/*      $OpenBSD: db_run.c,v 1.33 2025/07/22 09:09:50 kettenis Exp $    */
/*      $NetBSD: db_run.c,v 1.8 1996/02/05 01:57:12 christos Exp $      */

/*
 * Mach Operating System
 * Copyright (c) 1993,1992,1991,1990 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 "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
 */

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

#include <machine/db_machdep.h>

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

#ifdef SOFTWARE_SSTEP
db_breakpoint_t db_not_taken_bkpt = 0;
db_breakpoint_t db_taken_bkpt = 0;
#endif

int             db_inst_count;

#include <ddb/db_watch.h>
#include <ddb/db_output.h>
#include <ddb/db_sym.h>
#include <ddb/db_extern.h>

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

int     db_sstep_print;
int             db_loop_count;
int             db_call_depth;

int
db_stop_at_pc(db_regs_t *regs, int *is_breakpoint)
{
        vaddr_t         pc, old_pc;
        db_breakpoint_t bkpt;

        db_clear_breakpoints();
        db_clear_watchpoints();
        old_pc = pc = PC_REGS(regs);

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

        /*
         * Now check for a breakpoint at this address.
         */
        bkpt = db_find_breakpoint(pc);
        if (bkpt) {
                if (--bkpt->count == 0) {
                        db_clear_single_step(regs);
                        bkpt->count = bkpt->init_count;
                        *is_breakpoint = 1;
                        return 1;       /* stop here */
                } else {
                        return 0;       /* continue */
                }
        } else if (*is_breakpoint
#ifdef SOFTWARE_SSTEP
            && !((db_taken_bkpt && db_taken_bkpt->address == pc) ||
            (db_not_taken_bkpt && db_not_taken_bkpt->address == pc))
#endif
            ) {
#ifdef PC_ADVANCE
                PC_ADVANCE(regs);
#else
# ifdef SET_PC_REGS
                SET_PC_REGS(regs, old_pc);
# else
                PC_REGS(regs) = old_pc;
# endif
#endif
        }
        db_clear_single_step(regs);

        *is_breakpoint = 0;

        if (db_run_mode == STEP_INVISIBLE) {
                db_run_mode = STEP_CONTINUE;
                return 0;       /* continue */
        }
        if (db_run_mode == STEP_COUNT) {
                return 0; /* 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);
                                db_printf("\n");
                        }
                        return 0;       /* continue */
                }
        }
        if (db_run_mode == STEP_RETURN) {
                db_expr_t ins = db_get_value(pc, sizeof(int), 0);

                /* 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);
                                        db_printf("\n");
                                }
                        }
                        if (inst_call(ins))
                                db_call_depth++;
                        return 0;       /* continue */
                }
        }
        if (db_run_mode == STEP_CALLT) {
                db_expr_t ins = db_get_value(pc, sizeof(int), 0);

                /* continue until call or return */

                if (!inst_call(ins) && !inst_return(ins) &&
                    !inst_trap_return(ins)) {
                        return 0;       /* continue */
                }
        }
        db_run_mode = STEP_NONE;
        return 1;
}

void
db_restart_at_pc(db_regs_t *regs, int watchpt)
{
        vaddr_t pc = PC_REGS(regs);

        if ((db_run_mode == STEP_COUNT) || (db_run_mode == STEP_RETURN) ||
            (db_run_mode == STEP_CALLT)) {
                db_expr_t       ins;

                /*
                 * We are about to execute this instruction,
                 * so count it now.
                 */
                ins = db_get_value(pc, sizeof(int), 0);
                db_inst_count++;
#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), 0);
                        db_inst_count++;
                }
#endif  /* SOFTWARE_SSTEP */
        }

        if (db_run_mode == STEP_CONTINUE) {
                if (watchpt || db_find_breakpoint(pc)) {
                        /*
                         * Step over breakpoint/watchpoint.
                         */
                        db_run_mode = STEP_INVISIBLE;
                        db_set_single_step(regs);
                } else {
                        db_set_breakpoints();
                        db_set_watchpoints();
                }
        } else if (db_run_mode != STEP_NONE) {
                db_set_single_step(regs);
        }
}

void
db_single_step(db_regs_t *regs)
{
        if (db_run_mode == STEP_CONTINUE) {
                db_run_mode = STEP_INVISIBLE;
                db_set_single_step(regs);
        }
}

/* single-step */
void
db_single_step_cmd(db_expr_t addr, int have_addr, db_expr_t count, char *modif)
{
        int     print = 0;

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

        if (modif[0] == 'p')
                print = 1;

        db_run_mode = STEP_ONCE;
        db_loop_count = count;
        db_sstep_print = print;
        db_inst_count = 0;

        db_cmd_loop_done = 1;
}

/* trace and print until call/return */
void
db_trace_until_call_cmd(db_expr_t addr, int have_addr, db_expr_t count,
    char *modif)
{
        int     print = 0;

        if (modif[0] == 'p')
                print = 1;

        db_run_mode = STEP_CALLT;
        db_sstep_print = print;
        db_inst_count = 0;

        db_cmd_loop_done = 1;
}

void
db_trace_until_matching_cmd(db_expr_t addr, int have_addr, db_expr_t count,
    char *modif)
{
        int     print = 0;

        if (modif[0] == 'p')
                print = 1;

        db_run_mode = STEP_RETURN;
        db_call_depth = 1;
        db_sstep_print = print;
        db_inst_count = 0;

        db_cmd_loop_done = 1;
}

/* continue */
void
db_continue_cmd(db_expr_t addr, int 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_cmd_loop_done = 1;
}

#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 int
 *      inst_branch(ins),       returns true if the instruction might branch
 * extern unsigned
 *      branch_taken(ins, pc, getreg_val, regs),
 *                              return the address the instruction might
 *                              branch to
 *      getreg_val(regs, reg),  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.
 */

void
db_set_single_step(db_regs_t *regs)
{
        vaddr_t pc = PC_REGS(regs);
#ifndef SOFTWARE_SSTEP_EMUL
        vaddr_t brpc;
        u_int inst;

        /*
         * User was stopped at pc, e.g. the instruction
         * at pc was not executed.
         */
        inst = db_get_value(pc, sizeof(int), 0);
        if (inst_branch(inst) || inst_call(inst) || inst_return(inst)) {
                brpc = branch_taken(inst, pc, getreg_val, regs);
                if (brpc != pc) {       /* self-branches are hopeless */
                        db_taken_bkpt = db_set_temp_breakpoint(brpc);
                }
#if 0
                /* XXX this seems like a true bug, no?  */
                pc = next_instr_address(pc, 1);
#endif
        }
#endif /*SOFTWARE_SSTEP_EMUL*/
        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_taken_bkpt != 0) {
                db_delete_temp_breakpoint(db_taken_bkpt);
                db_taken_bkpt = 0;
        }
        if (db_not_taken_bkpt != 0) {
                db_delete_temp_breakpoint(db_not_taken_bkpt);
                db_not_taken_bkpt = 0;
        }
}

#endif  /* SOFTWARE_SSTEP */