a7be240d17
[ Upstream commit b78f26926b17cc289e4f16b63363abe0aa2e8efc ]
Geert reported that the GIC driver locks up on a Renesas system
since 005c34ae4b44f085 ("irqchip/gic: Atomically update affinity")
fixed the driver to use writeb_relaxed() instead of writel_relaxed().
As it turns out, the interconnect used on this system mandates
32bit wide accesses for all MMIO transactions, even if the GIC
architecture specifically mandates for some registers to be byte
accessible. Gahhh...
Work around the issue by crudly detecting the offending system,
and falling back to an inefficient RMW+lock implementation.
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/CAMuHMdV+Ev47K5NO8XHsanSq5YRMCHn2gWAQyV-q2LpJVy9HiQ@mail.gmail.com
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.