X-Git-Url: https://git.saurik.com/apple/xnu.git/blobdiff_plain/89b3af67bb32e691275bf6fa803d1834b2284115..4d15aeb193b2c68f1d38666c317f8d3734f5f083:/osfmk/i386/asm64.h

diff --git a/osfmk/i386/asm64.h b/osfmk/i386/asm64.h
index bb1a51c0b..b576f792d 100644
--- a/osfmk/i386/asm64.h
+++ b/osfmk/i386/asm64.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2006 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 2006-2012 Apple Inc. All rights reserved.
  *
  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
  * 
@@ -28,35 +28,30 @@
 
 /* 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