Kernel Standard Architecture for 11.11

UNDER CONSTRUCTION

Summary

Release Note

This section should include a paragraph describing the end-user impact of this change. It is meant to be included in the release notes of the first release in which it is implemented. (Not all of these will actually be included in the release notes, at the release manager's discretion; but writing them is a useful exercise.)

It is mandatory.

Rationale

User stories

Assumptions

Design

You can have subsections that better describe specific parts of the issue.

Implementation

This section should describe a plan of action (the "how") to implement the changes discussed. Could include subsections like:

Code Changes

Code changes should include an overview of what needs to change, and in some cases even the specific details.

Migration

Include:

  • data migration, if any
  • redirects from old URLs to new ones, if any
  • how users will be pointed to the new way of doing things, if necessary.

Test/Demo Plan

It's important that we are able to test new features, and demonstrate them to users. Use this section to describe a short plan that anybody can follow that demonstrates the feature is working. This can then be used during testing, and to show off after release. Please add an entry to http://testcases.qa.ubuntu.com/Coverage/NewFeatures for tracking test coverage.

This need not be added or completed until the specification is nearing beta.

Unresolved issues

This should highlight any issues that should be addressed in further specifications, and not problems with the specification itself; since any specification with problems cannot be approved.

BoF agenda and discussion

Agenda

  • Thumb-2 kernel support
    • OMAP3/4: done
    • imx51: mostly done -- power management testing needed (volunteers?)
    • Need to document the fixes needed, so that other people can start to share the work.

Discussion

  • Next steps:
  • Get it [Thumb-2] building on imx
  • Get it building on other SOCs
  • ACTION; dmart to document what he needed to do get it working
  • ACTION: dmart to follow up with each landing team
  • robher: Any generic thumb2 issues remaining?
  • dmart: No major issues, only BSP-specific issues at this point.
  • ACTION: follow up to see if Versatile Express can be built in thumb2 by default in Linaro kernels -- cmarinas says it works
    • Still no systematic benchmarking / code size metrics: what can we do here?
  • Arnd: The kernel changes should not matter in terms of performance. We should run benchmarks and if we see regressions, it means there's something in kernel that needs fixing.
    • kprobes for Thumb-2: ongoing (Tixy)
    • Are there any other kernel features known still to be broken with Thumb-2?
  • perf: breakpoints not working, assuming that sizeof(unsigned long) == sizeof(instructions). issue is in tool, not in kernel.
  • ACTION: Linaro to look into above
  • ACTION: Look into kgdb
  • jonmasters: Do jumplabels work? ACTION: Will ping Jason [Baron] (maintiner) to look into it.
  • Dynamic ftrace support. On x86, Steven R. had to sync up with GCC developers to support new flag that moves mcount call earlier in functions. Linaro toolchain team is looking into this.
  • ACTION: Tixy to reproduce/fix thumb2 relocation problems in loading modules
    • Cortex-A15 support
  • Will: CPU or platform support?
  • Dmart: Both. Primary goal is CPU support, allows for vendor platform enablement. Will have FPGA platforms for development.
  • <cmarinas> Hopefully A15 (LPAE, timers) will get into mainline for 2.6.41 (we need more pressure on rmk :))

  • ACTION: Nicolas to pull Catalin's A15 tree into Linaro's 2.6.39 tree: http://git.kernel.org/?p=linux/kernel/git/cmarinas/linux-2.6-cm.git;a=summary

  • Virtualization support on A15 is under development.
  • There is ongoing work at the Columbia University for KVM on A15
  • Arnd: Having KVM support in kernel is probably not hardware. Do we watn to target QEMU for main target or do we want to use the new KVM tool.
  • ACTION: Follow up with Peter Maydell re qemu model for KVM
  • ACTION: Will to ping KVM on A15 developer
  • ACTION: Follow up with KVM community in regards to KVMtool, see what they have and if we should pull it into our side
  • Arnd: Is there anything we need to worry about to run Linux on other hypervisors?
  • Will: There's no mandated hypervisor ABI.
  • ACTION: Have follow up discussion regarding hypervisor interface (Arnd, Will, ?)
  • Arnd: Ideal would be to have defined device driver interfaces between hypervisor and guest (cmarinas: initial API discussion https://lists.cs.columbia.edu/pipermail/android-virt/2011-May/000168.html)

    • platform availablity currently limited - expected to have limited hardware availability mid-cycle
    • ensure kernel support is in the linaro tree during the 11.11 cycle
    • What else is needed?
  • Support for security interface/trustzone. What is it? Can we have a standard? ARM is not pushing a standard ABI.
  • gcl: We need to have standard interface, other SW vendors will want this. What is the forum to have this discussion?
  • Linus W.: Trusted Execution Environment is the standard. Cross-architecture.
  • ACTION: Linaro to find out who to follow up with.
  • ACTION: TSC needs to discuss this and get partner's views
  • ACTION: Follow up with Global Platform regarding standarization of secure firmware interface
  • Arnd: Can we have an open source version of the secure firmware?
  • gcl: Would be a good reference.

Summary of Actions

  • ACTION; [dmart] to document what he needed to do get it [Thumb-2] working
  • ACTION: [dmart] to follow up with each landing team
  • ACTION: [+] follow up to see if Versatile Express can be built in thumb2 by default in Linaro kernels -- cmarinas says it works
  • ACTION: [+] run comparitive benchmark of ARM/Thumb-2 kernel using lmbench
  • ACTION: [+] follow up with infrastructure team about tracking code-size metrics for linaro kernel builds
  • ACTION: [tixy] complete kprobes for Thumb-2
  • ACTION: investigate whether breakpoints facility in perf userspace tool is broken (assuming that sizeof(unsigned long) == sizeof(instructions))
  • ACTION: [+] Check whether work is needed to get kgdb working with Thumb-2.
  • ACTION: [+] Check whether perf jump labels (CONFIG_JUMP_LABEL) need work for Thumb-2 (maybe follow up with the maintainer Jason Baron)
  • ACTION: [Tixy] to reproduce/report/fix the thumb2 relocation problems he encountered when loading modules
  • ACTION: [npitre] to pull Catalin's A15 tree into Linaro's 2.6.39 tree: http://git.kernel.org/?p=linux/kernel/git/cmarinas/linux-2.6-cm.git;a=summary

  • ACTION: [dmart] follow up with arnd to decrypt this from the session notes: "There is ongoing work at the Columbia University for KVM on A15 - https://lists.cs.columbia.edu/pipermail/android-virt/2011-May/thread.html - Arnd: Having KVM support in kernel is probably not hardware. Do we watn to target QEMU for main target or do we want to use the new KVM tool. - ACTION: Follow up with Peter Maydell re qemu model for KVM"

  • ACTION: [Will Deacon] to ping KVM-on-A15 developer
  • ACTION: Follow up with KVM community in regards to KVMtool, see what they have and if we should pull it into our side
  • ACTION: Have follow up discussion regarding hypervisor interface (Arnd, Will, ?) [Arnd:] Ideal would be to have defined device driver interfaces between hypervisor and guest (cmarinas: initial API discussion https://lists.cs.columbia.edu/pipermail/android-virt/2011-May/000168.html)

  • ACTION: Linaro to find out who to follow up with re TrustZone/security environment interface standardisation (GlobalPlatform, ARM, ... ?)

  • ACTION: Linaro TSC needs to discuss TrustZone/security environment interface standardisation/integration and get partners' views

[+] indicates possible new-starter tasks


CategorySpec

Specs/KernelStandardArchitectureO (last modified 2011-05-19 15:46:03)