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-rw-r--r--grub-core/gdb/cstub.c366
1 files changed, 366 insertions, 0 deletions
diff --git a/grub-core/gdb/cstub.c b/grub-core/gdb/cstub.c
new file mode 100644
index 0000000..b64acd7
--- /dev/null
+++ b/grub-core/gdb/cstub.c
@@ -0,0 +1,366 @@
+/* cstub.c - machine independent portion of remote GDB stub */
+/*
+ * Copyright (C) 2006 Lubomir Kundrak
+ *
+ * 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
+ * (at your option) 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.
+ */
+
+#include <grub/misc.h>
+#include <grub/cpu/gdb.h>
+#include <grub/gdb.h>
+#include <grub/serial.h>
+#include <grub/backtrace.h>
+
+static const char hexchars[] = "0123456789abcdef";
+int grub_gdb_regs[GRUB_MACHINE_NR_REGS];
+
+#define GRUB_GDB_COMBUF_SIZE 400 /* At least sizeof(grub_gdb_regs)*2 are needed for
+ register packets. */
+static char grub_gdb_inbuf[GRUB_GDB_COMBUF_SIZE + 1];
+static char grub_gdb_outbuf[GRUB_GDB_COMBUF_SIZE + 1];
+
+struct grub_serial_port *grub_gdb_port;
+
+static int
+hex (char ch)
+{
+ if ((ch >= 'a') && (ch <= 'f'))
+ return (ch - 'a' + 10);
+ if ((ch >= '0') && (ch <= '9'))
+ return (ch - '0');
+ if ((ch >= 'A') && (ch <= 'F'))
+ return (ch - 'A' + 10);
+ return (-1);
+}
+
+/* Scan for the sequence $<data>#<checksum>. */
+static char *
+grub_gdb_getpacket (void)
+{
+ char *buffer = &grub_gdb_inbuf[0];
+ unsigned char checksum;
+ unsigned char xmitcsum;
+ int count;
+ int ch;
+
+ while (1)
+ {
+ /* Wait around for the start character, ignore all other
+ characters. */
+ while ((ch = grub_serial_port_fetch (grub_gdb_port)) != '$');
+
+ retry:
+ checksum = 0;
+ xmitcsum = -1;
+ count = 0;
+
+ /* Now read until a # or end of buffer is found. */
+ while (count < GRUB_GDB_COMBUF_SIZE)
+ {
+ do
+ ch = grub_serial_port_fetch (grub_gdb_port);
+ while (ch < 0);
+ if (ch == '$')
+ goto retry;
+ if (ch == '#')
+ break;
+ checksum += ch;
+ buffer[count] = ch;
+ count = count + 1;
+ }
+ buffer[count] = 0;
+ if (ch == '#')
+ {
+ do
+ ch = grub_serial_port_fetch (grub_gdb_port);
+ while (ch < 0);
+ xmitcsum = hex (ch) << 4;
+ do
+ ch = grub_serial_port_fetch (grub_gdb_port);
+ while (ch < 0);
+ xmitcsum += hex (ch);
+
+ if (checksum != xmitcsum)
+ grub_serial_port_put (grub_gdb_port, '-'); /* Failed checksum. */
+ else
+ {
+ grub_serial_port_put (grub_gdb_port, '+'); /* Successful transfer. */
+
+ /* If a sequence char is present, reply the sequence ID. */
+ if (buffer[2] == ':')
+ {
+ grub_serial_port_put (grub_gdb_port, buffer[0]);
+ grub_serial_port_put (grub_gdb_port, buffer[1]);
+
+ return &buffer[3];
+ }
+ return &buffer[0];
+ }
+ }
+ }
+}
+
+/* Send the packet in buffer. */
+static void
+grub_gdb_putpacket (char *buffer)
+{
+ grub_uint8_t checksum;
+
+ /* $<packet info>#<checksum>. */
+ do
+ {
+ char *ptr;
+ grub_serial_port_put (grub_gdb_port, '$');
+ checksum = 0;
+
+ for (ptr = buffer; *ptr; ptr++)
+ {
+ grub_serial_port_put (grub_gdb_port, *ptr);
+ checksum += *ptr;
+ }
+
+ grub_serial_port_put (grub_gdb_port, '#');
+ grub_serial_port_put (grub_gdb_port, hexchars[checksum >> 4]);
+ grub_serial_port_put (grub_gdb_port, hexchars[checksum & 0xf]);
+ }
+ while (grub_serial_port_fetch (grub_gdb_port) != '+');
+}
+
+/* Convert the memory pointed to by mem into hex, placing result in buf.
+ Return a pointer to the last char put in buf (NULL). */
+static char *
+grub_gdb_mem2hex (char *mem, char *buf, grub_size_t count)
+{
+ grub_size_t i;
+ unsigned char ch;
+
+ for (i = 0; i < count; i++)
+ {
+ ch = *mem++;
+ *buf++ = hexchars[ch >> 4];
+ *buf++ = hexchars[ch % 16];
+ }
+ *buf = 0;
+ return (buf);
+}
+
+/* Convert the hex array pointed to by buf into binary to be placed in mem.
+ Return a pointer to the character after the last byte written. */
+static char *
+grub_gdb_hex2mem (char *buf, char *mem, int count)
+{
+ int i;
+ unsigned char ch;
+
+ for (i = 0; i < count; i++)
+ {
+ ch = hex (*buf++) << 4;
+ ch = ch + hex (*buf++);
+ *mem++ = ch;
+ }
+ return (mem);
+}
+
+/* Convert hex characters to int and return the number of characters
+ processed. */
+static int
+grub_gdb_hex2int (char **ptr, grub_uint64_t *int_value)
+{
+ int num_chars = 0;
+ int hex_value;
+
+ *int_value = 0;
+
+ while (**ptr)
+ {
+ hex_value = hex (**ptr);
+ if (hex_value >= 0)
+ {
+ *int_value = (*int_value << 4) | hex_value;
+ num_chars++;
+ }
+ else
+ break;
+
+ (*ptr)++;
+ }
+
+ return (num_chars);
+}
+
+/* This function does all command procesing for interfacing to gdb. */
+void __attribute__ ((regparm(3)))
+grub_gdb_trap (int trap_no)
+{
+ unsigned int sig_no;
+ int stepping;
+ grub_uint64_t addr;
+ grub_uint64_t length;
+ char *ptr;
+
+ if (!grub_gdb_port)
+ {
+ grub_printf ("Unhandled exception 0x%x at ", trap_no);
+ grub_backtrace_print_address ((void *) grub_gdb_regs[PC]);
+ grub_printf ("\n");
+ grub_backtrace_pointer ((void *) grub_gdb_regs[EBP]);
+ grub_fatal ("Unhandled exception");
+ }
+
+ sig_no = grub_gdb_trap2sig (trap_no);
+
+ ptr = grub_gdb_outbuf;
+
+ /* Reply to host that an exception has occurred. */
+
+ *ptr++ = 'T'; /* Notify gdb with signo, PC, FP and SP. */
+
+ *ptr++ = hexchars[sig_no >> 4];
+ *ptr++ = hexchars[sig_no & 0xf];
+
+ /* Stack pointer. */
+ *ptr++ = hexchars[SP];
+ *ptr++ = ':';
+ ptr = grub_gdb_mem2hex ((char *) &grub_gdb_regs[ESP], ptr, 4);
+ *ptr++ = ';';
+
+ /* Frame pointer. */
+ *ptr++ = hexchars[FP];
+ *ptr++ = ':';
+ ptr = grub_gdb_mem2hex ((char *) &grub_gdb_regs[EBP], ptr, 4);
+ *ptr++ = ';';
+
+ /* Program counter. */
+ *ptr++ = hexchars[PC];
+ *ptr++ = ':';
+ ptr = grub_gdb_mem2hex ((char *) &grub_gdb_regs[PC], ptr, 4);
+ *ptr++ = ';';
+
+ *ptr = '\0';
+
+ grub_gdb_putpacket (grub_gdb_outbuf);
+
+ stepping = 0;
+
+ while (1)
+ {
+ grub_gdb_outbuf[0] = 0;
+ ptr = grub_gdb_getpacket ();
+
+ switch (*ptr++)
+ {
+ case '?':
+ grub_gdb_outbuf[0] = 'S';
+ grub_gdb_outbuf[1] = hexchars[sig_no >> 4];
+ grub_gdb_outbuf[2] = hexchars[sig_no & 0xf];
+ grub_gdb_outbuf[3] = 0;
+ break;
+
+ /* Return values of the CPU registers. */
+ case 'g':
+ grub_gdb_mem2hex ((char *) grub_gdb_regs, grub_gdb_outbuf,
+ sizeof (grub_gdb_regs));
+ break;
+
+ /* Set values of the CPU registers -- return OK. */
+ case 'G':
+ grub_gdb_hex2mem (ptr, (char *) grub_gdb_regs,
+ sizeof (grub_gdb_regs));
+ grub_strcpy (grub_gdb_outbuf, "OK");
+ break;
+
+ /* Set the value of a single CPU register -- return OK. */
+ case 'P':
+ {
+ grub_uint64_t regno;
+
+ if (grub_gdb_hex2int (&ptr, &regno) && *ptr++ == '=')
+ if (regno < GRUB_MACHINE_NR_REGS)
+ {
+ grub_gdb_hex2mem (ptr, (char *) &grub_gdb_regs[regno], 4);
+ grub_strcpy (grub_gdb_outbuf, "OK");
+ break;
+ }
+ /* FIXME: GDB requires setting orig_eax. I don't know what's
+ this register is about. For now just simulate setting any
+ registers. */
+ grub_strcpy (grub_gdb_outbuf, /*"E01"*/ "OK");
+ break;
+ }
+
+ /* mAA..AA,LLLL: Read LLLL bytes at address AA..AA. */
+ case 'm':
+ /* Try to read %x,%x. Set ptr = 0 if successful. */
+ if (grub_gdb_hex2int (&ptr, &addr))
+ if (*(ptr++) == ',')
+ if (grub_gdb_hex2int (&ptr, &length))
+ {
+ ptr = 0;
+ grub_gdb_mem2hex ((char *) (grub_addr_t) addr,
+ grub_gdb_outbuf, length);
+ }
+ if (ptr)
+ grub_strcpy (grub_gdb_outbuf, "E01");
+ break;
+
+ /* MAA..AA,LLLL: Write LLLL bytes at address AA.AA -- return OK. */
+ case 'M':
+ /* Try to read %x,%x. Set ptr = 0 if successful. */
+ if (grub_gdb_hex2int (&ptr, &addr))
+ if (*(ptr++) == ',')
+ if (grub_gdb_hex2int (&ptr, &length))
+ if (*(ptr++) == ':')
+ {
+ grub_gdb_hex2mem (ptr, (char *) (grub_addr_t) addr, length);
+ grub_strcpy (grub_gdb_outbuf, "OK");
+ ptr = 0;
+ }
+ if (ptr)
+ {
+ grub_strcpy (grub_gdb_outbuf, "E02");
+ }
+ break;
+
+ /* sAA..AA: Step one instruction from AA..AA(optional). */
+ case 's':
+ stepping = 1;
+ /* FALLTHROUGH */
+
+ /* cAA..AA: Continue at address AA..AA(optional). */
+ case 'c':
+ /* try to read optional parameter, pc unchanged if no parm */
+ if (grub_gdb_hex2int (&ptr, &addr))
+ grub_gdb_regs[PC] = addr;
+
+ /* Clear the trace bit. */
+ grub_gdb_regs[PS] &= 0xfffffeff;
+
+ /* Set the trace bit if we're stepping. */
+ if (stepping)
+ grub_gdb_regs[PS] |= 0x100;
+
+ return;
+
+ /* Kill the program. */
+ case 'k':
+ /* Do nothing. */
+ return;
+ }
+
+ /* Reply to the request. */
+ grub_gdb_putpacket (grub_gdb_outbuf);
+ }
+}
+
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