osfmk/i386/asm64.h

   1 /*
   2  * Copyright (c) 2006 Apple Computer, 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 #if __i386__
  32 /*
  33  * Long jump to 64-bit space from 32-bit compatibility mode.
  34  */
  35 #define ENTER_64BIT_MODE()                      \
  36         .code32                                 ;\
  37         .byte   0xea    /* far jump longmode */ ;\
  38         .long   1f                              ;\
  39         .word   KERNEL64_CS                     ;\
  40         .code64                                 ;\
  41 1:
  42
  43 /*
  44  * Here in long mode but still running below 4G.
  45  * "Near" jump into uber-space.
  46  */
  47 #define ENTER_UBERSPACE()                       \
  48         mov     2f,%rax                         ;\
  49         jmp     *%rax                           ;\
  50 2:      .long   3f                              ;\
  51         .long   KERNEL_UBER_BASE_HI32           ;\
  52 3:
  53
  54 /*
  55  * Long jump to 32-bit compatibility mode from 64-bit space.
  56  */
  57 #define ENTER_COMPAT_MODE()                     \
  58         ljmp    *(%rip)                         ;\
  59         .long   4f                              ;\
  60         .word   KERNEL32_CS                     ;\
  61         .code32                                 ;\
  62 4:
  63
  64 #else
  65
  66 /*
  67  * Long jump to 64-bit space from 32-bit compatibility mode.
  68  * Effected, in fact, by a long return ..
  69  *  - we push the 64-bit kernel code selector KERNEL64_CS
  70  *  - call .+1 to get EIP on stack
  71  *  - adjust return address after lret
  72  *  - lret to return to next instruction but 64-bit mode.
  73  */
  74 #define ENTER_64BIT_MODE()                      \
  75         push    $KERNEL64_CS                    ;\
  76         call    1f                              ;\
  77 1:      addl    $(2f-1b), (%esp)                ;\
  78         lret                                    ;\
  79 2:      .code64
  80
  81 /*
  82  * Long jump to 32-bit compatibility mode from 64-bit space.
  83  * Effected by long return similar to ENTER_64BIT_MODE.
  84  */
  85 #define ENTER_COMPAT_MODE()                     \
  86         call    3f                              ;\
  87 3:      addq    $(4f-3b), (%rsp)                ;\
  88         movl    $KERNEL32_CS, 4(%rsp)           ;\
  89         lret                                    ;\
  90 4:      .code32
  91
  92 #endif