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Mark Brown c66e5205fd arm64/sme: Move storage of reg_smidr to __cpuinfo_store_cpu() 
commit d3c7c48d00 upstream.

In commit 892f7237b3 ("arm64: Delay initialisation of
cpuinfo_arm64::reg_{zcr,smcr}") we moved access to ZCR, SMCR and SMIDR
later in the boot process in order to ensure that we don't attempt to
interact with them if SVE or SME is disabled on the command line.
Unfortunately when initialising the boot CPU in init_cpu_features() we work
on a copy of the struct cpuinfo_arm64 for the boot CPU used only during
boot, not the percpu copy used by the sysfs code. The expectation of the
feature identification code was that the ID registers would be read in
__cpuinfo_store_cpu() and the values not modified by init_cpu_features().

The main reason for the original change was to avoid early accesses to
ZCR on practical systems that were seen shipping with SVE reported in ID
registers but traps enabled at EL3 and handled as fatal errors, SME was
rolled in due to the similarity with SVE. Since then we have removed the
early accesses to ZCR and SMCR in commits:

  abef0695f9 ("arm64/sve: Remove ZCR pseudo register from cpufeature code")
  391208485c ("arm64/sve: Remove SMCR pseudo register from cpufeature code")

so only the SMIDR_EL1 part of the change remains. Since SMIDR_EL1 is
only trapped via FEAT_IDST and not the SME trap it is less likely to be
affected by similar issues, and the factors that lead to issues with SVE
are less likely to apply to SME.

Since we have not yet seen practical SME systems that need to use a
command line override (and are only just beginning to see SME systems at
all) and the ID register read is much more likely to be safe let's just
store SMIDR_EL1 along with all the other ID register reads in
__cpuinfo_store_cpu().

This issue wasn't apparent when testing on emulated platforms that do not
report values in SMIDR_EL1.

Fixes: 892f7237b3 ("arm64: Delay initialisation of cpuinfo_arm64::reg_{zcr,smcr}")
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20241217-arm64-fix-boot-cpu-smidr-v3-1-7be278a85623@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2025-02-17 10:05:05 +01:00
arch arm64/sme: Move storage of reg_smidr to __cpuinfo_store_cpu() 2025-02-17 10:05:05 +01:00
block partitions: ldm: remove the initial kernel-doc notation 2025-02-08 09:56:52 +01:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto crypto: api - Fix boot-up self-test race 2025-02-08 09:57:28 +01:00
Documentation arm64: Filter out SVE hwcaps when FEAT_SVE isn't implemented 2025-02-17 10:05:04 +01:00
drivers accel/ivpu: Fix Qemu crash when running in passthrough 2025-02-17 10:05:04 +01:00
fs binfmt_flat: Fix integer overflow bug on 32 bit systems 2025-02-17 10:05:04 +01:00
include md: reintroduce md-linear 2025-02-17 10:05:04 +01:00
init Compiler Attributes: disable __counted_by for clang < 19.1.3 2024-12-05 14:02:45 +01:00
io_uring io_uring/uring_cmd: use cached cmd_op in io_uring_cmd_sock() 2025-02-08 09:58:10 +01:00
ipc ipc: fix memleak if msg_init_ns failed in create_ipc_ns 2024-12-05 14:03:02 +01:00
kernel sched/fair: Fix inaccurate h_nr_runnable accounting with delayed dequeue 2025-02-17 10:04:57 +01:00
lib lockdep: Fix upper limit for LOCKDEP_*_BITS configs 2025-02-17 10:04:44 +01:00
LICENSES LICENSES: add 0BSD license text 2024-09-01 20:43:24 -07:00
mm memcg: fix soft lockup in the OOM process 2025-02-08 09:58:19 +01:00
net rxrpc: Fix call state set to not include the SERVER_SECURING state 2025-02-17 10:05:02 +01:00
rust rust: kbuild: set bindgen's Rust target version 2024-12-19 18:13:22 +01:00
samples samples/landlock: Fix possible NULL dereference in parse_path() 2025-02-08 09:57:11 +01:00
scripts kbuild: switch from lz4c to lz4 for compression 2025-02-08 09:58:12 +01:00
security tomoyo: don't emit warning in tomoyo_write_control() 2025-02-17 10:04:50 +01:00
sound ALSA: hda/realtek: Enable Mute LED on HP Laptop 14s-fq1xxx 2025-02-17 10:05:03 +01:00
tools udp: gso: do not drop small packets when PMTU reduces 2025-02-17 10:05:00 +01:00
usr initramfs: shorten cmd_initfs in usr/Makefile 2024-07-16 01:07:52 +09:00
virt KVM: x86: switch hugepage recovery thread to vhost_task 2024-12-05 14:02:43 +01:00
.clang-format clang-format: Update with v6.11-rc1's for_each macro list 2024-08-02 13:20:31 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore Add Jeff Kirsher to .get_maintainer.ignore 2024-03-08 11:36:54 +00:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore Kbuild updates for v6.12 2024-09-24 13:02:06 -07:00
.mailmap mailmap: add entry for Thorsten Blum 2024-11-07 14:14:59 -08:00
.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 MAINTAINERS: Remove self from DSA entry 2024-11-03 12:52:38 -08:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS MAINTAINERS: update location of media main tree 2024-12-05 14:02:42 +01:00
Makefile Linux 6.12.13 2025-02-08 09:58:20 +01:00
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.