From 2bc6b218717b9d08f466f88209251d54bc09b207 Mon Sep 17 00:00:00 2001 From: Fuad Tabba Date: Tue, 22 Sep 2026 19:14:30 +0100 Subject: arm64/boot: Disable trapping of PMZR_EL0 writes to EL2 __init_el2_fgt2() writes one mask to both HDFGRTR2_EL2 and HDFGWTR2_EL2. PMZR_EL0 is write-only, so its trap bit, nPMZR_EL0, exists only in HDFGWTR2_EL2 and is therefore never set: a PMZR_EL0 write from the host traps to EL2, where the nVHE hypervisor has no handler and BUG()s. The kernel never writes PMZR_EL0, but kernel.perf_user_access=1 has the PMU driver set PMUSERENR_EL0.UEN for a task with a user-read event, so a write from EL0 reaches the trap and takes the host down without a panic message. Accumulate the HDFGWTR2_EL2 bits separately, as __init_el2_fgt() already does for HDFGWTR_EL2, and set nPMZR_EL0 with the other FEAT_PMUv3p9 bits. Fixes: 858c7bfcb35e1 ("arm64/boot: Enable EL2 requirements for FEAT_PMUv3p9") Cc: stable@vger.kernel.org Signed-off-by: Fuad Tabba Reviewed-by: Anshuman Khandual Reviewed-by: Oliver Upton Signed-off-by: Will Deacon --- .../process/contribution-maturity-model.rst | 109 +++++++++++++++++++++ 1 file changed, 109 insertions(+) create mode 100644 Documentation/process/contribution-maturity-model.rst (limited to 'Documentation/process/contribution-maturity-model.rst') diff --git a/Documentation/process/contribution-maturity-model.rst b/Documentation/process/contribution-maturity-model.rst new file mode 100644 index 000000000..b87ab34de --- /dev/null +++ b/Documentation/process/contribution-maturity-model.rst @@ -0,0 +1,109 @@ +.. SPDX-License-Identifier: GPL-2.0 + +======================================== +Linux Kernel Contribution Maturity Model +======================================== + + +Background +========== + +As a part of the 2021 Linux Kernel Maintainers’ Summit, there was a +`discussion `_ about the challenges in +recruiting kernel maintainers as well as maintainer succession. Some of +the conclusions from that discussion included that companies which are a +part of the Linux Kernel community need to allow engineers to be +maintainers as part of their job, so they can grow into becoming +respected leaders and eventually, kernel maintainers. To support a +strong talent pipeline, developers should be allowed and encouraged to +take on upstream contributions such as reviewing other people’s patches, +refactoring kernel infrastructure, and writing documentation. + +To that end, the Linux Foundation Technical Advisory Board (TAB) +proposes this Linux Kernel Contribution Maturity Model. These common +expectations for upstream community engagement aim to increase the +influence of individual developers, increase the collaboration of +organizations, and improve the overall health of the Linux Kernel +ecosystem. + +The TAB urges organizations to continuously evaluate their Open Source +maturity model and commit to improvements to align with this model. To +be effective, this evaluation should incorporate feedback from across +the organization, including management and developers at all seniority +levels. In the spirit of Open Source, we encourage organizations to +publish their evaluations and plans to improve their engagement with the +upstream community. + +Level 0 +======= + +* Software Engineers are not allowed to contribute patches to the Linux + kernel. + + +Level 1 +======= + +* Software Engineers are allowed to contribute patches to the Linux + kernel, either as part of their job responsibilities or on their own + time. + +Level 2 +======= + +* Software Engineers are expected to contribute to the Linux Kernel as + part of their job responsibilities. +* Software Engineers will be supported to attend Linux-related + conferences as a part of their job. +* A Software Engineer’s upstream code contributions will be considered + in promotion and performance reviews. + +Level 3 +======= + +* Software Engineers are expected to review patches (including patches + authored by engineers from other companies) as part of their job + responsibilities +* Contributing presentations or papers to Linux-related or academic + conferences (such those organized by the Linux Foundation, Usenix, + ACM, etc.), are considered part of an engineer’s work. +* A Software Engineer’s community contributions will be considered in + promotion and performance reviews. +* Organizations will regularly report metrics of their open source + contributions and track these metrics over time. These metrics may be + published only internally within the organization, or at the + organization’s discretion, some or all may be published externally. + Metrics that are strongly suggested include: + + * The number of upstream kernel contributions by team or organization + (e.g., all people reporting up to a manager, director, or VP). + * The percentage of kernel developers who have made upstream + contributions relative to the total kernel developers in the + organization. + * The time interval between kernels used in the organization’s servers + and/or products, and the publication date of the upstream kernel + upon which the internal kernel is based. + * The number of out-of-tree commits present in internal kernels. + +Level 4 +======= + +* Software Engineers are encouraged to spend a portion of their work + time focused on Upstream Work, which is defined as reviewing patches, + serving on program committees, improving core project infrastructure + such as writing or maintaining tests, upstream tech debt reduction, + writing documentation, etc. +* Software Engineers are supported in helping to organize Linux-related + conferences. +* Organizations will consider community member feedback in official + performance reviews. + +Level 5 +======= + +* Upstream kernel development is considered a formal job position, with + at least a third of the engineer’s time spent doing Upstream Work. +* Organizations will actively seek out community member feedback as a + factor in official performance reviews. +* Organizations will regularly report internally on the ratio of + Upstream Work to work focused on directly pursuing business goals. -- cgit v1.3.1