riscv: sbi: add SBI FWFT extension calls

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>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
Link: https://lore.kernel.org/r/20250523101932.1594077-6-cleger@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com>

diff --git a/arch/riscv/kernel/sbi.c b/arch/riscv/kernel/sbi.c
index 818efafdc8e9788eaa670515a36115a21d0a4b22..53836a9235e320a35bb5ef04e1f39926d753e438 100644 (file)
--- 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;
+
 struct fwft_set_req {
        u32 feature;
        unsigned long value;
@@ -326,7 +328,15 @@ static void cpu_sbi_fwft_set(void *arg)
  */
 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);
 }
 
 /**
@@ -348,6 +358,9 @@ int sbi_fwft_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)) {
+                       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;