Arm News Archives

A set of 35 patches were posted on Sunday for introducing ARM64 Guarded Control Stack (GCS) support to the Linux kernel. This is akin to x86 Shadow Stack support for hardware-protected stacks of return addresses to help fend off ROP attacks.

The ARM64 (AArch64) architecture code has seen some clean-ups and support for new Arm ISA features with the in-development Linux 6.5 kernel.

Arm and NXP engineers have posted the initial open-source Linux driver patches for an Ethos-U driver for their machine learning processor to enable Linux to dispatch AI inference jobs to the hardware. It's yet another inference/accelerator driver working its way toward the mainline kernel but is off to a rocky start with many code issues being raised.

For helping to ensure optimal performance of AArch64 binaries generated by LLVM/Clang for the Neoverse-V2 processor cores, LLVM 17 Git has received a proper Neoverse-V2 scheduling model.

Arm today announced the new high-end Cortex-X4 CPU core design for delivering their most powerful Cortex compute cluster.

On Monday the ARM64 (AArch64) architecture code changes were submitted for the in-development Linux 6.4 kernel along with the various SoC updates and various platform/machine additions for ARM hardware with this new kernel version.

Toward the end of last year Arm detailed Scalable Matrix Extension 2 (SME2) for adding more capabilities to Armv9-A around speedy matrix processing. Merged this morning is initial support for SME2 within Binutils as part of the GNU compiler toolchain for the GNU Assembler.

In addition to the mainline Linux kernel seeing recent support for the Arm-powered Lenovo ThinkPad X13s and Lenovo Yoga C630, among others, another Lenovo model working toward mainline kernel support is the Lenovo Flex 5G.

Along with all of the Arm SoC and board updates that were merged to the mainline Linux 6.3 kernel earlier in the week, the ARM64 (AArch64) architecture changes have also landed for this next Linux kernel version.

Ahead of the Linux 6.3 merge window officially opening up following the Linux 6.2 stable release tomorrow, Arnd Bergmann has already mailed in his pull requests of the Arm SoC and defconfig updates for this next kernel version. Most notable is having mainline support for the Qualcomm Snapdragon 8 Gen 2 as well as some other new, high-end embedded SoCs.

While initial Scalable Matrix Extension (SME) support for the Linux kernel only was mainlined last year to the kernel tree, Arm already has SME 2 and SME 2.1 support on the way to mainline.

Arm ended out January by publishing an early request for comments (RFC) version of its Confidential Compute Architecture (CCA) support for the Linux kernel so there can be KVM virtualization integration around Arm CCA, a KVM user-space ABI for managing Realms, and Linux guest support for Arm Realms.

Much of the Rust programming language support/infrastructure for the Linux kernel thus far has been with an x86_64 focus while obviously AArch64 is an important target as well. It's nice to see Arm Limited engineers working on the Rust Linux kernel support for AArch64/ARM64.

The Armv8.1-M based Cortex-M85 processor support has made it into the GCC 13 compiler for this highest performing Cortex-M processor use for MCUs and embedded applications.

The SoC tree's "for-next" branch has picked up a big set of patches that is set to lighten the kernel by 154k lines of code, documentation, and DeviceTree files in clearing out some old drivers and obsolete board/machine support.

Ampere Computing's SMPro is a system control processor that is an Arm Cortex-M3 serving as a co-processor and handles interfacing with the BMC, error handling, system booting, power fail detection, and other tasks. The SMPro is found starting with Ampere Computing's current Ampere Altra server processors while in Linux 6.2 a lot of its functionality is finally being upstreamed into the mainline Linux kernel.

The 64-bit Arm (ARM64 / AArch64) architecture improvements have landed in the Linux 6.2 kernel.

All of the Arm SoC support additions and DeviceTree updates have been merged for the Linux 6.2 merge window. There is support for a number of additional Qualcomm Snapdragon SoCs in the kernel as well as having the initial mainline bits for the Apple M1 Pro/Ultra/Max SoC variants.

Leading AArch64 server processor vendor Ampere Computing announced this summer AmpereOne as the branding for their next-generation AArch64 "cloud native" server processor design succeeding their current Ampere Altra / Ampere Altra Max processors based on Neoverse-N1. While the AmpereOne processors have yet to be formally launched, with the new AArch64 core being an original design, Ampere Computing has already been submitting support patches to the open-source compilers. The latest twist in this enablement is now acknowledging a new "Ampere-1A" variant.

The Linux kernel built with Clang has supported Shadow Call Stack "SCS: to prevent return address overwrites. With patches building up for Linux 6.2, Dynamic Shadow Call Stack is being implemented to avoid the overhead of SCS on processors supporting pointer authentication (PAC).

Made public earlier this year was Spectre-BHB / BHI as a speculative execution vulnerability similar to Spectre V2 and affecting Intel and Arm CPUs. At the time Neoverse N2 / N1 / V1 and older cores like Cortex-A15 / A57 / A72 were known to be vulnerable and required software mitigations. The upcoming AmpereOne is also vulnerable to Spectre-BHB and has a patch now on its way to the Linux kernel for mitigating this Spectre class vulnerability.

The 64-bit Arm (ARM64 / AArch64) architecture changes were merged last week for the ongoing Linux 6.1 merge window.

The Arm SoC and platform enablement pull requests were sent out this morning that provide the Linux 6.1 kernel with support for several new SoCs, various platforms including some newer smartphones, and other hardware support improvements.

Disclosed back in March was the Spectre-BHB / Branch History Injection (BHI) speculative execution vulnerability that on the Arm side affected CPUs from the likes of the Cortex-A15 through A78 series as well as the likes of the X1, X2, and A710, plus the Neoverse E1 / N1 / N2 / V1 CPUs. Now for Linux 6.1, a command-line option is being added for ARM64 to be able to disable the Spectre-BHB mitigation due to the "great impact" to performance.

When it comes to Linux on Arm laptops the recent excitement has been around the Asahi Linux porting work for the Apple M2 MacBooks and Linux 6.0 supporting the Qualcomm Snapdragon 8cx Gen3 and the flagship Lenovo ThinkPad X13s Arm laptop. Launched a few years ago though was the Lenovo Yoga C630 powered by a Qualcomm Snapdragon 850 and thanks now to the work of Linaro that older Arm laptop is seeing Linux support improvements.

The 64-bit Arm (ARM64) architecture updates have already been sent in for Linux 5.20 ahead of the merge window formally opening.

The "THP_SWAP" option for the Linux kernel allows swapping transparent huge-pages in one piece without splitting. With Linux 5.20 the 64-bit Arm kernel (ARM64 / AArch64) will now support this option as a performance optimization.

When it comes to compressing textures using the Adaptive Scalable Texture Compression (ASTC) format that is supported by the OpenGL / OpenGL ES / Vulkan APIs, Arm's ASTC Encoder has long reigned supreme. Out today is ASTC-Encoder 4.0 as the latest performance-boosting update to this open-source compressor.

A feature supported by the GNU Compiler Collection (GCC) that sadly isn't used more often is function multi-versioning (FMV) for supporting multiple versions of a function with the given function selected based upon the target processor in use. GCC FMV on x86_64 allows for different functions to be used whether supporting SSE4.2, AVX, or even a particular CPU micro-architecture. Arm is finally working on GCC function multi-versioning support for AArch64.

Support for Arm's Cortex-M85 based on Armv8.1-M has been added for the LLVM 15.0 compiler release this fall.

Arm today announced their second-generation Armv9 CPU designs with the Cortex-X3 and Cortex-A715. Arm also refreshed the Cortex-A510 to allow for more cores and a power reduction.

The GNU C Library (Glibc) now has a memory copy (memcpy) implementation optimized for Arm's Scalable Vector Extension (SVE) that can "significantly" improve performance.

While Docker can already run on AArch64 Linux, the mainline Linux kernel's default configuration "defconfig" lacks a few features for allowing it to run out-of-the-box. An Arm engineer is proposing adjusting those defaults to make it more easily/straight-forward to run Docker on 64-bit Arm.

Another set of Arm SoC and platform changes have been submitted for the in-development Linux 5.19 merge window.

The various ARM SoC and machine/platform updates have landed in the Linux 5.19 kernel with a number of notable additions.

Last year Ampere Computing announced they were designing their own in-house AArch64 server/cloud processor cores to succeed their current Ampere Altra / Ampere Altra Max processors leveraging Arm Neoverse N1 cores. The company announced today that their first in-house cloud native processor core designs will be marketed under the AmpereOne branding.

The 64-bit Arm (AArch64) architecture changes have been merged into the in-development Linux 5.19 kernel.

Merged today into mainline LLVM 15.0 for the Clang compiler is Ampere Computing's support for "Ampere1", their next-generation server processor featuring their in-house "Ampere Cores" core design.

It looks like Linux 5.19 will have all the base preparations in place for Arm Scalable Matrix Extension (SME) support.

Last weekend saw the release of Box86 0.2.6 and Box64 0.1.8 for enjoying x86 and x86_64 Linux binaries on 64-bit Arm and other CPU architectures. Out today meanwhile is the release of FEX-Emu 2204 as another open-source project making it easy to run x86/x86_64 binaries on AArch64.

Since 2015 the Linux kernel has supported UEFI mirrored memory functionality for x86/x86_64 while now Huawei is working on adding that functionality for AArch64.

ADLINK Technology today announced a new developer platform based on Ampere Altra for software development, cloud, and related workloads. The ADLINK Ampere Altra Developer Platform is based on their COM-HPC module and pairs with 32, 64, or 80-core Ampere Altra processors.

In addition to supporting the Tesla FSD chip, Raspberry Pi Zero 2 W, and other new Arm SoCs in Linux 5.18, this kernel will also be more secure for 64-bit Arm with adding Shadow Call Stack support.

The upcoming Linux 5.18 kernel has mainline support available for Tesla's full self-driving SoC along with other interesting Arm hardware.

Arm continues working on improving the open-source compiler support for their forthcoming Armv9 processor designs. The latest to report on is the tuning additions for the Neoverse-N2 and Neoverse "Demeter" targets.

The 64-bit Arm (ARM64 / AArch64) architecture code updates have been submitted ahead of the Linux 5.18 merge window opening next week.

While still a work-in-progress and dependent upon other Arm SoC patches for actual functionality, on Friday the initial Arm Mali "Valhall" patches were sent out for the Panfrost Direct Rendering Manager (DRM) driver.

The Arm Mali Valhall architecture reverse-engineering started last summer and while limited in the reverse engineering capabilities for several months, it looks like by this summer we'll hopefully see a working driver for Arm's newer graphics IP.

Qualcomm only announced the Snapdragon 8 Gen 1 and X65 platforms at the end of November but already they have managed to provide timely mainline support for these latest high-end SoCs. This is great to see compared to the days of slow to materialize mainline support for new Arm SoCs, which still persists among some vendors with either belated mainline support or only focusing on vendor downstream kernels. The big batch of Arm SoC/platform changes have landed for Linux 5.17.

While the Linux 5.17 merge window hasn't opened up yet, there have been a few early pull requests sent out this week ahead of this imminent next kernel cycle. One of those already sent out is the ARM64/AArch64 CPU architecture code updates for Linux 5.17.