Merge remote-tracking branch 'remotes/palmer/tags/riscv-for-master-4.1-sf0' into staging

RISC-V Patches for the 4.1 Soft Freeze, Part 1

This tag contains a handful of patches that I'd like to target for 4.1:

* An emulation for SiFive's GPIO device.
* A fix to disallow sfence.vma from userspace.
* Additional decodetree cleanups that should have no functional impact.
* C extension emulation fidelity fixes that were noticed as part of that
  cleanup process.
* A new "spike" target, along with the deprecation of a handful of old
  targets and CPUs.
* Some initial infastructure related to the hypervisor extension.
* An emulation fidelity fix that prevents prevents arbitrary bits in the
  SIP CSR from being set.
* A small performance improvement that avoids excessive TLB flushing
  when the ASID does not change.

This time I've used a new testing workflow: I've tested on both 32-bit
and 64-bit builds of OpenEmbedded, via the default OpenSBI-based boot
flow.

# gpg: Signature made Sat 25 May 2019 01:05:57 BST
# gpg:                using RSA key 00CE76D1834960DFCE886DF8EF4CA1502CCBAB41
# gpg:                issuer "palmer@dabbelt.com"
# gpg: Good signature from "Palmer Dabbelt <palmer@dabbelt.com>" [unknown]
# gpg:                 aka "Palmer Dabbelt <palmer@sifive.com>" [unknown]
# gpg: WARNING: This key is not certified with a trusted signature!
# gpg:          There is no indication that the signature belongs to the owner.
# Primary key fingerprint: 00CE 76D1 8349 60DF CE88  6DF8 EF4C A150 2CCB AB41

* remotes/palmer/tags/riscv-for-master-4.1-sf0: (29 commits)
  target/riscv: Only flush TLB if SATP.ASID changes
  target/riscv: More accurate handling of `sip` CSR
  target/riscv: Add checks for several RVC reserved operands
  target/riscv: Add the HGATP register masks
  target/riscv: Add the HSTATUS register masks
  target/riscv: Add Hypervisor CSR macros
  target/riscv: Allow setting mstatus virtulisation bits
  target/riscv: Add the MPV and MTL mstatus bits
  target/riscv: Improve the scause logic
  target/riscv: Trigger interrupt on MIP update asynchronously
  target/riscv: Mark privilege level 2 as reserved
  riscv: spike: Add a generic spike machine
  target/riscv: Deprecate the generic no MMU CPUs
  target/riscv: Add a base 32 and 64 bit CPU
  target/riscv: Create settable CPU properties
  riscv: virt: Allow specifying a CPU via commandline
  linux-user/riscv: Add the CPU type as a comment
  target/riscv: Remove unused include of riscv_htif.h for virt board riscv
  target/riscv: Remove spaces from register names
  target/riscv: Split gen_arith_imm into functional and temp
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>