projects / mirror_edk2.git / blame
| Commit | Line | Data |
|---|---|---|
| c05de360 AP |
1 | ;------------------------------------------------------------------------------\r |
| 2 | ; @file\r | |
| 3 | ; Transition from 16 bit real mode into 32 bit flat protected mode\r | |
| 4 | ;\r | |
| 5 | ; Copyright (c) 2008 - 2010, Intel Corporation. All rights reserved.<BR>\r | |
| 6 | ; Copyright (c) 2019, Citrix Systems, Inc.\r | |
| 7 | ; SPDX-License-Identifier: BSD-2-Clause-Patent\r | |
| 8 | ;\r | |
| 9 | ;------------------------------------------------------------------------------\r | |
| 10 | \r | |
| 11 | %define SEC_DEFAULT_CR0 0x00000023\r | |
| 12 | %define SEC_DEFAULT_CR4 0x640\r | |
| 13 | \r | |
| 14 | BITS 16\r | |
| 15 | \r | |
| 16 | ;\r | |
| 17 | ; Modified: EAX, EBX\r | |
| 18 | ;\r | |
| 19 | ; @param[out] DS Selector allowing flat access to all addresses\r | |
| 20 | ; @param[out] ES Selector allowing flat access to all addresses\r | |
| 21 | ; @param[out] FS Selector allowing flat access to all addresses\r | |
| 22 | ; @param[out] GS Selector allowing flat access to all addresses\r | |
| 23 | ; @param[out] SS Selector allowing flat access to all addresses\r | |
| 24 | ;\r | |
| 25 | TransitionFromReal16To32BitFlat:\r | |
| 26 | \r | |
| 27 | debugShowPostCode POSTCODE_16BIT_MODE\r | |
| 28 | \r | |
| 29 | cli\r | |
| 30 | \r | |
| 31 | mov bx, 0xf000\r | |
| 32 | mov ds, bx\r | |
| 33 | \r | |
| 34 | mov bx, ADDR16_OF(gdtr)\r | |
| 35 | \r | |
| 36 | o32 lgdt [cs:bx]\r | |
| 37 | \r | |
| 38 | mov eax, SEC_DEFAULT_CR0\r | |
| 39 | mov cr0, eax\r | |
| 40 | \r | |
| 41 | jmp LINEAR_CODE_SEL:dword ADDR_OF(jumpTo32BitAndLandHere)\r | |
| 42 | BITS 32\r | |
| 43 | jumpTo32BitAndLandHere:\r | |
| 44 | \r | |
| 45 | mov eax, SEC_DEFAULT_CR4\r | |
| 46 | mov cr4, eax\r | |
| 47 | \r | |
| 48 | debugShowPostCode POSTCODE_32BIT_MODE\r | |
| 49 | \r | |
| 50 | mov ax, LINEAR_SEL\r | |
| 51 | mov ds, ax\r | |
| 52 | mov es, ax\r | |
| 53 | mov fs, ax\r | |
| 54 | mov gs, ax\r | |
| 55 | mov ss, ax\r | |
| 56 | \r | |
| f198e254 AP |
57 | ; parameter for Flat32SearchForBfvBase\r |
| 58 | xor eax, eax ; Start searching from top of 4GB for BfvBase\r | |
| 59 | \r | |
| c05de360 AP |
60 | OneTimeCallRet TransitionFromReal16To32BitFlat\r |
| 61 | \r | |
| 62 | ALIGN 2\r | |
| 63 | \r | |
| 64 | gdtr:\r | |
| 65 | dw GDT_END - GDT_BASE - 1 ; GDT limit\r | |
| 66 | dd ADDR_OF(GDT_BASE)\r | |
| 67 | \r | |
| 68 | ALIGN 16\r | |
| 69 | \r | |
| 70 | ;\r | |
| 71 | ; Macros for GDT entries\r | |
| 72 | ;\r | |
| 73 | \r | |
| 74 | %define PRESENT_FLAG(p) (p << 7)\r | |
| 75 | %define DPL(dpl) (dpl << 5)\r | |
| 76 | %define SYSTEM_FLAG(s) (s << 4)\r | |
| 77 | %define DESC_TYPE(t) (t)\r | |
| 78 | \r | |
| 79 | ; Type: data, expand-up, writable, accessed\r | |
| 80 | %define DATA32_TYPE 3\r | |
| 81 | \r | |
| 82 | ; Type: execute, readable, expand-up, accessed\r | |
| 83 | %define CODE32_TYPE 0xb\r | |
| 84 | \r | |
| 85 | ; Type: execute, readable, expand-up, accessed\r | |
| 86 | %define CODE64_TYPE 0xb\r | |
| 87 | \r | |
| 88 | %define GRANULARITY_FLAG(g) (g << 7)\r | |
| 89 | %define DEFAULT_SIZE32(d) (d << 6)\r | |
| 90 | %define CODE64_FLAG(l) (l << 5)\r | |
| 91 | %define UPPER_LIMIT(l) (l)\r | |
| 92 | \r | |
| 93 | ;\r | |
| 94 | ; The Global Descriptor Table (GDT)\r | |
| 95 | ;\r | |
| 96 | \r | |
| 97 | GDT_BASE:\r | |
| 98 | ; null descriptor\r | |
| 99 | NULL_SEL equ $-GDT_BASE\r | |
| 100 | DW 0 ; limit 15:0\r | |
| 101 | DW 0 ; base 15:0\r | |
| 102 | DB 0 ; base 23:16\r | |
| 103 | DB 0 ; sys flag, dpl, type\r | |
| 104 | DB 0 ; limit 19:16, flags\r | |
| 105 | DB 0 ; base 31:24\r | |
| 106 | \r | |
| 107 | ; linear data segment descriptor\r | |
| 108 | LINEAR_SEL equ $-GDT_BASE\r | |
| 109 | DW 0xffff ; limit 15:0\r | |
| 110 | DW 0 ; base 15:0\r | |
| 111 | DB 0 ; base 23:16\r | |
| 112 | DB PRESENT_FLAG(1)|DPL(0)|SYSTEM_FLAG(1)|DESC_TYPE(DATA32_TYPE)\r | |
| 113 | DB GRANULARITY_FLAG(1)|DEFAULT_SIZE32(1)|CODE64_FLAG(0)|UPPER_LIMIT(0xf)\r | |
| 114 | DB 0 ; base 31:24\r | |
| 115 | \r | |
| 116 | ; linear code segment descriptor\r | |
| 117 | LINEAR_CODE_SEL equ $-GDT_BASE\r | |
| 118 | DW 0xffff ; limit 15:0\r | |
| 119 | DW 0 ; base 15:0\r | |
| 120 | DB 0 ; base 23:16\r | |
| 121 | DB PRESENT_FLAG(1)|DPL(0)|SYSTEM_FLAG(1)|DESC_TYPE(CODE32_TYPE)\r | |
| 122 | DB GRANULARITY_FLAG(1)|DEFAULT_SIZE32(1)|CODE64_FLAG(0)|UPPER_LIMIT(0xf)\r | |
| 123 | DB 0 ; base 31:24\r | |
| 124 | \r | |
| 125 | %ifdef ARCH_X64\r | |
| 126 | ; linear code (64-bit) segment descriptor\r | |
| 127 | LINEAR_CODE64_SEL equ $-GDT_BASE\r | |
| 128 | DW 0xffff ; limit 15:0\r | |
| 129 | DW 0 ; base 15:0\r | |
| 130 | DB 0 ; base 23:16\r | |
| 131 | DB PRESENT_FLAG(1)|DPL(0)|SYSTEM_FLAG(1)|DESC_TYPE(CODE64_TYPE)\r | |
| 132 | DB GRANULARITY_FLAG(1)|DEFAULT_SIZE32(0)|CODE64_FLAG(1)|UPPER_LIMIT(0xf)\r | |
| 133 | DB 0 ; base 31:24\r | |
| 134 | %endif\r | |
| 135 | \r | |
| 136 | GDT_END:\r | |
| 137 | \r |