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

Clément Léger
2025-03-14T11:21:27Z

On 13/03/2025 13:44, Andrew Jones wrote:
> 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.

Not only it doesn't knows about DENIED_LOCKED but also another bunch of
errors. I'll add them in a separate commit.

>
>> }
>>
>> 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)

Oh yes that was for testing purpose and I incorrectly squashed it.

>
>> + (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,

Clément

> Thanks,
> drew