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

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