599 lines
14 KiB
C
599 lines
14 KiB
C
/* taken from arch/powerpc/kernel/ppc-stub.c */
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/****************************************************************************
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THIS SOFTWARE IS NOT COPYRIGHTED
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HP offers the following for use in the public domain. HP makes no
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warranty with regard to the software or its performance and the
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user accepts the software "AS IS" with all faults.
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HP DISCLAIMS ANY WARRANTIES, EXPRESS OR IMPLIED, WITH REGARD
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TO THIS SOFTWARE INCLUDING BUT NOT LIMITED TO THE WARRANTIES
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OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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****************************************************************************/
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/****************************************************************************
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* Header: remcom.c,v 1.34 91/03/09 12:29:49 glenne Exp $
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*
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* Module name: remcom.c $
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* Revision: 1.34 $
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* Date: 91/03/09 12:29:49 $
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* Contributor: Lake Stevens Instrument Division$
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*
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* Description: low level support for gdb debugger. $
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*
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* Considerations: only works on target hardware $
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*
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* Written by: Glenn Engel $
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* ModuleState: Experimental $
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*
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* NOTES: See Below $
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*
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* Modified for SPARC by Stu Grossman, Cygnus Support.
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*
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* This code has been extensively tested on the Fujitsu SPARClite demo board.
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*
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* To enable debugger support, two things need to happen. One, a
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* call to set_debug_traps() is necessary in order to allow any breakpoints
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* or error conditions to be properly intercepted and reported to gdb.
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* Two, a breakpoint needs to be generated to begin communication. This
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* is most easily accomplished by a call to breakpoint(). Breakpoint()
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* simulates a breakpoint by executing a trap #1.
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*
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*************
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*
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* The following gdb commands are supported:
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*
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* command function Return value
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*
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* g return the value of the CPU registers hex data or ENN
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* G set the value of the CPU registers OK or ENN
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* qOffsets Get section offsets. Reply is Text=xxx;Data=yyy;Bss=zzz
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*
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* mAA..AA,LLLL Read LLLL bytes at address AA..AA hex data or ENN
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* MAA..AA,LLLL: Write LLLL bytes at address AA.AA OK or ENN
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*
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* c Resume at current address SNN ( signal NN)
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* cAA..AA Continue at address AA..AA SNN
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*
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* s Step one instruction SNN
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* sAA..AA Step one instruction from AA..AA SNN
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*
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* k kill
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*
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* ? What was the last sigval ? SNN (signal NN)
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*
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* bBB..BB Set baud rate to BB..BB OK or BNN, then sets
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* baud rate
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*
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* All commands and responses are sent with a packet which includes a
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* checksum. A packet consists of
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*
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* $<packet info>#<checksum>.
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*
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* where
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* <packet info> :: <characters representing the command or response>
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* <checksum> :: <two hex digits computed as modulo 256 sum of <packetinfo>>
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*
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* When a packet is received, it is first acknowledged with either '+' or '-'.
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* '+' indicates a successful transfer. '-' indicates a failed transfer.
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*
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* Example:
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*
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* Host: Reply:
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* $m0,10#2a +$00010203040506070809101112131415#42
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*
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****************************************************************************/
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#include <common.h>
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#include <kgdb.h>
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#include <command.h>
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#undef KGDB_DEBUG
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/*
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* BUFMAX defines the maximum number of characters in inbound/outbound buffers
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*/
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#define BUFMAX 1024
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static char remcomInBuffer[BUFMAX];
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static char remcomOutBuffer[BUFMAX];
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static char remcomRegBuffer[BUFMAX];
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static int initialized = 0;
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static int kgdb_active;
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static struct pt_regs entry_regs;
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static long error_jmp_buf[BUFMAX/2];
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static int longjmp_on_fault = 0;
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#ifdef KGDB_DEBUG
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static int kdebug = 1;
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#endif
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static const char hexchars[]="0123456789abcdef";
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/* Convert ch from a hex digit to an int */
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static int
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hex(unsigned 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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/* 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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*/
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static unsigned char *
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mem2hex(char *mem, char *buf, int count)
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{
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char *tmp;
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unsigned char ch;
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/*
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* We use the upper half of buf as an intermediate buffer for the
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* raw memory copy. Hex conversion will work against this one.
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*/
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tmp = buf + count;
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longjmp_on_fault = 1;
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memcpy(tmp, mem, count);
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while (count-- > 0) {
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ch = *tmp++;
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*buf++ = hexchars[ch >> 4];
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*buf++ = hexchars[ch & 0xf];
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}
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*buf = 0;
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longjmp_on_fault = 0;
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return (unsigned char *)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 fetched from buf.
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*/
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static char *
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hex2mem(char *buf, char *mem, int count)
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{
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int hexValue;
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char *tmp_raw, *tmp_hex;
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/*
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* We use the upper half of buf as an intermediate buffer for the
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* raw memory that is converted from hex.
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*/
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tmp_raw = buf + count * 2;
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tmp_hex = tmp_raw - 1;
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longjmp_on_fault = 1;
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while (tmp_hex >= buf) {
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tmp_raw--;
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hexValue = hex(*tmp_hex--);
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if (hexValue < 0)
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kgdb_error(KGDBERR_NOTHEXDIG);
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*tmp_raw = hexValue;
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hexValue = hex(*tmp_hex--);
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if (hexValue < 0)
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kgdb_error(KGDBERR_NOTHEXDIG);
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*tmp_raw |= hexValue << 4;
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}
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memcpy(mem, tmp_raw, count);
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kgdb_flush_cache_range((void *)mem, (void *)(mem+count));
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longjmp_on_fault = 0;
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return buf;
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}
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/*
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* While we find nice hex chars, build an int.
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* Return number of chars processed.
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*/
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static int
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hexToInt(char **ptr, int *intValue)
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{
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int numChars = 0;
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int hexValue;
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*intValue = 0;
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longjmp_on_fault = 1;
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while (**ptr) {
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hexValue = hex(**ptr);
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if (hexValue < 0)
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break;
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*intValue = (*intValue << 4) | hexValue;
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numChars ++;
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(*ptr)++;
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}
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longjmp_on_fault = 0;
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return (numChars);
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}
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/* scan for the sequence $<data>#<checksum> */
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static void
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getpacket(char *buffer)
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{
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unsigned char checksum;
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unsigned char xmitcsum;
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int i;
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int count;
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unsigned char ch;
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do {
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/* wait around for the start character, ignore all other
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* characters */
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while ((ch = (getDebugChar() & 0x7f)) != '$') {
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#ifdef KGDB_DEBUG
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if (kdebug)
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putc(ch);
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#endif
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;
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}
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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 < BUFMAX) {
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ch = getDebugChar() & 0x7f;
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if (ch == '#')
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break;
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checksum = checksum + ch;
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buffer[count] = ch;
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count = count + 1;
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}
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if (count >= BUFMAX)
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continue;
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buffer[count] = 0;
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if (ch == '#') {
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xmitcsum = hex(getDebugChar() & 0x7f) << 4;
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xmitcsum |= hex(getDebugChar() & 0x7f);
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if (checksum != xmitcsum)
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putDebugChar('-'); /* failed checksum */
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else {
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putDebugChar('+'); /* successful transfer */
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/* if a sequence char is present, reply the ID */
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if (buffer[2] == ':') {
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putDebugChar(buffer[0]);
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putDebugChar(buffer[1]);
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/* remove sequence chars from buffer */
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count = strlen(buffer);
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for (i=3; i <= count; i++)
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buffer[i-3] = buffer[i];
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}
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}
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}
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} while (checksum != xmitcsum);
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}
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/* send the packet in buffer. */
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static void
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putpacket(unsigned char *buffer)
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{
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unsigned char checksum;
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int count;
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unsigned char ch, recv;
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/* $<packet info>#<checksum>. */
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do {
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putDebugChar('$');
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checksum = 0;
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count = 0;
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while ((ch = buffer[count])) {
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putDebugChar(ch);
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checksum += ch;
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count += 1;
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}
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putDebugChar('#');
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putDebugChar(hexchars[checksum >> 4]);
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putDebugChar(hexchars[checksum & 0xf]);
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recv = getDebugChar();
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} while ((recv & 0x7f) != '+');
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}
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/*
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* This function does all command processing for interfacing to gdb.
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*/
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static int
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handle_exception (struct pt_regs *regs)
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{
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int addr;
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int length;
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char *ptr;
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kgdb_data kd;
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int i;
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if (!initialized) {
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printf("kgdb: exception before kgdb is initialized! huh?\n");
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return (0);
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}
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/* probably should check which exception occured as well */
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if (longjmp_on_fault) {
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longjmp_on_fault = 0;
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kgdb_longjmp(error_jmp_buf, KGDBERR_MEMFAULT);
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panic("kgdb longjump failed!\n");
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}
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if (kgdb_active) {
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printf("kgdb: unexpected exception from within kgdb\n");
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return (0);
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}
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kgdb_active = 1;
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kgdb_interruptible(0);
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printf("kgdb: handle_exception; trap [0x%x]\n", kgdb_trap(regs));
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if (kgdb_setjmp(error_jmp_buf) != 0)
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panic("kgdb: error or fault in entry init!\n");
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kgdb_enter(regs, &kd);
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entry_regs = *regs;
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ptr = remcomOutBuffer;
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*ptr++ = 'T';
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*ptr++ = hexchars[kd.sigval >> 4];
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*ptr++ = hexchars[kd.sigval & 0xf];
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for (i = 0; i < kd.nregs; i++) {
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kgdb_reg *rp = &kd.regs[i];
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*ptr++ = hexchars[rp->num >> 4];
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*ptr++ = hexchars[rp->num & 0xf];
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*ptr++ = ':';
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ptr = (char *)mem2hex((char *)&rp->val, ptr, 4);
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*ptr++ = ';';
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}
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*ptr = 0;
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#ifdef KGDB_DEBUG
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if (kdebug)
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printf("kgdb: remcomOutBuffer: %s\n", remcomOutBuffer);
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#endif
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putpacket((unsigned char *)&remcomOutBuffer);
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while (1) {
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volatile int errnum;
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remcomOutBuffer[0] = 0;
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getpacket(remcomInBuffer);
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ptr = &remcomInBuffer[1];
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#ifdef KGDB_DEBUG
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if (kdebug)
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printf("kgdb: remcomInBuffer: %s\n", remcomInBuffer);
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#endif
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errnum = kgdb_setjmp(error_jmp_buf);
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if (errnum == 0) switch (remcomInBuffer[0]) {
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case '?': /* report most recent signal */
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remcomOutBuffer[0] = 'S';
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remcomOutBuffer[1] = hexchars[kd.sigval >> 4];
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remcomOutBuffer[2] = hexchars[kd.sigval & 0xf];
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remcomOutBuffer[3] = 0;
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break;
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#ifdef KGDB_DEBUG
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case 'd':
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/* toggle debug flag */
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kdebug ^= 1;
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break;
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#endif
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case 'g': /* return the value of the CPU registers. */
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length = kgdb_getregs(regs, remcomRegBuffer, BUFMAX);
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mem2hex(remcomRegBuffer, remcomOutBuffer, length);
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break;
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case 'G': /* set the value of the CPU registers */
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length = strlen(ptr);
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if ((length & 1) != 0) kgdb_error(KGDBERR_BADPARAMS);
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hex2mem(ptr, remcomRegBuffer, length/2);
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kgdb_putregs(regs, remcomRegBuffer, length/2);
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strcpy(remcomOutBuffer,"OK");
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break;
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case 'm': /* mAA..AA,LLLL Read LLLL bytes at address AA..AA */
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/* Try to read %x,%x. */
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if (hexToInt(&ptr, &addr)
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&& *ptr++ == ','
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&& hexToInt(&ptr, &length)) {
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mem2hex((char *)addr, remcomOutBuffer, length);
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} else {
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kgdb_error(KGDBERR_BADPARAMS);
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}
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break;
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case 'M': /* MAA..AA,LLLL: Write LLLL bytes at address AA.AA return OK */
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/* Try to read '%x,%x:'. */
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if (hexToInt(&ptr, &addr)
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&& *ptr++ == ','
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&& hexToInt(&ptr, &length)
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&& *ptr++ == ':') {
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hex2mem(ptr, (char *)addr, length);
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strcpy(remcomOutBuffer, "OK");
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} else {
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kgdb_error(KGDBERR_BADPARAMS);
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}
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break;
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case 'k': /* kill the program, actually return to monitor */
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kd.extype = KGDBEXIT_KILL;
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*regs = entry_regs;
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goto doexit;
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case 'C': /* CSS continue with signal SS */
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*ptr = '\0'; /* ignore the signal number for now */
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/* fall through */
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case 'c': /* cAA..AA Continue; address AA..AA optional */
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/* try to read optional parameter, pc unchanged if no parm */
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kd.extype = KGDBEXIT_CONTINUE;
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if (hexToInt(&ptr, &addr)) {
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kd.exaddr = addr;
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kd.extype |= KGDBEXIT_WITHADDR;
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}
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goto doexit;
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case 'S': /* SSS single step with signal SS */
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*ptr = '\0'; /* ignore the signal number for now */
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/* fall through */
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case 's':
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kd.extype = KGDBEXIT_SINGLE;
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if (hexToInt(&ptr, &addr)) {
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kd.exaddr = addr;
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kd.extype |= KGDBEXIT_WITHADDR;
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}
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doexit:
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/* Need to flush the instruction cache here, as we may have deposited a
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* breakpoint, and the icache probably has no way of knowing that a data ref to
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* some location may have changed something that is in the instruction cache.
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*/
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kgdb_flush_cache_all();
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kgdb_exit(regs, &kd);
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kgdb_active = 0;
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kgdb_interruptible(1);
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return (1);
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case 'r': /* Reset (if user process..exit ???)*/
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panic("kgdb reset.");
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break;
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case 'P': /* Pr=v set reg r to value v (r and v are hex) */
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if (hexToInt(&ptr, &addr)
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&& *ptr++ == '='
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&& ((length = strlen(ptr)) & 1) == 0) {
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hex2mem(ptr, remcomRegBuffer, length/2);
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kgdb_putreg(regs, addr,
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remcomRegBuffer, length/2);
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strcpy(remcomOutBuffer,"OK");
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} else {
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kgdb_error(KGDBERR_BADPARAMS);
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}
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break;
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} /* switch */
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if (errnum != 0)
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sprintf(remcomOutBuffer, "E%02d", errnum);
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#ifdef KGDB_DEBUG
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if (kdebug)
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printf("kgdb: remcomOutBuffer: %s\n", remcomOutBuffer);
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#endif
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/* reply to the request */
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putpacket((unsigned char *)&remcomOutBuffer);
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} /* while(1) */
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}
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/*
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* kgdb_init must be called *after* the
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* monitor is relocated into ram
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*/
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void
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kgdb_init(void)
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{
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kgdb_serial_init();
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debugger_exception_handler = handle_exception;
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initialized = 1;
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putDebugStr("kgdb ready\n");
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puts("ready\n");
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}
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void
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kgdb_error(int errnum)
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{
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longjmp_on_fault = 0;
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kgdb_longjmp(error_jmp_buf, errnum);
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panic("kgdb_error: longjmp failed!\n");
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}
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/* Output string in GDB O-packet format if GDB has connected. If nothing
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output, returns 0 (caller must then handle output). */
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int
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kgdb_output_string (const char* s, unsigned int count)
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{
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char buffer[512];
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count = (count <= (sizeof(buffer) / 2 - 2))
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? count : (sizeof(buffer) / 2 - 2);
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buffer[0] = 'O';
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mem2hex ((char *)s, &buffer[1], count);
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putpacket((unsigned char *)&buffer);
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return 1;
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}
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void
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breakpoint(void)
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{
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if (!initialized) {
|
|
printf("breakpoint() called b4 kgdb init\n");
|
|
return;
|
|
}
|
|
|
|
kgdb_breakpoint(0, 0);
|
|
}
|
|
|
|
int
|
|
do_kgdb(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
|
|
{
|
|
printf("Entering KGDB mode via exception handler...\n\n");
|
|
kgdb_breakpoint(argc - 1, argv + 1);
|
|
printf("\nReturned from KGDB mode\n");
|
|
return 0;
|
|
}
|
|
|
|
U_BOOT_CMD(
|
|
kgdb, CONFIG_SYS_MAXARGS, 1, do_kgdb,
|
|
"enter gdb remote debug mode",
|
|
"[arg0 arg1 .. argN]\n"
|
|
" - executes a breakpoint so that kgdb mode is\n"
|
|
" entered via the exception handler. To return\n"
|
|
" to the monitor, the remote gdb debugger must\n"
|
|
" execute a \"continue\" or \"quit\" command.\n"
|
|
"\n"
|
|
" if a program is loaded by the remote gdb, any args\n"
|
|
" passed to the kgdb command are given to the loaded\n"
|
|
" program if it is executed (see the \"hello_world\"\n"
|
|
" example program in the U-Boot examples directory)."
|
|
);
|