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Kristina Martsenko authored
To enable pointer auth for the kernel, we're going to need to check for
the presence of address auth and generic auth using alternative_if. We
currently have two cpucaps for each, but alternative_if needs to check a
single cpucap. So define meta-capabilities that are present when either
of the current two capabilities is present.

Leave the existing four cpucaps in place, as they are still needed to
check for mismatched systems where one CPU has the architected algorithm
but another has the IMP DEF algorithm.

Note, the meta-capabilities were present before but were removed in
commit a56005d3 ("arm64: cpufeature: Reduce number of pointer auth
CPU caps from 6 to 4") and commit 1e013d06 ("arm64: cpufeature: Rework
ptr auth hwcaps using multi_entry_cap_matches"), as they were not needed
then. Note, unlike before, the current patch checks the cpucap values
directly, instead of reading the CPU ID register value.

Reviewed-by: default avatarSuzuki K Poulose <suzuki.poulose@arm.com>
Reviewed-by: default avatarKees Cook <keescook@chromium.org>
Reviewed-by: default avatarVincenzo Frascino <Vincenzo.Frascino@arm.com>
Signed-off-by: default avatarKristina Martsenko <kristina.martsenko@arm.com>
[Amit: commit message and macro rebase, use __system_matches_cap]
Signed-off-by: default avatarAmit Daniel Kachhap <amit.kachhap@arm.com>
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
cfef06bd
History
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.