diff options
Diffstat (limited to 'contrib/syslinux-4.02/com32/gdbstub')
| -rw-r--r-- | contrib/syslinux-4.02/com32/gdbstub/Makefile | 49 | ||||
| -rw-r--r-- | contrib/syslinux-4.02/com32/gdbstub/gdbstub.c | 569 | ||||
| -rw-r--r-- | contrib/syslinux-4.02/com32/gdbstub/int.S | 77 | ||||
| -rw-r--r-- | contrib/syslinux-4.02/com32/gdbstub/main.c | 142 | ||||
| -rw-r--r-- | contrib/syslinux-4.02/com32/gdbstub/serial.c | 193 | ||||
| -rw-r--r-- | contrib/syslinux-4.02/com32/gdbstub/serial.h | 14 |
6 files changed, 1044 insertions, 0 deletions
diff --git a/contrib/syslinux-4.02/com32/gdbstub/Makefile b/contrib/syslinux-4.02/com32/gdbstub/Makefile new file mode 100644 index 0000000..5513876 --- /dev/null +++ b/contrib/syslinux-4.02/com32/gdbstub/Makefile @@ -0,0 +1,49 @@ +## ----------------------------------------------------------------------- +## +## Copyright 2001-2008 H. Peter Anvin - All Rights Reserved +## +## 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, Inc., 51 Franklin St, Fifth Floor, +## Boston MA 02110-1301, USA; either version 2 of the License, or +## (at your option) any later version; incorporated herein by reference. +## +## ----------------------------------------------------------------------- + +## +## GDB remote debugging +## + +topdir = ../.. +include ../MCONFIG + +CFLAGS += -fPIE + +LIBS = ../libutil/libutil_com.a ../lib/libcom32.a $(LIBGCC) +LNXLIBS = ../libutil/libutil_lnx.a + +MODULES = gdbstub.c32 +TESTFILES = + +OBJS = main.o int.o serial.o gdbstub.o + +all: $(MODULES) $(TESTFILES) + +gdbstub.elf : $(OBJS) $(LIBS) $(C_LIBS) + $(LD) $(LDFLAGS) -o $@ $^ + +tidy dist clean: + rm -f *.o *.lo *.a *.lst *.elf .*.d *.tmp + +clean: tidy + rm -f *.lnx + +spotless: clean + rm -f *.lss *.c32 *.com + rm -f *~ \#* + +install: + mkdir -m 755 -p $(INSTALLROOT)$(AUXDIR) + install -m 644 $(MODULES) $(INSTALLROOT)$(AUXDIR) + +-include .*.d diff --git a/contrib/syslinux-4.02/com32/gdbstub/gdbstub.c b/contrib/syslinux-4.02/com32/gdbstub/gdbstub.c new file mode 100644 index 0000000..bd19add --- /dev/null +++ b/contrib/syslinux-4.02/com32/gdbstub/gdbstub.c @@ -0,0 +1,569 @@ +/* + * 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(); +} diff --git a/contrib/syslinux-4.02/com32/gdbstub/int.S b/contrib/syslinux-4.02/com32/gdbstub/int.S new file mode 100644 index 0000000..2a1ff9d --- /dev/null +++ b/contrib/syslinux-4.02/com32/gdbstub/int.S @@ -0,0 +1,77 @@ + .section ".text","ax" + +#define SIGTRAP 5 + +#define SIZEOF_I386_REGS 32 +#define SIZEOF_I386_FLAGS 4 + +/* When invoked, the stack contains: eflags, cs, eip, signo. */ +#define IH_OFFSET_GDB_REGS ( 0 ) +#define IH_OFFSET_GDB_EIP ( IH_OFFSET_GDB_REGS + SIZEOF_I386_REGS ) +#define IH_OFFSET_GDB_EFLAGS ( IH_OFFSET_GDB_EIP + 4 ) +#define IH_OFFSET_GDB_SEG_REGS ( IH_OFFSET_GDB_EFLAGS + SIZEOF_I386_FLAGS ) +#define IH_OFFSET_GDB_END ( IH_OFFSET_GDB_SEG_REGS + 6 * 4 ) +#define IH_OFFSET_OLD_EIP ( IH_OFFSET_GDB_END ) +#define IH_OFFSET_OLD_CS ( IH_OFFSET_OLD_EIP + 4 ) +#define IH_OFFSET_OLD_EFLAGS ( IH_OFFSET_OLD_CS + 4 ) +#define IH_OFFSET_END ( IH_OFFSET_OLD_EFLAGS + 4 ) + +/* We also access the stack whilst still storing or restoring + * the register snapshot. Since ESP is in flux, we need + * special offsets. + */ +#define IH_OFFSET_FLUX_OLD_CS ( IH_OFFSET_OLD_CS - 44 ) +#define IH_OFFSET_FLUX_OLD_EFLAGS ( IH_OFFSET_OLD_EFLAGS - 40 ) +#define IH_OFFSET_FLUX_OLD_EIP ( IH_OFFSET_OLD_EIP - 36 ) +#define IH_OFFSET_FLUX_END ( IH_OFFSET_END - 20 ) + + .global int_handler +int_handler: + /* Store CPU state in GDB register snapshot */ + pushw $0 + pushw %gs + pushw $0 + pushw %fs + pushw $0 + pushw %es + pushw $0 + pushw %ds + pushw $0 + pushw %ss + pushw $0 + pushw IH_OFFSET_FLUX_OLD_CS + 2(%esp) + pushl IH_OFFSET_FLUX_OLD_EFLAGS(%esp) + pushl IH_OFFSET_FLUX_OLD_EIP(%esp) + pushl %edi + pushl %esi + pushl %ebp + leal IH_OFFSET_FLUX_END(%esp), %edi + pushl %edi /* old ESP */ + pushl %ebx + pushl %edx + pushl %ecx + pushl %eax + + /* Call GDB stub exception handler */ + movl $SIGTRAP, %eax + movl %esp, %edx + call gdbstub_handler + + /* Restore CPU state from GDB register snapshot */ + popl %eax + popl %ecx + popl %edx + popl %ebx + addl $4, %esp /* Changing ESP currently not supported */ + popl %ebp + popl %esi + popl %edi + popl IH_OFFSET_FLUX_OLD_EIP(%esp) + popl IH_OFFSET_FLUX_OLD_EFLAGS(%esp) + popl IH_OFFSET_FLUX_OLD_CS(%esp) + popl %ss + popl %ds + popl %es + popl %fs + popl %gs + iret diff --git a/contrib/syslinux-4.02/com32/gdbstub/main.c b/contrib/syslinux-4.02/com32/gdbstub/main.c new file mode 100644 index 0000000..2ff9f28 --- /dev/null +++ b/contrib/syslinux-4.02/com32/gdbstub/main.c @@ -0,0 +1,142 @@ +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <console.h> +#include <com32.h> +#include <syslinux/loadfile.h> +#include "serial.h" + +#define X86_INT_DB 1 +#define X86_INT_BP 3 +#define COM32_IDT ((void*)0x100000) +#define COM32_LOAD_ADDR ((void*)0x101000) +#define STACK_SIZE 0x1000 + +extern char _start[], _end[]; + +struct reloc_info { + void *data; + size_t len; + uint32_t old_esp; + uint32_t reloc_base; +}; + +static inline void error(const char *msg) +{ + fputs(msg, stderr); +} + +static inline uint32_t reloc_ptr(struct reloc_info *ri, void *ptr) +{ + return ri->reloc_base + (uint32_t) ((char *)ptr - _start); +} + +static void hijack_interrupt(int intn, uint32_t handler) +{ + struct { + uint32_t lo; + uint32_t hi; + } *idt = COM32_IDT; + + idt[intn].lo = (idt[intn].lo & 0xffff0000) | (handler & 0x0000ffff); + idt[intn].hi = (idt[intn].hi & 0x0000ffff) | (handler & 0xffff0000); +} + +static void shift_cmdline(struct com32_sys_args *com32) +{ + char *p; + + /* Skip leading whitespace */ + for (p = com32->cs_cmdline; *p != '\0' && *p == ' '; p++) ; + + /* Skip first word */ + for (; *p != '\0' && *p != ' '; p++) ; + + /* Skip whitespace after first word */ + for (; *p != '\0' && *p == ' '; p++) ; + + com32->cs_cmdline = p; +} + +static __noreturn reloc_entry(struct reloc_info *ri) +{ + extern char int_handler[]; + size_t stack_frame_size = sizeof(struct com32_sys_args) + 4; + struct com32_sys_args *com32; + uint32_t module_esp; + + hijack_interrupt(X86_INT_DB, reloc_ptr(ri, int_handler)); + hijack_interrupt(X86_INT_BP, reloc_ptr(ri, int_handler)); + + /* Copy module to load address */ + memcpy(COM32_LOAD_ADDR, ri->data, ri->len); + + /* Copy stack frame onto module stack */ + module_esp = (ri->reloc_base - stack_frame_size) & ~15; + memcpy((void *)module_esp, (void *)ri->old_esp, stack_frame_size); + + /* Fix up command line */ + com32 = (struct com32_sys_args *)(module_esp + 4); + shift_cmdline(com32); + + /* Set up CPU state to run module and enter GDB */ + asm volatile ("movl %0, %%esp\n\t" + "pushf\n\t" + "pushl %%cs\n\t" + "pushl %1\n\t" + "jmp *%2\n\t"::"r" (module_esp), + "c"(COM32_LOAD_ADDR), "r"(reloc_ptr(ri, int_handler)) + ); + for (;;) ; /* shut the compiler up */ +} + +static inline __noreturn reloc(void *ptr, size_t len) +{ + extern uint32_t __entry_esp; + size_t total_size = _end - _start; + __noreturn(*entry_fn) (struct reloc_info *); + struct reloc_info ri; + uint32_t esp; + char *dest; + + /* Calculate relocation address, preserve current stack */ + asm volatile ("movl %%esp, %0\n\t":"=m" (esp)); + dest = (char *)((esp - STACK_SIZE - total_size) & ~3); + + /* Calculate entry point in relocated code */ + entry_fn = (void *)(dest + ((char *)reloc_entry - _start)); + + /* Copy all sections to relocation address */ + printf("Relocating %d bytes from %p to %p\n", total_size, _start, dest); + memcpy(dest, _start, total_size); + + /* Call into relocated code */ + ri.data = ptr; + ri.len = len; + ri.old_esp = __entry_esp; + ri.reloc_base = (uint32_t) dest; + entry_fn(&ri); +} + +int main(int argc, char *argv[]) +{ + void *data; + size_t data_len; + + openconsole(&dev_null_r, &dev_stdcon_w); + + if (argc < 2) { + error("Usage: gdbstub.c32 com32_file arguments...\n"); + return 1; + } + + if (loadfile(argv[1], &data, &data_len)) { + error("Unable to load file\n"); + return 1; + } + + serial_init(); + + /* No more lib calls after this point */ + reloc(data, data_len); +} diff --git a/contrib/syslinux-4.02/com32/gdbstub/serial.c b/contrib/syslinux-4.02/com32/gdbstub/serial.c new file mode 100644 index 0000000..8c69b02 --- /dev/null +++ b/contrib/syslinux-4.02/com32/gdbstub/serial.c @@ -0,0 +1,193 @@ +/* + * The serial port interface routines implement a simple polled i/o + * interface to a standard serial port. Due to the space restrictions + * for the boot blocks, no BIOS support is used (since BIOS requires + * expensive real/protected mode switches), instead the rudimentary + * BIOS support is duplicated here. + * + * The base address and speed for the i/o port are passed from the + * Makefile in the COMCONSOLE and CONSPEED preprocessor macros. The + * line control parameters are currently hard-coded to 8 bits, no + * parity, 1 stop bit (8N1). This can be changed in init_serial(). + */ + +#include <stddef.h> +#include <sys/io.h> +#include "serial.h" + +/* Set default values if none specified */ + +#ifndef COMCONSOLE +#define COMCONSOLE 0x3f8 +#endif + +#ifndef COMSPEED +#define COMSPEED 9600 +#endif + +#ifndef COMDATA +#define COMDATA 8 +#endif + +#ifndef COMPARITY +#define COMPARITY 0 +#endif + +#ifndef COMSTOP +#define COMSTOP 1 +#endif + +#undef UART_BASE +#define UART_BASE ( COMCONSOLE ) + +#undef UART_BAUD +#define UART_BAUD ( COMSPEED ) + +#if ((115200%UART_BAUD) != 0) +#error Bad ttys0 baud rate +#endif + +#define COMBRD (115200/UART_BAUD) + +/* Line Control Settings */ +#define UART_LCS ( ( ( (COMDATA) - 5 ) << 0 ) | \ + ( ( (COMPARITY) ) << 3 ) | \ + ( ( (COMSTOP) - 1 ) << 2 ) ) + +/* Data */ +#define UART_RBR 0x00 +#define UART_TBR 0x00 + +/* Control */ +#define UART_IER 0x01 +#define UART_IIR 0x02 +#define UART_FCR 0x02 +#define UART_LCR 0x03 +#define UART_MCR 0x04 +#define UART_DLL 0x00 +#define UART_DLM 0x01 + +/* Status */ +#define UART_LSR 0x05 +#define UART_LSR_TEMPT 0x40 /* Transmitter empty */ +#define UART_LSR_THRE 0x20 /* Transmit-hold-register empty */ +#define UART_LSR_BI 0x10 /* Break interrupt indicator */ +#define UART_LSR_FE 0x08 /* Frame error indicator */ +#define UART_LSR_PE 0x04 /* Parity error indicator */ +#define UART_LSR_OE 0x02 /* Overrun error indicator */ +#define UART_LSR_DR 0x01 /* Receiver data ready */ + +#define UART_MSR 0x06 +#define UART_SCR 0x07 + +#define uart_readb(addr) inb(addr) +#define uart_writeb(val,addr) outb((val),(addr)) + +/* + * void serial_putc(int ch); + * Write character `ch' to port UART_BASE. + */ +void serial_putc(int ch) +{ + int status; + for (;;) { + status = uart_readb(UART_BASE + UART_LSR); + if (status & UART_LSR_THRE) { + /* TX buffer emtpy */ + uart_writeb(ch, UART_BASE + UART_TBR); + break; + } + } +} + +/* + * int serial_getc(void); + * Read a character from port UART_BASE. + */ +int serial_getc(void) +{ + int status; + int ch; + do { + status = uart_readb(UART_BASE + UART_LSR); + } while ((status & 1) == 0); + ch = uart_readb(UART_BASE + UART_RBR); /* fetch (first) character */ + ch &= 0x7f; /* remove any parity bits we get */ + if (ch == 0x7f) { /* Make DEL... look like BS */ + ch = 0x08; + } + return ch; +} + +/* + * int serial_init(void); + * Initialize port UART_BASE to speed COMSPEED, line settings 8N1. + */ +void serial_init(void) +{ + int status; + int divisor, lcs; + + divisor = COMBRD; + lcs = UART_LCS; + +#ifdef COMPRESERVE + lcs = uart_readb(UART_BASE + UART_LCR) & 0x7f; + uart_writeb(0x80 | lcs, UART_BASE + UART_LCR); + divisor = + (uart_readb(UART_BASE + UART_DLM) << 8) | uart_readb(UART_BASE + + UART_DLL); + uart_writeb(lcs, UART_BASE + UART_LCR); +#endif + + /* Set Baud Rate Divisor to COMSPEED, and test to see if the + * serial port appears to be present. + */ + uart_writeb(0x80 | lcs, UART_BASE + UART_LCR); + uart_writeb(0xaa, UART_BASE + UART_DLL); + if (uart_readb(UART_BASE + UART_DLL) != 0xaa) { + goto out; + } + uart_writeb(0x55, UART_BASE + UART_DLL); + if (uart_readb(UART_BASE + UART_DLL) != 0x55) { + goto out; + } + uart_writeb(divisor & 0xff, UART_BASE + UART_DLL); + if (uart_readb(UART_BASE + UART_DLL) != (divisor & 0xff)) { + goto out; + } + uart_writeb(0xaa, UART_BASE + UART_DLM); + if (uart_readb(UART_BASE + UART_DLM) != 0xaa) { + goto out; + } + uart_writeb(0x55, UART_BASE + UART_DLM); + if (uart_readb(UART_BASE + UART_DLM) != 0x55) { + goto out; + } + uart_writeb((divisor >> 8) & 0xff, UART_BASE + UART_DLM); + if (uart_readb(UART_BASE + UART_DLM) != ((divisor >> 8) & 0xff)) { + goto out; + } + uart_writeb(lcs, UART_BASE + UART_LCR); + + /* disable interrupts */ + uart_writeb(0x0, UART_BASE + UART_IER); + + /* disable fifo's */ + uart_writeb(0x00, UART_BASE + UART_FCR); + + /* Set clear to send, so flow control works... */ + uart_writeb((1 << 1), UART_BASE + UART_MCR); + + /* Flush the input buffer. */ + do { + /* rx buffer reg + * throw away (unconditionally the first time) + */ + (void)uart_readb(UART_BASE + UART_RBR); + /* line status reg */ + status = uart_readb(UART_BASE + UART_LSR); + } while (status & UART_LSR_DR); +out: + return; +} diff --git a/contrib/syslinux-4.02/com32/gdbstub/serial.h b/contrib/syslinux-4.02/com32/gdbstub/serial.h new file mode 100644 index 0000000..bb27a62 --- /dev/null +++ b/contrib/syslinux-4.02/com32/gdbstub/serial.h @@ -0,0 +1,14 @@ +#ifndef _GPXE_SERIAL_H +#define _GPXE_SERIAL_H + +/** @file + * + * Serial driver functions + * + */ + +extern void serial_putc(int ch); +extern int serial_getc(void); +extern void serial_init(void); + +#endif /* _GPXE_SERIAL_H */ |