On Thu, Jun 8, 2023 at 5:43 PM Andrew Jones <ajones@ventanamicro.com> wrote:
>
> On Thu, Jun 08, 2023 at 12:23:10AM -0700, Tommy Wu wrote:
> > 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.
>
> Is there an M-mode software PoC for this with implemented handlers?
>
> Thanks,
> drew
>
Sorry for the late reply.
We implement a simple RNMI trap handler in the customized OpenSBI [1], and
use the work from Damien Hedde [2] to inject the RNMI interrupt. We can test
the RNMI functionality with the signal injection in the customized QEMU [3].
I’ll include the test case in the latest upstream email.
[1] https://github.com/TommyWu-fdgkhdkgh/opensbi/commits/dev/twu/master
[2] https://lists.gnu.org/archive/html/qemu-devel/2019-06/msg06232.html
[3] https://github.com/TommyWu-fdgkhdkgh/qemu/tree/dev/twu/master
> >
> > Changelog:
> >
> > v4
> > * Fix some coding style issues.
> > ( Thank Daniel for the suggestions. )
> >
> > 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 | 18 ++++
> > target/riscv/cpu.h | 11 +++
> > target/riscv/cpu_bits.h | 23 ++++++
> > target/riscv/cpu_helper.c | 81 ++++++++++++++++--
> > 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 | 49 +++++++++++
> > 11 files changed, 300 insertions(+), 5 deletions(-)
> >
> > --
> > 2.31.1
> >
> >