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Currently the detection+enablement of boot cpucaps is separate from the patching of boot cpucap alternatives, which means there's a period where cpus_have_cap($CAP) and alternative_has_cap($CAP) may be mismatched. It would be preferable to manage the boot cpucaps in the same way as the system cpucaps, both for clarity and to minimize the risk of accidental usage of code relying upon an alternative which has not yet been patched. This patch aligns the handling of boot cpucaps with the handling of system cpucaps: * The existing setup_boot_cpu_capabilities() function is moved to be closer to the setup_system_capabilities() and setup_system_features() functions so that they're more clearly related and more likely to be updated together in future. * The patching of boot cpucap alternatives is moved into setup_boot_cpu_capabilities(), immediately after boot cpucaps are detected and enabled. * A new setup_boot_cpu_features() function is added to mirror setup_system_features(); this handles initialization of cpucap data structures and calls setup_boot_cpu_capabilities(). This makes init_cpu_features() a closer mirror to update_cpu_features(), and makes smp_prepare_boot_cpu() a closer mirror to smp_cpus_done(). Importantly, while these changes alter the structure of the code, they retain the existing order of calls to: init_cpu_features(); // prefix initializing feature regs init_cpucap_indirect_list(); detect_system_supports_pseudo_nmi(); update_cpu_capabilities(SCOPE_BOOT_CPU | SCOPE_LOCAL_CPU); enable_cpu_capabilities(SCOPE_BOOT_CPU); apply_boot_alternatives(); ... and hence there should be no functional change as a result of this patch; this is purely a structural cleanup. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20231212170910.3745497-3-mark.rutland@arm.com Signed-off-by: Will Deacon <will@kernel.org>
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.