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UefiCpuPkg/PiSmmCpuDxeSmm: update comments in IA32 SmmStartup()
[mirror_edk2.git] / UefiCpuPkg / PiSmmCpuDxeSmm / Ia32 / SmmInit.nasm
1 ;------------------------------------------------------------------------------ ;
2 ; Copyright (c) 2016 - 2018, Intel Corporation. All rights reserved.<BR>
3 ; This program and the accompanying materials
4 ; are licensed and made available under the terms and conditions of the BSD License
5 ; which accompanies this distribution. The full text of the license may be found at
6 ; http://opensource.org/licenses/bsd-license.php.
7 ;
8 ; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
9 ; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
10 ;
11 ; Module Name:
12 ;
13 ; SmmInit.nasm
14 ;
15 ; Abstract:
16 ;
17 ; Functions for relocating SMBASE's for all processors
18 ;
19 ;-------------------------------------------------------------------------------
20
21 extern ASM_PFX(SmmInitHandler)
22 extern ASM_PFX(mRebasedFlag)
23 extern ASM_PFX(mSmmRelocationOriginalAddress)
24
25 global ASM_PFX(gSmmCr3)
26 global ASM_PFX(gSmmCr4)
27 global ASM_PFX(gSmmCr0)
28 global ASM_PFX(gSmmJmpAddr)
29 global ASM_PFX(gSmmInitStack)
30 global ASM_PFX(gcSmiInitGdtr)
31 global ASM_PFX(gcSmmInitSize)
32 global ASM_PFX(gcSmmInitTemplate)
33
34 %define PROTECT_MODE_CS 0x8
35 %define PROTECT_MODE_DS 0x20
36
37 SECTION .text
38
39 ASM_PFX(gcSmiInitGdtr):
40 DW 0
41 DQ 0
42
43 global ASM_PFX(SmmStartup)
44 ASM_PFX(SmmStartup):
45 DB 0x66
46 mov eax, 0x80000001 ; read capability
47 cpuid
48 DB 0x66
49 mov ebx, edx ; rdmsr will change edx. keep it in ebx.
50 DB 0x66, 0xb8 ; mov eax, imm32
51 ASM_PFX(gSmmCr3): DD 0
52 mov cr3, eax
53 DB 0x67, 0x66
54 lgdt [cs:ebp + (ASM_PFX(gcSmiInitGdtr) - ASM_PFX(SmmStartup))]
55 DB 0x66, 0xb8 ; mov eax, imm32
56 ASM_PFX(gSmmCr4): DD 0
57 mov cr4, eax
58 DB 0x66
59 mov ecx, 0xc0000080 ; IA32_EFER MSR
60 rdmsr
61 DB 0x66
62 test ebx, BIT20 ; check NXE capability
63 jz .1
64 or ah, BIT3 ; set NXE bit
65 wrmsr
66 .1:
67 DB 0x66, 0xb8 ; mov eax, imm32
68 ASM_PFX(gSmmCr0): DD 0
69 DB 0xbf, PROTECT_MODE_DS, 0 ; mov di, PROTECT_MODE_DS
70 mov cr0, eax
71 DB 0x66, 0xea ; jmp far [ptr48]
72 ASM_PFX(gSmmJmpAddr):
73 DD @32bit
74 DW PROTECT_MODE_CS
75 @32bit:
76 mov ds, edi
77 mov es, edi
78 mov fs, edi
79 mov gs, edi
80 mov ss, edi
81 DB 0xbc ; mov esp, imm32
82 ASM_PFX(gSmmInitStack): DD 0
83 call ASM_PFX(SmmInitHandler)
84 rsm
85
86 BITS 16
87 ASM_PFX(gcSmmInitTemplate):
88 mov ebp, ASM_PFX(SmmStartup)
89 sub ebp, 0x30000
90 jmp ebp
91
92 ASM_PFX(gcSmmInitSize): DW $ - ASM_PFX(gcSmmInitTemplate)
93
94 BITS 32
95 global ASM_PFX(SmmRelocationSemaphoreComplete)
96 ASM_PFX(SmmRelocationSemaphoreComplete):
97 push eax
98 mov eax, [ASM_PFX(mRebasedFlag)]
99 mov byte [eax], 1
100 pop eax
101 jmp [ASM_PFX(mSmmRelocationOriginalAddress)]
102
103 global ASM_PFX(PiSmmCpuSmmInitFixupAddress)
104 ASM_PFX(PiSmmCpuSmmInitFixupAddress):
105 ret