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Alexandru Elisei 2f754c81c8 arm64: cpufeature: Allow different PMU versions in ID_DFR0_EL1 
[ Upstream commit 506506cad3 ]

Commit b20d1ba3cf ("arm64: cpufeature: allow for version discrepancy in
PMU implementations") made it possible to run Linux on a machine with PMUs
with different versions without tainting the kernel. The patch relaxed the
restriction only for the ID_AA64DFR0_EL1.PMUVer field, and missed doing the
same for ID_DFR0_EL1.PerfMon , which also reports the PMU version, but for
the AArch32 state.

For example, with Linux running on two clusters with different PMU
versions, the kernel is tainted when bringing up secondaries with the
following message:

[    0.097027] smp: Bringing up secondary CPUs ...
[..]
[    0.142805] Detected PIPT I-cache on CPU4
[    0.142805] CPU features: SANITY CHECK: Unexpected variation in SYS_ID_DFR0_EL1. Boot CPU: 0x00000004011088, CPU4: 0x00000005011088
[    0.143555] CPU features: Unsupported CPU feature variation detected.
[    0.143702] GICv3: CPU4: found redistributor 10000 region 0:0x000000002f180000
[    0.143702] GICv3: CPU4: using allocated LPI pending table @0x00000008800d0000
[    0.144888] CPU4: Booted secondary processor 0x0000010000 [0x410fd0f0]

The boot CPU implements FEAT_PMUv3p1 (ID_DFR0_EL1.PerfMon, bits 27:24, is
0b0100), but CPU4, part of the other cluster, implements FEAT_PMUv3p4
(ID_DFR0_EL1.PerfMon = 0b0101).

Treat the PerfMon field as FTR_NONSTRICT and FTR_EXACT to pass the sanity
check and to match how PMUVer is treated for the 64bit ID register.

Fixes: b20d1ba3cf ("arm64: cpufeature: allow for version discrepancy in PMU implementations")
Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com>
Link: https://lore.kernel.org/r/20220617111332.203061-1-alexandru.elisei@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2022-08-17 15:14:10 +02:00
arch
block block: fix default IO priority handling again 2022-08-11 13:22:02 +02:00
certs certs: make system keyring depend on x509 parser 2022-07-24 12:53:55 -07:00
crypto crypto: s390 - do not depend on CRYPTO_HW for SIMD implementations 2022-07-06 20:04:06 -07:00
Documentation arm64: errata: Remove AES hwcap for COMPAT tasks 2022-08-17 15:14:00 +02:00
drivers soc: amlogic: Fix refcount leak in meson-secure-pwrc.c 2022-08-17 15:14:08 +02:00
fs ext2: Add more validity checks for inode counts 2022-08-17 15:14:00 +02:00
include wait: Fix __wait_event_hrtimeout for RT/DL tasks 2022-08-17 15:14:06 +02:00
init gcc-12: disable '-Warray-bounds' universally for now 2022-06-09 10:11:12 -07:00
ipc ipc: Free mq_sysctls if ipc namespace creation failed 2022-06-22 17:47:41 -05:00
kernel PM: hibernate: defer device probing when resuming from hibernation 2022-08-17 15:14:06 +02:00
lib kasan: test: Silence GCC 12 warnings 2022-08-17 15:14:06 +02:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
mm Two hotfixes, both cc:stable. 2022-07-29 21:02:35 -07:00
net netfilter: nf_tables: fix null deref due to zeroed list head 2022-08-17 15:13:59 +02:00
samples Fixes and minor clean ups for tracing: 2022-07-12 16:17:40 -07:00
scripts scripts/gdb: Fix gdb 'lx-symbols' command 2022-07-21 10:40:55 -07:00
security selinux: Add boundary check in put_entry() 2022-08-17 15:14:06 +02:00
sound ALSA: hda/realtek: Add a quirk for HP OMEN 15 (8786) mute LED 2022-08-17 15:13:46 +02:00
tools wireguard: selftests: set CONFIG_NONPORTABLE on riscv32 2022-08-17 15:13:50 +02:00
usr Not a lot of material this cycle. Many singleton patches against various 2022-05-27 11:22:03 -07:00
virt KVM: Do not incorporate page offset into gfn=>pfn cache user address 2022-08-17 15:13:43 +02:00
.clang-format clang-format: Fix space after for_each macros 2022-05-20 19:27:16 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.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: split the second line of *.mod into *.usyms 2022-05-08 03:16:59 +09:00
.mailmap ARM: SoC fixes for 5.19, part 4 2022-07-27 09:43:07 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: mark ARM/PALM TREO SUPPORT orphan 2022-07-07 15:17:00 +02:00
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 Pin control fixes for the v5.19 kernel cycle: 2022-07-22 12:24:04 -07:00
Makefile Makefile: link with -z noexecstack --no-warn-rwx-segments 2022-08-17 15:13:39 +02:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -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 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.