--- /dev/null
+/*
+ * Copyright (C) 2008 Stefan Hajnoczi <stefanha@gmail.com>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+/**
+ * @file
+ *
+ * GDB stub for remote debugging
+ *
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <ctype.h>
+#include <byteswap.h>
+#include <ipxe/gdbstub.h>
+#include "gdbmach.h"
+
+enum {
+ POSIX_EINVAL = 0x1c, /* used to report bad arguments to GDB */
+ SIZEOF_PAYLOAD = 256, /* buffer size of GDB payload data */
+};
+
+struct gdbstub {
+ struct gdb_transport *trans;
+ int exit_handler; /* leave interrupt handler */
+
+ int signo;
+ gdbreg_t *regs;
+
+ void ( * parse ) ( struct gdbstub *stub, char ch );
+ uint8_t cksum1;
+
+ /* Buffer for payload data when parsing a packet. Once the
+ * packet has been received, this buffer is used to hold
+ * the reply payload. */
+ char buf [ SIZEOF_PAYLOAD + 4 ]; /* $...PAYLOAD...#XX */
+ char *payload; /* start of payload */
+ int len; /* length of payload */
+};
+
+/* Packet parser states */
+static void gdbstub_state_new ( struct gdbstub *stub, char ch );
+static void gdbstub_state_data ( struct gdbstub *stub, char ch );
+static void gdbstub_state_cksum1 ( struct gdbstub *stub, char ch );
+static void gdbstub_state_cksum2 ( struct gdbstub *stub, char ch );
+static void gdbstub_state_wait_ack ( struct gdbstub *stub, char ch );
+
+static uint8_t gdbstub_from_hex_digit ( char ch ) {
+ return ( isdigit ( ch ) ? ch - '0' : tolower ( ch ) - 'a' + 0xa ) & 0xf;
+}
+
+static uint8_t gdbstub_to_hex_digit ( uint8_t b ) {
+ b &= 0xf;
+ return ( b < 0xa ? '0' : 'a' - 0xa ) + b;
+}
+
+/*
+ * To make reading/writing device memory atomic, we check for
+ * 2- or 4-byte aligned operations and handle them specially.
+ */
+
+static void gdbstub_from_hex_buf ( char *dst, char *src, int lenbytes ) {
+ if ( lenbytes == 2 && ( ( unsigned long ) dst & 0x1 ) == 0 ) {
+ uint16_t i = gdbstub_from_hex_digit ( src [ 2 ] ) << 12 |
+ gdbstub_from_hex_digit ( src [ 3 ] ) << 8 |
+ gdbstub_from_hex_digit ( src [ 0 ] ) << 4 |
+ gdbstub_from_hex_digit ( src [ 1 ] );
+ * ( uint16_t * ) dst = cpu_to_le16 ( i );
+ } else if ( lenbytes == 4 && ( ( unsigned long ) dst & 0x3 ) == 0 ) {
+ uint32_t i = gdbstub_from_hex_digit ( src [ 6 ] ) << 28 |
+ gdbstub_from_hex_digit ( src [ 7 ] ) << 24 |
+ gdbstub_from_hex_digit ( src [ 4 ] ) << 20 |
+ gdbstub_from_hex_digit ( src [ 5 ] ) << 16 |
+ gdbstub_from_hex_digit ( src [ 2 ] ) << 12 |
+ gdbstub_from_hex_digit ( src [ 3 ] ) << 8 |
+ gdbstub_from_hex_digit ( src [ 0 ] ) << 4 |
+ gdbstub_from_hex_digit ( src [ 1 ] );
+ * ( uint32_t * ) dst = cpu_to_le32 ( i );
+ } else {
+ while ( lenbytes-- > 0 ) {
+ *dst++ = gdbstub_from_hex_digit ( src [ 0 ] ) << 4 |
+ gdbstub_from_hex_digit ( src [ 1 ] );
+ src += 2;
+ }
+ }
+}
+
+static void gdbstub_to_hex_buf ( char *dst, char *src, int lenbytes ) {
+ if ( lenbytes == 2 && ( ( unsigned long ) src & 0x1 ) == 0 ) {
+ uint16_t i = cpu_to_le16 ( * ( uint16_t * ) src );
+ dst [ 0 ] = gdbstub_to_hex_digit ( i >> 4 );
+ dst [ 1 ] = gdbstub_to_hex_digit ( i );
+ dst [ 2 ] = gdbstub_to_hex_digit ( i >> 12 );
+ dst [ 3 ] = gdbstub_to_hex_digit ( i >> 8 );
+ } else if ( lenbytes == 4 && ( ( unsigned long ) src & 0x3 ) == 0 ) {
+ uint32_t i = cpu_to_le32 ( * ( uint32_t * ) src );
+ dst [ 0 ] = gdbstub_to_hex_digit ( i >> 4 );
+ dst [ 1 ] = gdbstub_to_hex_digit ( i );
+ dst [ 2 ] = gdbstub_to_hex_digit ( i >> 12 );
+ dst [ 3 ] = gdbstub_to_hex_digit ( i >> 8 );
+ dst [ 4 ] = gdbstub_to_hex_digit ( i >> 20 );
+ dst [ 5 ] = gdbstub_to_hex_digit ( i >> 16);
+ dst [ 6 ] = gdbstub_to_hex_digit ( i >> 28 );
+ dst [ 7 ] = gdbstub_to_hex_digit ( i >> 24 );
+ } else {
+ while ( lenbytes-- > 0 ) {
+ *dst++ = gdbstub_to_hex_digit ( *src >> 4 );
+ *dst++ = gdbstub_to_hex_digit ( *src );
+ src++;
+ }
+ }
+}
+
+static uint8_t gdbstub_cksum ( char *data, int len ) {
+ uint8_t cksum = 0;
+ while ( len-- > 0 ) {
+ cksum += ( uint8_t ) *data++;
+ }
+ return cksum;
+}
+
+static void gdbstub_tx_packet ( struct gdbstub *stub ) {
+ uint8_t cksum = gdbstub_cksum ( stub->payload, stub->len );
+ stub->buf [ 0 ] = '$';
+ stub->buf [ stub->len + 1 ] = '#';
+ stub->buf [ stub->len + 2 ] = gdbstub_to_hex_digit ( cksum >> 4 );
+ stub->buf [ stub->len + 3 ] = gdbstub_to_hex_digit ( cksum );
+ stub->trans->send ( stub->buf, stub->len + 4 );
+ stub->parse = gdbstub_state_wait_ack;
+}
+
+/* GDB commands */
+static void gdbstub_send_ok ( struct gdbstub *stub ) {
+ stub->payload [ 0 ] = 'O';
+ stub->payload [ 1 ] = 'K';
+ stub->len = 2;
+ gdbstub_tx_packet ( stub );
+}
+
+static void gdbstub_send_num_packet ( struct gdbstub *stub, char reply, int num ) {
+ stub->payload [ 0 ] = reply;
+ stub->payload [ 1 ] = gdbstub_to_hex_digit ( ( char ) num >> 4 );
+ stub->payload [ 2 ] = gdbstub_to_hex_digit ( ( char ) num );
+ stub->len = 3;
+ gdbstub_tx_packet ( stub );
+}
+
+/* Format is arg1,arg2,...,argn:data where argn are hex integers and data is not an argument */
+static int gdbstub_get_packet_args ( struct gdbstub *stub, unsigned long *args, int nargs, int *stop_idx ) {
+ int i;
+ char ch = 0;
+ int argc = 0;
+ unsigned long val = 0;
+ for ( i = 1; i < stub->len && argc < nargs; i++ ) {
+ ch = stub->payload [ i ];
+ if ( ch == ':' ) {
+ break;
+ } else if ( ch == ',' ) {
+ args [ argc++ ] = val;
+ val = 0;
+ } else {
+ val = ( val << 4 ) | gdbstub_from_hex_digit ( ch );
+ }
+ }
+ if ( stop_idx ) {
+ *stop_idx = i;
+ }
+ if ( argc < nargs ) {
+ args [ argc++ ] = val;
+ }
+ return ( ( i == stub->len || ch == ':' ) && argc == nargs );
+}
+
+static void gdbstub_send_errno ( struct gdbstub *stub, int errno ) {
+ gdbstub_send_num_packet ( stub, 'E', errno );
+}
+
+static void gdbstub_report_signal ( struct gdbstub *stub ) {
+ gdbstub_send_num_packet ( stub, 'S', stub->signo );
+}
+
+static void gdbstub_read_regs ( struct gdbstub *stub ) {
+ gdbstub_to_hex_buf ( stub->payload, ( char * ) stub->regs, GDBMACH_SIZEOF_REGS );
+ stub->len = GDBMACH_SIZEOF_REGS * 2;
+ gdbstub_tx_packet ( stub );
+}
+
+static void gdbstub_write_regs ( struct gdbstub *stub ) {
+ if ( stub->len != 1 + GDBMACH_SIZEOF_REGS * 2 ) {
+ gdbstub_send_errno ( stub, POSIX_EINVAL );
+ return;
+ }
+ gdbstub_from_hex_buf ( ( char * ) stub->regs, &stub->payload [ 1 ], GDBMACH_SIZEOF_REGS );
+ gdbstub_send_ok ( stub );
+}
+
+static void gdbstub_read_mem ( struct gdbstub *stub ) {
+ unsigned long args [ 2 ];
+ if ( !gdbstub_get_packet_args ( stub, args, sizeof args / sizeof args [ 0 ], NULL ) ) {
+ gdbstub_send_errno ( stub, POSIX_EINVAL );
+ return;
+ }
+ args [ 1 ] = ( args [ 1 ] < SIZEOF_PAYLOAD / 2 ) ? args [ 1 ] : SIZEOF_PAYLOAD / 2;
+ gdbstub_to_hex_buf ( stub->payload, ( char * ) args [ 0 ], args [ 1 ] );
+ stub->len = args [ 1 ] * 2;
+ gdbstub_tx_packet ( stub );
+}
+
+static void gdbstub_write_mem ( struct gdbstub *stub ) {
+ unsigned long args [ 2 ];
+ int colon;
+ if ( !gdbstub_get_packet_args ( stub, args, sizeof args / sizeof args [ 0 ], &colon ) ||
+ colon >= stub->len || stub->payload [ colon ] != ':' ||
+ ( stub->len - colon - 1 ) % 2 != 0 ) {
+ gdbstub_send_errno ( stub, POSIX_EINVAL );
+ return;
+ }
+ gdbstub_from_hex_buf ( ( char * ) args [ 0 ], &stub->payload [ colon + 1 ], ( stub->len - colon - 1 ) / 2 );
+ gdbstub_send_ok ( stub );
+}
+
+static void gdbstub_continue ( struct gdbstub *stub, int single_step ) {
+ gdbreg_t pc;
+ if ( stub->len > 1 && gdbstub_get_packet_args ( stub, &pc, 1, NULL ) ) {
+ gdbmach_set_pc ( stub->regs, pc );
+ }
+ gdbmach_set_single_step ( stub->regs, single_step );
+ stub->exit_handler = 1;
+ /* Reply will be sent when we hit the next breakpoint or interrupt */
+}
+
+static void gdbstub_breakpoint ( struct gdbstub *stub ) {
+ unsigned long args [ 3 ];
+ int enable = stub->payload [ 0 ] == 'Z' ? 1 : 0;
+ if ( !gdbstub_get_packet_args ( stub, args, sizeof args / sizeof args [ 0 ], NULL ) ) {
+ gdbstub_send_errno ( stub, POSIX_EINVAL );
+ return;
+ }
+ if ( gdbmach_set_breakpoint ( args [ 0 ], args [ 1 ], args [ 2 ], enable ) ) {
+ gdbstub_send_ok ( stub );
+ } else {
+ /* Not supported */
+ stub->len = 0;
+ gdbstub_tx_packet ( stub );
+ }
+}
+
+static void gdbstub_rx_packet ( struct gdbstub *stub ) {
+ switch ( stub->payload [ 0 ] ) {
+ case '?':
+ gdbstub_report_signal ( stub );
+ break;
+ case 'g':
+ gdbstub_read_regs ( stub );
+ break;
+ case 'G':
+ gdbstub_write_regs ( stub );
+ break;
+ case 'm':
+ gdbstub_read_mem ( stub );
+ break;
+ case 'M':
+ gdbstub_write_mem ( stub );
+ break;
+ case 'c': /* Continue */
+ case 'k': /* Kill */
+ case 's': /* Step */
+ case 'D': /* Detach */
+ gdbstub_continue ( stub, stub->payload [ 0 ] == 's' );
+ if ( stub->payload [ 0 ] == 'D' ) {
+ gdbstub_send_ok ( stub );
+ }
+ break;
+ case 'Z': /* Insert breakpoint */
+ case 'z': /* Remove breakpoint */
+ gdbstub_breakpoint ( stub );
+ break;
+ default:
+ stub->len = 0;
+ gdbstub_tx_packet ( stub );
+ break;
+ }
+}
+
+/* GDB packet parser */
+static void gdbstub_state_new ( struct gdbstub *stub, char ch ) {
+ if ( ch == '$' ) {
+ stub->len = 0;
+ stub->parse = gdbstub_state_data;
+ }
+}
+
+static void gdbstub_state_data ( struct gdbstub *stub, char ch ) {
+ if ( ch == '#' ) {
+ stub->parse = gdbstub_state_cksum1;
+ } else if ( ch == '$' ) {
+ stub->len = 0; /* retry new packet */
+ } else {
+ /* If the length exceeds our buffer, let the checksum fail */
+ if ( stub->len < SIZEOF_PAYLOAD ) {
+ stub->payload [ stub->len++ ] = ch;
+ }
+ }
+}
+
+static void gdbstub_state_cksum1 ( struct gdbstub *stub, char ch ) {
+ stub->cksum1 = gdbstub_from_hex_digit ( ch ) << 4;
+ stub->parse = gdbstub_state_cksum2;
+}
+
+static void gdbstub_state_cksum2 ( struct gdbstub *stub, char ch ) {
+ uint8_t their_cksum;
+ uint8_t our_cksum;
+
+ stub->parse = gdbstub_state_new;
+ their_cksum = stub->cksum1 + gdbstub_from_hex_digit ( ch );
+ our_cksum = gdbstub_cksum ( stub->payload, stub->len );
+ if ( their_cksum == our_cksum ) {
+ stub->trans->send ( "+", 1 );
+ if ( stub->len > 0 ) {
+ gdbstub_rx_packet ( stub );
+ }
+ } else {
+ stub->trans->send ( "-", 1 );
+ }
+}
+
+static void gdbstub_state_wait_ack ( struct gdbstub *stub, char ch ) {
+ if ( ch == '+' ) {
+ stub->parse = gdbstub_state_new;
+ } else {
+ /* This retransmit is very aggressive but necessary to keep
+ * in sync with GDB. */
+ gdbstub_tx_packet ( stub );
+ }
+}
+
+static void gdbstub_parse ( struct gdbstub *stub, char ch ) {
+ stub->parse ( stub, ch );
+}
+
+static struct gdbstub stub = {
+ .parse = gdbstub_state_new
+};
+
+void gdbstub_handler ( int signo, gdbreg_t *regs ) {
+ char packet [ SIZEOF_PAYLOAD + 4 ];
+ size_t len, i;
+
+ /* A transport must be set up */
+ if ( !stub.trans ) {
+ return;
+ }
+
+ stub.signo = signo;
+ stub.regs = regs;
+ stub.exit_handler = 0;
+ gdbstub_report_signal ( &stub );
+ while ( !stub.exit_handler && ( len = stub.trans->recv ( packet, sizeof ( packet ) ) ) > 0 ) {
+ for ( i = 0; i < len; i++ ) {
+ gdbstub_parse ( &stub, packet [ i ] );
+ }
+ }
+}
+
+struct gdb_transport *find_gdb_transport ( const char *name ) {
+ struct gdb_transport *trans;
+
+ for_each_table_entry ( trans, GDB_TRANSPORTS ) {
+ if ( strcmp ( trans->name, name ) == 0 ) {
+ return trans;
+ }
+ }
+ return NULL;
+}
+
+void gdbstub_start ( struct gdb_transport *trans ) {
+ stub.trans = trans;
+ stub.payload = &stub.buf [ 1 ];
+ gdbmach_init();
+ gdbmach_breakpoint();
+}
Code Review / kvmfornfv.git / blobdiff