github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-06-05 21:15:53 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph
Linux kernel source tree
985,226 Commits 1 Branch 933 Tags 20 GiB
C 97%
Assembly 1%
Shell 0.6%
Rust 0.5%
Python 0.4%
Other 0.3%
71d3adbb28
Go to file
Ionela Voinescu 71d3adbb28 arm64: errata: add detection for AMEVCNTR01 incrementing incorrectly 
commit e89d120c4b upstream.

The AMU counter AMEVCNTR01 (constant counter) should increment at the same
rate as the system counter. On affected Cortex-A510 cores, AMEVCNTR01
increments incorrectly giving a significantly higher output value. This
results in inaccurate task scheduler utilization tracking and incorrect
feedback on CPU frequency.

Work around this problem by returning 0 when reading the affected counter
in key locations that results in disabling all users of this counter from
using it either for frequency invariance or as FFH reference counter. This
effect is the same to firmware disabling affected counters.

Details on how the two features are affected by this erratum:

 - AMU counters will not be used for frequency invariance for affected
   CPUs and CPUs in the same cpufreq policy. AMUs can still be used for
   frequency invariance for unaffected CPUs in the system. Although
   unlikely, if no alternative method can be found to support frequency
   invariance for affected CPUs (cpufreq based or solution based on
   platform counters) frequency invariance will be disabled. Please check
   the chapter on frequency invariance at
   Documentation/scheduler/sched-capacity.rst for details of its effect.

 - Given that FFH can be used to fetch either the core or constant counter
   values, restrictions are lifted regarding any of these counters
   returning a valid (!0) value. Therefore FFH is considered supported
   if there is a least one CPU that support AMUs, independent of any
   counters being disabled or affected by this erratum. Clarifying
   comments are now added to the cpc_ffh_supported(), cpu_read_constcnt()
   and cpu_read_corecnt() functions.

The above is achieved through adding a new erratum: ARM64_ERRATUM_2457168.

Signed-off-by: Ionela Voinescu <ionela.voinescu@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: James Morse <james.morse@arm.com>
Link: https://lore.kernel.org/r/20220819103050.24211-1-ionela.voinescu@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-09-15 11:32:06 +02:00
arch arm64: errata: add detection for AMEVCNTR01 incrementing incorrectly 2022-09-15 11:32:06 +02:00
block blk-mq: fix io hung due to missing commit_rqs 2022-08-31 17:15:24 +02:00
certs certs/blacklist_hashes.c: fix const confusion in certs blacklist 2022-06-22 14:13:17 +02:00
crypto KEYS: asymmetric: enforce SM2 signature use pkey algo 2022-08-21 15:16:22 +02:00
Documentation arm64: errata: add detection for AMEVCNTR01 incrementing incorrectly 2022-09-15 11:32:06 +02:00
drivers hwmon: (mr75203) enable polling for all VM channels 2022-09-15 11:32:06 +02:00
fs afs: Use the operation issue time instead of the reply time for callbacks 2022-09-15 11:32:05 +02:00
include debugfs: add debugfs_lookup_and_remove() 2022-09-15 11:32:03 +02:00
init Kconfig: Add option for asm goto w/ tied outputs to workaround clang-13 bug 2022-06-09 10:21:25 +02:00
ipc ipc/mqueue: use get_tree_nodev() in mqueue_get_tree() 2022-06-09 10:21:17 +02:00
kernel swiotlb: avoid potential left shift overflow 2022-09-15 11:32:06 +02:00
lib lib/vdso: Mark do_hres_timens() and do_coarse_timens() __always_inline() 2022-09-05 10:28:58 +02:00
LICENSES LICENSES/deprecated: add Zlib license text 2020-09-16 14:33:49 +02:00
mm Revert "mm: kmemleak: take a full lowmem check in kmemleak_*_phys()" 2022-09-15 11:32:02 +02:00
net sch_sfb: Also store skb len before calling child enqueue 2022-09-15 11:32:06 +02:00
samples x86: Prepare inline-asm for straight-line-speculation 2022-07-25 11:26:29 +02:00
scripts kbuild: Fix include path in scripts/Makefile.modpost 2022-09-05 10:28:55 +02:00
security apparmor: Fix memleak in aa_simple_write_to_buffer() 2022-08-25 11:37:53 +02:00
sound ASoC: mchp-spdiftx: Fix clang -Wbitfield-constant-conversion 2022-09-15 11:32:06 +02:00
tools perf python: Fix build when PYTHON_CONFIG is user supplied 2022-08-31 17:15:24 +02:00
usr usr/include/Makefile: add linux/nfc.h to the compile-test coverage 2022-02-01 17:25:48 +01:00
virt KVM: Add infrastructure and macro to mark VM as bugged 2022-08-21 15:16:24 +02:00
.clang-format RDMA 5.10 pull request 2020-10-17 11:18:18 -07:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore kbuild: generate Module.symvers only when vmlinux exists 2021-05-19 10:12:59 +02:00
.mailmap mailmap: add two more addresses of Uwe Kleine-König 2020-12-06 10:19:07 -08:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Jason Cooper to CREDITS 2020-11-30 10:20:34 +01:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS MAINTAINERS: add Amir as xfs maintainer for 5.10.y 2022-07-02 16:39:22 +02:00
Makefile Linux 5.10.142 2022-09-08 11:11:41 +02:00
README

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 Restructured Text 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.