_AST:
sigval = SIGINT;
break;
case T_TEXTFAULT:
case T_DATAFAULT:
sigval = SIGSEGV;
break;
case T_ALIGN:
sigval = SIGBUS;
break;
case T_ILLINST:
case T_PRIVINST:
case T_DIV0:
sigval = SIGILL;
break;
case T_FPE:
sigval = SIGFPE;
break;
case T_BREAKPOINT:
sigval = SIGTRAP;
break;
case T_KGDB_EXEC:
sigval = SIGIOT;
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.
*/
kgdb_connect(verbose)
int verbose;
{
if (kgdb_dev < 0 || kgdb_getc == NULL)
return;
fb_unblank();
if (verbose)
printf("kgdb waiting...");
__asm("ta %0" :: "n" (T_KGDB_EXEC)); /* trap into kgdb */
}
/*
* Decide what to do on panic.
*/
kgdb_panic()
{
if (kgdb_dev >= 0 && kgdb_getc != NULL &&
kgdb_active == 0 && kgdb_debug_panic)
kgdb_connect(1);
}
/*
* Definitions exported from gdb (& then made prettier).
*/
#define GDB_G0 0
#define GDB_O0 8
#define GDB_L0 16
#define GDB_I0 24
#define GDB_FP0 32
#define GDB_Y 64
#define GDB_PSR 65
#define GDB_WIM 66
#define GDB_TBR 67
#define GDB_PC 68
#define GDB_NPC 69
#define GDB_FSR 70
#define GDB_CSR 71
#define NUM_REGS 72
#define REGISTER_BYTES (NUM_REGS * 4)
#define REGISTER_BYTE(n) ((n) * 4)
/*
* Translate the values stored in the kernel regs struct to the format
* understood by gdb.
*/
void
regs_to_gdb(tf, gdb_regs)
struct trapframe *tf;
u_long *gdb_regs;
{
/* %g0..%g7 and %o0..%o7: from trapframe */
gdb_regs[0] = 0;
kgdb_copy((caddr_t)&tf->tf_global[1], (caddr_t)&gdb_regs[1], 15 * 4);
/* %l0..%l7 and %i0..%i7: from stack */
kgdb_copy((caddr_t)tf->tf_out[6], (caddr_t)&gdb_regs[GDB_L0], 16 * 4);
/* %f0..%f31 -- fake, kernel does not use FP */
bzero((caddr_t)&gdb_regs[GDB_FP0], 32 * 4);
/* %y, %psr, %wim, %tbr, %pc, %npc, %fsr, %csr */
gdb_regs[GDB_Y] = tf->tf_y;
gdb_regs[GDB_PSR] = tf->tf_psr;
gdb_regs[GDB_WIM] = tf->tf_global[0]; /* input only! */
gdb_regs[GDB_TBR] = 0; /* fake */
gdb_regs[GDB_PC] = tf->tf_pc;
gdb_regs[GDB_NPC] = tf->tf_npc;
gdb_regs[GDB_FSR] = 0; /* fake */
gdb_regs[GDB_CSR] = 0; /* fake */
}
/*
* Reverse the above.
*/
void
gdb_to_regs(tf, gdb_regs)
struct trapframe *tf;
u_long *gdb_regs;
{
kgdb_copy((caddr_t)&gdb_regs[1], (caddr_t)&tf->tf_global[1], 15 * 4);
kgdb_copy((caddr_t)&gdb_regs[GDB_L0], (caddr_t)tf->tf_out[6]);
tf->tf_y = gdb_regs[GDB_Y];
tf->tf_psr = gdb_regs[GDB_PSR];
tf->tf_pc = gdb_regs[GDB_PC];
tf->tf_npc = gdb_regs[GDB_NPC];
}
static u_long reg_cache[NUM_REGS];
static u_char inbuffer[SL_RPCSIZE];
static u_char outbuffer[SL_RPCSIZE];
/*
* This function does all command procesing for interfacing to
* a remote gdb.
*/
int
kgdb_trap(type, tf)
int type;
register struct trapframe *tf;
{
register u_long len;
caddr_t addr;
register u_char *cp;
register u_char out, in;
register int outlen;
int inlen;
u_long gdb_regs[NUM_REGS];
if (kgdb_dev < 0 || kgdb_getc == NULL) {
/* not debugging */
return (0);
}
if (kgdb_active == 0) {
if (type != T_KGDB_EXEC) {
/* No debugger active -- let trap handle this. */
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();
if (KGDB_CMD(in) != KGDB_EXEC || (in & KGDB_ACK) != 0)
return (0);
while (GETC() != FRAME_END)
continue;
/*
* 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;
}
if (type == T_KGDB_EXEC) {
/* bypass the trap instruction that got us here */
tf->tf_pc = tf->tf_npc;
tf->tf_npc += 4;
} else {
/*
* 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);
}
/*
* Stick frame regs into our reg cache then tell remote host
* that an exception has occured.
*/
regs_to_gdb(tf, gdb_regs);
for (;;) {
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 output 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((caddr_t)&gdb_regs[len],
(caddr_t)&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) {
register int j = cp[len];
kgdb_copy((caddr_t)&cp[len + 1],
(caddr_t)&gdb_regs[j], 4);
reg_cache[j] = gdb_regs[j];
}
gdb_to_regs(tf, gdb_regs);
outlen = 0;
break;
case KGDB_MEM_R:
len = inbuffer[0];
kgdb_copy((caddr_t)&inbuffer[1], (caddr_t)&addr, 4);
if (len > SL_MAXDATA) {
outlen = 1;
outbuffer[0] = E2BIG;
} else if (!kgdb_acc(addr, len, B_READ, 1)) {
outlen = 1;
outbuffer[0] = EFAULT;
} else {
outlen = len + 1;
outbuffer[0] = 0;
kgdb_copy(addr, (caddr_t)&outbuffer[1], len);
}
break;
case KGDB_MEM_W:
len = inlen - 4;
kgdb_copy((caddr_t)inbuffer, (caddr_t)&addr, 4);
outlen = 1;
if (!kgdb_acc(addr, len, B_READ, 0))
outbuffer[0] = EFAULT;
else {
outbuffer[0] = 0;
if (!kgdb_acc(addr, len, B_WRITE, 0))
kdb_mkwrite(addr, len);
kgdb_copy((caddr_t)&inbuffer[4], addr, len);
}
break;
case KGDB_KILL:
kgdb_active = 0;
printf("kgdb detached\n");
/* FALLTHROUGH */
case KGDB_CONT:
kgdb_send(out, 0, 0);
return (1);
case KGDB_EXEC:
default:
/* Unknown command. Ack with a null message. */
outlen = 0;
break;
}
/* Send the reply */
kgdb_send(out, outbuffer, outlen);
}
}
extern int kernacc();
extern void chgkprot();
extern char *kernel_map; /* XXX! */
extern char *curproc; /* XXX! */
/*
* XXX do kernacc and useracc calls if safe, otherwise use PTE protections.
*/
kgdb_acc(addr, len, rw, usertoo)
caddr_t addr;
int len, rw, usertoo;
{
extern char end[];
int pte;
/* XXX icky: valid address but causes timeout */
if (addr >= (caddr_t)0xfffff000)
return (0);
if (kernel_map != NULL) {
if (kernacc(addr, len, rw))
return (1);
if (usertoo && curproc && useracc(addr, len, rw))
return (1);
}
addr = (caddr_t)((int)addr & ~PGOFSET);
for (; len > 0; len -= NBPG, addr += NBPG) {
if (((int)addr >> PG_VSHIFT) != 0 &&
((int)addr >> PG_VSHIFT) != -1)
return (0);
pte = getpte(addr);
if ((pte & PG_V) == 0 || rw == B_WRITE && (pte & PG_W) == 0)
return (0);
}
return (1);
}
kdb_mkwrite(addr, len)
register caddr_t addr;
register int len;
{
if (kernel_map != NULL) {
chgkprot(addr, len, B_WRITE);
return;
}
addr = (caddr_t)((int)addr & ~PGOFSET);
for (; len > 0; len -= NBPG, addr += NBPG)
setpte(addr, getpte(addr) | PG_W);
}
#endif