Download Crate CSM16 Specifications

Table of Contents
1
Introduction .....................................................................................................1
1.1
1.2
1.3
2
Design Discussion .............................................................................................2
2.1
2.2
2.3
2.4
2.5
2.6
2.7
3
Overview ..............................................................................................1
Scope ...................................................................................................1
Rationale ..............................................................................................1
Definitions of Terms................................................................................2
CSM-Specific References .........................................................................3
CSM Overview .......................................................................................3
2.3.1
Legacy Overview .......................................................................3
2.3.2
Differences between Traditional BIOS and EFI ...............................4
2.3.3
BDS Legacy Flow .......................................................................5
2.3.4
Components of CSM ..................................................................6
CSM Architecture ...................................................................................6
2.4.1
Overview .................................................................................6
2.4.2
EfiCompatibility .........................................................................8
2.4.3
Compatibility16 ....................................................................... 14
2.4.4
CompatibilitySmm ................................................................... 16
2.4.5
Thunk and Reverse Thunk Overview........................................... 16
Interactions between CSM and Legacy BIOS ............................................. 18
2.5.1
BDS and Legacy Drivers ........................................................... 18
2.5.2
16-Bit Traditional Code ............................................................ 20
Assumptions ........................................................................................ 22
2.6.1
External Assumptions .............................................................. 22
2.6.2
Internal Assumptions ............................................................... 22
2.6.3
Design Assumptions ................................................................ 23
Valid EFI and Legacy Combinations ......................................................... 24
Code Definitions ............................................................................................. 26
3.1
3.2
Introduction ........................................................................................ 26
EfiCompatibility Code ............................................................................ 27
3.2.1
Legacy BIOS Protocol ............................................................... 27
EFI_LEGACY_BIOS_PROTOCOL .............................................................. 27
EFI_LEGACY_BIOS_PROTOCOL.Int86() ................................................... 29
EFI_LEGACY_BIOS_PROTOCOL.FarCall86() .............................................. 35
EFI_LEGACY_BIOS_PROTOCOL.CheckPciRom() ........................................ 37
EFI_LEGACY_BIOS_PROTOCOL.InstallPciRom() ........................................ 38
EFI_LEGACY_BIOS_PROTOCOL.LegacyBoot() ........................................... 40
EFI_LEGACY_BIOS_PROTOCOL.UpdateKeyboardLedStatus() ...................... 43
EFI_LEGACY_BIOS_PROTOCOL.GetBbsInfo()............................................ 44
EFI_LEGACY_BIOS_PROTOCOL.ShadowAllLegacyOproms() ........................ 45
EFI_LEGACY_BIOS_PROTOCOL.PrepareToBootEfi() ................................... 46
EFI_LEGACY_BIOS_PROTOCOL.GetLegacyRegion() ................................... 47
EFI_LEGACY_BIOS_PROTOCOL.CopyLegacyRegion() ................................. 49
EFI_LEGACY_BIOS_PROTOCOL.BootUnconventionalDevice() ...................... 50
3.2.2
Legacy BIOS Platform Protocol .................................................. 52
EFI_LEGACY_BIOS_PLATFORM_PROTOCOL .............................................. 52
EFI_LEGACY_BIOS_PLATFORM_PROTOCOL.GetPlatformInfo() ..................... 54
EfiGetPlatformBinaryMpTable ................................................................. 57
EfiGetPlatformBinaryOemIntData ........................................................... 59
EfiGetPlatformBinaryOem16Data ............................................................ 61
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