443838e6ff
[ Upstream commit 0609e200246bfd3b7516091c491bec4308349055 ]
Jon reports that the Spectre-BHB init code is filling up the kernel log
with spurious notifications about which mitigation has been enabled,
every time any CPU comes out of a low power state.
Given that Spectre-BHB mitigations are system wide, only a single
mitigation can be enabled, and we already print an error if two types of
CPUs coexist in a single system that require different Spectre-BHB
mitigations.
This means that the pr_info() that describes the selected mitigation
does not need to be emitted for each CPU anyway, and so we can simply
emit it only once.
In order to clarify the above in the log message, update it to describe
that the selected mitigation will be enabled on all CPUs, including ones
that are unaffected. If another CPU comes up later that is affected and
requires a different mitigation, we report an error as before.
Fixes: b9baf5c8c5c3 ("ARM: Spectre-BHB workaround")
Tested-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Sasha Levin <sashal@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.