mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/
synced 2026-11-10 20:48:12 +00:00
No description
- C 96.8%
- Assembly 0.9%
- Rust 0.7%
- Shell 0.6%
- Python 0.5%
- Other 0.3%
c0900d15d3
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> |
History
|
|
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .clippy.toml | ||
| .cocciconfig | ||
| .editorconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| 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.