365 lines
8.6 KiB
C
365 lines
8.6 KiB
C
/* cstub.c - machine independent portion of remote GDB stub */
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/*
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* Copyright (C) 2006 Lubomir Kundrak
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU 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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#include <grub/misc.h>
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#include <grub/cpu/gdb.h>
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#include <grub/gdb.h>
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#include <grub/serial.h>
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#include <grub/backtrace.h>
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static const char hexchars[] = "0123456789abcdef";
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int grub_gdb_regs[GRUB_MACHINE_NR_REGS];
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#define GRUB_GDB_COMBUF_SIZE 400 /* At least sizeof(grub_gdb_regs)*2 are needed for
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register packets. */
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static char grub_gdb_inbuf[GRUB_GDB_COMBUF_SIZE + 1];
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static char grub_gdb_outbuf[GRUB_GDB_COMBUF_SIZE + 1];
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struct grub_serial_port *grub_gdb_port;
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static int
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hex (char ch)
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{
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if ((ch >= 'a') && (ch <= 'f'))
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return (ch - 'a' + 10);
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if ((ch >= '0') && (ch <= '9'))
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return (ch - '0');
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if ((ch >= 'A') && (ch <= 'F'))
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return (ch - 'A' + 10);
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return (-1);
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}
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/* Scan for the sequence $<data>#<checksum>. */
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static char *
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grub_gdb_getpacket (void)
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{
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char *buffer = &grub_gdb_inbuf[0];
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unsigned char checksum;
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unsigned char xmitcsum;
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int count;
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int ch;
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while (1)
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{
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/* Wait around for the start character, ignore all other
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characters. */
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while ((ch = grub_serial_port_fetch (grub_gdb_port)) != '$');
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retry:
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checksum = 0;
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xmitcsum = -1;
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count = 0;
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/* Now read until a # or end of buffer is found. */
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while (count < GRUB_GDB_COMBUF_SIZE)
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{
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do
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ch = grub_serial_port_fetch (grub_gdb_port);
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while (ch < 0);
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if (ch == '$')
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goto retry;
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if (ch == '#')
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break;
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checksum += ch;
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buffer[count] = ch;
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count = count + 1;
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}
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buffer[count] = 0;
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if (ch == '#')
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{
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do
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ch = grub_serial_port_fetch (grub_gdb_port);
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while (ch < 0);
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xmitcsum = hex (ch) << 4;
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do
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ch = grub_serial_port_fetch (grub_gdb_port);
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while (ch < 0);
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xmitcsum += hex (ch);
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if (checksum != xmitcsum)
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grub_serial_port_put (grub_gdb_port, '-'); /* Failed checksum. */
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else
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{
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grub_serial_port_put (grub_gdb_port, '+'); /* Successful transfer. */
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/* If a sequence char is present, reply the sequence ID. */
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if (buffer[2] == ':')
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{
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grub_serial_port_put (grub_gdb_port, buffer[0]);
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grub_serial_port_put (grub_gdb_port, buffer[1]);
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return &buffer[3];
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}
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return &buffer[0];
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}
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}
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}
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}
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/* Send the packet in buffer. */
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static void
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grub_gdb_putpacket (char *buffer)
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{
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grub_uint8_t checksum;
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/* $<packet info>#<checksum>. */
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do
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{
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char *ptr;
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grub_serial_port_put (grub_gdb_port, '$');
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checksum = 0;
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for (ptr = buffer; *ptr; ptr++)
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{
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grub_serial_port_put (grub_gdb_port, *ptr);
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checksum += *ptr;
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}
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grub_serial_port_put (grub_gdb_port, '#');
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grub_serial_port_put (grub_gdb_port, hexchars[checksum >> 4]);
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grub_serial_port_put (grub_gdb_port, hexchars[checksum & 0xf]);
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}
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while (grub_serial_port_fetch (grub_gdb_port) != '+');
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}
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/* Convert the memory pointed to by mem into hex, placing result in buf.
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Return a pointer to the last char put in buf (NULL). */
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static char *
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grub_gdb_mem2hex (char *mem, char *buf, grub_size_t count)
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{
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grub_size_t i;
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unsigned char ch;
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for (i = 0; i < count; i++)
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{
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ch = *mem++;
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*buf++ = hexchars[ch >> 4];
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*buf++ = hexchars[ch % 16];
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}
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*buf = 0;
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return (buf);
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}
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/* Convert the hex array pointed to by buf into binary to be placed in mem.
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Return a pointer to the character after the last byte written. */
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static char *
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grub_gdb_hex2mem (char *buf, char *mem, int count)
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{
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int i;
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unsigned char ch;
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for (i = 0; i < count; i++)
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{
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ch = hex (*buf++) << 4;
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ch = ch + hex (*buf++);
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*mem++ = ch;
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}
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return (mem);
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}
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/* Convert hex characters to int and return the number of characters
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processed. */
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static int
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grub_gdb_hex2int (char **ptr, grub_uint64_t *int_value)
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{
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int num_chars = 0;
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int hex_value;
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*int_value = 0;
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while (**ptr)
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{
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hex_value = hex (**ptr);
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if (hex_value >= 0)
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{
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*int_value = (*int_value << 4) | hex_value;
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num_chars++;
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}
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else
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break;
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(*ptr)++;
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}
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return (num_chars);
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}
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/* This function does all command procesing for interfacing to gdb. */
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void
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grub_gdb_trap (int trap_no)
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{
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unsigned int sig_no;
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int stepping;
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grub_uint64_t addr;
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grub_uint64_t length;
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char *ptr;
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if (!grub_gdb_port)
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{
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grub_printf ("Unhandled exception 0x%x at ", trap_no);
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grub_backtrace_print_address ((void *) grub_gdb_regs[PC]);
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grub_printf ("\n");
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grub_backtrace_pointer ((void *) grub_gdb_regs[EBP]);
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grub_abort ();
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}
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sig_no = grub_gdb_trap2sig (trap_no);
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ptr = grub_gdb_outbuf;
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/* Reply to host that an exception has occurred. */
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*ptr++ = 'T'; /* Notify gdb with signo, PC, FP and SP. */
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*ptr++ = hexchars[sig_no >> 4];
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*ptr++ = hexchars[sig_no & 0xf];
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/* Stack pointer. */
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*ptr++ = hexchars[SP];
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*ptr++ = ':';
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ptr = grub_gdb_mem2hex ((char *) &grub_gdb_regs[ESP], ptr, 4);
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*ptr++ = ';';
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/* Frame pointer. */
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*ptr++ = hexchars[FP];
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*ptr++ = ':';
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ptr = grub_gdb_mem2hex ((char *) &grub_gdb_regs[EBP], ptr, 4);
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*ptr++ = ';';
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/* Program counter. */
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*ptr++ = hexchars[PC];
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*ptr++ = ':';
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ptr = grub_gdb_mem2hex ((char *) &grub_gdb_regs[PC], ptr, 4);
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*ptr++ = ';';
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*ptr = '\0';
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grub_gdb_putpacket (grub_gdb_outbuf);
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stepping = 0;
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while (1)
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{
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grub_gdb_outbuf[0] = 0;
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ptr = grub_gdb_getpacket ();
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switch (*ptr++)
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{
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case '?':
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grub_gdb_outbuf[0] = 'S';
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grub_gdb_outbuf[1] = hexchars[sig_no >> 4];
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grub_gdb_outbuf[2] = hexchars[sig_no & 0xf];
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grub_gdb_outbuf[3] = 0;
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break;
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/* Return values of the CPU registers. */
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case 'g':
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grub_gdb_mem2hex ((char *) grub_gdb_regs, grub_gdb_outbuf,
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sizeof (grub_gdb_regs));
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break;
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/* Set values of the CPU registers -- return OK. */
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case 'G':
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grub_gdb_hex2mem (ptr, (char *) grub_gdb_regs,
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sizeof (grub_gdb_regs));
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grub_strcpy (grub_gdb_outbuf, "OK");
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break;
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/* Set the value of a single CPU register -- return OK. */
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case 'P':
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{
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grub_uint64_t regno;
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if (grub_gdb_hex2int (&ptr, ®no) && *ptr++ == '=')
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if (regno < GRUB_MACHINE_NR_REGS)
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{
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grub_gdb_hex2mem (ptr, (char *) &grub_gdb_regs[regno], 4);
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grub_strcpy (grub_gdb_outbuf, "OK");
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break;
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}
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/* FIXME: GDB requires setting orig_eax. I don't know what's
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this register is about. For now just simulate setting any
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registers. */
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grub_strcpy (grub_gdb_outbuf, /*"E01"*/ "OK");
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break;
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}
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/* mAA..AA,LLLL: Read LLLL bytes at address AA..AA. */
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case 'm':
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/* Try to read %x,%x. Set ptr = 0 if successful. */
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if (grub_gdb_hex2int (&ptr, &addr))
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if (*(ptr++) == ',')
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if (grub_gdb_hex2int (&ptr, &length))
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{
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ptr = 0;
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grub_gdb_mem2hex ((char *) (grub_addr_t) addr,
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grub_gdb_outbuf, length);
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}
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if (ptr)
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grub_strcpy (grub_gdb_outbuf, "E01");
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break;
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/* MAA..AA,LLLL: Write LLLL bytes at address AA.AA -- return OK. */
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case 'M':
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/* Try to read %x,%x. Set ptr = 0 if successful. */
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if (grub_gdb_hex2int (&ptr, &addr))
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if (*(ptr++) == ',')
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if (grub_gdb_hex2int (&ptr, &length))
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if (*(ptr++) == ':')
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{
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grub_gdb_hex2mem (ptr, (char *) (grub_addr_t) addr, length);
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grub_strcpy (grub_gdb_outbuf, "OK");
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ptr = 0;
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}
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if (ptr)
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{
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grub_strcpy (grub_gdb_outbuf, "E02");
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}
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break;
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/* sAA..AA: Step one instruction from AA..AA(optional). */
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case 's':
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stepping = 1;
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/* cAA..AA: Continue at address AA..AA(optional). */
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case 'c':
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/* try to read optional parameter, pc unchanged if no parm */
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if (grub_gdb_hex2int (&ptr, &addr))
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grub_gdb_regs[PC] = addr;
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/* Clear the trace bit. */
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grub_gdb_regs[PS] &= 0xfffffeff;
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/* Set the trace bit if we're stepping. */
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if (stepping)
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grub_gdb_regs[PS] |= 0x100;
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return;
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/* Kill the program. */
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case 'k':
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/* Do nothing. */
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return;
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}
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/* Reply to the request. */
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grub_gdb_putpacket (grub_gdb_outbuf);
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}
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}
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