-#------------------------------------------------------------------------------
-#
-# Copyright (c) 2006 - 2008, Intel Corporation
-# All rights reserved. This program and the accompanying materials
-# are licensed and made available under the terms and conditions of the BSD License
-# which accompanies this distribution. The full text of the license may be found at
-# http://opensource.org/licenses/bsd-license.php
-#
-# THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
-# WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
-#
-# Module Name:
-#
-# DisablePaging64.S
-#
-# Abstract:
-#
-# AsmDisablePaging64 function
-#
-# Notes:
-#
-#------------------------------------------------------------------------------
-
-
-
-#------------------------------------------------------------------------------
-# VOID
-# EFIAPI
-# InternalX86DisablePaging64 (
-# IN UINT16 Cs,
-# IN UINT64 EntryPoint,
-# IN UINT64 Context1, OPTIONAL
-# IN UINT32 Context2, OPTIONAL
-# IN UINT64 NewStack
-# );
-#------------------------------------------------------------------------------
-
-.global ASM_PFX(InternalX86DisablePaging64)
-ASM_PFX(InternalX86DisablePaging64):
- cli
- shl $0x20,%rcx # rcx[32..47] <- Cs
- lea L1, %eax
+#------------------------------------------------------------------------------\r
+#\r
+# Copyright (c) 2006 - 2009, Intel Corporation\r
+# All rights reserved. This program and the accompanying materials\r
+# are licensed and made available under the terms and conditions of the BSD License\r
+# which accompanies this distribution. The full text of the license may be found at\r
+# http://opensource.org/licenses/bsd-license.php\r
+#\r
+# THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
+# WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
+#\r
+# Module Name:\r
+#\r
+# DisablePaging64.S\r
+#\r
+# Abstract:\r
+#\r
+# AsmDisablePaging64 function\r
+#\r
+# Notes:\r
+#\r
+#------------------------------------------------------------------------------\r
+\r
+ \r
+\r
+#------------------------------------------------------------------------------\r
+# VOID\r
+# EFIAPI\r
+# InternalX86DisablePaging64 (\r
+# IN UINT16 Cs,\r
+# IN UINT32 EntryPoint,\r
+# IN UINT32 Context1, OPTIONAL\r
+# IN UINT32 Context2, OPTIONAL\r
+# IN UINT32 NewStack\r
+# );\r
+#------------------------------------------------------------------------------\r
+\r
+ASM_GLOBAL ASM_PFX(InternalX86DisablePaging64)\r
+ASM_PFX(InternalX86DisablePaging64):\r
+ cli \r
+ lea L1(%rip), %rsi # rsi <- The start address of transition code\r
+ mov 0x28(%rsp), %edi # rdi <- New stack\r
+ sub $64, %edi # rdi <- use 64 byte in stack to hold transition code \r
+ mov %edi, %r10d # r10 <- The start address of transicition code below 4G\r
+ lea _mTransitionEnd(%rip), %rax # rax <- end of transition code\r
+ sub %rsi, %rax # rax <- The size of transition piece code\r
+ push %rcx # save rcx to stack\r
+ mov %rax, %rcx # rcx <- The size of transition piece code\r
+ rep\r
+ movsb # copy transition code to (new stack - 64byte) below 4G\r
+ pop %rcx # restore rcx\r
+ \r
mov %r8d, %esi \r
- or %rax, %rcx # rcx[0..47] <- Cs:@F\r
mov %r9d, %edi \r
mov 0x28(%rsp), %eax # eax <- New Stack\r
- push %rcx\r
- ret # switch to compatibility mode\r
-L1:
- mov %eax,%esp # set up new stack
- mov %cr0,%rax
- btr $0x1f,%eax
- mov %rax,%cr0 # disable paging
- mov $0xc0000080,%ecx
- rdmsr
- and $0xfe,%ah # clear LME
- wrmsr
- mov %cr4,%rax
- and $0xdf,%al # clear PAE
- mov %rax,%cr4
- push %rdi # push Context2
- push %rsi # push Context1
- callq *%rdx # transfer control to EntryPoint
- jmp . # no one should get here
-
+ push %rcx # push Cs to stack\r
+ push %r10\r
+ .byte 0x48, 0xcb # retq: Use far return to load CS register from stack\r
+ # (Use raw byte code since some GNU assemblers generates incorrect code for "retq") \r
+L1:\r
+ mov %eax,%esp # set up new stack\r
+ mov %cr0,%rax\r
+ btr $0x1f,%eax\r
+ mov %rax,%cr0 # disable paging\r
+\r
+ mov %rdx,%rbx # save EntryPoint to rbx, for rdmsr will overwrite rdx\r
+ mov $0xc0000080,%ecx\r
+ rdmsr \r
+ and $0xfe,%ah # clear LME\r
+ wrmsr \r
+ mov %cr4,%rax\r
+ and $0xdf,%al # clear PAE\r
+ mov %rax,%cr4\r
+ push %rdi # push Context2\r
+ push %rsi # push Context1\r
+ callq *%rbx # transfer control to EntryPoint\r
+ jmp . # no one should get here\r
+\r_mTransitionEnd :\r