path: root/arch/sparc/kernel/sparc-stub.c

/* $Id: sparc-stub.c,v 1.28 2001/10/30 04:54:21 davem Exp $
 * sparc-stub.c:  KGDB support for the Linux kernel.
 *
 * Modifications to run under Linux
 * Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
 *
 * This file originally came from the gdb sources, and the
 * copyright notices have been retained below.
 */

/****************************************************************************

		THIS SOFTWARE IS NOT COPYRIGHTED

   HP offers the following for use in the public domain.  HP makes no
   warranty with regard to the software or its performance and the
   user accepts the software "AS IS" with all faults.

   HP DISCLAIMS ANY WARRANTIES, EXPRESS OR IMPLIED, WITH REGARD
   TO THIS SOFTWARE INCLUDING BUT NOT LIMITED TO THE WARRANTIES
   OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.

****************************************************************************/

/****************************************************************************
 *  Header: remcom.c,v 1.34 91/03/09 12:29:49 glenne Exp $
 *
 *  Module name: remcom.c $
 *  Revision: 1.34 $
 *  Date: 91/03/09 12:29:49 $
 *  Contributor:     Lake Stevens Instrument Division$
 *
 *  Description:     low level support for gdb debugger. $
 *
 *  Considerations:  only works on target hardware $
 *
 *  Written by:      Glenn Engel $
 *  ModuleState:     Experimental $
 *
 *  NOTES:           See Below $
 *
 *  Modified for SPARC by Stu Grossman, Cygnus Support.
 *
 *  This code has been extensively tested on the Fujitsu SPARClite demo board.
 *
 *  To enable debugger support, two things need to happen.  One, a
 *  call to set_debug_traps() is necessary in order to allow any breakpoints
 *  or error conditions to be properly intercepted and reported to gdb.
 *  Two, a breakpoint needs to be generated to begin communication.  This
 *  is most easily accomplished by a call to breakpoint().  Breakpoint()
 *  simulates a breakpoint by executing a trap #1.
 *
 *************
 *
 *    The following gdb commands are supported:
 *
 * command          function                               Return value
 *
 *    g             return the value of the CPU registers  hex data or ENN
 *    G             set the value of the CPU registers     OK or ENN
 *
 *    mAA..AA,LLLL  Read LLLL bytes at address AA..AA      hex data or ENN
 *    MAA..AA,LLLL: Write LLLL bytes at address AA.AA      OK or ENN
 *
 *    c             Resume at current address              SNN   ( signal NN)
 *    cAA..AA       Continue at address AA..AA             SNN
 *
 *    s             Step one instruction                   SNN
 *    sAA..AA       Step one instruction from AA..AA       SNN
 *
 *    k             kill
 *
 *    ?             What was the last sigval ?             SNN   (signal NN)
 *
 *    bBB..BB	    Set baud rate to BB..BB		   OK or BNN, then sets
 *							   baud rate
 *
 * All commands and responses are sent with a packet which includes a
 * checksum.  A packet consists of
 *
 * $<packet info>#<checksum>.
 *
 * where
 * <packet info> :: <characters representing the command or response>
 * <checksum>    :: < two hex digits computed as modulo 256 sum of <packetinfo>>
 *
 * When a packet is received, it is first acknowledged with either '+' or '-'.
 * '+' indicates a successful transfer.  '-' indicates a failed transfer.
 *
 * Example:
 *
 * Host:                  Reply:
 * $m0,10#2a               +$00010203040506070809101112131415#42
 *
 ****************************************************************************/

#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>

#include <asm/system.h>
#include <asm/signal.h>
#include <asm/oplib.h>
#include <asm/head.h>
#include <asm/traps.h>
#include <asm/vac-ops.h>
#include <asm/kgdb.h>
#include <asm/pgalloc.h>
#include <asm/pgtable.h>
#include <asm/cacheflush.h>

/*
 *
 * external low-level support routines
 */

extern void putDebugChar(char);   /* write a single character      */
extern char getDebugChar(void);   /* read and return a single char */

/*
 * BUFMAX defines the maximum number of characters in inbound/outbound buffers
 * at least NUMREGBYTES*2 are needed for register packets
 */
#define BUFMAX 2048

static int initialized;	/* !0 means we've been initialized */

static const char hexchars[]="0123456789abcdef";

#define NUMREGS 72

/* Number of bytes of registers.  */
#define NUMREGBYTES (NUMREGS * 4)
enum regnames {G0, G1, G2, G3, G4, G5, G6, G7,
		 O0, O1, O2, O3, O4, O5, SP, O7,
		 L0, L1, L2, L3, L4, L5, L6, L7,
		 I0, I1, I2, I3, I4, I5, FP, I7,

		 F0, F1, F2, F3, F4, F5, F6, F7,
		 F8, F9, F10, F11, F12, F13, F14, F15,
		 F16, F17, F18, F19, F20, F21, F22, F23,
		 F24, F25, F26, F27, F28, F29, F30, F31,
		 Y, PSR, WIM, TBR, PC, NPC, FPSR, CPSR };


extern void trap_low(void);  /* In arch/sparc/kernel/entry.S */

unsigned long get_sun4cpte(unsigned long addr)
{
	unsigned long entry;

	__asm__ __volatile__("\n\tlda [%1] %2, %0\n\t" : 
			     "=r" (entry) :
			     "r" (addr), "i" (ASI_PTE));
	return entry;
}

unsigned long get_sun4csegmap(unsigned long addr)
{
	unsigned long entry;

	__asm__ __volatile__("\n\tlduba [%1] %2, %0\n\t" : 
			     "=r" (entry) :
			     "r" (addr), "i" (ASI_SEGMAP));
	return entry;
}

#if 0
/* Have to sort this out. This cannot be done after initialization. */
static void flush_cache_all_nop(void) {}
#endif

/* Place where we save old trap entries for restoration */
struct tt_entry kgdb_savettable[256];
typedef void (*trapfunc_t)(void);

/* Helper routine for manipulation of kgdb_savettable */
static inline void copy_ttentry(struct tt_entry *src, struct tt_entry *dest)
{
	dest->inst_one = src->inst_one;
	dest->inst_two = src->inst_two;
	dest->inst_three = src->inst_three;
	dest->inst_four = src->inst_four;
}

/* Initialize the kgdb_savettable so that debugging can commence */
static void eh_init(void)
{
	int i;

	for(i=0; i < 256; i++)
		copy_ttentry(&sparc_ttable[i], &kgdb_savettable[i]);
}

/* Install an exception handler for kgdb */
static void exceptionHandler(int tnum, trapfunc_t trap_entry)
{
	unsigned long te_addr = (unsigned long) trap_entry;

	/* Make new vector */
	sparc_ttable[tnum].inst_one =
		SPARC_BRANCH((unsigned long) te_addr,
			     (unsigned long) &sparc_ttable[tnum].inst_one);
	sparc_ttable[tnum].inst_two = SPARC_RD_PSR_L0;
	sparc_ttable[tnum].inst_three = SPARC_NOP;
	sparc_ttable[tnum].inst_four = SPARC_NOP;
}

/* Convert ch from a hex digit to an int */
static int
hex(unsigned char ch)
{
	if (ch >= 'a' && ch <= 'f')
		return ch-'a'+10;
	if (ch >= '0' && ch <= '9')
		return ch-'0';
	if (ch >= 'A' && ch <= 'F')
		return ch-'A'+10;
	return -1;
}

/* scan for the sequence $<data>#<checksum>     */
static void
getpacket(char *buffer)
{
	unsigned char checksum;
	unsigned char xmitcsum;
	int i;
	int count;
	unsigned char ch;

	do {
		/* wait around for the start character, ignore all other characters */
		while ((ch = (getDebugChar() & 0x7f)) != '$') ;

		checksum = 0;
		xmitcsum = -1;

		count = 0;

		/* now, read until a # or end of buffer is found */
		while (count < BUFMAX) {
			ch = getDebugChar() & 0x7f;
			if (ch == '#')
				break;
			checksum = checksum + ch;
			buffer[count] = ch;
			count = count + 1;
		}

		if (count >= BUFMAX)
			continue;