Re: [PATCH v3 03/17] riscv: sbi: add SBI FWFT extension calls

Andrew Jones
2025-03-13T12:44:18Z

On Mon, Mar 10, 2025 at 04:12:10PM +0100, Clément Léger wrote:
> Add FWFT extension calls. This will be ratified in SBI V3.0 hence, it is
> provided as a separate commit that can be left out if needed.
>
> Signed-off-by: Clément Léger <cleger@rivosinc.com>
> ---
> arch/riscv/kernel/sbi.c | 30 ++++++++++++++++++++++++++++--
> 1 file changed, 28 insertions(+), 2 deletions(-)
>
> diff --git a/arch/riscv/kernel/sbi.c b/arch/riscv/kernel/sbi.c
> index 256910db1307..af8e2199e32d 100644
> --- a/arch/riscv/kernel/sbi.c
> +++ b/arch/riscv/kernel/sbi.c
> @@ -299,9 +299,19 @@ static int __sbi_rfence_v02(int fid, const struct cpumask *cpu_mask,
> return 0;
> }
>
> +static bool sbi_fwft_supported;
> +
> int sbi_fwft_get(u32 feature, unsigned long *value)
> {
> - return -EOPNOTSUPP;
> + struct sbiret ret;
> +
> + if (!sbi_fwft_supported)
> + return -EOPNOTSUPP;
> +
> + ret = sbi_ecall(SBI_EXT_FWFT, SBI_EXT_FWFT_GET,
> + feature, 0, 0, 0, 0, 0);
> +
> + return sbi_err_map_linux_errno(ret.error);
> }
>
> /**
> @@ -314,7 +324,15 @@ int sbi_fwft_get(u32 feature, unsigned long *value)
> */
> int sbi_fwft_set(u32 feature, unsigned long value, unsigned long flags)
> {
> - return -EOPNOTSUPP;
> + struct sbiret ret;
> +
> + if (!sbi_fwft_supported)
> + return -EOPNOTSUPP;
> +
> + ret = sbi_ecall(SBI_EXT_FWFT, SBI_EXT_FWFT_SET,
> + feature, value, flags, 0, 0, 0);
> +
> + return sbi_err_map_linux_errno(ret.error);

sbi_err_map_linux_errno() doesn't know about SBI_ERR_DENIED_LOCKED.

> }
>
> struct fwft_set_req {
> @@ -389,6 +407,9 @@ static int sbi_fwft_feature_local_set(u32 feature, unsigned long value,
> int sbi_fwft_all_cpus_set(u32 feature, unsigned long value, unsigned long flags,
> bool revert_on_fail)
> {
> + if (!sbi_fwft_supported)
> + return -EOPNOTSUPP;
> +
> if (feature & SBI_FWFT_GLOBAL_FEATURE_BIT)
> return sbi_fwft_set(feature, value, flags);
>
> @@ -719,6 +740,11 @@ void __init sbi_init(void)
> pr_info("SBI DBCN extension detected\n");
> sbi_debug_console_available = true;
> }
> + if ((sbi_spec_version >= sbi_mk_version(2, 0)) &&

Should check sbi_mk_version(3, 0)

> + (sbi_probe_extension(SBI_EXT_FWFT) > 0)) {
> + pr_info("SBI FWFT extension detected\n");
> + sbi_fwft_supported = true;
> + }
> } else {
> __sbi_set_timer = __sbi_set_timer_v01;
> __sbi_send_ipi = __sbi_send_ipi_v01;
> --
> 2.47.2
>

Thanks,
drew