kgdb.c

linux内核源码

/* Convert the array, in hexadecimal representation, pointed to by buf into
   binary representation. Put the result in mem, and return a pointer to
   the character after the last byte written. */
static unsigned char *hex2mem(unsigned char *mem, char *buf, int count);

/* Put the content of the array, in binary representation, pointed to by buf
   into memory pointed to by mem, and return a pointer to
   the character after the last byte written. */
static unsigned char *bin2mem(unsigned char *mem, unsigned char *buf, int count);

/* Await the sequence $<data>#<checksum> and store <data> in the array buffer
   returned. */
static void getpacket(char *buffer);

/* Send $<data>#<checksum> from the <data> in the array buffer. */
static void putpacket(char *buffer);

/* Build and send a response packet in order to inform the host the
   stub is stopped. */
static void stub_is_stopped(int sigval);

/* All expected commands are sent from remote.c. Send a response according
   to the description in remote.c. Not static since it needs to be reached
   from assembler code. */
void handle_exception(int sigval);

/* Performs a complete re-start from scratch. ETRAX specific. */
static void kill_restart(void);

/******************** Prototypes for global functions. ***********************/

/* The string str is prepended with the GDB printout token and sent. */
void putDebugString(const unsigned char *str, int len);

/* A static breakpoint to be used at startup. */
void breakpoint(void);

/* Avoid warning as the internal_stack is not used in the C-code. */
#define USEDVAR(name)    { if (name) { ; } }
#define USEDFUN(name) { void (*pf)(void) = (void *)name; USEDVAR(pf) }

/********************************** Packet I/O ******************************/
/* BUFMAX defines the maximum number of characters in
   inbound/outbound buffers */
/* FIXME: How do we know it's enough? */
#define BUFMAX 512

/* Run-length encoding maximum length. Send 64 at most. */
#define RUNLENMAX 64

/* Definition of all valid hexadecimal characters */
static const char hexchars[] = "0123456789abcdef";

/* The inbound/outbound buffers used in packet I/O */
static char input_buffer[BUFMAX];
static char output_buffer[BUFMAX];

/* Error and warning messages. */
enum error_type
{
	SUCCESS, E01, E02, E03, E04, E05, E06,
};

static char *error_message[] =
{
	"",
	"E01 Set current or general thread - H[c,g] - internal error.",
	"E02 Change register content - P - cannot change read-only register.",
	"E03 Thread is not alive.", /* T, not used. */
	"E04 The command is not supported - [s,C,S,!,R,d,r] - internal error.",
	"E05 Change register content - P - the register is not implemented..",
	"E06 Change memory content - M - internal error.",
};

/********************************** Breakpoint *******************************/
/* Use an internal stack in the breakpoint and interrupt response routines.
   FIXME: How do we know the size of this stack is enough?
   Global so it can be reached from assembler code. */
#define INTERNAL_STACK_SIZE 1024
char internal_stack[INTERNAL_STACK_SIZE];

/* Due to the breakpoint return pointer, a state variable is needed to keep
   track of whether it is a static (compiled) or dynamic (gdb-invoked)
   breakpoint to be handled. A static breakpoint uses the content of register
   ERP as it is whereas a dynamic breakpoint requires subtraction with 2
   in order to execute the instruction. The first breakpoint is static; all
   following are assumed to be dynamic. */
static int dynamic_bp = 0;

/********************************* String library ****************************/
/* Single-step over library functions creates trap loops. */

/* Copy char s2[] to s1[]. */
static char*
gdb_cris_strcpy(char *s1, const char *s2)
{
	char *s = s1;

	for (s = s1; (*s++ = *s2++) != '\0'; )
		;
	return s1;
}

/* Find length of s[]. */
static int
gdb_cris_strlen(const char *s)
{
	const char *sc;

	for (sc = s; *sc != '\0'; sc++)
		;
	return (sc - s);
}

/* Find first occurrence of c in s[n]. */
static void*
gdb_cris_memchr(const void *s, int c, int n)
{
	const unsigned char uc = c;
	const unsigned char *su;

	for (su = s; 0 < n; ++su, --n)
		if (*su == uc)
			return (void *)su;
	return NULL;
}
/******************************* Standard library ****************************/
/* Single-step over library functions creates trap loops. */
/* Convert string to long. */
static int
gdb_cris_strtol(const char *s, char **endptr, int base)
{
	char *s1;
	char *sd;
	int x = 0;

	for (s1 = (char*)s; (sd = gdb_cris_memchr(hexchars, *s1, base)) != NULL; ++s1)
		x = x * base + (sd - hexchars);

        if (endptr) {
                /* Unconverted suffix is stored in endptr unless endptr is NULL. */
                *endptr = s1;
        }

	return x;
}

/********************************* Register image ****************************/

/* Write a value to a specified register in the register image of the current
   thread. Returns status code SUCCESS, E02 or E05. */
static int
write_register(int regno, char *val)
{
	int status = SUCCESS;

        if (regno >= R0 && regno <= ACR) {
		/* Consecutive 32-bit registers. */
		hex2mem((unsigned char *)&reg.r0 + (regno - R0) * sizeof(unsigned int),
			val, sizeof(unsigned int));

	} else if (regno == BZ || regno == VR || regno == WZ || regno == DZ) {
		/* Read-only registers. */
		status = E02;

	} else if (regno == PID) {
		/* 32-bit register. (Even though we already checked SRS and WZ, we cannot
		   combine this with the EXS - SPC write since SRS and WZ have different size.) */
		hex2mem((unsigned char *)&reg.pid, val, sizeof(unsigned int));

	} else if (regno == SRS) {
		/* 8-bit register. */
		hex2mem((unsigned char *)&reg.srs, val, sizeof(unsigned char));

	} else if (regno >= EXS && regno <= SPC) {
		/* Consecutive 32-bit registers. */
		hex2mem((unsigned char *)&reg.exs + (regno - EXS) * sizeof(unsigned int),
			 val, sizeof(unsigned int));

       } else if (regno == PC) {
               /* Pseudo-register. Treat as read-only. */
               status = E02;

       } else if (regno >= S0 && regno <= S15) {
               /* 32-bit registers. */
               hex2mem((unsigned char *)&sreg.s0_0 + (reg.srs * 16 * sizeof(unsigned int)) + (regno - S0) * sizeof(unsigned int), val, sizeof(unsigned int));
	} else {
		/* Non-existing register. */
		status = E05;
	}
	return status;
}

/* Read a value from a specified register in the register image. Returns the
   value in the register or -1 for non-implemented registers. */
static int
read_register(char regno, unsigned int *valptr)
{
	int status = SUCCESS;

	/* We read the zero registers from the register struct (instead of just returning 0)
	   to catch errors. */

	if (regno >= R0 && regno <= ACR) {
		/* Consecutive 32-bit registers. */
		*valptr = *(unsigned int *)((char *)&reg.r0 + (regno - R0) * sizeof(unsigned int));

	} else if (regno == BZ || regno == VR) {
		/* Consecutive 8-bit registers. */
		*valptr = (unsigned int)(*(unsigned char *)
                                         ((char *)&reg.bz + (regno - BZ) * sizeof(char)));

	} else if (regno == PID) {
		/* 32-bit register. */
		*valptr =  *(unsigned int *)((char *)&reg.pid);

	} else if (regno == SRS) {
		/* 8-bit register. */
		*valptr = (unsigned int)(*(unsigned char *)((char *)&reg.srs));

	} else if (regno == WZ) {
		/* 16-bit register. */
		*valptr = (unsigned int)(*(unsigned short *)(char *)&reg.wz);

	} else if (regno >= EXS && regno <= PC) {
		/* Consecutive 32-bit registers. */
		*valptr = *(unsigned int *)((char *)&reg.exs + (regno - EXS) * sizeof(unsigned int));

	} else if (regno >= S0 && regno <= S15) {
		/* Consecutive 32-bit registers, located elsewhere. */
		*valptr = *(unsigned int *)((char *)&sreg.s0_0 + (reg.srs * 16 * sizeof(unsigned int)) + (regno - S0) * sizeof(unsigned int));

	} else {
		/* Non-existing register. */
		status = E05;
	}
	return status;

}

/********************************** Packet I/O ******************************/
/* Returns the character equivalent of a nibble, bit 7, 6, 5, and 4 of a byte,
   represented by int x. */
static inline char
highhex(int x)
{
	return hexchars[(x >> 4) & 0xf];
}

/* Returns the character equivalent of a nibble, bit 3, 2, 1, and 0 of a byte,
   represented by int x. */
static inline char
lowhex(int x)
{
	return hexchars[x & 0xf];
}

/* Returns the integer equivalent of a hexadecimal character. */
static int
hex(char ch)
{
	if ((ch >= 'a') && (ch <= 'f'))
		return (ch - 'a' + 10);
	if ((ch >= '0') && (ch <= '9'))
		return (ch - '0');
	if ((ch >= 'A') && (ch <= 'F'))
		return (ch - 'A' + 10);
	return -1;
}

/* Convert the memory, pointed to by mem into hexadecimal representation.
   Put the result in buf, and return a pointer to the last character
   in buf (null). */

static char *
mem2hex(char *buf, unsigned char *mem, int count)
{
	int i;
	int ch;

        if (mem == NULL) {
		/* Invalid address, caught by 'm' packet handler. */
                for (i = 0; i < count; i++) {
                        *buf++ = '0';
                        *buf++ = '0';
                }
        } else {
                /* Valid mem address. */
		for (i = 0; i < count; i++) {
			ch = *mem++;
			*buf++ = highhex (ch);
			*buf++ = lowhex (ch);
		}
        }
        /* Terminate properly. */
	*buf = '\0';
	return buf;
}

/* Same as mem2hex, but puts it in network byte order. */
static char *
mem2hex_nbo(char *buf, unsigned char *mem, int count)
{
	int i;
	int ch;

	mem += count - 1;
	for (i = 0; i < count; i++) {
		ch = *mem--;
		*buf++ = highhex (ch);
		*buf++ = lowhex (ch);
        }

        /* Terminate properly. */
	*buf = '\0';
	return buf;
}

/* Convert the array, in hexadecimal representation, pointed to by buf into
   binary representation. Put the result in mem, and return a pointer to
   the character after the last byte written. */
static unsigned char*
hex2mem(unsigned char *mem, char *buf, int count)
{
	int i;
	unsigned char ch;
	for (i = 0; i < count; i++) {
		ch = hex (*buf++) << 4;
		ch = ch + hex (*buf++);
		*mem++ = ch;
	}
	return mem;
}

/* Put the content of the array, in binary representation, pointed to by buf
   into memory pointed to by mem, and return a pointer to the character after
   the last byte written.
   Gdb will escape $, #, and the escape char (0x7d). */
static unsigned char*
bin2mem(unsigned char *mem, unsigned char *buf, int count)
{
	int i;
	unsigned char *next;
	for (i = 0; i < count; i++) {
		/* Check for any escaped characters. Be paranoid and
		   only unescape chars that should be escaped. */
		if (*buf == 0x7d) {
			next = buf + 1;
			if (*next == 0x3 || *next == 0x4 || *next == 0x5D) {
				 /* #, $, ESC */
				buf++;
				*buf += 0x20;
			}
		}
		*mem++ = *buf++;
	}
	return mem;
}

/* Await the sequence $<data>#<checksum> and store <data> in the array buffer
   returned. */
static void
getpacket(char *buffer)
{
	unsigned char checksum;
	unsigned char xmitcsum;
	int i;
	int count;
	char ch;

	do {
		while((ch = getDebugChar ()) != '$')
			/* Wait for the start character $ and ignore all other characters */;
		checksum = 0;
		xmitcsum = -1;
		count = 0;
		/* Read until a # or the end of the buffer is reached */
		while (count < BUFMAX) {
			ch = getDebugChar();
			if (ch == '#')
				break;
			checksum = checksum + ch;
			buffer[count] = ch;
			count = count + 1;
		}

		if (count >= BUFMAX)
			continue;

		buffer[count] = 0;

		if (ch == '#') {
			xmitcsum = hex(getDebugChar()) << 4;
			xmitcsum += hex(getDebugChar());
			if (checksum != xmitcsum) {
				/* Wrong checksum */
				putDebugChar('-');
			} else {
				/* Correct checksum */
				putDebugChar('+');
				/* If sequence characters are received, reply with them */
				if (buffer[2] == ':') {
					putDebugChar(buffer[0]);
					putDebugChar(buffer[1]);
					/* Remove the sequence characters from the buffer */
					count = gdb_cris_strlen(buffer);
					for (i = 3; i <= count; i++)
						buffer[i - 3] = buffer[i];
				}
			}
		}
	} while (checksum != xmitcsum);
}

/* Send $<data>#<checksum> from the <data> in the array buffer. */