diff options
Diffstat (limited to 'MdePkg/Library/BaseLib/X64/DisablePaging64.S')
| -rw-r--r-- | MdePkg/Library/BaseLib/X64/DisablePaging64.S | 82 |
1 files changed, 82 insertions, 0 deletions
diff --git a/MdePkg/Library/BaseLib/X64/DisablePaging64.S b/MdePkg/Library/BaseLib/X64/DisablePaging64.S new file mode 100644 index 000000000000..66d57f68bd74 --- /dev/null +++ b/MdePkg/Library/BaseLib/X64/DisablePaging64.S @@ -0,0 +1,82 @@ +#------------------------------------------------------------------------------ +# +# Copyright (c) 2006 - 2009, Intel Corporation. All rights reserved.<BR> +# 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 UINT32 EntryPoint, +# IN UINT32 Context1, OPTIONAL +# IN UINT32 Context2, OPTIONAL +# IN UINT32 NewStack +# ); +#------------------------------------------------------------------------------ + +ASM_GLOBAL ASM_PFX(InternalX86DisablePaging64) +ASM_PFX(InternalX86DisablePaging64): + cli + lea L1(%rip), %rsi # rsi <- The start address of transition code + mov 0x28(%rsp), %edi # rdi <- New stack + lea _mTransitionEnd(%rip), %rax # rax <- end of transition code + sub %rsi, %rax # rax <- The size of transition piece code + add $4, %rax # round rax up to the next 4 byte boundary + and $0xfc, %al + sub %rax, %rdi # rdi <- use stack to hold transition code + mov %edi, %r10d # r10 <- The start address of transicition code below 4G + push %rcx # save rcx to stack + mov %rax, %rcx # rcx <- The size of transition piece code + rep + movsb # copy transition code to (new stack - 64byte) below 4G + pop %rcx # restore rcx + + mov %r8d, %esi + mov %r9d, %edi + mov %r10d, %eax + sub $4, %eax + push %rcx # push Cs to stack + push %r10 # push address of transition code on stack + .byte 0x48, 0xcb # retq: Use far return to load CS register from stack + # (Use raw byte code since some GNU assemblers generates incorrect code for "retq") +L1: + mov %eax,%esp # set up new stack + mov %cr0,%rax + btr $0x1f,%eax # clear CR0.PG + mov %rax,%cr0 # disable paging + + mov %edx,%ebx # save EntryPoint to ebx, for rdmsr will overwrite edx + 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 *%rbx # transfer control to EntryPoint + jmp . # no one should get here + +_mTransitionEnd : |