sys/ddb/db_watch.c

/*
 * 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.
 *
 *      $Id: db_watch.c,v 1.2 1993/10/16 16:47:32 rgrimes Exp $
 */

/*
 *      Author: Richard P. Draves, Carnegie Mellon University
 *      Date:   10/90
 */

#include "param.h"
#include "systm.h"
#include "proc.h"
#include "ddb/ddb.h"

#include <vm/vm_map.h>
#include <ddb/db_lex.h>
#include <ddb/db_watch.h>
#include <ddb/db_access.h>
#include <ddb/db_sym.h>

/*
 * Watchpoints.
 */

extern boolean_t db_map_equal();
extern boolean_t db_map_current();
extern vm_map_t db_map_addr();

boolean_t       db_watchpoints_inserted = TRUE;

#define NWATCHPOINTS    100
struct db_watchpoint    db_watch_table[NWATCHPOINTS];
db_watchpoint_t         db_next_free_watchpoint = &db_watch_table[0];
db_watchpoint_t         db_free_watchpoints = 0;
db_watchpoint_t         db_watchpoint_list = 0;

db_watchpoint_t
db_watchpoint_alloc()
{
        register db_watchpoint_t        watch;

        if ((watch = db_free_watchpoints) != 0) {
            db_free_watchpoints = watch->link;
            return (watch);
        }
        if (db_next_free_watchpoint == &db_watch_table[NWATCHPOINTS]) {
            db_printf("All watchpoints used.\n");
            return (0);
        }
        watch = db_next_free_watchpoint;
        db_next_free_watchpoint++;

        return (watch);
}

void
db_watchpoint_free(watch)
        register db_watchpoint_t        watch;
{
        watch->link = db_free_watchpoints;
        db_free_watchpoints = watch;
}

void
db_set_watchpoint(map, addr, size)
        vm_map_t        map;
        db_addr_t       addr;
        vm_size_t       size;
{
        register db_watchpoint_t        watch;

        if (map == NULL) {
            db_printf("No map.\n");
            return;
        }

        /*
         *      Should we do anything fancy with overlapping regions?
         */

        for (watch = db_watchpoint_list;
             watch != 0;
             watch = watch->link)
            if (db_map_equal(watch->map, map) &&
                (watch->loaddr == addr) &&
                (watch->hiaddr == addr+size)) {
                db_printf("Already set.\n");
                return;
            }

        watch = db_watchpoint_alloc();
        if (watch == 0) {
            db_printf("Too many watchpoints.\n");
            return;
        }

        watch->map = map;
        watch->loaddr = addr;
        watch->hiaddr = addr+size;

        watch->link = db_watchpoint_list;
        db_watchpoint_list = watch;

        db_watchpoints_inserted = FALSE;
}

void
db_delete_watchpoint(map, addr)
        vm_map_t        map;
        db_addr_t       addr;
{
        register db_watchpoint_t        watch;
        register db_watchpoint_t        *prev;

        for (prev = &db_watchpoint_list;
             (watch = *prev) != 0;
             prev = &watch->link)
            if (db_map_equal(watch->map, map) &&
                (watch->loaddr <= addr) &&
                (addr < watch->hiaddr)) {
                *prev = watch->link;
                db_watchpoint_free(watch);
                return;
            }

        db_printf("Not set.\n");
}

void
db_list_watchpoints()
{
        register db_watchpoint_t        watch;

        if (db_watchpoint_list == 0) {
            db_printf("No watchpoints set\n");
            return;
        }

        db_printf(" Map        Address  Size\n");
        for (watch = db_watchpoint_list;
             watch != 0;
             watch = watch->link)
            db_printf("%s%8x  %8x  %x\n",
                      db_map_current(watch->map) ? "*" : " ",
                      watch->map, watch->loaddr,
                      watch->hiaddr - watch->loaddr);
}

/* Delete watchpoint */
/*ARGSUSED*/
void
db_deletewatch_cmd(addr, have_addr, count, modif)
        db_expr_t       addr;
        int             have_addr;
        db_expr_t       count;
        char *          modif;
{
        db_delete_watchpoint(db_map_addr(addr), addr);
}

/* Set watchpoint */
/*ARGSUSED*/
void
db_watchpoint_cmd(addr, have_addr, count, modif)
        db_expr_t       addr;
        int             have_addr;
        db_expr_t       count;
        char *          modif;
{
        vm_size_t       size;
        db_expr_t       value;

        if (db_expression(&value))
            size = (vm_size_t) value;
        else
            size = 4;
        db_skip_to_eol();

        db_set_watchpoint(db_map_addr(addr), addr, size);
}

/* list watchpoints */
void
db_listwatch_cmd(db_expr_t dummy1, int dummy2, db_expr_t dummy3, char *dummmy4)
{
        db_list_watchpoints();
}

void
db_set_watchpoints()
{
        register db_watchpoint_t        watch;

        if (!db_watchpoints_inserted) {
            for (watch = db_watchpoint_list;
                 watch != 0;
                 watch = watch->link)
                pmap_protect(watch->map->pmap,
                             trunc_page(watch->loaddr),
                             round_page(watch->hiaddr),
                             VM_PROT_READ);

            db_watchpoints_inserted = TRUE;
        }
}

void
db_clear_watchpoints()
{
        db_watchpoints_inserted = FALSE;
}

boolean_t
db_find_watchpoint(map, addr, regs)
        vm_map_t        map;
        db_addr_t       addr;
        db_regs_t       *regs;
{
        register db_watchpoint_t watch;
        db_watchpoint_t found = 0;

        for (watch = db_watchpoint_list;
             watch != 0;
             watch = watch->link)
            if (db_map_equal(watch->map, map)) {
                if ((watch->loaddr <= addr) &&
                    (addr < watch->hiaddr))
                    return (TRUE);
                else if ((trunc_page(watch->loaddr) <= addr) &&
                         (addr < round_page(watch->hiaddr)))
                    found = watch;
            }

        /*
         *      We didn't hit exactly on a watchpoint, but we are
         *      in a protected region.  We want to single-step
         *      and then re-protect.
         */

        if (found) {
            db_watchpoints_inserted = FALSE;
            db_single_step(regs);
        }

        return (FALSE);
}