This patchset added support for Smrnmi Extension in RISC-V.

There are four new CSRs and one new instruction added to allow NMI to be
resumable in RISC-V, which are:

=============================================================
  * mnscratch (0x740)
  * mnepc     (0x741)
  * mncause   (0x742)
  * mnstatus  (0x744)
=============================================================
  * mnret: To return from RNMI interrupt/exception handler.
=============================================================

RNMI also has higher priority than any other interrupts or exceptions
and cannot be disabled by software.

RNMI may be used to route to other devices such as Bus Error Unit or
Watchdog Timer in the future.

The interrupt/exception trap handler addresses of RNMI are
implementation defined.

Changelog:

v3
  * Update to the newest version of Smrnmi extension specification.

v2
  * split up the series into more commits for convenience of review.
  * add missing rnmi_irqvec and rnmi_excpvec properties to riscv_harts.

Tommy Wu (4):
  target/riscv: Add Smrnmi cpu extension.
  target/riscv: Add Smrnmi CSRs.
  target/riscv: Handle Smrnmi interrupt and exception.
  target/riscv: Add Smrnmi mnret instruction.

 hw/riscv/riscv_hart.c                         | 21 +++++
 include/hw/riscv/riscv_hart.h                 |  4 +
 target/riscv/cpu.c                            | 19 +++++
 target/riscv/cpu.h                            | 11 +++
 target/riscv/cpu_bits.h                       | 23 +++++
 target/riscv/cpu_helper.c                     | 84 +++++++++++++++++--
 target/riscv/csr.c                            | 82 ++++++++++++++++++
 target/riscv/helper.h                         |  1 +
 target/riscv/insn32.decode                    |  3 +
 .../riscv/insn_trans/trans_privileged.c.inc   | 12 +++
 target/riscv/op_helper.c                      | 51 +++++++++++
 11 files changed, 306 insertions(+), 5 deletions(-)

-- 
2.31.1