Linux Plumbers Conference 2022

Session

linux/arch MC

Sep 13, 2022, 10:00 AM

"Meeting 1&2" (Clayton Hotel on Burlington Road)

Description

The linux/arch MC aims to bring architecture maintainers in one room to discuss how can we improve architecture specific code and its integration with the generic kernel

54. High memory management API changes

Ira Weiny

9/13/22, 10:00 AM

There was a time when the Linux kernel was 32bit but hardware systems had much
more than 1GB of memory. A solution was developed to allow the use of high
memory (HIGHMEM). High memory was excluded from the kernel direct map and was
temporarily mapped into and out of the kernel as needed. These mappings were
made via kmap_*() calls.

With the prevalence of 64bit kernels the usefulness...

274. Mitigating speculative execution attacks with ASI - follow up

Junaid Shahid (Google), Ofir Weisse (Google)

9/13/22, 10:30 AM

In this talk we will argue the case for adopting ASI in upstream Linux.

Speculative execution attacks, such as L1TF, MDS, LVI, (and many others) pose significant security risks to hypervisors and VMs, from neighboring malicious VMs. The sheer number of proposed patches/fixes is quite high, each with its own non-trivial impact on performance. A complete mitigation for these attacks...

189. Consolidating representations of the physical memory

Mike Rapoport (IBM)

9/13/22, 11:00 AM

We have several coarse representations of the physical memory consisting of
[start, end, flags] structures per memory region. There is memblock that
some architectures keep after boot, there is iomem_resource tree and
"System RAM" nodes in that tree, there are memory blocks exposed in sysfs
and then there are per-architecture structures, sometimes even several per
architecture.

The...

133. LoongArch: What we will do next

Huacai Chen, Jianmin Lv (Loongson), Xuerui WANG

9/13/22, 12:00 PM

• cleaner way forward for compatibility with the "old-world" (the
  earlier in-house MIPS-clone firmware and kernel ABI of LoongArch), if
  possible;
• cleaner approach to support both standard UEFI and the Loongson-custom
  boot protocols, if possible;
• way forward for supporting zboot in EFI stub boot flow.

310. Extending EFI support in Linux to new architectures

Ard Biesheuvel (Google), Ilias Apalodimas

9/13/22, 12:30 PM

An overview will be presented of recent work in the Linux/EFI
subsystem and associated projects (u-boot, Tianocore, systemd), with a
focus on generic support for the various new architectures that have
adopted EFI as a supported boot flow. This includes UEFI secure boot
and/or measured boot on non-Tianocore based EFI implementations,
generic decompressor support in Linux and early...

118. Make LL/SC arch has a strict forward guarantee

Mr Ren Guo

9/13/22, 1:00 PM

For the architecture that uses load-link/store-conditional to implement atomic semantics, ll/sc can effectively reduce the complexity and cost of embedded processors and is very attractive for products with up to two cores in a single cluster. However, compared with the AMO architecture, it may not have enough forward guarantee, causing the risk of livelock. Therefore, CPUs based on the ll/sc...