The Server Base System Architecture (SBSA) is a hardware system architecture for

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s based on 64-bit

ARM In human anatomy, the arm refers to the upper limb in common usage, although academically the term specifically means the upper arm between the glenohumeral joint (shoulder joint) and the elbow joint. The distal part of the upper limb between ...

processors.

Rationale

Historically, ARM-based products have often been tailored for specific applications and power profiles. Variation between ARM-based hardware platforms has been an impediment requiring operating system adjustments for each product. The SBSA seeks to strengthen the ARM ecosystem by specifying a minimal set of standardized features so that an OS built for this standard platform should function correctly without modification on all hardware products compliant with the specification.

Features

* CPU features * Memory management * Peripheral access * Interrupts * Watchdog (errant system detection) Existing specifications for USB, PCIe, ACPI, TPM, and other standards are incorporated to solidify the specification.

Server Base Boot Requirements

Firmware In computing Computing is any goal-oriented activity requiring, benefiting from, or creating computer, computing machinery. It includes the study and experimentation of algorithmic processes, and the development of both computer hardware, h ...

issues are addressed separately in the Server Base Boot Requirements (SBBR) specification.

Platform validation

The Architecture Compliance Suite (ACS) checks whether an environment is compliant with the SBSA specification, and is provided under an Apache 2 open source license. It is available at https://github.com/ARM-software/sbsa-acs.

Compliance levels

The specification defines levels of compliance, with level 0 being the most basic, and successive levels building on prior levels. In the words of the spec, "Unless explicitly stated, all specification items belonging to level N apply to levels greater than N."

Level 0, 1, and 2

Levels 0, 1, and 2 have been deprecated and folded into level 3.

Level 3

Level 3 contains base-level specifications for: * PE (Processing Element--a core) features * Memory map * Interrupt controller * PPI (peripheral interrupt) assignments * MMU behavior * Clock and timer subsystem * Wake up semantics * Power state semantics * Watchdogs * Peripheral subsystems

Level 4

Extends level 3, e.g. with support for RAS fault recovery extensions of ARMv8.2 spec.

Level 5

Extends level 4, e.g. with support for stage 2 translation control from hypervisor as specified in ARMv8.4.

Level 6

Extends level 5, e.g. with support for

speculative execution Speculative execution is an optimization (computer science), optimization technique where a computer system performs some task that may not be needed. Work is done before it is known whether it is actually needed, so as to prevent a delay that woul ...

safety features.

Level 7

Extends level 6, e.g. with support for Arm Memory System Resource Partitioning and Monitoring (MPAM) and Performance Monitoring Unit (PMU) features.

Versions

Initial public version

Initial public version of the SBSA was announced on January 29, 2014.

SBSA Version 3.0

SBSA Version 3.0 was released on February 1, 2016.

SBSA Version 5.0

SBSA Version 5.0 was released on May 30, 2018.

SBSA Version 6.0

SBSA Version 6.0 was released on September 16, 2019.

SBSA Version 6.1

SBSA Version 6.1 was released on September 15, 2020.

SBSA Version 7.0

SBSA Version 7.0 was released on January 31, 2021.

SBSA Version 7.1

SBSA Version 7.1 was released on October 6, 2022.

References

{{compu-stub ARM architecture Computer hardware standards