2fc83c2cd7
Add an initial math64.h similar to linux/math64.h with functions mul_u64_u64_div64() and mul_u64_u32_shr(). This isn't a direct copy of include/linux/math64.h as that doesn't define mul_u64_u64_div64(). Implementation was written by Peter Zilkstra based on linux/math64.h and div64.h[1]. The original implementation was not optimal on arm64 as __int128 division is not optimal with a call out to __udivti3, so I dropped the __int128 variant of mul_u64_u64_div64(). [1] https://lore.kernel.org/lkml/20200322101848.GF2452@worktop.programming.kicks-ass.net/ Signed-off-by: Rob Herring <robh@kernel.org> Acked-by: Jiri Olsa <jolsa@redhat.com> Acked-by: Namhyung Kim <namhyung@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Itaru Kitayama <itaru.kitayama@gmail.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Will Deacon <will@kernel.org> Link: http://lore.kernel.org/lkml/20210414155412.3697605-2-robh@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.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.