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caina e67091609c Revert "irqchip/mbigen: Fix mbigen node address layout"
This reverts commit 6be6cba9c4.

Commit 6be6cba9c4 ("irqchip/mbigen: Fix mbigen node address layout")
appears to cause a regression on Hi1616.

On-board hns NIC has two ports, enahisic2i0 and enahisic2i1, both
behind mbigen-v2.  Port 0 works; port 1 cannot pass any traffic.

Their interrupt pins fall on different mbigen nodes:

  enahisic2i0: pins 1152-1198 -> all in node 9
  enahisic2i1: pins 1200-1246 -> node 9 (1200-1215) + node 10 (1216-1246)

  (nid = (hwirq - 64) / 128 + 1; pin 1215 = node 9, pin 1216 = node 10)

/proc/interrupts shows the break happens exactly at the node boundary:

  enahisic2i1-rx0  pin 1200  count 102   <- node 9
  enahisic2i1-rx5  pin 1215  count   1   <- node 9, last pin
  enahisic2i1-tx5  pin 1216  count   0   <- node 10, first pin
  enahisic2i1-rx6  pin 1218  count   0   <- node 10
  ...all node 10 pins stay at zero.

Port 0 (entirely node 9) is unaffected.  Reverting the commit restores
normal operation.

The commit assumes CLEAR occupies a full 4 KB page at [0xa000, 0xb000)
and collides with node 10, so node 10+ gets shifted by 0x1000.

But get_mbigen_clear_reg() uses flat, chip-wide addressing -- it never
multiplies by the node ID:

    *addr = (hwirq / 32) * 4 + REG_MBIGEN_CLEAR_OFFSET;  /* 0xa000 */

Over the valid hwirq range [64, 1407], CLEAR only spans 0xa008-0xa0af
(168 bytes).  Node 10's registers are:

    TYPE: 0xa000-0xa00f  (16 B)   overlaps CLEAR by 8 B (0xa008-0xa00f)
    VEC:  0xa200-0xa3ff  (512 B)  no overlap with CLEAR

Shifting the whole page moves VEC from 0xa200 to 0xb200.  The hardware
reads the event ID from the fixed silicon address 0xa200 on interrupt
firing, but software wrote it to 0xb200 -- so the hardware gets an
uninitialised value and the interrupt is lost.

The only real overlap is 8 bytes of TYPE.  It can only trigger when a
single mbigen instance has devices on both node 1 (CLEAR 0xa008) and
node 10 (TYPE 0xa008).  On Hi1616 those nodes are on separate mbigen
instances, so it never triggers.

Fixes: 6be6cba9c4 ("irqchip/mbigen: Fix mbigen node address layout")
Suggested-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: caina <caina@uniontech.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Acked-by: Yipeng Zou <zouyipeng@huawei.com>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260821091720.16665-1-caina@uniontech.com
History 2026-09-04 16:12:53 +02:00
arch - Fix UM build regression caused by the removal of the UM 2026-08-30 10:19:11 -07:00
block for-7.3/block-20260819 2026-08-20 13:55:16 -07:00
certs treewide: fix indentation and whitespace in Kconfig files 2026-05-28 21:24:42 -07:00
crypto This push fixes a memory allocation overrun in crypto acomp. 2026-08-28 09:28:40 -07:00
Documentation irqdomain: Delete irq_domain_add_linear() 2026-09-04 08:40:07 +02:00
drivers Revert "irqchip/mbigen: Fix mbigen node address layout" 2026-09-04 16:12:53 +02:00
fs tracing fixes for v7.3: 2026-08-30 09:22:00 -07:00
include irqdomain: Delete irq_domain_add_linear() 2026-09-04 08:40:07 +02:00
init Bootconfig updates for v7.3: 2026-08-25 08:59:09 -07:00
io_uring io_uring-7.3-20260828 2026-08-28 16:51:14 -07:00
ipc mm.git review status for master..mm-nonmm-stable 2026-08-23 08:07:11 -07:00
kernel - Revert a commit to spinlock cleanup guards that got caught up 2026-08-30 09:57:35 -07:00
lib mm.git review status for linus..mm-stable 2026-08-27 09:17:06 -07:00
LICENSES LICENSES: Add modern form of the LGPL-2.1 tags to the usage guide section 2025-10-22 07:58:19 +02:00
mm mm.git review status for linus..mm-stable 2026-08-27 09:17:06 -07:00
net A wide variety of mostly CephFS fixes and cleanups, split between 2026-08-28 11:51:05 -07:00
rust Rust fixes for v7.3 2026-08-30 09:47:39 -07:00
samples tracing fixes for v7.3: 2026-08-30 09:22:00 -07:00
scripts Coccinelle patches for Linux v7.3 2026-08-30 10:42:40 -07:00
security Hi, 2026-08-28 09:36:27 -07:00
sound sound fixes for 7.3-rc1 2026-08-28 10:01:02 -07:00
tools Rust fixes for v7.3 2026-08-30 09:47:39 -07:00
usr usr: Correct a spelling by changing a letter 2026-08-05 14:51:58 +02:00
virt Arm: 2026-08-25 11:48:04 -07:00
.clang-format drm/bridge: rename drm_for_each_bridge_in_chain_scoped() to drm_for_each_bridge_in_chain() 2026-07-14 17:55:51 +02:00
.clippy.toml rust: bump Clippy's MSRV and clean incompatible_msrv allows 2026-04-07 09:51:39 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.editorconfig editorconfig: add rst extension 2026-01-26 19:07:09 -08:00
.get_maintainer.ignore .get_maintainer.ignore: add Nathan Chancellor 2026-08-03 21:10:12 -07:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore SPDX patches for 7.2-rc1 2026-06-22 12:06:22 -07:00
.mailmap CREDITS/mailmap: add some info about Darrick J. Wong 2026-08-30 10:29:08 -07:00
.pylintrc docs: Move the python libraries to tools/lib/python 2025-11-18 09:22:40 -07:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS CREDITS/mailmap: add some info about Darrick J. Wong 2026-08-30 10:29:08 -07:00
Kbuild checksyscalls: move instance functionality into generic code 2026-04-05 09:21:32 +02:00
Kconfig io_uring: Rename KConfig to Kconfig 2025-02-19 14:53:27 -07:00
MAINTAINERS SCSI updates for 7.3 2026-08-29 11:55:36 -07:00
Makefile Linux 7.3-rc1 2026-08-30 13:34:40 -07:00
README README: remove out of place emdashes 2026-07-15 10:51:29 -06:00

Linux kernel
============

The Linux kernel is the core of any Linux operating system. It manages hardware,
system resources, and provides the fundamental services for all other software.

Quick Start
-----------

* Report a bug: See Documentation/admin-guide/reporting-issues.rst
* Get the latest kernel: https://kernel.org
* Build the kernel: See Documentation/admin-guide/quickly-build-trimmed-linux.rst
* Join the community: https://lore.kernel.org/

Essential Documentation
-----------------------

All users should be familiar with:

* Building requirements: Documentation/process/changes.rst
* Code of Conduct: Documentation/process/code-of-conduct.rst
* License: See COPYING

Documentation can be built with make htmldocs or viewed online at:
https://www.kernel.org/doc/html/latest/


Who Are You?
============

Find your role below:

* New Kernel Developer: Getting started with kernel development
* Academic Researcher: Studying kernel internals and architecture
* Security Expert: Hardening and vulnerability analysis
* Backport/Maintenance Engineer: Maintaining stable kernels
* System Administrator: Configuring and troubleshooting
* Maintainer: Leading subsystems and reviewing patches
* Hardware Vendor: Writing drivers for new hardware
* Distribution Maintainer: Packaging kernels for distros
* AI Coding Assistant: LLMs and AI-powered development tools


For Specific Users
==================

New Kernel Developer
--------------------

Welcome! Start your kernel development journey here:

* Getting Started: Documentation/process/development-process.rst
* Your First Patch: Documentation/process/submitting-patches.rst
* Coding Style: Documentation/process/coding-style.rst
* Build System: Documentation/kbuild/index.rst
* Development Tools: Documentation/dev-tools/index.rst
* Kernel Hacking Guide: Documentation/kernel-hacking/hacking.rst
* Core APIs: Documentation/core-api/index.rst

Academic Researcher
-------------------

Explore the kernel's architecture and internals:

* Researcher Guidelines: Documentation/process/researcher-guidelines.rst
* Memory Management: Documentation/mm/index.rst
* Scheduler: Documentation/scheduler/index.rst
* Networking Stack: Documentation/networking/index.rst
* Filesystems: Documentation/filesystems/index.rst
* RCU (Read-Copy Update): Documentation/RCU/index.rst
* Locking Primitives: Documentation/locking/index.rst
* Power Management: Documentation/power/index.rst

Security Expert
---------------

Security documentation and hardening guides:

* Security Documentation: Documentation/security/index.rst
* LSM Development: Documentation/security/lsm-development.rst
* Self Protection: Documentation/security/self-protection.rst
* Reporting Vulnerabilities: Documentation/process/security-bugs.rst
* CVE Procedures: Documentation/process/cve.rst
* Embargoed Hardware Issues: Documentation/process/embargoed-hardware-issues.rst
* Security Features: Documentation/userspace-api/seccomp_filter.rst

Backport/Maintenance Engineer
-----------------------------

Maintain and stabilize kernel versions:

* Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst
* Backporting Guide: Documentation/process/backporting.rst
* Applying Patches: Documentation/process/applying-patches.rst
* Subsystem Profile: Documentation/maintainer/maintainer-entry-profile.rst
* Git for Maintainers: Documentation/maintainer/configure-git.rst

System Administrator
--------------------

Configure, tune, and troubleshoot Linux systems:

* Admin Guide: Documentation/admin-guide/index.rst
* Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst
* Sysctl Tuning: Documentation/admin-guide/sysctl/index.rst
* Tracing/Debugging: Documentation/trace/index.rst
* Performance Security: Documentation/admin-guide/perf-security.rst
* Hardware Monitoring: Documentation/hwmon/index.rst

Maintainer
----------

Lead kernel subsystems and manage contributions:

* Maintainer Handbook: Documentation/maintainer/index.rst
* Pull Requests: Documentation/maintainer/pull-requests.rst
* Managing Patches: Documentation/maintainer/modifying-patches.rst
* Rebasing and Merging: Documentation/maintainer/rebasing-and-merging.rst
* Development Process: Documentation/process/maintainer-handbooks.rst
* Maintainer Entry Profile: Documentation/maintainer/maintainer-entry-profile.rst
* Git Configuration: Documentation/maintainer/configure-git.rst

Hardware Vendor
---------------

Write drivers and support new hardware:

* Driver API Guide: Documentation/driver-api/index.rst
* Driver Model: Documentation/driver-api/driver-model/driver.rst
* Device Drivers: Documentation/driver-api/infrastructure.rst
* Bus Types: Documentation/driver-api/driver-model/bus.rst
* Device Tree Bindings: Documentation/devicetree/bindings/
* Power Management: Documentation/driver-api/pm/index.rst
* DMA API: Documentation/core-api/dma-api.rst

Distribution Maintainer
-----------------------

Package and distribute the kernel:

* Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst
* ABI Documentation: Documentation/ABI/README
* Kernel Configuration: Documentation/kbuild/kconfig.rst
* Module Signing: Documentation/admin-guide/module-signing.rst
* Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst
* Tainted Kernels: Documentation/admin-guide/tainted-kernels.rst

AI Coding Assistant
-------------------

CRITICAL: If you are an LLM or AI-powered coding assistant, you MUST read and
follow the AI coding assistants documentation before contributing to the Linux
kernel:

* Documentation/process/coding-assistants.rst

This documentation contains essential requirements about licensing, attribution,
and the Developer Certificate of Origin that all AI tools must comply with.


Communication and Support
=========================

* Mailing Lists: https://lore.kernel.org/
* IRC: #kernelnewbies on irc.oftc.net
* Bugzilla: https://bugzilla.kernel.org/
* MAINTAINERS file: Lists subsystem maintainers and mailing lists
* Email Clients: Documentation/process/email-clients.rst