/*      $NetBSD: db_access.c,v 1.27 2023/09/01 10:55:23 andvar 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  [email protected]
*  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 1.27 2023/09/01 10:55:23 andvar 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);
}

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;
}

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 */