Hagfish: UEFI Bootloader for Barrelfish

Barrelfish is a new research operating system being built from scratch and released by ETH Zurich in Switzerland, originally in collaboration with Microsoft Research and now partly supported by HP Enterprise Labs, Huawei, Cisco, Oracle, and VMware. […]

Hagfish is the Barrelfish/ARMv8 UEFI loader prototype: Hagfish (it’s a basal chordate i.e. something like the ancestor of all fishes). Hagfish is a second-stage bootloader for Barrelfish on UEFI platforms, most importantly the ARMv8 server platform. […]

http://www.barrelfish.org/

https://github.com/BarrelfishOS/hagfish

https://github.com/BarrelfishOS/uefi-sdk

ARM Technical Learning Resources

Tom Stevens of ARM posted a blog with a new list of links for developers new to ARM. About 40 links, mostly on ARM assembly and C, Cortex-M, NEON, ARMv8/AArch64. Here’s a list of the initial 10 or so links’s titles:

Getting Started with ARM Microcontroller and Assembly Programming
How to Load Constants in Assembly for ARM Architecture
Branch and Call Sequences Explained
Building Customized Debug and Trace Solutions for Multicore SoCs
Caches and Self-Modifying Code
Code Size: A Comprehensive Comparison of MicroMIPS32 and Thumb Code Size Using Many Megabytes of Customer Code
How to Call a Function from ARM Assembler
Designing in ARM: Part One- Switching Microcontrollers
Getting Started with ARM Assembly and C Programming
Detecting Overflow from MUL

Full article:
https://community.arm.com/groups/processors/blog/2015/03/03/important-arm-technical-learning-resources

If this were done outside ARM.com, it’d probably github-hosted and called ‘awesome-arm-development.md’. (BTW, I’m slowly working on an ‘awesome firmware’ link collection, if someone doesn’t do one first…)

Linux ACPI support for ARM-v8

Earlier this month, Linaro announced their effort to upstream the Linux patches to enable ACPI on ARMv8. It appears the patch may make it in Linux 4.1, but it is not done yet.

The Linaro blog post credits a large list of people who helped: UEFI Forums’ ACPI Working Group, Linaro, ARM, Red Hat, Huwaei, Qualcomm, AMD, AMD, APM, HP, other Linaro LEG members, and Linux kernel maintainers, including Linus.

As part of this effort, on March 26th, ARM hosted a Firmware Summit focused on ARMv8 and ACPI, with dozens attending, including SoC vendors, BIOS vendors, firmware and kernel developers, ODMs and OEMs.

The Linux kernel checking comment for this patchset includes this description:

‘This series introduces preliminary ACPI 5.1 support to the arm64 kernel using the “hardware reduced” profile. We don’t support any peripherals yet, so it’s fairly limited in scope:
– MEMORY init (UEFI)
– ACPI discovery (RSDP via UEFI)
– CPU init (FADT)
– GIC init (MADT)
– SMP boot (MADT + PSCI)
– ACPI Kconfig options (dependent on EXPERT)
ACPI for arm64 has been in development for a while now and hardware has been available that can boot with either FDT or ACPI tables. This has been made possible by both changes to the ACPI spec to cater for ARM-based machines (known as “hardware-reduced” in ACPI parlance) but also a Linaro-driven effort to get this supported on top of the Linux kernel. This pull request is the result of that work. These changes allow us to initialise the CPUs, interrupt controller, and timers via ACPI tables, with memory information and cmdline coming from EFI. We don’t support a hybrid ACPI/FDT scheme. Of course, there is still plenty of work to do (a serial console would be nice!) but I expect that to happen on a per-driver basis after this core series has been merged.’

Upon accepting the patch, Linus said:

‘No earth-shattering new features come to mind, even if initial support for ACPI on arm64 looks funny. Depending on what you care about, your notion of “big new feature” may differ from mine, of course. There’s a lot of work all over, and some of it might just make a big difference to your use cases.’

This *is* big new feature, if you care about firmware and Linux.
More Information:

https://www.linaro.org/blog/collaborative-effort-to-upstream-acpi/