Intel® Platform Innovation Framework for UEFI—CSM Spec, Rev. 98
This specification describes the high-level design of the Compatibility Support Module (CSM) code that is required for an implementation of the Intel® Platform Innovation Framework for EFI (hereafter referred to as the "Framework"). The CSM provides compatibility support between the Framework and traditional, legacy... BIOS code and allows booting a traditional OS or booting an EFI OS off a device that requires a traditional option ROM (OpROM). This specification does the following:
• Describes the basic components of the CSM
• Defines how to use traditional BIOS option ROMs (OpROMs) to boot an EFI operating system (OS)
• Defines how to boot a traditional OS
• Provides code definitions for compatibility-related services, protocols, functions, and type definitions that are architecturally required by the Intel® Platform Innovation Framework for EFI Architecture Specification
Read the full Intel® Platform Innovation Framework for UEFI—CSM Spec, Rev. 98.