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 --- Documentation/process/maintainer-devicetree.rst | 72 +++++++++++++++++++++++++ 1 file changed, 72 insertions(+) create mode 100644 Documentation/process/maintainer-devicetree.rst (limited to 'Documentation/process/maintainer-devicetree.rst') diff --git a/Documentation/process/maintainer-devicetree.rst b/Documentation/process/maintainer-devicetree.rst new file mode 100644 index 000000000..ecc3ed638 --- /dev/null +++ b/Documentation/process/maintainer-devicetree.rst @@ -0,0 +1,72 @@ +.. SPDX-License-Identifier: GPL-2.0 + +====================================== +Devicetree and Open Firmware Subsystem +====================================== + +Other Process Documents +----------------------- + +Please see the documents in Documentation/devicetree/bindings/ for information +on how to write proper Devicetree bindings and how to submit patches. + +Patch Review and Handling +------------------------- + +Patches handled by Devicetree maintainers are processed differently depending +on the patch type: + +1. Core OF driver code, e.g. drivers/of/: + patches are reviewed and applied by DT maintainers. + +2. Devicetree bindings: + patches are reviewed by DT maintainers, but should be applied by subsystem + maintainers except in certain cases. See also *For kernel maintainers* in + Documentation/devicetree/bindings/submitting-patches.rst. + +3. DTS and drivers: + DT maintainers might provide comments, but review is generally not expected. + DTS must pass schema checks (dtbs_check) or at least do not add any + new warnings. + +Patchwork +~~~~~~~~~ + +Devicetree maintainers review patches using Patchwork, so the current status of +a patch can be checked there. For typical driver submissions, Patchwork +receives the entire patch set, but only a few patches are usually Devicetree +bindings that are reviewed by DT maintainers. + +Explanation of Patchwork statuses: + + - **New**: Not yet processed by the automation toolset. + - **Needs ACK**: Waiting for review by DT maintainers. + - **Handled Elsewhere**: Non-DT patch; not being reviewed here. + - **RFC**: Patch was likely ignored because it was an incomplete RFC. + - **Changes Requested**: Patch was reviewed and DT maintainers expect changes. + - **Accepted**: Patch was reviewed and applied by DT maintainers to their tree. + - **Not Applicable**: Patch was reviewed and is likely in good shape, with a + *Reviewed-by* or *Acked-by* tag provided, but DT maintainers expect someone + else to apply it. + +Patch Re-review and Pinging +~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Due to the high volume of email traffic, Devicetree maintainers do not read +every email they receive and instead rely on Patchwork during the review +process. They also often skip patches that have already been reviewed. + +As a result, maintainers might miss: + +1. Questions about already reviewed patches. +2. Pings, for example when a patch has been reviewed by DT maintainers but has + not been picked up by subsystem maintainers. + +Such cases can be addressed by: + +1. Pinging DT maintainers on the IRC channel. +2. Dropping the DT maintainer’s *Acked-by* or *Reviewed-by* tag when sending a new + version of the patch set, together with an explanation in the patch + changelog describing why the tag was removed and what is expected from DT + maintainers. + -- cgit v1.3.1