Re: [PATCH v5 04/13] riscv: sbi: add SBI FWFT extension calls

On 24/04/2025 13:06, Andrew Jones wrote:

On Thu, Apr 17, 2025 at 02:19:51PM +0200, 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 | 20 +++++++++++++++++++- 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/kernel/sbi.c b/arch/riscv/kernel/sbi.c index 379981c2bb21..7b062189b184 100644 --- a/arch/riscv/kernel/sbi.c +++ b/arch/riscv/kernel/sbi.c @@ -299,6 +299,8 @@ static int __sbi_rfence_v02(int fid, const struct cpumask *cpu_mask, return 0; } +static bool sbi_fwft_supported;

At some point we may want an SBI extension bitmap, but this is only the second SBI extension supported boolean that I'm aware of, so I guess we're still OK for now.

That seems reasonable to have a bitmap rather than duplicating *ext*_supported. If that's something that bothers you, I can take care of it and use a bitmap. SSE will also have a sse_supported boolean but in it's own driver file though.

...

/**

• sbi_fwft_set() - Set a feature on the local hart
• @feature: The feature ID to be set

@@ -309,7 +311,15 @@ static int __sbi_rfence_v02(int fid, const struct cpumask *cpu_mask, */ 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);

} struct fwft_set_req { @@ -348,6 +358,9 @@ int sbi_fwft_local_set_cpumask(const cpumask_t *mask, u32 feature, .error = ATOMIC_INIT(0), };

• if (!sbi_fwft_supported)

• return -EOPNOTSUPP;
  

• if (feature & SBI_FWFT_GLOBAL_FEATURE_BIT) return -EINVAL;

@@ -679,6 +692,11 @@ void __init sbi_init(void) pr_info("SBI DBCN extension detected\n"); sbi_debug_console_available = true; }

• if ((sbi_spec_version >= sbi_mk_version(3, 0)) &&
  

•     (sbi_probe_extension(SBI_EXT_FWFT) > 0)) {
  

Unnecessary (), but I see it's consistent with the expressions above.

I can fix the other ones as well in another commit.

...

• 	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;

-- 2.49.0

Thanks,

Clément

Besides the () nit

Reviewed-by: Andrew Jones ajones@ventanamicro.com