Merge remote-tracking branch 'remotes/riscv/tags/riscv-qemu-2.13-pull-20180506' into...

Merge remote-tracking branch 'remotes/riscv/tags/riscv-qemu-2.13-pull-20180506' into staging

RISC-V: QEMU 2.13 Privileged ISA emulation updates

Several code cleanups, minor specification conformance changes,
fixes to make ROM read-only and add device-tree size checks.

* Honour privileged ISA v1.10 counter enable CSRs.
* Implements WARL behavior for CSRs that don't support writes
  * Past behavior of raising traps was non-conformant
    with the RISC-V Privileged ISA Specification v1.10.
* Allow S-mode access to sstatus.MXR when priv ISA >= v1.10
* Sets mtval/stval to zero on exceptions without addresses
  * Past behavior of leaving the last value was non-conformant
    with the RISC-V Privileged ISA Specition v1.10. mtval/stval
    must be set on all exceptions; to zero if not supported.
* Make ROMs read-only and implement device-tree size checks
  * Uses memory_region_init_rom and rom_add_blob_fixed_as
* Adds hexidecimal instruction bytes to disassembly output.
* Fixes missing break statement for rv128 disassembly.
* Several code cleanups
  * Replacing hard-coded constants with enums
  * Dead-code elimination

This is an incremental pull that contains 20 reviewed changes out
of 38 changes currently queued in the qemu-2.13-for-upstream branch.

# gpg: Signature made Sun 06 May 2018 00:27:37 BST
# gpg:                using DSA key 6BF1D7B357EF3E4F
# gpg: Good signature from "Michael Clark <michaeljclark@mac.com>"
# gpg:                 aka "Michael Clark <mjc@sifive.com>"
# gpg:                 aka "Michael Clark <michael@metaparadigm.com>"
# 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: 7C99 930E B17C D8BA 073D  5EFA 6BF1 D7B3 57EF 3E4F

* remotes/riscv/tags/riscv-qemu-2.13-pull-20180506:
  RISC-V: Mark ROM read-only after copying in code
  RISC-V: No traps on writes to misa,minstret,mcycle
  RISC-V: Make mtvec/stvec ignore vectored traps
  RISC-V: Add mcycle/minstret support for -icount auto
  RISC-V: Use [ms]counteren CSRs when priv ISA >= v1.10
  RISC-V: Allow S-mode mxr access when priv ISA >= v1.10
  RISC-V: Clear mtval/stval on exceptions without info
  RISC-V: Hardwire satp to 0 for no-mmu case
  RISC-V: Update E and I extension order
  RISC-V: Remove erroneous comment from translate.c
  RISC-V: Remove EM_RISCV ELF_MACHINE indirection
  RISC-V: Make virt header comment title consistent
  RISC-V: Make some header guards more specific
  RISC-V: Fix missing break statement in disassembler
  RISC-V: Include instruction hex in disassembly
  RISC-V: Remove unused class definitions
  RISC-V: Remove identity_translate from load_elf
  RISC-V: Use ROM base address and size from memmap
  RISC-V: Make virt board description match spike
  RISC-V: Replace hardcoded constants with enum values

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