38e937ca8e
standard byte order functions in the kernel). Small cleanup. git-svn-id: file:///srv/svn/repos/haiku/trunk/current@7705 a95241bf-73f2-0310-859d-f6bbb57e9c96
505 lines
8.0 KiB
C
505 lines
8.0 KiB
C
/* Contains the code to interface with a remote GDB */
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/*
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** Copyright 2002, Manuel J. Petit. All rights reserved.
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** Distributed under the terms of the NewOS License.
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*/
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#include <string.h>
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#include <stdarg.h>
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#include <stdio.h>
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#include <vm.h>
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#include <smp.h>
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#include <debug.h>
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#include <gdb.h>
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#include <arch/dbg_console.h>
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enum { INIT= 0, CMDREAD, CKSUM1, CKSUM2, WAITACK, QUIT, GDBSTATES };
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static char cmd[512];
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static int cmd_ptr;
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static int checksum;
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static char reply[512];
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static char safe_mem[512];
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/*
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* utility functions
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*/
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static int
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parse_nibble(int input)
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{
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int nibble = 0xff;
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if (input >= '0' && input <= '9')
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nibble = input - '0';
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if (input >= 'A' && input <= 'F')
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nibble = 0x0a + input - 'A';
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if (input >= 'a' && input <= 'f')
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nibble = 0x0a + input - 'a';
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return nibble;
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}
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/*
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* GDB protocol ACK & NAK & Reply
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*
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*/
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static void
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gdb_ack(void)
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{
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dbg_putch('+');
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}
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static void
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gdb_nak(void)
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{
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dbg_putch('-');
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}
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static void
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gdb_resend_reply(void)
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{
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dbg_puts(reply);
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}
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static void
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gdb_reply(char const *fmt, ...)
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{
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int i;
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int len;
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int sum;
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va_list args;
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va_start(args, fmt);
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reply[0] = '$';
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vsprintf(reply + 1, fmt, args);
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va_end(args);
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len = strlen(reply);
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sum = 0;
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for (i = 1; i < len; i++) {
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sum += reply[i];
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}
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sum %= 256;
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sprintf(reply + len, "#%02x", sum);
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gdb_resend_reply();
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}
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static void
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gdb_regreply(int const *regs, int numregs)
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{
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int i;
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int len;
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int sum;
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reply[0] = '$';
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for (i = 0; i < numregs; i++) {
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sprintf(reply+1+8*i, "%08lx", B_HOST_TO_BENDIAN_INT32(regs[i]));
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}
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len = strlen(reply);
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sum = 0;
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for (i = 1; i < len; i++) {
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sum += reply[i];
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}
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sum %= 256;
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sprintf(reply + len, "#%02x", sum);
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gdb_resend_reply();
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}
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static void
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gdb_memreply(char const *bytes, int numbytes)
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{
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int i;
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int len;
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int sum;
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reply[0] = '$';
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for (i = 0; i < numbytes; i++) {
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sprintf(reply+1+2*i, "%02x", (uint8)bytes[i]);
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}
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len = strlen(reply);
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sum = 0;
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for (i = 1; i < len; i++) {
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sum += reply[i];
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}
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sum %= 256;
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sprintf(reply + len, "#%02x", sum);
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gdb_resend_reply();
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}
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/*
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* checksum verification
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*/
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static int
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gdb_verify_checksum(void)
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{
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int i;
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int len;
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int sum;
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len = strlen(cmd);
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sum = 0;
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for (i = 0; i < len; i++) {
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sum += cmd[i];
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}
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sum %= 256;
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return (sum == checksum) ? 1 : 0;
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}
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/*
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* command parsing an dispatching
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*/
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static int
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gdb_parse_command(void)
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{
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if (!gdb_verify_checksum()) {
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gdb_nak();
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return INIT;
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} else
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gdb_ack();
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switch (cmd[0]) {
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case 'H':
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/*
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* Command H (actually Hct) is used to select
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* the current thread (-1 meaning all threads)
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* We just fake we recognize the the command
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* and send an 'OK' response.
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*/
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gdb_reply("OK");
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break;
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case 'q':
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{
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extern unsigned __data_start;
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extern unsigned __bss_start;
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/*
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* There are several q commands:
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*
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* qXXXX Request info about XXXX.
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* QXXXX=yyyy Set value of XXXX to yyyy.
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* qOffsets Get segment offsets
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*
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* Currently we only support the 'qOffsets'
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* form.
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*
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* *Note* that we actually have to lie,
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* At first thought looks like we should
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* return '_start', '__data_start' &
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* '__bss_start', however gdb gets
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* confused because the kernel link script
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* pre-links at 0x80000000. To keep gdb
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* gdb happy we just substract that amount.
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*/
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if (strcmp(cmd+1, "Offsets") == 0) {
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gdb_reply("Text=%x;Data=%x;Bss=%x", 0,
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((unsigned)(&__data_start))-0x80000000,
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((unsigned)(&__bss_start))-0x80000000);
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} else
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gdb_reply("ENS");
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}
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break;
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case '?':
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/*
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* command '?' is used for retrieving the signal
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* that stopped the program. Fully implemeting
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* this command requires help from the debugger,
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* by now we just fake a SIGKILL
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*/
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gdb_reply("S09"); /* SIGKILL = 9 */
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break;
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case 'g':
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{
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int cpu;
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/*
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* command 'g' is used for reading the register
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* file. Faked by now.
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*
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* For x86 the register order is:
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*
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* eax, ebx, ecx, edx,
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* esp, ebp, esi, edi,
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* eip, eflags,
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* cs, ss, ds, es
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*
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* Note that even thought the segment descriptors
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* are actually 16 bits wide, gdb requires them
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* as 32 bit integers. Note also that for some
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* reason (unknown to me) gdb wants the register
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* dump in *big endian* format.
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*/
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cpu = smp_get_current_cpu();
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gdb_regreply(dbg_register_file[cpu], 14);
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}
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break;
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case 'm':
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{
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char *ptr;
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unsigned address;
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unsigned len;
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/*
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* The 'm' command has the form mAAA,LLL
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* where AAA is the address and LLL is the
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* number of bytes.
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*/
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ptr = cmd+1;
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address = 0;
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len = 0;
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while (ptr && *ptr && (*ptr != ',')) {
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address <<= 4;
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address += parse_nibble(*ptr);
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ptr += 1;
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}
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if (*ptr == ',')
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ptr+= 1;
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while (ptr && *ptr) {
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len <<= 4;
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len += parse_nibble(*ptr);
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ptr += 1;
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}
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if (len> 128)
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len = 128;
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/*
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* We cannot directly access the requested memory
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* for gdb may be trying to access an stray pointer
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* We copy the memory to a safe buffer using
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* the bulletproof user_memcpy().
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*/
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if (user_memcpy(safe_mem, (char *)address, len) < 0)
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gdb_reply("E02");
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else
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gdb_memreply(safe_mem, len);
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}
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break;
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case 'k':
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/*
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* Command 'k' actual semantics is 'kill the damn thing'.
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* However gdb sends that command when you disconnect
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* from a debug session. I guess that 'kill' for the
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* kernel would map to reboot... however that's a
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* a very mean thing to do, instead we just quit
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* the gdb state machine and fallback to the regular
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* kernel debugger command prompt.
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*/
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return QUIT;
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default:
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gdb_reply("E01");
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break;
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}
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return WAITACK;
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}
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/*
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* GDB protocol state machine
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*/
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static int
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gdb_init_handler(int input)
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{
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switch (input) {
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case '$':
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memset(cmd, 0, sizeof(cmd));
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cmd_ptr = 0;
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return CMDREAD;
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default:
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#if 0
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gdb_nak();
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#else
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/*
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* looks to me like we should send
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* a NAK here but it kinda works
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* better if we just gobble all
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* junk chars silently
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*/
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#endif
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return INIT;
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}
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}
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static int
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gdb_cmdread_handler(int input)
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{
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switch (input) {
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case '#':
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return CKSUM1;
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default:
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cmd[cmd_ptr] = input;
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cmd_ptr += 1;
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return CMDREAD;
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}
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}
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static int
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gdb_cksum1_handler(int input)
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{
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int nibble = parse_nibble(input);
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if (nibble == 0xff) {
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#if 0
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gdb_nak();
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return INIT;
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#else
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/*
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* looks to me like we should send
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* a NAK here but it kinda works
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* better if we just gobble all
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* junk chars silently
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*/
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#endif
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}
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checksum = nibble << 4;
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return CKSUM2;
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}
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static int
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gdb_cksum2_handler(int input)
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{
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int nibble = parse_nibble(input);
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if (nibble == 0xff) {
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#if 0
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gdb_nak();
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return INIT;
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#else
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/*
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* looks to me like we should send
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* a NAK here but it kinda works
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* better if we just gobble all
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* junk chars silently
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*/
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#endif
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}
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checksum += nibble;
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return gdb_parse_command();
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}
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static int
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gdb_waitack_handler(int input)
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{
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switch (input) {
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case '+':
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return INIT;
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case '-':
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gdb_resend_reply();
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return WAITACK;
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default:
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/*
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* looks like gdb and us are out of synch,
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* send a NAK and retry from INIT state.
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*/
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gdb_nak();
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return INIT;
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}
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}
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static int
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gdb_quit_handler(int input)
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{
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(void)(input);
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/*
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* actually we should never be here
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*/
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return QUIT;
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}
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static int (*dispatch_table[GDBSTATES])(int) = {
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&gdb_init_handler,
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&gdb_cmdread_handler,
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&gdb_cksum1_handler,
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&gdb_cksum2_handler,
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&gdb_waitack_handler,
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&gdb_quit_handler
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};
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static int
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gdb_state_dispatch(int curr, int input)
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{
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if (curr < INIT || curr >= GDBSTATES)
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return QUIT;
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return dispatch_table[curr](input);
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}
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static int
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gdb_state_machine(void)
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{
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int state = INIT;
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int c;
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while (state != QUIT) {
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c = arch_dbg_con_read();
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state = gdb_state_dispatch(state, c);
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}
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return 0;
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}
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int
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cmd_gdb(int argc, char **argv)
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{
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(void)(argc);
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(void)(argv);
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return gdb_state_machine();
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}
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