xnu-3789.70.16.tar.gz

[apple/xnu.git] / osfmk / i386 / asm64.h

diff --git a/osfmk/i386/asm64.h b/osfmk/i386/asm64.h
index a47fcf3699abc5d90d97f3d81491ce4fc62d5b56..b576f792d879756a50817262e23c84e608e330f4 100644 (file)
--- a/osfmk/i386/asm64.h
+++ b/osfmk/i386/asm64.h
@@ -1,56 +1,57 @@
 /*
- * Copyright (c) 2006 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 2006-2012 Apple Inc. All rights reserved.
  *
- * @APPLE_LICENSE_HEADER_START@
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
  * 
- * The contents of this file constitute Original Code as defined in and
- * are subject to the Apple Public Source License Version 1.1 (the
- * "License").  You may not use this file except in compliance with the
- * License.  Please obtain a copy of the License at
- * http://www.apple.com/publicsource and read it before using this file.
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. The rights granted to you under the License
+ * may not be used to create, or enable the creation or redistribution of,
+ * unlawful or unlicensed copies of an Apple operating system, or to
+ * circumvent, violate, or enable the circumvention or violation of, any
+ * terms of an Apple operating system software license agreement.
  * 
- * This Original Code and all software distributed under the License are
- * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this file.
+ * 
+ * The Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
- * License for the specific language governing rights and limitations
- * under the License.
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
+ * limitations under the License.
  * 
- * @APPLE_LICENSE_HEADER_END@
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  */
 
 /* Helper macros for 64-bit mode switching */
 
+
 /*
  * Long jump to 64-bit space from 32-bit compatibility mode.
+ * Effected, in fact, by a long return ..
+ *  - we push the 64-bit kernel code selector KERNEL64_CS
+ *  - call .+1 to get EIP on stack
+ *  - adjust return address after lret
+ *  - lret to return to next instruction but 64-bit mode.
  */
 #define        ENTER_64BIT_MODE()                      \
-       .code32                                 ;\
-       .byte   0xea    /* far jump longmode */ ;\
-       .long   1f                              ;\
-       .word   KERNEL64_CS                     ;\
-        .code64                                        ;\
-1:
-
-/*
- * Here in long mode but still running below 4G.
- * "Near" jump into uber-space.
- */
-#define        ENTER_UBERSPACE()                       \
-        mov     2f,%rax                                ;\
-        jmp     *%rax                          ;\
-2:      .long   3f                             ;\
-        .long   KERNEL_UBER_BASE_HI32          ;\
-3:     
+       push    $KERNEL64_CS                    ;\
+       call    1f                              ;\
+1:     addl    $(2f-1b), (%esp)                ;\
+       lret                                    ;\
+2:     .code64
 
 /*
  * Long jump to 32-bit compatibility mode from 64-bit space.
+ * Effected by long return similar to ENTER_64BIT_MODE.
  */
 #define ENTER_COMPAT_MODE()                    \
-       ljmp    *4f                             ;\
-4:     .long   5f                              ;\
-       .word   KERNEL_CS                       ;\
-       .code32                                 ;\
-5:
+       call    3f                              ;\
+3:     addq    $(4f-3b), (%rsp)                ;\
+       movl    $KERNEL32_CS, 4(%rsp)           ;\
+       lret                                    ;\
+4:     .code32