Re: [PATCH v3 0/2] Export debug triggers as an extension

[Andrew Jones]

On Thu, Feb 29, 2024 at 07:07:43PM +0530, Himanshu Chauhan wrote:
> All the CPUs may or may not implement the debug triggers (sdtrig)
> extension. The presence of it should be dynamically detectable.
> This patch exports the debug triggers as an extension which
> can be turned on or off by sdtrig=<true/false> option. It is
> turned on by default.
> 
> "sdtrig" is concatenated to ISA string when it is enabled.
> Like so:
>     rv64imafdch_zicbom_*_sdtrig_*_sstc_svadu
> 
> Changes from v1:
>    - Replaced the debug property with ext_sdtrig
>    - Marked it experimenatal by naming it x-sdtrig
>    - x-sdtrig is added to ISA string
>    - Reversed the patch order
> 
> Changes from v2:
>    - Mark debug property as deprecated and replace internally with sdtrig 
> extension

I'm getting lost in our discussions, but I thought we needed both in case
a machine only implements debug 0.13, since sdtrig is at least 'more than'
debug, even if backwards compatible (which I also wasn't sure was the
case). If, OTOH, QEMU's debug implementation exactly implements sdtrig's
specification, then I'm in favor of deprecating the 'debug' extension.

Thanks,
drew


>    - setting/unsetting debug property shows warning and sets/unsets ext_sdtrig
>    - sdtrig is added to ISA string as RISC-V debug specification is frozen
> 
> Himanshu Chauhan (2):
>   target/riscv: Mark debug property as deprecated
>   target/riscv: Export sdtrig in ISA string
> 
>  target/riscv/cpu.c        | 38 +++++++++++++++++++++++++++++++++++---
>  target/riscv/cpu_cfg.h    |  2 +-
>  target/riscv/cpu_helper.c |  2 +-
>  target/riscv/csr.c        |  2 +-
>  target/riscv/machine.c    |  2 +-
>  5 files changed, 39 insertions(+), 7 deletions(-)
> 
> -- 
> 2.34.1
> 
>