RISC-V Linux Port v1

[Palmer Dabbelt]

We'd like to submit for inclusion in Linux a port for the RISC-V architecture.
While it is doubtlessly not complete, we think it is far enough along to start
the upstreaming process.  Our binutils and GCC ports have been accepted and
released, and we plan on submitting glibc patches soon.

This port targets Version 1.10 of the RISC-V Privileged ISA, and supports both
the RV32 and RV64 user ISAs.  The RISC-V community and the 60-some member
companies of the RISC-V Foundation are quite eager to have a single, standard
Linux port.  We thank you in advance for your help in this process and for your
feedback on the software contribution itself.

These patches build and boot on top of 4.12-rc2.  I understand that the merge
window is closed, but it was suggested that the best time to submit a new
architecture port would be right after an RC2 as the earliest point at which
the tree is usually generally churn-free enough.  While we optimistically hope
that we can get the port in for the 4.13 merge window, we're also eager to
ensure that the user-visible ABI is sane so we can proceed with our glibc port.
We'd like to at least get any user ABI issues shaken out as soon as possible,
even if we don't make it into 4.13.

Albert and I will volunteer to maintain this port if it's OK with everyone.

We'd like to thank the various members of the RISC-V software community who
have helped us with the port.

Thanks!

In addition to the threaded messages, our port can be found on Git Hib

  https://github.com/riscv/riscv-linux/tree/riscv-for-submission-v1

[PATCH 1/7] RISC-V: Top-Level Makefile for riscv{32,64}
[PATCH 2/7] RISC-V: arch/riscv Makefile and Kconfigs
[PATCH 3/7] RISC-V: Device Tree Documentation
[PATCH 4/7] RISC-V: arch/riscv/include
[PATCH 5/7] RISC-V: arch/riscv/lib
[PATCH 6/7] RISC-V: arch/riscv/kernel
[PATCH 7/7] RISC-V: arch/riscv/mm