596 lines
14 KiB
C
596 lines
14 KiB
C
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/****************************************************************************
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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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*
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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 <string.h>
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#include <signal.h>
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#include "dbgmon.h"
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#include "parser.h"
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#include "ctype.h"
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/************************************************************************
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*
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* external low-level support routines
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*/
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extern putchar(); /* write a single character */
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extern getchar(); /* read and return a single char */
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/************************************************************************/
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/* Stuff for stdio-like gets_debugger_check() */
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#define CTRL(x) ('x'&0x1f)
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#define DEL 0x7f
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#define INTR CTRL(C)
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#define BELL 0x7
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#define PROMPT "? "
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#define BUFSIZE 512 /* Big enough for register packets */
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static int initialized = 0; /* !0 means we've been initialized */
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static char hexchars[]="0123456789abcdef";
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extern unsigned int _regs[]; /* Saved registers from client */
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/* Convert ch from a hex digit to an int */
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static int
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hex(ch)
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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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/* scan for the sequence $<data>#<checksum> */
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static void
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getpacket(buffer)
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char *buffer;
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{
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unsigned char checksum;
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unsigned char xmitcsum;
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int i;
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int count;
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unsigned char ch;
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/* At this point, the start character ($) has been received through
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* the debug monitor parser. Get the remaining characters and
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* process them.
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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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/* read until a # or end of buffer is found */
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while (count < BUFSIZE)
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{
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ch = getchar();
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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 >= BUFSIZE)
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buffer[count] = 0;
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if (ch == '#')
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{
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xmitcsum = hex(getchar()) << 4;
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xmitcsum |= hex(getchar());
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#if 0
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/* Humans shouldn't have to figure out checksums to type to it. */
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putchar ('+');
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return;
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#endif
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if (checksum != xmitcsum)
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{
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putchar('-'); /* failed checksum */
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return; /* Back to monitor loop */
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}
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else
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{
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putchar('+'); /* 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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putchar(buffer[0]);
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putchar(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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/* Buffer command received- go and process it. */
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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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putpacket(buffer)
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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;
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/* $<packet info>#<checksum>. */
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do
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{
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putchar('$');
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checksum = 0;
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count = 0;
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while (ch = buffer[count])
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{
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if (! putchar(ch))
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return;
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checksum += ch;
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count += 1;
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}
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putchar('#');
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putchar(hexchars[checksum >> 4]);
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putchar(hexchars[checksum & 0xf]);
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}
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while (getchar() != '+');
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}
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static char remcomInBuffer[BUFSIZE];
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static char remcomOutBuffer[BUFSIZE];
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/* Indicate to caller of mem2hex or hex2mem that there has been an error. */
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static volatile int mem_err = 0;
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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), in case of mem fault,
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* return 0.
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* If MAY_FAULT is non-zero, then we will handle memory faults by returning
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* a 0, else treat a fault like any other fault in the stub.
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*/
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static unsigned char *
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mem2hex(mem, buf, count, may_fault)
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unsigned char *mem;
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unsigned char *buf;
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int count;
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int may_fault;
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{
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unsigned char ch;
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while (count-- > 0)
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{
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ch = *mem++;
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if (mem_err)
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return 0;
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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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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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hex2mem(buf, mem, count, may_fault)
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unsigned char *buf;
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unsigned char *mem;
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int count;
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int may_fault;
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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 |= hex(*buf++);
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*mem++ = ch;
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if (mem_err)
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return 0;
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}
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return mem;
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}
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/* This table contains the mapping between SPARC hardware trap types, and
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signals, which are primarily what GDB understands. It also indicates
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which hardware traps we need to commandeer when initializing the stub. */
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static struct hard_trap_info
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{
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unsigned char tt; /* Trap type code for SPARClite */
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unsigned char signo; /* Signal that we map this trap into */
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} hard_trap_info[] = {
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{0x06, SIGSEGV}, /* instruction access error */
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{0x0a, SIGILL}, /* privileged instruction */
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{0x0a, SIGILL}, /* illegal instruction */
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{0x0b, SIGEMT}, /* cp disabled */
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{0x07, SIGSEGV}, /* data access exception */
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{0x09, SIGTRAP}, /* ta 1 - normal breakpoint instruction */
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{0, 0} /* Must be last */
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};
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/* Convert the SPARC hardware trap type code to a unix signal number. */
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static int
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computeSignal(tt)
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int tt;
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{
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struct hard_trap_info *ht;
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for (ht = hard_trap_info; ht->tt && ht->signo; ht++)
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if (ht->tt == tt)
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return ht->signo;
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return SIGHUP; /* default for things we don't know about */
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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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while (**ptr)
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{
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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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return (numChars);
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}
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/* This function lets GDB know that an exception has occured. */
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static void
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debug_handle_exception ()
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{
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int tt; /* Trap type */
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int sigval;
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char *ptr;
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tt = (_regs[R_CAUSE] >> 2) & 0x0f;
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/* reply to host that an exception has occurred */
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sigval = computeSignal(tt);
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ptr = remcomOutBuffer;
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*ptr++ = 'T';
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*ptr++ = hexchars[sigval >> 4];
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*ptr++ = hexchars[sigval & 0xf];
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*ptr++ = hexchars[R_EPC >> 4];
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*ptr++ = hexchars[R_EPC & 0xf];
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*ptr++ = ':';
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ptr = mem2hex((char *)&_regs[R_EPC], ptr, 4, 0);
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*ptr++ = ';';
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*ptr++ = hexchars[R_FP >> 4];
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*ptr++ = hexchars[R_FP & 0xf];
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*ptr++ = ':';
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ptr = mem2hex((char *)&_regs[R_FP], ptr, 4, 0);
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*ptr++ = ';';
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*ptr++ = hexchars[R_SP >> 4];
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*ptr++ = hexchars[R_SP & 0xf];
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*ptr++ = ':';
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ptr = mem2hex((char *)&_regs[R_SP], ptr, 4, 0);
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*ptr++ = ';';
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*ptr++ = 0;
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putpacket(remcomOutBuffer);
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return;
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}
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void process_packet()
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{
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char *ptr;
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int length;
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int addr;
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int sigval;
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int tt; /* Trap type */
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remcomOutBuffer[0] = 0;
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getpacket(remcomInBuffer);
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switch (remcomInBuffer[0])
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{
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/* Return Last SIGVAL */
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case '?':
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tt = (_regs[R_CAUSE] >> 2) & 0x0f;
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sigval = computeSignal(tt);
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remcomOutBuffer[0] = 'S';
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remcomOutBuffer[1] = hexchars[sigval >> 4];
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|
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remcomOutBuffer[2] = hexchars[sigval & 0xf];
|
||
|
|
remcomOutBuffer[3] = 0;
|
||
|
|
break;
|
||
|
|
|
||
|
|
/* toggle debug flag */
|
||
|
|
|
||
|
|
case 'd':
|
||
|
|
break;
|
||
|
|
|
||
|
|
/* Return the values of the CPU registers */
|
||
|
|
|
||
|
|
case 'g':
|
||
|
|
ptr = remcomOutBuffer;
|
||
|
|
ptr = mem2hex((char *)_regs, ptr, 32 * 4, 0); /* General Purpose Registers */
|
||
|
|
ptr = mem2hex((char *)&_regs[R_EPC], ptr, 9 * 4, 0); /* CP0 Registers */
|
||
|
|
break;
|
||
|
|
|
||
|
|
/* set the value of the CPU registers - return OK */
|
||
|
|
|
||
|
|
case 'G':
|
||
|
|
ptr = &remcomInBuffer[1];
|
||
|
|
hex2mem(ptr, (char *)_regs, 32 * 4, 0); /* General Purpose Registers */
|
||
|
|
hex2mem(ptr + 32 * 4 * 2, (char *)&_regs[R_EPC], 9 * 4, 0); /* CP0 Registers */
|
||
|
|
strcpy(remcomOutBuffer,"OK");
|
||
|
|
break;
|
||
|
|
|
||
|
|
/* mAA..AA,LLLL Read LLLL bytes at address AA..AA */
|
||
|
|
|
||
|
|
case 'm':
|
||
|
|
ptr = &remcomInBuffer[1];
|
||
|
|
if (hexToInt(&ptr, &addr) && *ptr++ == ',' && hexToInt(&ptr, &length))
|
||
|
|
{
|
||
|
|
if (mem2hex((char *)addr, remcomOutBuffer, length, 1))
|
||
|
|
break;
|
||
|
|
strcpy (remcomOutBuffer, "E03");
|
||
|
|
}
|
||
|
|
else
|
||
|
|
strcpy(remcomOutBuffer,"E01");
|
||
|
|
break;
|
||
|
|
|
||
|
|
/* MAA..AA,LLLL: Write LLLL bytes at address AA.AA return OK */
|
||
|
|
|
||
|
|
case 'M':
|
||
|
|
ptr = &remcomInBuffer[1];
|
||
|
|
if (hexToInt(&ptr, &addr) && *ptr++ == ',' && hexToInt(&ptr, &length) && *ptr++ == ':')
|
||
|
|
{
|
||
|
|
if (hex2mem(ptr, (char *)addr, length, 1))
|
||
|
|
strcpy(remcomOutBuffer, "OK");
|
||
|
|
else
|
||
|
|
strcpy(remcomOutBuffer, "E03");
|
||
|
|
}
|
||
|
|
else
|
||
|
|
strcpy(remcomOutBuffer, "E02");
|
||
|
|
break;
|
||
|
|
|
||
|
|
/* cAA..AA Continue at address AA..AA(optional) */
|
||
|
|
|
||
|
|
case 'c':
|
||
|
|
|
||
|
|
/* try to read optional parameter, pc unchanged if no parm */
|
||
|
|
|
||
|
|
ptr = &remcomInBuffer[1];
|
||
|
|
if (hexToInt(&ptr, &addr))
|
||
|
|
{
|
||
|
|
gdb_go ( addr );
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
dbg_cont();
|
||
|
|
}
|
||
|
|
return;
|
||
|
|
|
||
|
|
/* kill the program */
|
||
|
|
|
||
|
|
case 'k':
|
||
|
|
break;
|
||
|
|
|
||
|
|
/* Reset */
|
||
|
|
|
||
|
|
case 'r':
|
||
|
|
break;
|
||
|
|
|
||
|
|
/* switch */
|
||
|
|
|
||
|
|
}
|
||
|
|
|
||
|
|
/* Reply to the request */
|
||
|
|
|
||
|
|
putpacket(remcomOutBuffer);
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
/*
|
||
|
|
* gets_debugger_check - This is the same as the stdio gets, but we also
|
||
|
|
* check for a leading $ in the buffer. This so we
|
||
|
|
* gracefully handle the GDB protocol packets.
|
||
|
|
*/
|
||
|
|
|
||
|
|
char *
|
||
|
|
gets_debugger_check(buf)
|
||
|
|
char *buf;
|
||
|
|
{
|
||
|
|
register char c;
|
||
|
|
char *bufp;
|
||
|
|
|
||
|
|
bufp = buf;
|
||
|
|
for (;;)
|
||
|
|
{
|
||
|
|
c = getchar();
|
||
|
|
switch (c)
|
||
|
|
{
|
||
|
|
|
||
|
|
/* quote next char */
|
||
|
|
|
||
|
|
case '$':
|
||
|
|
if ( buf == bufp )
|
||
|
|
process_packet();
|
||
|
|
break;
|
||
|
|
|
||
|
|
case CTRL(V):
|
||
|
|
c = getchar();
|
||
|
|
if (bufp < &buf[LINESIZE-3])
|
||
|
|
{
|
||
|
|
rmw_byte (bufp++,c);
|
||
|
|
showchar(c);
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
putchar(BELL);
|
||
|
|
}
|
||
|
|
break;
|
||
|
|
|
||
|
|
case '\n':
|
||
|
|
case '\r':
|
||
|
|
putchar('\n');
|
||
|
|
rmw_byte (bufp,0);
|
||
|
|
return(buf);
|
||
|
|
|
||
|
|
case CTRL(H):
|
||
|
|
case DEL:
|
||
|
|
if (bufp > buf)
|
||
|
|
{
|
||
|
|
bufp--;
|
||
|
|
putchar(CTRL(H));
|
||
|
|
putchar(' ');
|
||
|
|
putchar(CTRL(H));
|
||
|
|
}
|
||
|
|
break;
|
||
|
|
|
||
|
|
case CTRL(U):
|
||
|
|
if (bufp > buf)
|
||
|
|
{
|
||
|
|
printf("^U\n%s", PROMPT);
|
||
|
|
bufp = buf;
|
||
|
|
}
|
||
|
|
break;
|
||
|
|
|
||
|
|
case '\t':
|
||
|
|
c = ' ';
|
||
|
|
|
||
|
|
default:
|
||
|
|
/*
|
||
|
|
* Make sure there's room for this character
|
||
|
|
* plus a trailing \n and 0 byte
|
||
|
|
*/
|
||
|
|
if (isprint(c) && bufp < &buf[LINESIZE-3])
|
||
|
|
{
|
||
|
|
rmw_byte ( bufp++, c );
|
||
|
|
putchar(c);
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
putchar(BELL);
|
||
|
|
}
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|