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Catalin Marinas 83df26299d arm64: Ensure bits ASID[15:8] are masked out when the kernel uses 8-bit ASIDs 
commit c0900d15d3 upstream.

Linux currently sets the TCR_EL1.AS bit unconditionally during CPU
bring-up. On an 8-bit ASID CPU, this is RES0 and ignored, otherwise
16-bit ASIDs are enabled. However, if running in a VM and the hypervisor
reports 8-bit ASIDs (ID_AA64MMFR0_EL1.ASIDBits == 0) on a 16-bit ASIDs
CPU, Linux uses bits 8 to 63 as a generation number for tracking old
process ASIDs. The bottom 8 bits of this generation end up being written
to TTBR1_EL1 and also used for the ASID-based TLBI operations as the
upper 8 bits of the ASID. Following an ASID roll-over event we can have
threads of the same application with the same 8-bit ASID but different
generation numbers running on separate CPUs. Both TLB caching and the
TLBI operations will end up using different actual 16-bit ASIDs for the
same process.

A similar scenario can happen in a big.LITTLE configuration if the boot
CPU only uses 8-bit ASIDs while secondary CPUs have 16-bit ASIDs.

Ensure that the ASID generation is only tracked by bits 16 and up,
leaving bits 15:8 as 0 if the kernel uses 8-bit ASIDs. Note that
clearing TCR_EL1.AS is not sufficient since the architecture requires
that the top 8 bits of the ASID passed to TLBI instructions are 0 rather
than ignored in such configuration.

Cc: stable@vger.kernel.org
Cc: Will Deacon <will@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: James Morse <james.morse@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20241203151941.353796-1-catalin.marinas@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2024-12-14 19:54:33 +01:00
arch arm64: Ensure bits ASID[15:8] are masked out when the kernel uses 8-bit ASIDs 2024-12-14 19:54:33 +01:00
block block: fix ordering between checking BLK_MQ_S_STOPPED request adding 2024-12-14 19:54:04 +01:00
certs certs: Fix build error when PKCS#11 URI contains semicolon 2023-02-09 11:28:11 +01:00
crypto crypto: api - Add crypto_clone_tfm 2024-12-14 19:53:51 +01:00
Documentation dt-bindings: serial: rs485: Fix rs485-rts-delay property 2024-12-14 19:54:03 +01:00
drivers can: mcp251xfd: mcp251xfd_get_tef_len(): work around erratum DS80000789E 6. 2024-12-14 19:54:32 +01:00
fs ksmbd: fix Out-of-Bounds Write in ksmbd_vfs_stream_write 2024-12-14 19:54:32 +01:00
include scatterlist: fix incorrect func name in kernel-doc 2024-12-14 19:54:31 +01:00
init initramfs: avoid filename buffer overrun 2024-12-14 19:53:14 +01:00
io_uring io_uring: fix possible deadlock in io_register_iowq_max_workers() 2024-11-17 15:07:21 +01:00
ipc ipc: fix memleak if msg_init_ns failed in create_ipc_ns 2024-12-14 19:54:06 +01:00
kernel tracing: Fix cmp_entries_dup() to respect sort() comparison rules 2024-12-14 19:54:32 +01:00
lib maple_tree: refine mas_store_root() on storing NULL 2024-12-14 19:54:13 +01:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
mm mm: page_alloc: move mlocked flag clearance into free_pages_prepare() 2024-12-14 19:54:31 +01:00
net tcp_bpf: Fix the sk_mem_uncharge logic in tcp_bpf_sendmsg 2024-12-14 19:54:30 +01:00
rust rust: macros: provide correct provenance when constructing THIS_MODULE 2024-10-17 15:22:24 +02:00
samples bpf: Fix the xdp_adjust_tail sample prog issue 2024-12-14 19:53:27 +01:00
scripts modpost: remove incorrect code in do_eisa_entry() 2024-12-14 19:54:09 +01:00
security apparmor: test: Fix memory leak for aa_unpack_strdup() 2024-12-14 19:53:59 +01:00
sound ALSA: usb-audio: Notify xrun for low-latency mode 2024-12-14 19:54:30 +01:00
tools tools: Override makefile ARCH variable if defined, but empty 2024-12-14 19:54:30 +01:00
usr usr/gen_init_cpio.c: remove unnecessary -1 values from int file 2022-10-03 14:21:44 -07:00
virt KVM: Fix a data race on last_boosted_vcpu in kvm_vcpu_on_spin() 2024-06-27 13:46:21 +02:00
.clang-format inet: ping: use hlist_nulls rcu iterator during lookup 2022-12-01 12:42:46 +01:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore Remove *.orig pattern from .gitignore 2024-10-17 15:21:15 +02:00
.mailmap 9 hotfixes. 6 for MM, 3 for other areas. Four of these patches address 2022-12-10 17:10:52 -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 Michal Marek from Kbuild maintainers 2022-11-16 14:53:00 +09:00
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: add leah to 6.1 MAINTAINERS file 2024-05-17 11:56:16 +02:00
Makefile Linux 6.1.119 2024-11-22 15:37:35 +01:00
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.