/*
 * Mach Operating System
 * Copyright (c) 1991,1990 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
 * 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 the
 * rights to redistribute these changes.
 *
 * $FreeBSD: src/sys/ddb/db_run.c,v 1.18 1999/08/28 00:41:10 peter Exp $
 */

/*
 *      Author: David B. Golub, Carnegie Mellon University
 *      Date:   7/90
 */

/*
 * Commands to run process.
 */
#include <sys/param.h>

#include <vm/vm.h>

#include <ddb/ddb.h>
#include <ddb/db_break.h>
#include <ddb/db_access.h>

static int      db_run_mode;
#define STEP_NONE       0
#define STEP_ONCE       1
#define STEP_RETURN     2
#define STEP_CALLT      3
#define STEP_CONTINUE   4
#define STEP_INVISIBLE  5
#define STEP_COUNT      6

static boolean_t        db_sstep_print;
static int              db_loop_count;
static int              db_call_depth;

int             db_inst_count;
int             db_load_count;
int             db_store_count;

#ifndef db_set_single_step
extern void     db_set_single_step (db_regs_t *regs);
#endif
#ifndef db_clear_single_step
extern void     db_clear_single_step (db_regs_t *regs);
#endif

#ifdef notused
static void     db_single_step (db_regs_t *regs);
#endif

boolean_t
db_stop_at_pc(boolean_t *is_breakpoint)
{
        db_addr_t       pc;
        db_breakpoint_t bkpt;

        db_clear_single_step(DDB_REGS);
        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

        /*
         * Now check for a breakpoint at this address.
         */
        bkpt = db_find_breakpoint_here(pc);
        if (bkpt) {
            if (--bkpt->count == 0) {
                bkpt->count = bkpt->init_count;
                *is_breakpoint = TRUE;
                return (TRUE);  /* stop here */
            }
        } else if (*is_breakpoint) {
#ifdef __x86_64__
                ddb_regs.tf_rip += 1;
#endif
        }

        *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_printf("\t\t");
                    db_print_loc_and_inst(pc, DDB_REGS);
                    db_printf("\n");
                }
                return (FALSE); /* continue */
            }
        }
        if (db_run_mode == STEP_RETURN) {
            db_expr_t ins = db_get_value(pc, sizeof(int), FALSE);

            /* 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]     ", db_inst_count);
                        for (i = db_call_depth; --i > 0; )
                            db_printf("  ");
                        db_print_loc_and_inst(pc, DDB_REGS);
                        db_printf("\n");
                    }
                }
                if (inst_call(ins))
                    db_call_depth++;
                return (FALSE); /* continue */
            }
        }
        if (db_run_mode == STEP_CALLT) {
            db_expr_t ins = db_get_value(pc, sizeof(int), FALSE);

            /* continue until call or return */

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

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

        if ((db_run_mode == STEP_COUNT) ||
            (db_run_mode == STEP_RETURN) ||
            (db_run_mode == STEP_CALLT)) {
            db_expr_t   ins __unused;   /* seems used but gcc thinks not */

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

            ins = db_get_value(pc, sizeof(int), FALSE);
            db_inst_count++;
            db_load_count += inst_load(ins);
            db_store_count += inst_store(ins);
#ifdef  SOFTWARE_SSTEP
            /* XXX works on mips, but... */
            if (inst_branch(ins) || inst_call(ins)) {
                ins = db_get_value(next_instr_address(pc,1),
                                   sizeof(int), FALSE);
                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(pc)) {
                /*
                 * Step over breakpoint/watchpoint.
                 */
                db_run_mode = STEP_INVISIBLE;
                db_set_single_step(DDB_REGS);
            } else {
                db_set_breakpoints();
                db_set_watchpoints();
            }
        } else {
            db_set_single_step(DDB_REGS);
        }
}

#ifdef notused
static void
db_single_step(db_regs_t *regs)
{
        if (db_run_mode == STEP_CONTINUE) {
            db_run_mode = STEP_INVISIBLE;
            db_set_single_step(regs);
        }
}
#endif

#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)    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;

void
db_set_single_step(db_regs_t *regs)
{
        db_addr_t pc = PC_REGS(regs), brpc;
         unsigned        inst;

        /*
         *      User was stopped at pc, e.g. the instruction
         *      at pc was not executed.
         */
        inst = db_get_value(pc, sizeof(int), FALSE);
        if (inst_branch(inst) || inst_call(inst)) {
            brpc = branch_taken(inst, pc, regs);
            if (brpc != pc) {   /* self-branches are hopeless */
                db_taken_bkpt = db_set_temp_breakpoint(brpc);
            }
            pc = next_instr_address(pc,1);
        }
        pc = next_instr_address(pc,0);
        db_not_taken_bkpt = db_set_temp_breakpoint(pc);
}

void
db_clear_single_step(db_regs_t *regs)
{

        if (db_not_taken_bkpt != 0) {
            db_delete_temp_breakpoint(db_not_taken_bkpt);
            db_not_taken_bkpt = 0;
        }
        if (db_taken_bkpt != 0) {
            db_delete_temp_breakpoint(db_taken_bkpt);
            db_taken_bkpt = 0;
        }
}

#endif /* SOFTWARE_SSTEP */

extern boolean_t        db_cmd_loop_done;

/* single-step */
/*ARGSUSED*/
void
db_single_step_cmd(db_expr_t addr, boolean_t have_addr, db_expr_t count,
                   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_load_count = 0;
        db_store_count = 0;

        db_cmd_loop_done = TRUE;
}

/* trace and print until call/return */
/*ARGSUSED*/
void
db_trace_until_call_cmd(db_expr_t addr, boolean_t have_addr, db_expr_t count,
                        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_load_count = 0;
        db_store_count = 0;

        db_cmd_loop_done = TRUE;
}

/*ARGSUSED*/
void
db_trace_until_matching_cmd(db_expr_t addr, boolean_t have_addr,
                            db_expr_t count, 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_load_count = 0;
        db_store_count = 0;

        db_cmd_loop_done = TRUE;
}

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

        db_cmd_loop_done = TRUE;
}