Andrew Murray
addfc38672
When building for LSE atomics (CONFIG_ARM64_LSE_ATOMICS), if the hardware or toolchain doesn't support it the existing code will fallback to ll/sc atomics. It achieves this by branching from inline assembly to a function that is built with special compile flags. Further this results in the clobbering of registers even when the fallback isn't used increasing register pressure. Improve this by providing inline implementations of both LSE and ll/sc and use a static key to select between them, which allows for the compiler to generate better atomics code. Put the LL/SC fallback atomics in their own subsection to improve icache performance. Signed-off-by: Andrew Murray <andrew.murray@arm.com> Signed-off-by: Will Deacon <will@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.