osfmk/i386/asm64.h

   1 /*
   2  * Copyright (c) 2006-2012 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28
  29 /* Helper macros for 64-bit mode switching */
  30
  31
  32 /*
  33  * Long jump to 64-bit space from 32-bit compatibility mode.
  34  * Effected, in fact, by a long return ..
  35  *  - we push the 64-bit kernel code selector KERNEL64_CS
  36  *  - call .+1 to get EIP on stack
  37  *  - adjust return address after lret
  38  *  - lret to return to next instruction but 64-bit mode.
  39  */
  40 #define ENTER_64BIT_MODE()                      \
  41         push    $KERNEL64_CS                    ;\
  42         call    1f                              ;\
  43 1:      addl    $(2f-1b), (%esp)                ;\
  44         lret                                    ;\
  45 2:      .code64
  46
  47 /*
  48  * Long jump to 32-bit compatibility mode from 64-bit space.
  49  * Effected by long return similar to ENTER_64BIT_MODE.
  50  */
  51 #define ENTER_COMPAT_MODE()                     \
  52         call    3f                              ;\
  53 3:      addq    $(4f-3b), (%rsp)                ;\
  54         movl    $KERNEL32_CS, 4(%rsp)           ;\
  55         lret                                    ;\
  56 4:      .code32
  57