kgdb.c

linux内核源码

	/* Read watchpoints are set as access watchpoints, because of GDB's
	   inability to deal with pure read watchpoints. */
	if (type == '3')
		type = '4';

	if (type == '1') {
		/* Hardware breakpoint. */
		/* Bit 0 in BP_CTRL holds the configuration for I0. */
		if (!(sreg.s0_3 & 0x1)) {
			/* Not in use. */
			gdb_cris_strcpy(output_buffer, error_message[E04]);
			return;
		}
		/* Deconfigure. */
		sreg.s1_3 = 0;
		sreg.s2_3 = 0;
		sreg.s0_3 &= ~1;
	} else {
		int bp;
		unsigned int *bp_d_regs = &sreg.s3_3;
		/* Try to find a watchpoint that is configured for the
		   specified range, then check that read/write also matches. */

		/* Ugly pointer arithmetic, since I cannot rely on a
		   single switch (addr) as there may be several watchpoints with
		   the same start address for example. */

		for (bp = 0; bp < 6; bp++) {
			if (bp_d_regs[bp * 2] == addr &&
			    bp_d_regs[bp * 2 + 1] == (addr + len - 1)) {
				/* Matching range. */
				int bitpos = 2 + bp * 4;
				int rw_bits;

				/* Read/write bits for this BP. */
				rw_bits = (sreg.s0_3 & (0x3 << bitpos)) >> bitpos;

				if ((type == '3' && rw_bits == 0x1) ||
				    (type == '2' && rw_bits == 0x2) ||
				    (type == '4' && rw_bits == 0x3)) {
					/* Read/write matched. */
					break;
				}
			}
		}

		if (bp > 5) {
			/* No watchpoint matched. */
			gdb_cris_strcpy(output_buffer, error_message[E04]);
			return;
		}

		/* Found a matching watchpoint. Now, deconfigure it by
		   both disabling read/write in bp_ctrl and zeroing its
		   start/end addresses. */
		sreg.s0_3 &= ~(3 << (2 + (bp * 4)));
		bp_d_regs[bp * 2] = 0;
		bp_d_regs[bp * 2 + 1] = 0;
	}

	/* Note that we don't clear the S1 flag here. It's done when continuing.  */
	gdb_cris_strcpy(output_buffer, "OK");
}



/* All expected commands are sent from remote.c. Send a response according
   to the description in remote.c. */
void
handle_exception(int sigval)
{
	/* Avoid warning of not used. */

	USEDFUN(handle_exception);
	USEDVAR(internal_stack[0]);

	register_fixup(sigval);

	/* Send response. */
	stub_is_stopped(sigval);

	for (;;) {
		output_buffer[0] = '\0';
		getpacket(input_buffer);
		switch (input_buffer[0]) {
			case 'g':
				/* Read registers: g
				   Success: Each byte of register data is described by two hex digits.
				   Registers are in the internal order for GDB, and the bytes
				   in a register  are in the same order the machine uses.
				   Failure: void. */
			{
				char *buf;
				/* General and special registers. */
				buf = mem2hex(output_buffer, (char *)&reg, sizeof(registers));
				/* Support registers. */
				/* -1 because of the null termination that mem2hex adds. */
				mem2hex(buf,
					(char *)&sreg + (reg.srs * 16 * sizeof(unsigned int)),
					16 * sizeof(unsigned int));
				break;
			}
			case 'G':
				/* Write registers. GXX..XX
				   Each byte of register data  is described by two hex digits.
				   Success: OK
				   Failure: void. */
				/* General and special registers. */
				hex2mem((char *)&reg, &input_buffer[1], sizeof(registers));
				/* Support registers. */
				hex2mem((char *)&sreg + (reg.srs * 16 * sizeof(unsigned int)),
					&input_buffer[1] + sizeof(registers),
					16 * sizeof(unsigned int));
				gdb_cris_strcpy(output_buffer, "OK");
				break;

			case 'P':
				/* Write register. Pn...=r...
				   Write register n..., hex value without 0x, with value r...,
				   which contains a hex value without 0x and two hex digits
				   for each byte in the register (target byte order). P1f=11223344 means
				   set register 31 to 44332211.
				   Success: OK
				   Failure: E02, E05 */
				{
					char *suffix;
					int regno = gdb_cris_strtol(&input_buffer[1], &suffix, 16);
					int status;

					status = write_register(regno, suffix+1);

					switch (status) {
						case E02:
							/* Do not support read-only registers. */
							gdb_cris_strcpy(output_buffer, error_message[E02]);
							break;
						case E05:
							/* Do not support non-existing registers. */
							gdb_cris_strcpy(output_buffer, error_message[E05]);
							break;
						default:
							/* Valid register number. */
							gdb_cris_strcpy(output_buffer, "OK");
							break;
					}
				}
				break;

			case 'm':
				/* Read from memory. mAA..AA,LLLL
				   AA..AA is the address and LLLL is the length.
				   Success: XX..XX is the memory content.  Can be fewer bytes than
				   requested if only part of the data may be read. m6000120a,6c means
				   retrieve 108 byte from base address 6000120a.
				   Failure: void. */
				{
                                        char *suffix;
					unsigned char *addr = (unsigned char *)gdb_cris_strtol(&input_buffer[1],
                                                                                               &suffix, 16);
					int len = gdb_cris_strtol(suffix+1, 0, 16);

					/* Bogus read (i.e. outside the kernel's
					   segment)? . */
					if (!((unsigned int)addr >= 0xc0000000 &&
					      (unsigned int)addr < 0xd0000000))
						addr = NULL;

                                        mem2hex(output_buffer, addr, len);
                                }
				break;

			case 'X':
				/* Write to memory. XAA..AA,LLLL:XX..XX
				   AA..AA is the start address,  LLLL is the number of bytes, and
				   XX..XX is the binary data.
				   Success: OK
				   Failure: void. */
			case 'M':
				/* Write to memory. MAA..AA,LLLL:XX..XX
				   AA..AA is the start address,  LLLL is the number of bytes, and
				   XX..XX is the hexadecimal data.
				   Success: OK
				   Failure: void. */
				{
					char *lenptr;
					char *dataptr;
					unsigned char *addr = (unsigned char *)gdb_cris_strtol(&input_buffer[1],
										      &lenptr, 16);
					int len = gdb_cris_strtol(lenptr+1, &dataptr, 16);
					if (*lenptr == ',' && *dataptr == ':') {
						if (input_buffer[0] == 'M') {
							hex2mem(addr, dataptr + 1, len);
						} else /* X */ {
							bin2mem(addr, dataptr + 1, len);
						}
						gdb_cris_strcpy(output_buffer, "OK");
					}
					else {
						gdb_cris_strcpy(output_buffer, error_message[E06]);
					}
				}
				break;

			case 'c':
				/* Continue execution. cAA..AA
				   AA..AA is the address where execution is resumed. If AA..AA is
				   omitted, resume at the present address.
				   Success: return to the executing thread.
				   Failure: will never know. */

				if (input_buffer[1] != '\0') {
					/* FIXME: Doesn't handle address argument. */
					gdb_cris_strcpy(output_buffer, error_message[E04]);
					break;
				}

				/* Before continuing, make sure everything is set up correctly. */

				/* Set the SPC to some unlikely value.  */
				reg.spc = 0;
				/* Set the S1 flag to 0 unless some watchpoint is enabled (since setting
				   S1 to 0 would also disable watchpoints). (Note that bits 26-31 in BP_CTRL
				   are reserved, so don't check against those). */
				if ((sreg.s0_3 & 0x3fff) == 0) {
					reg.ccs &= ~(1 << (S_CCS_BITNR + CCS_SHIFT));
				}

				return;

			case 's':
				/* Step. sAA..AA
				   AA..AA is the address where execution is resumed. If AA..AA is
				   omitted, resume at the present address. Success: return to the
				   executing thread. Failure: will never know. */

				if (input_buffer[1] != '\0') {
					/* FIXME: Doesn't handle address argument. */
					gdb_cris_strcpy(output_buffer, error_message[E04]);
					break;
				}

				/* Set the SPC to PC, which is where we'll return
				   (deduced previously). */
				reg.spc = reg.pc;

				/* Set the S1 (first stacked, not current) flag, which will
				   kick into action when we rfe. */
				reg.ccs |= (1 << (S_CCS_BITNR + CCS_SHIFT));
				return;

                       case 'Z':

                               /* Insert breakpoint or watchpoint, Ztype,addr,length.
                                  Remote protocol says: A remote target shall return an empty string
                                  for an unrecognized breakpoint or watchpoint packet type. */
                               {
                                       char *lenptr;
                                       char *dataptr;
                                       int addr = gdb_cris_strtol(&input_buffer[3], &lenptr, 16);
                                       int len = gdb_cris_strtol(lenptr + 1, &dataptr, 16);
                                       char type = input_buffer[1];

				       insert_watchpoint(type, addr, len);
                                       break;
                               }

                       case 'z':
                               /* Remove breakpoint or watchpoint, Ztype,addr,length.
                                  Remote protocol says: A remote target shall return an empty string
                                  for an unrecognized breakpoint or watchpoint packet type. */
                               {
                                       char *lenptr;
                                       char *dataptr;
                                       int addr = gdb_cris_strtol(&input_buffer[3], &lenptr, 16);
                                       int len = gdb_cris_strtol(lenptr + 1, &dataptr, 16);
                                       char type = input_buffer[1];

                                       remove_watchpoint(type, addr, len);
                                       break;
                               }


			case '?':
				/* The last signal which caused a stop. ?
				   Success: SAA, where AA is the signal number.
				   Failure: void. */
				output_buffer[0] = 'S';
				output_buffer[1] = highhex(sigval);
				output_buffer[2] = lowhex(sigval);
				output_buffer[3] = 0;
				break;

			case 'D':
				/* Detach from host. D
				   Success: OK, and return to the executing thread.
				   Failure: will never know */
				putpacket("OK");
				return;

			case 'k':
			case 'r':
				/* kill request or reset request.
				   Success: restart of target.
				   Failure: will never know. */
				kill_restart();
				break;

			case 'C':
			case 'S':
			case '!':
			case 'R':
			case 'd':
				/* Continue with signal sig. Csig;AA..AA
				   Step with signal sig. Ssig;AA..AA
				   Use the extended remote protocol. !
				   Restart the target system. R0
				   Toggle debug flag. d
				   Search backwards. tAA:PP,MM
				   Not supported: E04 */

				/* FIXME: What's the difference between not supported
				   and ignored (below)? */
				gdb_cris_strcpy(output_buffer, error_message[E04]);
				break;

			default:
				/* The stub should ignore other request and send an empty
				   response ($#<checksum>). This way we can extend the protocol and GDB
				   can tell whether the stub it is talking to uses the old or the new. */
				output_buffer[0] = 0;
				break;
		}
		putpacket(output_buffer);
	}
}

void
kgdb_init(void)
{
	reg_intr_vect_rw_mask intr_mask;
	reg_ser_rw_intr_mask ser_intr_mask;

	/* Configure the kgdb serial port. */
#if defined(CONFIG_ETRAX_KGDB_PORT0)
	/* Note: no shortcut registered (not handled by multiple_interrupt).
	   See entry.S.  */
	set_exception_vector(SER0_INTR_VECT, kgdb_handle_exception);
	/* Enable the ser irq in the global config. */
	intr_mask = REG_RD(intr_vect, regi_irq, rw_mask);
	intr_mask.ser0 = 1;
	REG_WR(intr_vect, regi_irq, rw_mask, intr_mask);

	ser_intr_mask = REG_RD(ser, regi_ser0, rw_intr_mask);
	ser_intr_mask.data_avail = regk_ser_yes;
	REG_WR(ser, regi_ser0, rw_intr_mask, ser_intr_mask);
#elif defined(CONFIG_ETRAX_KGDB_PORT1)
	/* Note: no shortcut registered (not handled by multiple_interrupt).
	   See entry.S.  */
	set_exception_vector(SER1_INTR_VECT, kgdb_handle_exception);
	/* Enable the ser irq in the global config. */
	intr_mask = REG_RD(intr_vect, regi_irq, rw_mask);
	intr_mask.ser1 = 1;
	REG_WR(intr_vect, regi_irq, rw_mask, intr_mask);

	ser_intr_mask = REG_RD(ser, regi_ser1, rw_intr_mask);
	ser_intr_mask.data_avail = regk_ser_yes;
	REG_WR(ser, regi_ser1, rw_intr_mask, ser_intr_mask);
#elif defined(CONFIG_ETRAX_KGDB_PORT2)
	/* Note: no shortcut registered (not handled by multiple_interrupt).
	   See entry.S.  */
	set_exception_vector(SER2_INTR_VECT, kgdb_handle_exception);
	/* Enable the ser irq in the global config. */
	intr_mask = REG_RD(intr_vect, regi_irq, rw_mask);
	intr_mask.ser2 = 1;
	REG_WR(intr_vect, regi_irq, rw_mask, intr_mask);

	ser_intr_mask = REG_RD(ser, regi_ser2, rw_intr_mask);
	ser_intr_mask.data_avail = regk_ser_yes;
	REG_WR(ser, regi_ser2, rw_intr_mask, ser_intr_mask);
#elif defined(CONFIG_ETRAX_KGDB_PORT3)
	/* Note: no shortcut registered (not handled by multiple_interrupt).
	   See entry.S.  */
	set_exception_vector(SER3_INTR_VECT, kgdb_handle_exception);
	/* Enable the ser irq in the global config. */
	intr_mask = REG_RD(intr_vect, regi_irq, rw_mask);
	intr_mask.ser3 = 1;
	REG_WR(intr_vect, regi_irq, rw_mask, intr_mask);

	ser_intr_mask = REG_RD(ser, regi_ser3, rw_intr_mask);
	ser_intr_mask.data_avail = regk_ser_yes;
	REG_WR(ser, regi_ser3, rw_intr_mask, ser_intr_mask);
#endif

}
/* Performs a complete re-start from scratch. */
static void
kill_restart(void)
{
	machine_restart("");
}

/* Use this static breakpoint in the start-up only. */

void
breakpoint(void)
{
	kgdb_started = 1;
	dynamic_bp = 0;     /* This is a static, not a dynamic breakpoint. */
	__asm__ volatile ("break 8"); /* Jump to kgdb_handle_breakpoint. */
}

/****************************** End of file **********************************/