Re: [PATCH v2 2/2] target/riscv: Add short-isa-string option

[Alistair Francis]

On Tue, May 10, 2022 at 9:29 PM Tsukasa OI <research_trasio@irq.a4lg.com> wrote:
>
> Because some operating systems don't correctly parse long ISA extension
> string, this commit adds short-isa-string boolean option to disable
> generating long ISA extension strings on Device Tree.
>
> For instance, enabling Zfinx and Zdinx extensions and booting Linux (5.17 or
> earlier) with FPU support caused a kernel panic.
>
> Operating Systems which short-isa-string might be helpful:
>
> 1.  Linux (5.17 or earlier)
> 2.  FreeBSD (at least 14.0-CURRENT)
> 3.  OpenBSD (at least current development version)
>
> Signed-off-by: Tsukasa OI <research_trasio@irq.a4lg.com>

Acked-by: Alistair Francis <alistair.francis@wdc.com>

Alistair

> ---
>  target/riscv/cpu.c | 5 ++++-
>  target/riscv/cpu.h | 2 ++
>  2 files changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
> index 9f38e56316..4db3dce25a 100644
> --- a/target/riscv/cpu.c
> +++ b/target/riscv/cpu.c
> @@ -879,6 +879,8 @@ static Property riscv_cpu_properties[] = {
>      DEFINE_PROP_BOOL("x-aia", RISCVCPU, cfg.aia, false),
>
>      DEFINE_PROP_UINT64("resetvec", RISCVCPU, cfg.resetvec, DEFAULT_RSTVEC),
> +
> +    DEFINE_PROP_BOOL("short-isa-string", RISCVCPU, cfg.short_isa_string, 
> false),
>      DEFINE_PROP_END_OF_LIST(),
>  };
>
> @@ -1049,7 +1051,8 @@ char *riscv_isa_string(RISCVCPU *cpu)
>          }
>      }
>      *p = '\0';
> -    riscv_isa_string_ext(cpu, &isa_str, maxlen);
> +    if (!cpu->cfg.short_isa_string)
> +        riscv_isa_string_ext(cpu, &isa_str, maxlen);
>      return isa_str;
>  }
>
> diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
> index fe6c9a2c92..f5ff7294c6 100644
> --- a/target/riscv/cpu.h
> +++ b/target/riscv/cpu.h
> @@ -425,6 +425,8 @@ struct RISCVCPUConfig {
>      bool aia;
>      bool debug;
>      uint64_t resetvec;
> +
> +    bool short_isa_string;
>  };
>
>  typedef struct RISCVCPUConfig RISCVCPUConfig;
> --
> 2.34.1
>