1 /** @file
2 Provide legacy thunk interface for accessing Bios Video Rom.
3
4 Copyright (c) 2006 - 2007, Intel Corporation. All rights reserved.<BR>
5 This program and the accompanying materials
6 are licensed and made available under the terms and conditions of the BSD License
7 which accompanies this distribution. The full text of the license may be found at
8 http://opensource.org/licenses/bsd-license.php
9
10 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
11 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
12
13 **/
14
15 #include "BiosVideo.h"
16
17 #define EFI_CPU_EFLAGS_IF 0x200
18
19 /**
20 Initialize legacy environment for BIOS INI caller.
21
22 @param ThunkContext the instance pointer of THUNK_CONTEXT
23 **/
24 VOID
InitializeBiosIntCaller(THUNK_CONTEXT * ThunkContext)25 InitializeBiosIntCaller (
26 THUNK_CONTEXT *ThunkContext
27 )
28 {
29 EFI_STATUS Status;
30 UINT32 RealModeBufferSize;
31 UINT32 ExtraStackSize;
32 EFI_PHYSICAL_ADDRESS LegacyRegionBase;
33 UINT32 LegacyRegionSize;
34 //
35 // Get LegacyRegion
36 //
37 AsmGetThunk16Properties (&RealModeBufferSize, &ExtraStackSize);
38 LegacyRegionSize = (((RealModeBufferSize + ExtraStackSize) / EFI_PAGE_SIZE) + 1) * EFI_PAGE_SIZE;
39 LegacyRegionBase = 0x100000;
40 Status = gBS->AllocatePages (
41 AllocateMaxAddress,
42 EfiACPIMemoryNVS,
43 EFI_SIZE_TO_PAGES(LegacyRegionSize),
44 &LegacyRegionBase
45 );
46 ASSERT_EFI_ERROR (Status);
47
48 ThunkContext->RealModeBuffer = (VOID*)(UINTN)LegacyRegionBase;
49 ThunkContext->RealModeBufferSize = LegacyRegionSize;
50 ThunkContext->ThunkAttributes = THUNK_ATTRIBUTE_BIG_REAL_MODE|THUNK_ATTRIBUTE_DISABLE_A20_MASK_INT_15;
51 AsmPrepareThunk16(ThunkContext);
52 }
53
54 /**
55 Initialize interrupt redirection code and entries, because
56 IDT Vectors 0x68-0x6f must be redirected to IDT Vectors 0x08-0x0f.
57 Or the interrupt will lost when we do thunk.
58 NOTE: We do not reset 8259 vector base, because it will cause pending
59 interrupt lost.
60
61 @param Legacy8259 Instance pointer for EFI_LEGACY_8259_PROTOCOL.
62
63 **/
64 VOID
InitializeInterruptRedirection(IN EFI_LEGACY_8259_PROTOCOL * Legacy8259)65 InitializeInterruptRedirection (
66 IN EFI_LEGACY_8259_PROTOCOL *Legacy8259
67 )
68 {
69 EFI_STATUS Status;
70 EFI_PHYSICAL_ADDRESS LegacyRegionBase;
71 UINTN LegacyRegionLength;
72 UINT32 *IdtArray;
73 UINTN Index;
74 UINT8 ProtectedModeBaseVector;
75 UINT32 InterruptRedirectionCode[] = {
76 0x90CF08CD, // INT8; IRET; NOP
77 0x90CF09CD, // INT9; IRET; NOP
78 0x90CF0ACD, // INTA; IRET; NOP
79 0x90CF0BCD, // INTB; IRET; NOP
80 0x90CF0CCD, // INTC; IRET; NOP
81 0x90CF0DCD, // INTD; IRET; NOP
82 0x90CF0ECD, // INTE; IRET; NOP
83 0x90CF0FCD // INTF; IRET; NOP
84 };
85
86 //
87 // Get LegacyRegion
88 //
89 LegacyRegionLength = sizeof(InterruptRedirectionCode);
90 LegacyRegionBase = 0x100000;
91 Status = gBS->AllocatePages (
92 AllocateMaxAddress,
93 EfiACPIMemoryNVS,
94 EFI_SIZE_TO_PAGES(LegacyRegionLength),
95 &LegacyRegionBase
96 );
97 ASSERT_EFI_ERROR (Status);
98
99 //
100 // Copy code to legacy region
101 //
102 CopyMem ((VOID *)(UINTN)LegacyRegionBase, InterruptRedirectionCode, sizeof (InterruptRedirectionCode));
103
104 //
105 // Get VectorBase, it should be 0x68
106 //
107 Status = Legacy8259->GetVector (Legacy8259, Efi8259Irq0, &ProtectedModeBaseVector);
108 ASSERT_EFI_ERROR (Status);
109
110 //
111 // Patch IVT 0x68 ~ 0x6f
112 //
113 IdtArray = (UINT32 *) 0;
114 for (Index = 0; Index < 8; Index++) {
115 IdtArray[ProtectedModeBaseVector + Index] = ((EFI_SEGMENT (LegacyRegionBase + Index * 4)) << 16) | (EFI_OFFSET (LegacyRegionBase + Index * 4));
116 }
117
118 return ;
119 }
120
121 /**
122 Thunk to 16-bit real mode and execute a software interrupt with a vector
123 of BiosInt. Regs will contain the 16-bit register context on entry and
124 exit.
125
126 @param This Protocol instance pointer.
127 @param BiosInt Processor interrupt vector to invoke
128 @param Reg Register contexted passed into (and returned) from thunk to 16-bit mode
129
130 @retval TRUE Thunk completed, and there were no BIOS errors in the target code.
131 See Regs for status.
132 @retval FALSE There was a BIOS erro in the target code.
133 **/
134 BOOLEAN
135 EFIAPI
LegacyBiosInt86(IN BIOS_VIDEO_DEV * BiosDev,IN UINT8 BiosInt,IN IA32_REGISTER_SET * Regs)136 LegacyBiosInt86 (
137 IN BIOS_VIDEO_DEV *BiosDev,
138 IN UINT8 BiosInt,
139 IN IA32_REGISTER_SET *Regs
140 )
141 {
142 UINTN Status;
143 IA32_REGISTER_SET ThunkRegSet;
144 BOOLEAN Ret;
145 UINT16 *Stack16;
146 BOOLEAN Enabled;
147
148 ZeroMem (&ThunkRegSet, sizeof (ThunkRegSet));
149 ThunkRegSet.E.EFLAGS.Bits.Reserved_0 = 1;
150 ThunkRegSet.E.EFLAGS.Bits.Reserved_1 = 0;
151 ThunkRegSet.E.EFLAGS.Bits.Reserved_2 = 0;
152 ThunkRegSet.E.EFLAGS.Bits.Reserved_3 = 0;
153 ThunkRegSet.E.EFLAGS.Bits.IOPL = 3;
154 ThunkRegSet.E.EFLAGS.Bits.NT = 0;
155 ThunkRegSet.E.EFLAGS.Bits.IF = 1;
156 ThunkRegSet.E.EFLAGS.Bits.TF = 0;
157 ThunkRegSet.E.EFLAGS.Bits.CF = 0;
158
159 ThunkRegSet.E.EDI = Regs->E.EDI;
160 ThunkRegSet.E.ESI = Regs->E.ESI;
161 ThunkRegSet.E.EBP = Regs->E.EBP;
162 ThunkRegSet.E.EBX = Regs->E.EBX;
163 ThunkRegSet.E.EDX = Regs->E.EDX;
164 ThunkRegSet.E.ECX = Regs->E.ECX;
165 ThunkRegSet.E.EAX = Regs->E.EAX;
166 ThunkRegSet.E.DS = Regs->E.DS;
167 ThunkRegSet.E.ES = Regs->E.ES;
168
169 //
170 // The call to Legacy16 is a critical section to EFI
171 //
172 Enabled = SaveAndDisableInterrupts();
173
174 //
175 // Set Legacy16 state. 0x08, 0x70 is legacy 8259 vector bases.
176 //
177 Status = BiosDev->Legacy8259->SetMode (BiosDev->Legacy8259, Efi8259LegacyMode, NULL, NULL);
178 ASSERT_EFI_ERROR (Status);
179
180 Stack16 = (UINT16 *)((UINT8 *) BiosDev->ThunkContext->RealModeBuffer + BiosDev->ThunkContext->RealModeBufferSize - sizeof (UINT16));
181
182 ThunkRegSet.E.SS = (UINT16) (((UINTN) Stack16 >> 16) << 12);
183 ThunkRegSet.E.ESP = (UINT16) (UINTN) Stack16;
184
185 ThunkRegSet.E.Eip = (UINT16)((UINT32 *)NULL)[BiosInt];
186 ThunkRegSet.E.CS = (UINT16)(((UINT32 *)NULL)[BiosInt] >> 16);
187 BiosDev->ThunkContext->RealModeState = &ThunkRegSet;
188 AsmThunk16 (BiosDev->ThunkContext);
189
190 //
191 // Restore protected mode interrupt state
192 //
193 Status = BiosDev->Legacy8259->SetMode (BiosDev->Legacy8259, Efi8259ProtectedMode, NULL, NULL);
194 ASSERT_EFI_ERROR (Status);
195
196 //
197 // End critical section
198 //
199 SetInterruptState (Enabled);
200
201 Regs->E.EDI = ThunkRegSet.E.EDI;
202 Regs->E.ESI = ThunkRegSet.E.ESI;
203 Regs->E.EBP = ThunkRegSet.E.EBP;
204 Regs->E.EBX = ThunkRegSet.E.EBX;
205 Regs->E.EDX = ThunkRegSet.E.EDX;
206 Regs->E.ECX = ThunkRegSet.E.ECX;
207 Regs->E.EAX = ThunkRegSet.E.EAX;
208 Regs->E.SS = ThunkRegSet.E.SS;
209 Regs->E.CS = ThunkRegSet.E.CS;
210 Regs->E.DS = ThunkRegSet.E.DS;
211 Regs->E.ES = ThunkRegSet.E.ES;
212
213 CopyMem (&(Regs->E.EFLAGS), &(ThunkRegSet.E.EFLAGS), sizeof (UINT32));
214
215 Ret = (BOOLEAN) (Regs->E.EFLAGS.Bits.CF == 1);
216
217 return Ret;
218 }
219
220
221