![Shao Miller](/assets/img/avatar_default.png)
Changes were made to files where the licence text within the files themselves confirms that the files are GPL version 2 or later. Signed-off-by: Shao Miller <shao.miller@yrdsb.edu.on.ca> Modified-by: Michael Brown <mcb30@ipxe.org> Signed-off-by: Michael Brown <mcb30@ipxe.org>
400 lines
12 KiB
C
400 lines
12 KiB
C
/*
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* Copyright (C) 2008 Stefan Hajnoczi <stefanha@gmail.com>.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License, or any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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FILE_LICENCE ( GPL2_OR_LATER );
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/**
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* @file
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*
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* GDB stub for remote debugging
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*
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*/
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include <ctype.h>
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#include <byteswap.h>
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#include <ipxe/gdbstub.h>
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#include "gdbmach.h"
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enum {
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POSIX_EINVAL = 0x1c, /* used to report bad arguments to GDB */
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SIZEOF_PAYLOAD = 256, /* buffer size of GDB payload data */
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};
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struct gdbstub {
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struct gdb_transport *trans;
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int exit_handler; /* leave interrupt handler */
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int signo;
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gdbreg_t *regs;
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void ( * parse ) ( struct gdbstub *stub, char ch );
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uint8_t cksum1;
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/* Buffer for payload data when parsing a packet. Once the
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* packet has been received, this buffer is used to hold
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* the reply payload. */
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char buf [ SIZEOF_PAYLOAD + 4 ]; /* $...PAYLOAD...#XX */
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char *payload; /* start of payload */
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int len; /* length of payload */
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};
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/* Packet parser states */
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static void gdbstub_state_new ( struct gdbstub *stub, char ch );
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static void gdbstub_state_data ( struct gdbstub *stub, char ch );
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static void gdbstub_state_cksum1 ( struct gdbstub *stub, char ch );
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static void gdbstub_state_cksum2 ( struct gdbstub *stub, char ch );
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static void gdbstub_state_wait_ack ( struct gdbstub *stub, char ch );
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static uint8_t gdbstub_from_hex_digit ( char ch ) {
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return ( isdigit ( ch ) ? ch - '0' : tolower ( ch ) - 'a' + 0xa ) & 0xf;
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}
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static uint8_t gdbstub_to_hex_digit ( uint8_t b ) {
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b &= 0xf;
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return ( b < 0xa ? '0' : 'a' - 0xa ) + b;
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}
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/*
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* To make reading/writing device memory atomic, we check for
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* 2- or 4-byte aligned operations and handle them specially.
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*/
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static void gdbstub_from_hex_buf ( char *dst, char *src, int lenbytes ) {
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if ( lenbytes == 2 && ( ( unsigned long ) dst & 0x1 ) == 0 ) {
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uint16_t i = gdbstub_from_hex_digit ( src [ 2 ] ) << 12 |
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gdbstub_from_hex_digit ( src [ 3 ] ) << 8 |
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gdbstub_from_hex_digit ( src [ 0 ] ) << 4 |
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gdbstub_from_hex_digit ( src [ 1 ] );
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* ( uint16_t * ) dst = cpu_to_le16 ( i );
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} else if ( lenbytes == 4 && ( ( unsigned long ) dst & 0x3 ) == 0 ) {
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uint32_t i = gdbstub_from_hex_digit ( src [ 6 ] ) << 28 |
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gdbstub_from_hex_digit ( src [ 7 ] ) << 24 |
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gdbstub_from_hex_digit ( src [ 4 ] ) << 20 |
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gdbstub_from_hex_digit ( src [ 5 ] ) << 16 |
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gdbstub_from_hex_digit ( src [ 2 ] ) << 12 |
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gdbstub_from_hex_digit ( src [ 3 ] ) << 8 |
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gdbstub_from_hex_digit ( src [ 0 ] ) << 4 |
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gdbstub_from_hex_digit ( src [ 1 ] );
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* ( uint32_t * ) dst = cpu_to_le32 ( i );
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} else {
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while ( lenbytes-- > 0 ) {
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*dst++ = gdbstub_from_hex_digit ( src [ 0 ] ) << 4 |
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gdbstub_from_hex_digit ( src [ 1 ] );
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src += 2;
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}
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}
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}
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static void gdbstub_to_hex_buf ( char *dst, char *src, int lenbytes ) {
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if ( lenbytes == 2 && ( ( unsigned long ) src & 0x1 ) == 0 ) {
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uint16_t i = cpu_to_le16 ( * ( uint16_t * ) src );
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dst [ 0 ] = gdbstub_to_hex_digit ( i >> 4 );
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dst [ 1 ] = gdbstub_to_hex_digit ( i );
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dst [ 2 ] = gdbstub_to_hex_digit ( i >> 12 );
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dst [ 3 ] = gdbstub_to_hex_digit ( i >> 8 );
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} else if ( lenbytes == 4 && ( ( unsigned long ) src & 0x3 ) == 0 ) {
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uint32_t i = cpu_to_le32 ( * ( uint32_t * ) src );
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dst [ 0 ] = gdbstub_to_hex_digit ( i >> 4 );
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dst [ 1 ] = gdbstub_to_hex_digit ( i );
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dst [ 2 ] = gdbstub_to_hex_digit ( i >> 12 );
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dst [ 3 ] = gdbstub_to_hex_digit ( i >> 8 );
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dst [ 4 ] = gdbstub_to_hex_digit ( i >> 20 );
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dst [ 5 ] = gdbstub_to_hex_digit ( i >> 16);
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dst [ 6 ] = gdbstub_to_hex_digit ( i >> 28 );
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dst [ 7 ] = gdbstub_to_hex_digit ( i >> 24 );
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} else {
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while ( lenbytes-- > 0 ) {
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*dst++ = gdbstub_to_hex_digit ( *src >> 4 );
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*dst++ = gdbstub_to_hex_digit ( *src );
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src++;
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}
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}
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}
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static uint8_t gdbstub_cksum ( char *data, int len ) {
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uint8_t cksum = 0;
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while ( len-- > 0 ) {
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cksum += ( uint8_t ) *data++;
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}
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return cksum;
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}
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static void gdbstub_tx_packet ( struct gdbstub *stub ) {
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uint8_t cksum = gdbstub_cksum ( stub->payload, stub->len );
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stub->buf [ 0 ] = '$';
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stub->buf [ stub->len + 1 ] = '#';
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stub->buf [ stub->len + 2 ] = gdbstub_to_hex_digit ( cksum >> 4 );
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stub->buf [ stub->len + 3 ] = gdbstub_to_hex_digit ( cksum );
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stub->trans->send ( stub->buf, stub->len + 4 );
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stub->parse = gdbstub_state_wait_ack;
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}
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/* GDB commands */
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static void gdbstub_send_ok ( struct gdbstub *stub ) {
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stub->payload [ 0 ] = 'O';
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stub->payload [ 1 ] = 'K';
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stub->len = 2;
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gdbstub_tx_packet ( stub );
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}
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static void gdbstub_send_num_packet ( struct gdbstub *stub, char reply, int num ) {
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stub->payload [ 0 ] = reply;
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stub->payload [ 1 ] = gdbstub_to_hex_digit ( ( char ) num >> 4 );
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stub->payload [ 2 ] = gdbstub_to_hex_digit ( ( char ) num );
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stub->len = 3;
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gdbstub_tx_packet ( stub );
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}
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/* Format is arg1,arg2,...,argn:data where argn are hex integers and data is not an argument */
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static int gdbstub_get_packet_args ( struct gdbstub *stub, unsigned long *args, int nargs, int *stop_idx ) {
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int i;
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char ch = 0;
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int argc = 0;
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unsigned long val = 0;
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for ( i = 1; i < stub->len && argc < nargs; i++ ) {
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ch = stub->payload [ i ];
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if ( ch == ':' ) {
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break;
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} else if ( ch == ',' ) {
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args [ argc++ ] = val;
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val = 0;
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} else {
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val = ( val << 4 ) | gdbstub_from_hex_digit ( ch );
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}
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}
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if ( stop_idx ) {
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*stop_idx = i;
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}
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if ( argc < nargs ) {
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args [ argc++ ] = val;
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}
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return ( ( i == stub->len || ch == ':' ) && argc == nargs );
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}
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static void gdbstub_send_errno ( struct gdbstub *stub, int errno ) {
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gdbstub_send_num_packet ( stub, 'E', errno );
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}
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static void gdbstub_report_signal ( struct gdbstub *stub ) {
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gdbstub_send_num_packet ( stub, 'S', stub->signo );
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}
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static void gdbstub_read_regs ( struct gdbstub *stub ) {
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gdbstub_to_hex_buf ( stub->payload, ( char * ) stub->regs, GDBMACH_SIZEOF_REGS );
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stub->len = GDBMACH_SIZEOF_REGS * 2;
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gdbstub_tx_packet ( stub );
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}
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static void gdbstub_write_regs ( struct gdbstub *stub ) {
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if ( stub->len != 1 + GDBMACH_SIZEOF_REGS * 2 ) {
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gdbstub_send_errno ( stub, POSIX_EINVAL );
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return;
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}
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gdbstub_from_hex_buf ( ( char * ) stub->regs, &stub->payload [ 1 ], GDBMACH_SIZEOF_REGS );
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gdbstub_send_ok ( stub );
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}
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static void gdbstub_read_mem ( struct gdbstub *stub ) {
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unsigned long args [ 2 ];
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if ( !gdbstub_get_packet_args ( stub, args, sizeof args / sizeof args [ 0 ], NULL ) ) {
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gdbstub_send_errno ( stub, POSIX_EINVAL );
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return;
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}
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args [ 1 ] = ( args [ 1 ] < SIZEOF_PAYLOAD / 2 ) ? args [ 1 ] : SIZEOF_PAYLOAD / 2;
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gdbstub_to_hex_buf ( stub->payload, ( char * ) args [ 0 ], args [ 1 ] );
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stub->len = args [ 1 ] * 2;
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gdbstub_tx_packet ( stub );
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}
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static void gdbstub_write_mem ( struct gdbstub *stub ) {
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unsigned long args [ 2 ];
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int colon;
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if ( !gdbstub_get_packet_args ( stub, args, sizeof args / sizeof args [ 0 ], &colon ) ||
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colon >= stub->len || stub->payload [ colon ] != ':' ||
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( stub->len - colon - 1 ) % 2 != 0 ) {
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gdbstub_send_errno ( stub, POSIX_EINVAL );
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return;
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}
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gdbstub_from_hex_buf ( ( char * ) args [ 0 ], &stub->payload [ colon + 1 ], ( stub->len - colon - 1 ) / 2 );
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gdbstub_send_ok ( stub );
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}
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static void gdbstub_continue ( struct gdbstub *stub, int single_step ) {
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gdbreg_t pc;
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if ( stub->len > 1 && gdbstub_get_packet_args ( stub, &pc, 1, NULL ) ) {
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gdbmach_set_pc ( stub->regs, pc );
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}
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gdbmach_set_single_step ( stub->regs, single_step );
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stub->exit_handler = 1;
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/* Reply will be sent when we hit the next breakpoint or interrupt */
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}
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static void gdbstub_breakpoint ( struct gdbstub *stub ) {
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unsigned long args [ 3 ];
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int enable = stub->payload [ 0 ] == 'Z' ? 1 : 0;
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if ( !gdbstub_get_packet_args ( stub, args, sizeof args / sizeof args [ 0 ], NULL ) ) {
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gdbstub_send_errno ( stub, POSIX_EINVAL );
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return;
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}
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if ( gdbmach_set_breakpoint ( args [ 0 ], args [ 1 ], args [ 2 ], enable ) ) {
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gdbstub_send_ok ( stub );
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} else {
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/* Not supported */
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stub->len = 0;
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gdbstub_tx_packet ( stub );
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}
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}
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static void gdbstub_rx_packet ( struct gdbstub *stub ) {
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switch ( stub->payload [ 0 ] ) {
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case '?':
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gdbstub_report_signal ( stub );
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break;
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case 'g':
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gdbstub_read_regs ( stub );
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break;
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case 'G':
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gdbstub_write_regs ( stub );
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break;
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case 'm':
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gdbstub_read_mem ( stub );
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break;
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case 'M':
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gdbstub_write_mem ( stub );
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break;
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case 'c': /* Continue */
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case 'k': /* Kill */
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case 's': /* Step */
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case 'D': /* Detach */
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gdbstub_continue ( stub, stub->payload [ 0 ] == 's' );
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if ( stub->payload [ 0 ] == 'D' ) {
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gdbstub_send_ok ( stub );
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}
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break;
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case 'Z': /* Insert breakpoint */
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case 'z': /* Remove breakpoint */
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gdbstub_breakpoint ( stub );
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break;
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default:
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stub->len = 0;
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gdbstub_tx_packet ( stub );
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break;
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}
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}
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/* GDB packet parser */
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static void gdbstub_state_new ( struct gdbstub *stub, char ch ) {
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if ( ch == '$' ) {
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stub->len = 0;
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stub->parse = gdbstub_state_data;
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}
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}
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static void gdbstub_state_data ( struct gdbstub *stub, char ch ) {
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if ( ch == '#' ) {
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stub->parse = gdbstub_state_cksum1;
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} else if ( ch == '$' ) {
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stub->len = 0; /* retry new packet */
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} else {
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/* If the length exceeds our buffer, let the checksum fail */
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if ( stub->len < SIZEOF_PAYLOAD ) {
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stub->payload [ stub->len++ ] = ch;
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}
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}
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}
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static void gdbstub_state_cksum1 ( struct gdbstub *stub, char ch ) {
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stub->cksum1 = gdbstub_from_hex_digit ( ch ) << 4;
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stub->parse = gdbstub_state_cksum2;
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}
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static void gdbstub_state_cksum2 ( struct gdbstub *stub, char ch ) {
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uint8_t their_cksum;
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uint8_t our_cksum;
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stub->parse = gdbstub_state_new;
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their_cksum = stub->cksum1 + gdbstub_from_hex_digit ( ch );
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our_cksum = gdbstub_cksum ( stub->payload, stub->len );
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if ( their_cksum == our_cksum ) {
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stub->trans->send ( "+", 1 );
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if ( stub->len > 0 ) {
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gdbstub_rx_packet ( stub );
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}
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} else {
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stub->trans->send ( "-", 1 );
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}
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}
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static void gdbstub_state_wait_ack ( struct gdbstub *stub, char ch ) {
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if ( ch == '+' ) {
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stub->parse = gdbstub_state_new;
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} else {
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/* This retransmit is very aggressive but necessary to keep
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* in sync with GDB. */
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gdbstub_tx_packet ( stub );
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}
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}
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static void gdbstub_parse ( struct gdbstub *stub, char ch ) {
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stub->parse ( stub, ch );
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}
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static struct gdbstub stub = {
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.parse = gdbstub_state_new
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};
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void gdbstub_handler ( int signo, gdbreg_t *regs ) {
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char packet [ SIZEOF_PAYLOAD + 4 ];
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size_t len, i;
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/* A transport must be set up */
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if ( !stub.trans ) {
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return;
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}
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stub.signo = signo;
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stub.regs = regs;
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stub.exit_handler = 0;
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gdbstub_report_signal ( &stub );
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while ( !stub.exit_handler && ( len = stub.trans->recv ( packet, sizeof ( packet ) ) ) > 0 ) {
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for ( i = 0; i < len; i++ ) {
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gdbstub_parse ( &stub, packet [ i ] );
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}
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}
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}
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struct gdb_transport *find_gdb_transport ( const char *name ) {
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struct gdb_transport *trans;
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for_each_table_entry ( trans, GDB_TRANSPORTS ) {
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if ( strcmp ( trans->name, name ) == 0 ) {
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return trans;
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}
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}
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return NULL;
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}
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void gdbstub_start ( struct gdb_transport *trans ) {
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stub.trans = trans;
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stub.payload = &stub.buf [ 1 ];
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gdbmach_breakpoint();
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}
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