MdePkg BaseLib: Convert X64/DisablePaging64.asm to NASM

[mirror_edk2.git] / MdePkg / Library / BaseLib / X64 / DisablePaging64.nasm

diff --git a/MdePkg/Library/BaseLib/X64/DisablePaging64.nasm b/MdePkg/Library/BaseLib/X64/DisablePaging64.nasm
new file mode 100644 (file)
index 0000000..144176b
--- /dev/null
+++ b/MdePkg/Library/BaseLib/X64/DisablePaging64.nasm
@@ -0,0 +1,84 @@
+;------------------------------------------------------------------------------\r
+;\r
+; Copyright (c) 2006 - 2008, Intel Corporation. All rights reserved.<BR>\r
+; 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.Asm\r
+;\r
+; Abstract:\r
+;\r
+;   AsmDisablePaging64 function\r
+;\r
+; Notes:\r
+;\r
+;------------------------------------------------------------------------------\r
+\r
+    DEFAULT REL\r
+    SECTION .text\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
+global ASM_PFX(InternalX86DisablePaging64)\r
+ASM_PFX(InternalX86DisablePaging64):\r
+    cli\r
+    lea     rsi, [.0]                     ; rsi <- The start address of transition code\r
+    mov     edi, [rsp + 0x28]            ; rdi <- New stack\r
+    lea     rax, [mTransitionEnd]         ; rax <- end of transition code\r
+    sub     rax, rsi                    ; rax <- The size of transition piece code\r
+    add     rax, 4                      ; Round RAX up to the next 4 byte boundary\r
+    and     al, 0xfc\r
+    sub     rdi, rax                    ; rdi <- Use stack to hold transition code\r
+    mov     r10d, edi                   ; r10 <- The start address of transicition code below 4G\r
+    push    rcx                         ; save rcx to stack\r
+    mov     rcx, rax                    ; rcx <- The size of transition piece code\r
+    rep     movsb                       ; copy transition code to top of new stack which must be below 4GB\r
+    pop     rcx                         ; restore rcx\r
+\r
+    mov     esi, r8d\r
+    mov     edi, r9d\r
+    mov     eax, r10d                   ; eax <- start of the transition code on the stack\r
+    sub     eax, 4                      ; eax <- One slot below transition code on the stack\r
+    push    rcx                         ; push Cs to stack\r
+    push    r10                         ; push address of tansition code on stack\r
+    DB      0x48                         ; prefix to composite "retq" with next "retf"\r
+    retf                                ; Use far return to load CS register from stack\r
+\r
+; Start of transition code\r
+.0:\r
+    mov     esp, eax                    ; set up new stack\r
+    mov     rax, cr0\r
+    btr     eax, 31                     ; Clear CR0.PG\r
+    mov     cr0, rax                    ; disable paging and caches\r
+\r
+    mov     ebx, edx                    ; save EntryPoint to rbx, for rdmsr will overwrite rdx\r
+    mov     ecx, 0xc0000080\r
+    rdmsr\r
+    and     ah, ~ 1                   ; clear LME\r
+    wrmsr\r
+    mov     rax, cr4\r
+    and     al, ~ (1 << 5)           ; clear PAE\r
+    mov     cr4, rax\r
+    push    rdi                         ; push Context2\r
+    push    rsi                         ; push Context1\r
+    call    rbx                         ; transfer control to EntryPoint\r
+    hlt                                 ; no one should get here\r
+\r
+mTransitionEnd:\r
+\r