summaryrefslogtreecommitdiffstats
path: root/OvmfPkg/ResetVector/Main.asm
blob: 46cfa87c4c0a248d3bc6af11c17c4e071cb5a31c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
;------------------------------------------------------------------------------
; @file
; Main routine of the pre-SEC code up through the jump into SEC
;
; Copyright (c) 2008 - 2009, Intel Corporation. All rights reserved.<BR>
; SPDX-License-Identifier: BSD-2-Clause-Patent
;
;------------------------------------------------------------------------------


BITS    16

;
; Modified:  EBX, ECX, EDX, EBP
;
; @param[in,out]  RAX/EAX  Initial value of the EAX register
;                          (BIST: Built-in Self Test)
; @param[in,out]  DI       'BP': boot-strap processor, or
;                          'AP': application processor
; @param[out]     RBP/EBP  Address of Boot Firmware Volume (BFV)
; @param[out]     DS       Selector allowing flat access to all addresses
; @param[out]     ES       Selector allowing flat access to all addresses
; @param[out]     FS       Selector allowing flat access to all addresses
; @param[out]     GS       Selector allowing flat access to all addresses
; @param[out]     SS       Selector allowing flat access to all addresses
;
; @return         None  This routine jumps to SEC and does not return
;
Main16:
    OneTimeCall EarlyInit16

    ;
    ; Transition the processor from 16-bit real mode to 32-bit flat mode
    ;
    OneTimeCall TransitionFromReal16To32BitFlat

BITS    32

    ; Clear the WorkArea header. The SEV probe routines will populate the
    ; work area when detected.
    mov     byte[WORK_AREA_GUEST_TYPE], 0

%ifdef ARCH_X64

    jmp SearchBfv

;
; Entry point of Main32
;
Main32:
    OneTimeCall InitTdx

SearchBfv:

%endif

    ;
    ; Search for the Boot Firmware Volume (BFV)
    ;
    OneTimeCall Flat32SearchForBfvBase

    ;
    ; EBP - Start of BFV
    ;

    ;
    ; Search for the SEC entry point
    ;
    OneTimeCall Flat32SearchForSecEntryPoint

    ;
    ; ESI - SEC Core entry point
    ; EBP - Start of BFV
    ;

%ifdef ARCH_IA32

    ;
    ; SEV support can be built and run using the Ia32/X64 split environment.
    ; Set the OVMF/SEV work area as appropriate.
    ;
    OneTimeCall CheckSevFeatures

    ;
    ; Restore initial EAX value into the EAX register
    ;
    mov     eax, esp

    ;
    ; Jump to the 32-bit SEC entry point
    ;
    jmp     esi

%else

    ;
    ; Transition the processor from 32-bit flat mode to 64-bit flat mode
    ;
    OneTimeCall Transition32FlatTo64Flat

BITS    64

    ;
    ; Some values were calculated in 32-bit mode.  Make sure the upper
    ; 32-bits of 64-bit registers are zero for these values.
    ;
    mov     rax, 0x00000000ffffffff
    and     rsi, rax
    and     rbp, rax
    and     rsp, rax

    ;
    ; RSI - SEC Core entry point
    ; RBP - Start of BFV
    ;

    ;
    ; Restore initial EAX value into the RAX register
    ;
    mov     rax, rsp

    ;
    ; Jump to the 64-bit SEC entry point
    ;
    jmp     rsi

%endif