To fix
[mirror_edk2.git] / EdkModulePkg / Core / DxeIplPeim / Ia32 / VirtualMemory.c
1 /*++
2
3 Copyright (c) 2006, Intel Corporation
4 All rights reserved. This program and the accompanying materials
5 are licensed and made available under the terms and conditions of the BSD License
6 which accompanies this distribution. The full text of the license may be found at
7 http://opensource.org/licenses/bsd-license.php
8
9 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
10 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
11
12 Module Name:
13 VirtualMemory.c
14
15 Abstract:
16
17 x64 Virtual Memory Management Services in the form of an IA-32 driver.
18 Used to establish a 1:1 Virtual to Physical Mapping that is required to
19 enter Long Mode (x64 64-bit mode).
20
21 While we make a 1:1 mapping (identity mapping) for all physical pages
22 we still need to use the MTRR's to ensure that the cachability attirbutes
23 for all memory regions is correct.
24
25 The basic idea is to use 2MB page table entries where ever possible. If
26 more granularity of cachability is required then 4K page tables are used.
27
28 References:
29 1) IA-32 Intel(R) Atchitecture Software Developer's Manual Volume 1:Basic Architecture, Intel
30 2) IA-32 Intel(R) Atchitecture Software Developer's Manual Volume 2:Instruction Set Reference, Intel
31 3) IA-32 Intel(R) Atchitecture Software Developer's Manual Volume 3:System Programmer's Guide, Intel
32
33 --*/
34
35 #include "VirtualMemory.h"
36
37 UINTN
38 CreateIdentityMappingPageTables (
39 VOID
40 )
41 /*++
42
43 Routine Description:
44
45 Allocates and fills in the Page Directory and Page Table Entries to
46 establish a 1:1 Virtual to Physical mapping.
47
48 Arguments:
49
50 NumberOfProcessorPhysicalAddressBits - Number of processor address bits to use.
51 Limits the number of page table entries
52 to the physical address space.
53
54 Returns:
55
56 EFI_SUCCESS The 1:1 Virtual to Physical identity mapping was created
57
58 --*/
59 {
60 UINT8 PhysicalAddressBits;
61 EFI_PHYSICAL_ADDRESS PageAddress;
62 UINTN IndexOfPml4Entries;
63 UINTN IndexOfPdpEntries;
64 UINTN IndexOfPageDirectoryEntries;
65 UINTN NumberOfPml4EntriesNeeded;
66 UINTN NumberOfPdpEntriesNeeded;
67 PAGE_MAP_AND_DIRECTORY_POINTER *PageMapLevel4Entry;
68 PAGE_MAP_AND_DIRECTORY_POINTER *PageMap;
69 PAGE_MAP_AND_DIRECTORY_POINTER *PageDirectoryPointerEntry;
70 PAGE_TABLE_ENTRY *PageDirectoryEntry;
71 UINTN TotalPagesNum;
72 UINTN BigPageAddress;
73 VOID *Hob;
74
75 //
76 // Get physical address bits supported from CPU HOB.
77 //
78 PhysicalAddressBits = 36;
79
80 Hob = GetFirstHob (EFI_HOB_TYPE_CPU);
81 if (Hob != NULL) {
82 PhysicalAddressBits = ((EFI_HOB_CPU *) Hob)->SizeOfMemorySpace;
83 }
84
85 //
86 // Calculate the table entries needed.
87 //
88 if (PhysicalAddressBits <= 39 ) {
89 NumberOfPml4EntriesNeeded = 1;
90 NumberOfPdpEntriesNeeded = 1 << (PhysicalAddressBits - 30);
91 } else {
92 NumberOfPml4EntriesNeeded = 1 << (PhysicalAddressBits - 39);
93 NumberOfPdpEntriesNeeded = 512;
94 }
95
96 //
97 // Pre-allocate big pages to avoid later allocations.
98 //
99 TotalPagesNum = (NumberOfPdpEntriesNeeded + 1) * NumberOfPml4EntriesNeeded + 1;
100 BigPageAddress = (UINTN) AllocatePages (TotalPagesNum);
101 ASSERT (BigPageAddress != 0);
102
103 //
104 // By architecture only one PageMapLevel4 exists - so lets allocate storage for it.
105 //
106 PageMap = (VOID *) BigPageAddress;
107 BigPageAddress += EFI_PAGE_SIZE;
108
109 PageMapLevel4Entry = PageMap;
110 PageAddress = 0;
111 for (IndexOfPml4Entries = 0; IndexOfPml4Entries < NumberOfPml4EntriesNeeded; IndexOfPml4Entries++, PageMapLevel4Entry++) {
112 //
113 // Each PML4 entry points to a page of Page Directory Pointer entires.
114 // So lets allocate space for them and fill them in in the IndexOfPdpEntries loop.
115 //
116 PageDirectoryPointerEntry = (VOID *) BigPageAddress;
117 BigPageAddress += EFI_PAGE_SIZE;
118
119 //
120 // Make a PML4 Entry
121 //
122 PageMapLevel4Entry->Uint64 = (UINT64)(UINTN)PageDirectoryPointerEntry;
123 PageMapLevel4Entry->Bits.ReadWrite = 1;
124 PageMapLevel4Entry->Bits.Present = 1;
125
126 for (IndexOfPdpEntries = 0; IndexOfPdpEntries < NumberOfPdpEntriesNeeded; IndexOfPdpEntries++, PageDirectoryPointerEntry++) {
127 //
128 // Each Directory Pointer entries points to a page of Page Directory entires.
129 // So allocate space for them and fill them in in the IndexOfPageDirectoryEntries loop.
130 //
131 PageDirectoryEntry = (VOID *) BigPageAddress;
132 BigPageAddress += EFI_PAGE_SIZE;
133
134 //
135 // Fill in a Page Directory Pointer Entries
136 //
137 PageDirectoryPointerEntry->Uint64 = (UINT64)(UINTN)PageDirectoryEntry;
138 PageDirectoryPointerEntry->Bits.ReadWrite = 1;
139 PageDirectoryPointerEntry->Bits.Present = 1;
140
141 for (IndexOfPageDirectoryEntries = 0; IndexOfPageDirectoryEntries < 512; IndexOfPageDirectoryEntries++, PageDirectoryEntry++, PageAddress += 0x200000) {
142 //
143 // Fill in the Page Directory entries
144 //
145 PageDirectoryEntry->Uint64 = (UINT64)PageAddress;
146 PageDirectoryEntry->Bits.ReadWrite = 1;
147 PageDirectoryEntry->Bits.Present = 1;
148 PageDirectoryEntry->Bits.MustBe1 = 1;
149
150 }
151 }
152 }
153
154 //
155 // For the PML4 entries we are not using fill in a null entry.
156 // For now we just copy the first entry.
157 //
158 for (; IndexOfPml4Entries < 512; IndexOfPml4Entries++, PageMapLevel4Entry++) {
159 CopyMem (
160 PageMapLevel4Entry,
161 PageMap,
162 sizeof (PAGE_MAP_AND_DIRECTORY_POINTER)
163 );
164 }
165
166 return (UINTN)PageMap; // FIXME
167 }
168