d3d23fdb46
NFP supports u16 and u32 multiplication. Multiplication is done 8-bits per step, therefore we need 2 steps for u16 and 4 steps for u32. We also need one start instruction to initialize the sequence and one or two instructions to fetch the result depending on either you need the high halve of u32 multiplication. For ALU64, if either operand is beyond u32's value range, we reject it. One thing to note, if the source operand is BPF_K, then we need to check "imm" field directly, and we'd reject it if it is negative. Because for ALU64, "imm" (with s32 type) is expected to be sign extended to s64 which NFP mul doesn't support. For ALU32, it is fine for "imm" be negative though, because the result is 32-bits and here is no difference on the low halve of result for signed/unsigned mul, so we will get correct result. Signed-off-by: Jiong Wang <jiong.wang@netronome.com> Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com> Acked-by: Song Liu <songliubraving@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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.
See Documentation/00-INDEX for a list of what is contained in each file.
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.