path: root/ddb/db_run.c

/*
 * Mach Operating System
 * Copyright (c) 1993-1990 Carnegie Mellon University
 * All Rights Reserved.
 *
 * Permission to use, copy, modify and distribute this software and its
 * documentation is hereby granted, provided that both the copyright
 * notice and this permission notice appear in all copies of the
 * software, derivative works or modified versions, and any portions
 * thereof, and that both notices appear in supporting documentation.
 *
 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
 *
 * Carnegie Mellon requests users of this software to return to
 *
 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
 *  School of Computer Science
 *  Carnegie Mellon University
 *  Pittsburgh PA 15213-3890
 *
 * any improvements or extensions that they make and grant Carnegie Mellon
 * the rights to redistribute these changes.
 */
/*
 * 	Author: David B. Golub, Carnegie Mellon University
 *	Date:	7/90
 */

#if MACH_KDB

/*
 * Commands to run process.
 */
#include <mach/boolean.h>
#include <machine/db_machdep.h>

#include <ddb/db_lex.h>
#include <ddb/db_break.h>
#include <ddb/db_access.h>
#include <ddb/db_run.h>
#include <ddb/db_task_thread.h>
#include <ddb/db_command.h>
#include <ddb/db_examine.h>
#include <ddb/db_output.h>
#include <ddb/db_watch.h>
#include <ddb/db_cond.h>


int	db_run_mode;

boolean_t	db_sstep_print;
int		db_loop_count;
int		db_call_depth;

int		db_inst_count;
int		db_last_inst_count;
int		db_load_count;
int		db_store_count;

boolean_t
db_stop_at_pc(
	boolean_t	*is_breakpoint,
	task_t		task)
{
	db_addr_t		pc;
	db_thread_breakpoint_t  bkpt;

	db_clear_task_single_step(DDB_REGS, task);
	db_clear_breakpoints();
	db_clear_watchpoints();
	pc = PC_REGS(DDB_REGS);

#ifdef	FIXUP_PC_AFTER_BREAK
	if (*is_breakpoint) {
	    /*
	     * Breakpoint trap.  Fix up the PC if the
	     * machine requires it.
	     */
	    FIXUP_PC_AFTER_BREAK
	    pc = PC_REGS(DDB_REGS);
	}
#endif /* FIXUP_PC_AFTER_BREAK */

	/*
	 * Now check for a breakpoint at this address.
	 */
	bkpt = db_find_thread_breakpoint_here(task, pc);
	if (bkpt) {
	    if (db_cond_check(bkpt)) {
		*is_breakpoint = TRUE;
		return (TRUE);	/* stop here */
	    }
	}
	*is_breakpoint = FALSE;

	if (db_run_mode == STEP_INVISIBLE) {
	    db_run_mode = STEP_CONTINUE;
	    return (FALSE);	/* continue */
	}
	if (db_run_mode == STEP_COUNT) {
	    return (FALSE); /* continue */
	}
	if (db_run_mode == STEP_ONCE) {
	    if (--db_loop_count > 0) {
		if (db_sstep_print) {
		    db_print_loc_and_inst(pc, task);
		}
		return (FALSE);	/* continue */
	    }
	}
	if (db_run_mode == STEP_RETURN) {
	    /* WARNING: the following assumes an instruction fits an int */
	    db_expr_t ins = db_get_task_value(pc, sizeof(int), FALSE, task);

	    /* continue until matching return */

	    if (!inst_trap_return(ins) &&
		(!inst_return(ins) || --db_call_depth != 0)) {
		if (db_sstep_print) {
		    if (inst_call(ins) || inst_return(ins)) {
			int i;

			db_printf("[after %6d /%4d] ",
				  db_inst_count,
				  db_inst_count - db_last_inst_count);
			db_last_inst_count = db_inst_count;
			for (i = db_call_depth; --i > 0; )
			    db_printf("  ");
			db_print_loc_and_inst(pc, task);
			db_printf("\n");
		    }
		}
		if (inst_call(ins))
		    db_call_depth++;
		return (FALSE);	/* continue */
	    }
	}
	if (db_run_mode == STEP_CALLT) {
	    /* WARNING: the following assumes an instruction fits an int */
	    db_expr_t ins = db_get_task_value(pc, sizeof(int), FALSE, task);

	    /* continue until call or return */

	    if (!inst_call(ins) &&
		!inst_return(ins) &&
		!inst_trap_return(ins)) {
		return (FALSE);	/* continue */
	    }
	}
	if (db_find_breakpoint_here(task, pc))
		return(FALSE);
	db_run_mode = STEP_NONE;
	return (TRUE);
}

void
db_restart_at_pc(
	boolean_t watchpt,
	task_t	  task)
{
	db_addr_t pc = PC_REGS(DDB_REGS);

	if ((db_run_mode == STEP_COUNT) ||
	    (db_run_mode == STEP_RETURN) ||
	    (db_run_mode == STEP_CALLT)) {

	    /*
	     * We are about to execute this instruction,
	     * so count it now.
	     */

	    db_get_task_value(pc, sizeof(int), FALSE, task);
	    db_inst_count++;
	    db_load_count += inst_load(ins);
	    db_store_count += inst_store(ins);
#ifdef	SOFTWARE_SSTEP
	    db_addr_t brpc;
	    /* Account for instructions in delay slots */
	    brpc = next_instr_address(pc, 1, task);
	    if ((brpc != pc) && (inst_branch(ins) || inst_call(ins))) {
		/* Note: this ~assumes an instruction <= sizeof(int) */
		db_get_task_value(brpc, sizeof(int), FALSE, task);
		db_inst_count++;
		db_load_count += inst_load(ins);
		db_store_count += inst_store(ins);
	    }
#endif	/* SOFTWARE_SSTEP */
	}

	if (db_run_mode == STEP_CONTINUE) {
	    if (watchpt || db_find_breakpoint_here(task, pc)) {
		/*
		 * Step over breakpoint/watchpoint.
		 */
		db_run_mode = STEP_INVISIBLE;
		db_set_task_single_step(DDB_REGS, task);
	    } else {
		db_set_breakpoints();
		db_set_watchpoints();
	    }
	} else {
	    db_set_task_single_step(DDB_REGS, task);
	}
}

void
db_single_step(
	db_regs_t *regs,
	task_t	  task)
{
	if (db_run_mode == STEP_CONTINUE) {
	    db_run_mode = STEP_INVISIBLE;
	    db_set_task_single_step(regs, task);
	}
}

#ifdef	SOFTWARE_SSTEP
/*
 *	Software implementation of single-stepping.
 *	If your machine does not have a trace mode
 *	similar to the vax or sun ones you can use
 *	this implementation, done for the mips.
 *	Just define the above conditional and provide
 *	the functions/macros defined below.
 *
 * extern boolean_t
 *	inst_branch(),		returns true if the instruction might branch
 * extern unsigned
 *	branch_taken(),		return the address the instruction might
 *				branch to
 *	db_getreg_val();	return the value of a user register,
 *				as indicated in the hardware instruction
 *				encoding, e.g. 8 for r8
 *
 * next_instr_address(pc,bd,task) returns the address of the first
 *				instruction following the one at "pc",
 *				which is either in the taken path of
 *				the branch (bd==1) or not.  This is
 *				for machines (mips) with branch delays.
 *
 *	A single-step may involve at most 2 breakpoints -
 *	one for branch-not-taken and one for branch taken.
 *	If one of these addresses does not already have a breakpoint,
 *	we allocate a breakpoint and save it here.
 *	These breakpoints are deleted on return.
 */
db_breakpoint_t	db_not_taken_bkpt = 0;
db_breakpoint_t	db_taken_bkpt = 0;

db_breakpoint_t __attribute__ ((pure))
db_find_temp_breakpoint(task, addr)
	const task_t	task;
	db_addr_t	addr;
{
	if (db_taken_bkpt && (db_taken_bkpt->address == addr) &&
	    db_taken_bkpt->task == task)
		return db_taken_bkpt;
	if (db_not_taken_bkpt && (db_not_taken_bkpt->address == addr) &&
	    db_not_taken_bkpt->task == task)
		return db_not_taken_bkpt;
	return 0;
}

void
db_set_task_single_step(
	db_regs_t 	*regs,
	task_t		task)
{
	db_addr_t pc = PC_REGS(regs), brpc;
	unsigned int	inst;
	boolean_t       unconditional;

	/*
	 *	User was stopped at pc, e.g. the instruction
	 *	at pc was not executed.
	 */
	inst = db_get_task_value(pc, sizeof(int), FALSE, task);
	if (inst_branch(inst) || inst_call(inst)) {
	    extern db_expr_t getreg_val();

	    brpc = branch_taken(inst, pc, getreg_val, regs);
	    if (brpc != pc) {	/* self-branches are hopeless */
		db_taken_bkpt = db_set_temp_breakpoint(task, brpc);
	    } else
	        db_taken_bkpt = 0;
	    pc = next_instr_address(pc,1,task);
	}

	/* check if this control flow instruction is an unconditional transfer */
	unconditional = inst_unconditional_flow_transfer(inst);

	pc = next_instr_address(pc,0,task);
	/*
	  We only set the sequential breakpoint if previous instruction was not
	  an unconditional change of flow of control. If the previous instruction
	  is an unconditional change of flow of control, setting a breakpoint in the
	  next sequential location may set a breakpoint in data or in another routine,
	  which could screw up either the program or the debugger.
	  (Consider, for instance, that the next sequential instruction is the
	  start of a routine needed by the debugger.)
	*/
	if (!unconditional && db_find_breakpoint_here(task, pc) == 0) {
	    db_not_taken_bkpt = db_set_temp_breakpoint(task, pc);
	}
	else
	    db_not_taken_bkpt = 0;
}

void
db_clear_task_single_step(regs, task)
	const db_regs_t *regs;
	task_t	  	task;
{
	if (db_taken_bkpt != 0) {
	    db_delete_temp_breakpoint(task, db_taken_bkpt);
	    db_taken_bkpt = 0;
	}
	if (db_not_taken_bkpt != 0) {
	    db_delete_temp_breakpoint(task, db_not_taken_bkpt);
	    db_not_taken_bkpt = 0;
	}
}

#endif	/* SOFTWARE_SSTEP */


extern int	db_cmd_loop_done;

/* single-step */
/*ARGSUSED*/
void
db_single_step_cmd(addr, have_addr, count, modif)
	db_expr_t	addr;
	int		have_addr;
	db_expr_t	count;
	const char *	modif;
{
	boolean_t	print = FALSE;

	if (count == -1)
	    count = 1;

	if (modif[0] == 'p')
	    print = TRUE;

	db_run_mode = STEP_ONCE;
	db_loop_count = count;
	db_sstep_print = print;
	db_inst_count = 0;
	db_last_inst_count = 0;
	db_load_count = 0;
	db_store_count = 0;

	db_cmd_loop_done = 1;
}

/* trace and print until call/return */
/*ARGSUSED*/
void
db_trace_until_call_cmd(addr, have_addr, count, modif)
	db_expr_t	addr;
	int		have_addr;
	db_expr_t	count;
	const char *	modif;
{
	boolean_t	print = FALSE;

	if (modif[0] == 'p')
	    print = TRUE;

	db_run_mode = STEP_CALLT;
	db_sstep_print = print;
	db_inst_count = 0;
	db_last_inst_count = 0;
	db_load_count = 0;
	db_store_count = 0;

	db_cmd_loop_done = 1;
}

/*ARGSUSED*/
void
db_trace_until_matching_cmd(addr, have_addr, count, modif)
	db_expr_t	addr;
	int		have_addr;
	db_expr_t	count;
	const char *	modif;
{
	boolean_t	print = FALSE;

	if (modif[0] == 'p')
	    print = TRUE;

	db_run_mode = STEP_RETURN;
	db_call_depth = 1;
	db_sstep_print = print;
	db_inst_count = 0;
	db_last_inst_count = 0;
	db_load_count = 0;
	db_store_count = 0;

	db_cmd_loop_done = 1;
}

/* continue */
/*ARGSUSED*/
void
db_continue_cmd(addr, have_addr, count, modif)
	db_expr_t	addr;
	int		have_addr;
	db_expr_t	count;
	const char *	modif;
{
	if (modif[0] == 'c')
	    db_run_mode = STEP_COUNT;
	else
	    db_run_mode = STEP_CONTINUE;
	db_inst_count = 0;
	db_last_inst_count = 0;
	db_load_count = 0;
	db_store_count = 0;

	db_cmd_loop_done = 1;
}

boolean_t
db_in_single_step(void)
{
	return(db_run_mode != STEP_NONE && db_run_mode != STEP_CONTINUE);
}

#endif /* MACH_KDB */