diff options
Diffstat (limited to 'contrib/syslinux-4.02/gpxe/src/core/gdbstub.c')
| -rw-r--r-- | contrib/syslinux-4.02/gpxe/src/core/gdbstub.c | 397 |
1 files changed, 397 insertions, 0 deletions
diff --git a/contrib/syslinux-4.02/gpxe/src/core/gdbstub.c b/contrib/syslinux-4.02/gpxe/src/core/gdbstub.c new file mode 100644 index 0000000..c808395 --- /dev/null +++ b/contrib/syslinux-4.02/gpxe/src/core/gdbstub.c @@ -0,0 +1,397 @@ +/* + * 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., 675 Mass Ave, Cambridge, MA 02139, USA. + */ + +/** + * @file + * + * GDB stub for remote debugging + * + */ + +#include <stdlib.h> +#include <stdio.h> +#include <string.h> +#include <ctype.h> +#include <byteswap.h> +#include <gpxe/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_breakpoint(); +} |