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In case of the generic cache interface being used (Intel CPUs or a 64-bit system), the initialization sequence of the boot CPU is more complicated than necessary: - check if MTRR enabled, if yes, call mtrr_bp_pat_init() which will disable caching, set the PAT MSR, and reenable caching - call mtrr_cleanup(), in case that changed anything, call cache_cpu_init() doing the same caching disable/enable dance as above, but this time with setting the (modified) MTRR state (even if MTRR was disabled) AND setting the PAT MSR (again even with disabled MTRR) The sequence can be simplified a lot while removing potential inconsistencies: - check if MTRR enabled, if yes, call mtrr_cleanup() and then cache_cpu_init() This ensures to: - no longer disable/enable caching more than once - avoid to set MTRRs and/or the PAT MSR on the boot processor in case of MTRR cleanups even if MTRRs meant to be disabled With that mtrr_bp_pat_init() can be removed. Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lore.kernel.org/r/20221102074713.21493-10-jgross@suse.com Signed-off-by: Borislav Petkov <bp@suse.de>
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.