Bios Overview, Operating System Overview | Intel MultiProcessor

System Overview

2.2 BIOS Overview

A BIOS functions as an insulator between the hardware on one hand, and the operating system and applications software on the other. A standard uniprocessor BIOS performs the following functions:

∙Tests system components.

∙Builds configuration tables to be used by the operating system.

∙Initializes the processor and the rest of the system to a known state.

∙Provides run-time device-oriented services.

For a multiprocessor system, the BIOS may perform the following additional functions:

∙Pass configuration information to the operating system that identifies all processors and other multiprocessing components of the system.

∙Initialize all processors and the rest of the multiprocessing components to a known state.

This specification allows a wide range of capability in the BIOS. At the minimal end of the capability scale, the system developer can simply insert an MP floating pointer structure in the standard BIOS. The cost of this level of simplicity in the BIOS, however, is that the system developer has less flexibility in the design of the hardware. At the maximal end of the BIOS capability scale might be a BIOS that dynamically configures the system to provide resilience in the face of component malfunctions.

BIOS developers should read Chapters 3, 4, 5, and Appendix A to understand the tradeoffs between hardware and BIOS capabilities.

2.3 Operating System Overview

Enabling the creation of shrink-wrapped MP operating systems is one of the principal goals of this specification. This goal is achieved by allowing a flexible balance between the capabilities of the hardware and those of the BIOS. The potentially vast variety of hardware configurations is reduced by the BIOS to a few simple scenarios that can be readily handled by the low-level boot- up phase of the operating system.

Operating-system developers should read Chapters 3, 4, and 5, and Appendixes A and B to fully understand the interface between the BIOS and the operating system.

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Intel MultiProcessor manual Bios Overview, Operating System Overview

Contents

MultiProcessor Specification Copyright 1993-1997. Intel Corporation, All Rights Reserved Revision Revision History Date Revision HistoryPage Table of Contents Default Configurations MP Configuration TableContents Appendix B Operating System Programming Guidelines Appendix a System Bios Programming GuidelinesAppendix E Errata Glossary Tables Figures Examples Page Conceptual Overview Goals MultiProcessor Specification Features of the SpecificationScope Introduction Target AudienceOrganization of This Document Document Organization For More Information Conventions Used in This Document System Overview System Processors Hardware Overview System Overview Advanced Programmable Interrupt Controller 4 I/O Expansion Bus System Memory Operating System Overview Bios OverviewPage System Memory Configuration Hardware Specification System Memory Address Map System Memory Cacheability and Shareability Memory Cacheability Map Hardware Specification Locking External Cache Subsystem Multiprocessor Interrupt Control Posted Memory WriteApic Architecture Apic Versions Interrupt Modes PIC Mode PIC Mode Virtual Wire Mode via Local Apic Virtual Wire Mode Virtual Wire Mode via I/O Apic Symmetric I/O Mode Symmetric I/O Mode Floating Point Exception Interrupt Assignment of System Interrupts to the Apic Local UnitApic Memory Mapping Apic Identification Apic Interval Timers System-wide Reset Reset Support Processor-specific Init System-wide Init System Initial State Support for Fault-resilient Booting MP Configuration Table MultiProcessor Specification MP Floating Pointer Structure MP Configuration TableOffset Length Field Bytesbits in bits Description Information Bytes MP FeatureOffset Length Field Bytesbits Bits Description Information Byte MP Configuration Table Header MP Configuration Table Header MP Configuration Table Header Fields Base MP Configuration Table EntriesOffset Length Field Bytes Bits Description Apic Base MP Configuration Table Entry TypesProcessor Entries Length Entry Description Entry Type Code Bytes Comments Processor Entry Fields Bit Name Description Comments Feature Flags from Cpuid InstructionIntel486 and Pentium Processor Signatures Family Model Stepping a Description String Bus EntriesBUS ID BUS Type Bus Type String Description Bus Type String Values I/O Apic Entry Fields 3 I/O Apic Entries4 I/O Interrupt Assignment Entries Apic Entry I/O Interrupt Entry 10. I/O Interrupt Entry Fields 11. Interrupt Type Values Local Interrupt Assignment EntriesInterrupt Type Description Comments LINTIN# 12. Local Interrupt Entry FieldsDestination Local Apic ID Destination Local Apic Extended MP Configuration Table Entries System Address Space Mapping Entries 14. System Address Space Mapping Entry Fields 10. Example System with Multiple Bus Types and Bridge Types Bus Hierarchy Descriptor Entry Compatibility Bus Address Space Modifier Entry 12. Compatibility Bus Address Space Modifier Entry 16. Compatibility Bus Address Space Modifier Entry Fields Default Configurations Config Code CPUs Type Variant Schematic Discrete Apic ConfigurationsDefault Configurations Default Number Bus Default Configurations Default Configuration for Discrete Apic Integrated Apic Configurations Default Configuration for Integrated Apic First I/O Default Configuration Interrupt AssignmentsConfig INTINx Comments Assignment of I/O Interrupts to the Apic I/O Unit Level-triggered Interrupt Support All Local APICs Config LINTINx CommentsAssignment of System Interrupts to the Apic Local Unit Eisa and IRQ13 MultiProcessor Specification Bios Post Initialization System Bios Programming Guidelines Controlling the Application Processors Programming the Apic for Virtual Wire Mode System Bios Programming Guidelines Example A-1. Programming Local Apic for Virtual Wire Mode NMI Constructing the MP Configuration Table System Bios Programming Guidelines Page Operating System Programming Guidelines Operating System Boot-up Interrupt Mode Initialization and Handling Operating System Booting and Self-configuration Operating System Programming Guidelines Application Processor Startup Using Init IPI AP Shutdown Handling Using Startup IPI Handling TLB Invalidation Other IPI ApplicationsSpurious Apic Interrupts Handling Cache Flush Supporting Unequal Processors Page System Compliance Checklist Page Variable Interrupt Routing Interrupt Routing with Multiple APICs Fixed Interrupt Routing INTD# Bus Entries in Systems with More Than One PCI BusI/O Interrupt Assignment Entries for PCI Devices Multiple I/O Apic Multiple PCI Bus SystemsPage Errata 126 System Address Space Entry System Address Space Mapping Entries Address Base 14. System Address Space Mapping Entry FieldsEntry Length Address Type Space records must also be provided Bus Hierarchy Descriptor Entry Parent BUS BUS Informationsd Glossary Glossary-2 Order Number