/*-
 * SPDX-License-Identifier: MIT-CMU
 *
 * 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.
 */
/*
 *      Author: David B. Golub, Carnegie Mellon University
 *      Date:   7/90
 */

/*
 * Commands to run process.
 */

#include <sys/param.h>
#include <sys/kdb.h>
#include <sys/proc.h>
#include <sys/reg.h>
#include <sys/systm.h>

#include <machine/kdb.h>
#include <machine/pcb.h>

#include <vm/vm.h>

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

#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 int      db_run_mode = STEP_CONTINUE;

static bool             db_sstep_multiple;
static bool             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;

bool
db_stop_at_pc(int type, int code, bool *is_breakpoint, bool *is_watchpoint)
{
        db_addr_t       pc;
        db_breakpoint_t bkpt;

        *is_breakpoint = IS_BREAKPOINT_TRAP(type, code);
        *is_watchpoint = IS_WATCHPOINT_TRAP(type, code);
        pc = PC_REGS();

        db_clear_single_step();
        db_clear_breakpoints();
        db_clear_watchpoints();

#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();
        }
#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 */
            }
            return (false);     /* continue the countdown */
        } else if (*is_breakpoint) {
#ifdef BKPT_SKIP
                BKPT_SKIP;
#endif
        }

        *is_breakpoint = false; /* might be a breakpoint, but not ours */

        /*
         * If not stepping, then silently ignore single-step traps
         * (except for clearing the single-step-flag above).
         *
         * If stepping, then abort if the trap type is unexpected.
         * Breakpoints owned by us are expected and were handled above.
         * Single-steps are expected and are handled below.  All others
         * are unexpected.
         *
         * Only do either of these if the MD layer claims to classify
         * single-step traps unambiguously (by defining IS_SSTEP_TRAP).
         * Otherwise, fall through to the bad historical behaviour
         * given by turning unexpected traps into expected traps: if not
         * stepping, then expect only breakpoints and stop, and if
         * stepping, then expect only single-steps and step.
         */
#ifdef IS_SSTEP_TRAP
        if (db_run_mode == STEP_CONTINUE && IS_SSTEP_TRAP(type, code))
            return (false);
        if (db_run_mode != STEP_CONTINUE && !IS_SSTEP_TRAP(type, code)) {
            printf("Stepping aborted\n");
            return (true);
        }
#endif

        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);
                }
                return (false); /* continue */
            }
        }
        if (db_run_mode == STEP_RETURN) {
            /* continue until matching return */
            db_expr_t ins;

            ins = db_get_value(pc, sizeof(int), false);
            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);
                    }
                }
                if (inst_call(ins))
                    db_call_depth++;
                return (false); /* continue */
            }
        }
        if (db_run_mode == STEP_CALLT) {
            /* continue until call or return */
            db_expr_t ins;

            ins = db_get_value(pc, sizeof(int), false);
            if (!inst_call(ins) &&
                !inst_return(ins) &&
                !inst_trap_return(ins)) {
                return (false); /* continue */
            }
        }
        return (true);
}

void
db_restart_at_pc(bool watchpt)
{
        db_addr_t       pc = PC_REGS();

        if ((db_run_mode == STEP_COUNT) ||
            ((db_run_mode == STEP_ONCE) && db_sstep_multiple) ||
            (db_run_mode == STEP_RETURN) ||
            (db_run_mode == STEP_CALLT)) {
            /*
             * We are about to execute this instruction,
             * so count it now.
             */
            db_get_value(pc, sizeof(int), false);
            db_inst_count++;
            db_load_count += inst_load(ins);
            db_store_count += inst_store(ins);
        }

        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();
            } else {
                db_set_breakpoints();
                db_set_watchpoints();
            }
        } else {
            db_set_single_step();
        }
}

/* single-step */
/*ARGSUSED*/
void
db_single_step_cmd(db_expr_t addr, bool have_addr, db_expr_t count, char *modif)
{
        bool            print = false;

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

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

        db_run_mode = STEP_ONCE;
        db_loop_count = count;
        db_sstep_multiple = (count != 1);
        db_sstep_print = print;
        db_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(db_expr_t addr, bool have_addr, db_expr_t count,
    char *modif)
{
        bool    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 = 1;
}

/*ARGSUSED*/
void
db_trace_until_matching_cmd(db_expr_t addr, bool have_addr, db_expr_t count,
    char *modif)
{
        bool    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 = 1;
}

/* continue */
/*ARGSUSED*/
void
db_continue_cmd(db_expr_t addr, bool 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 = 1;
}