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When irqs are soft-disabled, MSR[EE] is volatile and can change from 1 to 0 asynchronously (if a PACA_IRQ_MUST_HARD_MASK interrupt hits). So it can not be used to check hard IRQ enabled status, except to confirm it is disabled. ppc64_runlatch_on/off functions use MSR this way to decide whether to re-enable MSR[EE] after disabling it, which leads to MSR[EE] being enabled when it shouldn't be (when a PACA_IRQ_MUST_HARD_MASK had disabled it between reading the MSR and clearing EE). This has been tolerated in the kernel previously, and it doesn't seem to cause a problem, but it is unexpected and may trip warnings or cause other problems as we tighten up this state management. Fix this by only re-enabling if PACA_IRQ_HARD_DIS is clear. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220926054305.2671436-5-npiggin@gmail.com
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.