xnu-792.10.96.tar.gz

[apple/xnu.git] / osfmk / ddb / db_run.c

/*
 * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * The contents of this file constitute Original Code as defined in and
 * are subject to the Apple Public Source License Version 1.1 (the
 * "License").  You may not use this file except in compliance with the
 * License.  Please obtain a copy of the License at
 * http://www.apple.com/publicsource and read it before using this file.
 * 
 * This Original Code and all software distributed under the License are
 * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
 * License for the specific language governing rights and limitations
 * under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
/*
 * @OSF_COPYRIGHT@
 */
/* 
 * 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 "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 <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_cond.h>
#include <ddb/db_examine.h>
#include <ddb/db_output.h>              /* For db_printf() */
#include <ddb/db_watch.h>
#include <kern/misc_protos.h>
#include <kern/debug.h>

#include <IOKit/IOPlatformExpert.h>

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;
int             db_max_inst_count = 1000;

#ifndef db_set_single_step
void db_set_task_single_step(
        register db_regs_t      *regs,
        task_t                  task);
#else
#define db_set_task_single_step(regs,task)      db_set_single_step(regs)
#endif
#ifndef db_clear_single_step
void db_clear_task_single_step(
        db_regs_t       *regs,
        task_t          task);
#else
#define db_clear_task_single_step(regs,task)    db_clear_single_step(regs)
#endif

extern jmp_buf_t *db_recover;
boolean_t db_step_again(void);

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

        db_clear_task_single_step(DDB_REGS, space);
        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_thread_breakpoint_here(space, 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) {
            jmp_buf_t *prev;
            jmp_buf_t db_jmpbuf;
            /* WARNING: the following assumes an instruction fits an int */
            db_expr_t ins = db_get_task_value(pc, sizeof(int), FALSE, space);

            /* continue until matching return */

            prev = db_recover;
            if (_setjmp(db_recover = &db_jmpbuf) == 0) {
                if (!inst_trap_return(ins) &&
                    (!inst_return(ins) || --db_call_depth != 0)) {
                        if (db_sstep_print) {
                            if (inst_call(ins) || inst_return(ins)) {
                                register 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++;
                        db_recover = prev;
                        if (db_step_again())
                                return (FALSE); /* continue */
                }
            }
            db_recover = prev;
        }
        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, space);

            /* continue until call or return */

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

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

        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_task_value(pc, sizeof(int), FALSE, task);
            db_inst_count++;
            db_load_count += db_inst_load(ins);
            db_store_count += db_inst_store(ins);
#ifdef  SOFTWARE_SSTEP
            /* 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) */
                ins = db_get_task_value(brpc, sizeof(int), FALSE, task);
                db_inst_count++;
                db_load_count += db_inst_load(ins);
                db_store_count += db_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);
        }
}

/*
 * 'n' and 'u' commands might never return.
 * Limit the maximum number of steps.
 */

boolean_t
db_step_again(void)
{
        if (db_inst_count && !(db_inst_count%db_max_inst_count)) {
                char c;
                db_printf("%d instructions, continue ? (y/n) ",
                          db_inst_count);
                c = cngetc();
                db_printf("\n");
                if(c == 'n')
                        return(FALSE);
        }
        return(TRUE);
}

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
db_find_temp_breakpoint(
        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(
        register db_regs_t      *regs,
        task_t                  task)
{
        db_addr_t pc = PC_REGS(regs), brpc;
        register unsigned int    inst;
        register 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();      /* XXX -- need prototype! */

            brpc = branch_taken(inst, pc, getreg_val, (unsigned char*)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);
        } else 
            pc = next_instr_address(pc,0,task);
        
        /* 
         * check if this control flow instruction is an
         * unconditional transfer
         */

        unconditional = inst_unconditional_flow_transfer(inst);

        /* 
          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_taken_bkpt == 0 || db_taken_bkpt->address != pc)) {
                db_not_taken_bkpt = db_set_temp_breakpoint(task, pc);
        } else
                db_not_taken_bkpt = 0;
}

void
db_clear_task_single_step(
        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 */
void
db_single_step_cmd(
        db_expr_t       addr,
        int             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_last_inst_count = 0;
        db_load_count = 0;
        db_store_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)
{
        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;
}

void
db_trace_until_matching_cmd(
        db_expr_t       addr,
        int             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_last_inst_count = 0;
        db_load_count = 0;
        db_store_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)
{
        /*
         * Though "cont/c" works fairly well, it's not really robust
         * enough to use in arbitrary situations, so disable it.
         * (Doesn't seem cost-effective to debug and fix what ails
         * it.)
         */
#if 0
        if (modif[0] == 'c')
            db_run_mode = STEP_COUNT;
        else
            db_run_mode = STEP_CONTINUE;
#else
        db_run_mode = STEP_CONTINUE;
#endif
        db_inst_count = 0;
        db_last_inst_count = 0;
        db_load_count = 0;
        db_store_count = 0;

        db_cmd_loop_done = 1;
}


/*
 * Switch to gdb
 */
void
db_to_gdb(
        void)
{
        extern unsigned int switch_debugger;

        switch_debugger=1;
}

/* gdb */
void    
db_continue_gdb(
        db_expr_t       addr, 
        int             have_addr,
        db_expr_t       count,   
        char *          modif)
{
        db_to_gdb();
        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);
}