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James Morse 9a697eff25 cacheinfo: Add arch hook to compress CPU h/w id into 32 bits for cache-id
Filesystems like resctrl use the cache-id exposed via sysfs to identify
groups of CPUs. The value is also used for PCIe cache steering tags. On
DT platforms cache-id is not something that is described in the
device-tree, but instead generated from the smallest CPU h/w id of the
CPUs associated with that cache.

CPU h/w ids may be larger than 32 bits.

Add a hook to allow architectures to compress the value from the devicetree
into 32 bits. Returning the same value is always safe as cache_of_set_id()
will stop if a value larger than 32 bits is seen.

For example, on arm64 the value is the MPIDR affinity register, which only
has 32 bits of affinity data, but spread accross the 64 bit field. An
arch-specific bit swizzle gives a 32 bit value.

Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Link: https://lore.kernel.org/r/20250711182743.30141-3-james.morse@arm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-07-16 15:04:27 +02:00
Documentation Docs/ABI: Fix sysfs-kernel-address_bits path 2025-07-01 12:18:47 +02:00
LICENSES LICENSES: add CC0-1.0 license text 2025-05-21 14:54:17 +02:00
arch Merge 6.16-rc3 into driver-core-next 2025-06-23 07:53:36 +02:00
block blk-mq-debugfs: use debugfs_get_aux() 2025-07-09 13:30:29 +02:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto crypto: ahash - Fix infinite recursion in ahash_def_finup 2025-06-18 17:02:02 +08:00
drivers cacheinfo: Add arch hook to compress CPU h/w id into 32 bits for cache-id 2025-07-16 15:04:27 +02:00
fs debugfs_get_aux(): allow storing non-const void * 2025-07-09 13:30:29 +02:00
include container_of: Document container_of() is not to be used in new code 2025-07-16 13:56:23 +02:00
init init: fix build warnings about export.h 2025-06-11 22:42:36 -07:00
io_uring io_uring-6.16-20250621 2025-06-21 08:40:45 -07:00
ipc - The 3 patch series "hung_task: extend blocking task stacktrace dump to 2025-05-31 19:12:53 -07:00
kernel Merge 6.16-rc3 into driver-core-next 2025-06-23 07:53:36 +02:00
lib This push fixes a regression in ahash (broken fallback finup) 2025-06-19 23:15:10 -07:00
mm vmscan: don't bother with debugfs_real_fops() 2025-07-09 13:30:28 +02:00
net Merge 6.16-rc3 into driver-core-next 2025-06-23 07:53:36 +02:00
rust rust: device: implement Device::as_bound() 2025-07-15 14:56:56 +02:00
samples samples/kobject: make attribute_group const 2025-07-16 13:32:53 +02:00
scripts Merge 6.16-rc3 into driver-core-next 2025-06-23 07:53:36 +02:00
security selinux: fix selinux_xfrm_alloc_user() to set correct ctx_len 2025-06-16 19:02:22 -04:00
sound ALSA: hda/realtek: Enable headset Mic on Positivo P15X 2025-06-20 10:05:46 +02:00
tools - Make sure the switch to the global hash is requested always under a lock so 2025-06-22 10:09:23 -07:00
usr usr/include: openrisc: don't HDRTEST bpf_perf_event.h 2025-05-12 15:03:17 +09:00
virt Merge branch 'kvm-lockdep-common' into HEAD 2025-05-28 06:29:17 -04:00
.clang-format Linux 6.15-rc5 2025-05-06 16:39:25 +10:00
.clippy.toml rust: clean Rust 1.88.0's warning about `clippy::disallowed_macros` configuration 2025-05-07 00:11:47 +02:00
.cocciconfig
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore MAINTAINERS: Retire Ralf Baechle 2024-11-12 15:48:59 +01:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore .gitignore: ignore Python compiled bytecode 2025-04-24 10:12:46 -06:00
.mailmap Including fixes from wireless. The ath12k fix to avoid FW crashes 2025-06-19 10:21:32 -07:00
.pylintrc docs: add a .pylintrc file with sys path for docs scripts 2025-04-09 12:10:33 -06:00
.rustfmt.toml
COPYING
CREDITS Update Christoph's Email address and make it consistent 2025-05-12 23:50:31 -07:00
Kbuild drm: ensure drm headers are self-contained and pass kernel-doc 2025-02-12 10:44:43 +02:00
Kconfig io_uring: Rename KConfig to Kconfig 2025-02-19 14:53:27 -07:00
MAINTAINERS rust: acpi: add `acpi::DeviceId` abstraction 2025-06-26 23:22:17 +02:00
Makefile Linux 6.16-rc3 2025-06-22 13:30:08 -07:00
README README: Fix spelling 2024-03-18 03:36:32 -06:00

README

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

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.