/*      $NetBSD: db_access.c,v 1.28 2026/02/25 05:34:42 skrll Exp $     */

/*
 * 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 the
 * rights to redistribute these changes.
 *
 *      Author: David B. Golub, Carnegie Mellon University
 *      Date:   7/90
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: db_access.c,v 1.28 2026/02/25 05:34:42 skrll Exp $");

#if defined(_KERNEL_OPT)
#include "opt_kgdb.h"
#endif

#include <sys/param.h>
#include <sys/proc.h>
#include <sys/endian.h>

#include <ddb/ddb.h>

/*
 * Access unaligned data items on aligned (longword)
 * boundaries.
 *
 * This file is shared by ddb, kgdb and crash(8).
 */

#if defined(DDB) || !defined(DDB) && !defined(KGDB)
#define _COMPILE_THIS
#endif

#if defined(_COMPILE_THIS) || defined(KGDB) && defined(SOFTWARE_SSTEP)

db_expr_t
db_get_value(db_addr_t addr, size_t size, bool is_signed)
{
        char data[sizeof(db_expr_t)] __aligned(sizeof(db_expr_t));
        uintmax_t uvalue;
        db_expr_t value;
        size_t i;

        db_read_bytes(addr, size, data);

        uvalue = 0;
#if BYTE_ORDER == LITTLE_ENDIAN
        for (i = size; i-- > 0;)
#else /* BYTE_ORDER == BIG_ENDIAN */
        for (i = 0; i < size; i++)
#endif /* BYTE_ORDER */
                uvalue = (uvalue << 8) + (data[i] & 0xFF);

        value = (db_expr_t)uvalue;

        if (size < sizeof(db_expr_t) && is_signed
            && (value & ((db_expr_t)1 << (8*size - 1)))) {
                value |= (unsigned long)~(db_expr_t)0 << (8*size - 1);
        }
        return (value);
}

#if defined DDB || defined _KMEMUSER
quad_t
db_get_qvalue(db_addr_t addr, size_t size, bool is_signed)
{
        uint64_t data;

        if (size < sizeof(uint64_t)) {
                if (is_signed)
                        return db_get_value(addr, size, true);
                return (uint32_t)db_get_value(addr, size, false);
        }

        if (size != sizeof(data)) {
                db_error("unsupported size\n");
                /*NOTREACHED*/
        }

        db_read_bytes(addr, sizeof(data), (char *)&data);
        return data;
}
#endif

void
db_put_value(db_addr_t addr, size_t size, db_expr_t value)
{
        char data[sizeof(db_expr_t)] __aligned(sizeof(db_expr_t));
        size_t i;

#if BYTE_ORDER == LITTLE_ENDIAN
        for (i = 0; i < size; i++)
#else /* BYTE_ORDER == BIG_ENDIAN */
        for (i = size; i-- > 0;)
#endif /* BYTE_ORDER */
        {
                data[i] = value & 0xFF;
                value >>= 8;
        }

        db_write_bytes(addr, size, data);
}

#endif  /* _COMPILE_THIS || KGDB && SOFTWARE_SSTEP */

#ifdef  _COMPILE_THIS

void *
db_read_ptr(const char *name)
{
        db_expr_t val;
        void *p;

        if (!db_value_of_name(name, &val)) {
                db_printf("db_read_ptr: cannot find `%s'\n", name);
                db_error(NULL);
                /* NOTREACHED */
        }
        db_read_bytes((db_addr_t)val, sizeof(p), (char *)&p);
        return p;
}

int
db_read_int(const char *name)
{
        db_expr_t val;
        int p;

        if (!db_value_of_name(name, &val)) {
                db_printf("db_read_int: cannot find `%s'\n", name);
                db_error(NULL);
                /* NOTREACHED */
        }
        db_read_bytes((db_addr_t)val, sizeof(p), (char *)&p);
        return p;
}

#endif  /* _COMPILE_THIS */