mirror of https://github.com/acidanthera/audk.git
151 lines
3.4 KiB
C
151 lines
3.4 KiB
C
/** @file
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C based implemention of IA32 interrupt handling only
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requiring a minimal assembly interrupt entry point.
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Copyright (c) 2006 - 2010, Intel Corporation. All rights reserved.<BR>
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This program and the accompanying materials
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are licensed and made available under the terms and conditions of the BSD License
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which accompanies this distribution. The full text of the license may be found at
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http://opensource.org/licenses/bsd-license.php
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THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
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WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
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**/
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#include "CpuDxe.h"
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#include "CpuGdt.h"
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//
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// Global descriptor table (GDT) Template
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//
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STATIC GDT_ENTRIES GdtTemplate = {
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//
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// NULL_SEL
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//
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{
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0x0, // limit 15:0
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0x0, // base 15:0
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0x0, // base 23:16
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0x0, // type
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0x0, // limit 19:16, flags
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0x0, // base 31:24
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},
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//
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// LINEAR_SEL
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//
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{
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0x0FFFF, // limit 0xFFFFF
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0x0, // base 0
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0x0,
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0x092, // present, ring 0, data, expand-up, writable
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0x0CF, // page-granular, 32-bit
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0x0,
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},
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//
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// LINEAR_CODE_SEL
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//
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{
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0x0FFFF, // limit 0xFFFFF
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0x0, // base 0
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0x0,
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0x09A, // present, ring 0, data, expand-up, writable
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0x0CF, // page-granular, 32-bit
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0x0,
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},
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//
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// SYS_DATA_SEL
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//
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{
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0x0FFFF, // limit 0xFFFFF
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0x0, // base 0
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0x0,
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0x092, // present, ring 0, data, expand-up, writable
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0x0CF, // page-granular, 32-bit
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0x0,
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},
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//
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// SYS_CODE_SEL
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//
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{
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0x0FFFF, // limit 0xFFFFF
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0x0, // base 0
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0x0,
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0x09A, // present, ring 0, data, expand-up, writable
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0x0CF, // page-granular, 32-bit
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0x0,
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},
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//
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// LINEAR_CODE64_SEL
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//
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{
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0x0FFFF, // limit 0xFFFFF
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0x0, // base 0
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0x0,
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0x09B, // present, ring 0, code, expand-up, writable
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0x0AF, // LimitHigh (CS.L=1, CS.D=0)
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0x0, // base (high)
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},
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//
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// SPARE4_SEL
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//
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{
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0x0, // limit 0
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0x0, // base 0
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0x0,
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0x0, // present, ring 0, data, expand-up, writable
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0x0, // page-granular, 32-bit
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0x0,
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},
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//
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// SPARE5_SEL
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//
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{
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0x0, // limit 0
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0x0, // base 0
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0x0,
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0x0, // present, ring 0, data, expand-up, writable
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0x0, // page-granular, 32-bit
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0x0,
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},
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};
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/**
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Initialize Global Descriptor Table.
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**/
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VOID
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InitGlobalDescriptorTable (
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VOID
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)
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{
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GDT_ENTRIES *gdt;
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IA32_DESCRIPTOR gdtPtr;
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//
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// Allocate Runtime Data for the GDT
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//
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gdt = AllocateRuntimePool (sizeof (GdtTemplate) + 8);
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ASSERT (gdt != NULL);
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gdt = ALIGN_POINTER (gdt, 8);
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//
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// Initialize all GDT entries
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//
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CopyMem (gdt, &GdtTemplate, sizeof (GdtTemplate));
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//
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// Write GDT register
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//
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gdtPtr.Base = (UINT32)(UINTN)(VOID*) gdt;
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gdtPtr.Limit = (UINT16) (sizeof (GdtTemplate) - 1);
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AsmWriteGdtr (&gdtPtr);
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//
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// Update selector (segment) registers base on new GDT
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//
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SetCodeSelector ((UINT16)CPU_CODE_SEL);
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SetDataSelectors ((UINT16)CPU_DATA_SEL);
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}
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