diff options
Diffstat (limited to 'contrib/syslinux/syslinux-4.03/com32/gdbstub/gdbstub.c')
| -rw-r--r-- | contrib/syslinux/syslinux-4.03/com32/gdbstub/gdbstub.c | 569 |
1 files changed, 0 insertions, 569 deletions
diff --git a/contrib/syslinux/syslinux-4.03/com32/gdbstub/gdbstub.c b/contrib/syslinux/syslinux-4.03/com32/gdbstub/gdbstub.c deleted file mode 100644 index bd19add..0000000 --- a/contrib/syslinux/syslinux-4.03/com32/gdbstub/gdbstub.c +++ /dev/null @@ -1,569 +0,0 @@ -/* - * 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 <stdint.h> -#include "serial.h" - -typedef uint32_t gdbreg_t; - -enum { - POSIX_EINVAL = 0x1c, /* used to report bad arguments to GDB */ - SIZEOF_PAYLOAD = 256, /* buffer size of GDB payload data */ - DR7_CLEAR = 0x00000400, /* disable hardware breakpoints */ - DR6_CLEAR = 0xffff0ff0, /* clear breakpoint status */ -}; - -/* The register snapshot, this must be in sync with interrupt handler and the - * GDB protocol. */ -enum { - GDBMACH_EAX, - GDBMACH_ECX, - GDBMACH_EDX, - GDBMACH_EBX, - GDBMACH_ESP, - GDBMACH_EBP, - GDBMACH_ESI, - GDBMACH_EDI, - GDBMACH_EIP, - GDBMACH_EFLAGS, - GDBMACH_CS, - GDBMACH_SS, - GDBMACH_DS, - GDBMACH_ES, - GDBMACH_FS, - GDBMACH_GS, - GDBMACH_NREGS, - GDBMACH_SIZEOF_REGS = GDBMACH_NREGS * sizeof(gdbreg_t) -}; - -/* Breakpoint types */ -enum { - GDBMACH_BPMEM, - GDBMACH_BPHW, - GDBMACH_WATCH, - GDBMACH_RWATCH, - GDBMACH_AWATCH, -}; - -struct gdbstub { - 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 */ -}; - -/** Hardware breakpoint, fields stored in x86 bit pattern form */ -struct hwbp { - int type; /* type (1=write watchpoint, 3=access watchpoint) */ - unsigned long addr; /* linear address */ - size_t len; /* length (0=1-byte, 1=2-byte, 3=4-byte) */ - int enabled; -}; - -static struct hwbp hwbps[4]; -static gdbreg_t dr7 = DR7_CLEAR; - -static inline void gdbmach_set_pc(gdbreg_t * regs, gdbreg_t pc) -{ - regs[GDBMACH_EIP] = pc; -} - -static inline void gdbmach_set_single_step(gdbreg_t * regs, int step) -{ - regs[GDBMACH_EFLAGS] &= ~(1 << 8); /* Trace Flag (TF) */ - regs[GDBMACH_EFLAGS] |= (step << 8); -} - -static inline void gdbmach_breakpoint(void) -{ - __asm__ __volatile__("int $3\n"); -} - -static struct hwbp *gdbmach_find_hwbp(int type, unsigned long addr, size_t len) -{ - struct hwbp *available = NULL; - unsigned int i; - for (i = 0; i < sizeof hwbps / sizeof hwbps[0]; i++) { - if (hwbps[i].type == type && hwbps[i].addr == addr - && hwbps[i].len == len) { - return &hwbps[i]; - } - if (!hwbps[i].enabled) { - available = &hwbps[i]; - } - } - return available; -} - -static void gdbmach_commit_hwbp(struct hwbp *bp) -{ - int regnum = bp - hwbps; - - /* Set breakpoint address */ - switch (regnum) { - case 0: -__asm__ __volatile__("movl %0, %%dr0\n": :"r"(bp->addr)); - break; - case 1: -__asm__ __volatile__("movl %0, %%dr1\n": :"r"(bp->addr)); - break; - case 2: -__asm__ __volatile__("movl %0, %%dr2\n": :"r"(bp->addr)); - break; - case 3: -__asm__ __volatile__("movl %0, %%dr3\n": :"r"(bp->addr)); - break; - } - - /* Set type */ - dr7 &= ~(0x3 << (16 + 4 * regnum)); - dr7 |= bp->type << (16 + 4 * regnum); - - /* Set length */ - dr7 &= ~(0x3 << (18 + 4 * regnum)); - dr7 |= bp->len << (18 + 4 * regnum); - - /* Set/clear local enable bit */ - dr7 &= ~(0x3 << 2 * regnum); - dr7 |= bp->enabled << 2 * regnum; -} - -int gdbmach_set_breakpoint(int type, unsigned long addr, size_t len, int enable) -{ - struct hwbp *bp; - - /* Check and convert breakpoint type to x86 type */ - switch (type) { - case GDBMACH_WATCH: - type = 0x1; - break; - case GDBMACH_AWATCH: - type = 0x3; - break; - default: - return 0; /* unsupported breakpoint type */ - } - - /* Only lengths 1, 2, and 4 are supported */ - if (len != 2 && len != 4) { - len = 1; - } - len--; /* convert to x86 breakpoint length bit pattern */ - - /* Set up the breakpoint */ - bp = gdbmach_find_hwbp(type, addr, len); - if (!bp) { - return 0; /* ran out of hardware breakpoints */ - } - bp->type = type; - bp->addr = addr; - bp->len = len; - bp->enabled = enable; - gdbmach_commit_hwbp(bp); - return 1; -} - -static void gdbmach_disable_hwbps(void) -{ - /* Store and clear hardware breakpoints */ - __asm__ __volatile__("movl %0, %%dr7\n"::"r"(DR7_CLEAR)); -} - -static void gdbmach_enable_hwbps(void) -{ - /* Clear breakpoint status register */ - __asm__ __volatile__("movl %0, %%dr6\n"::"r"(DR6_CLEAR)); - - /* Restore hardware breakpoints */ - __asm__ __volatile__("movl %0, %%dr7\n"::"r"(dr7)); -} - -/* 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 void serial_write(void *buf, size_t len) -{ - char *p = buf; - while (len-- > 0) - serial_putc(*p++); -} - -static uint8_t gdbstub_from_hex_digit(char ch) -{ - if (ch >= '0' && ch <= '9') - return ch - '0'; - else if (ch >= 'A' && ch <= 'F') - return ch - 'A' + 0xa; - else - return (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 = 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 = 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 = *(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 = *(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); - serial_write(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, (unsigned long *)&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) { - serial_write("+", 1); - if (stub->len > 0) { - gdbstub_rx_packet(stub); - } - } else { - serial_write("-", 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); - } -} - -void gdbstub_handler(int signo, gdbreg_t * regs) -{ - struct gdbstub stub; - - gdbmach_disable_hwbps(); - - stub.parse = gdbstub_state_new; - stub.payload = &stub.buf[1]; - stub.signo = signo; - stub.regs = regs; - stub.exit_handler = 0; - gdbstub_report_signal(&stub); - while (!stub.exit_handler) - stub.parse(&stub, serial_getc()); - - gdbmach_enable_hwbps(); -} |