2a952b03d1
NFP doesn't have integer divide instruction, this patch use reciprocal algorithm (the basic one, reciprocal_div) to emulate it. For each u32 divide, we would need 11 instructions to finish the operation. 7 (for multiplication) + 4 (various ALUs) = 11 Given NFP only supports multiplication no bigger than u32, we'd require divisor and dividend no bigger than that as well. Also eBPF doesn't support signed divide and has enforced this on C language level by failing compilation. However LLVM assembler hasn't enforced this, so it is possible for negative constant to leak in as a BPF_K operand through assembly code, we reject such cases as well. 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.