This SBI extensions enables supervisor mode to control feature that are under M-mode control (For instance, Svadu menvcfg ADUE bit, Ssdbltrp DTE, etc).
Signed-off-by: Clément Léger cleger@rivosinc.com --- arch/riscv/include/asm/sbi.h | 5 ++ arch/riscv/kernel/sbi.c | 97 ++++++++++++++++++++++++++++++++++++ 2 files changed, 102 insertions(+)
diff --git a/arch/riscv/include/asm/sbi.h b/arch/riscv/include/asm/sbi.h index bb077d0c912f..fc87c609c11a 100644 --- a/arch/riscv/include/asm/sbi.h +++ b/arch/riscv/include/asm/sbi.h @@ -503,6 +503,11 @@ int sbi_remote_hfence_vvma_asid(const struct cpumask *cpu_mask, unsigned long asid); long sbi_probe_extension(int ext);
+int sbi_fwft_all_cpus_set(u32 feature, unsigned long value, unsigned long flags, + bool revert_on_failure); +int sbi_fwft_get(u32 feature, unsigned long *value); +int sbi_fwft_set(u32 feature, unsigned long value, unsigned long flags); + /* Check if current SBI specification version is 0.1 or not */ static inline int sbi_spec_is_0_1(void) { diff --git a/arch/riscv/kernel/sbi.c b/arch/riscv/kernel/sbi.c index 1989b8cade1b..256910db1307 100644 --- a/arch/riscv/kernel/sbi.c +++ b/arch/riscv/kernel/sbi.c @@ -299,6 +299,103 @@ static int __sbi_rfence_v02(int fid, const struct cpumask *cpu_mask, return 0; }
+int sbi_fwft_get(u32 feature, unsigned long *value) +{ + return -EOPNOTSUPP; +} + +/** + * sbi_fwft_set() - Set a feature on all online cpus + * @feature: The feature to be set + * @value: The feature value to be set + * @flags: FWFT feature set flags + * + * Return: 0 on success, appropriate linux error code otherwise. + */ +int sbi_fwft_set(u32 feature, unsigned long value, unsigned long flags) +{ + return -EOPNOTSUPP; +} + +struct fwft_set_req { + u32 feature; + unsigned long value; + unsigned long flags; + cpumask_t mask; +}; + +static void cpu_sbi_fwft_set(void *arg) +{ + struct fwft_set_req *req = arg; + + if (sbi_fwft_set(req->feature, req->value, req->flags)) + cpumask_clear_cpu(smp_processor_id(), &req->mask); +} + +static int sbi_fwft_feature_local_set(u32 feature, unsigned long value, + unsigned long flags, + bool revert_on_fail) +{ + int ret; + unsigned long prev_value; + cpumask_t tmp; + struct fwft_set_req req = { + .feature = feature, + .value = value, + .flags = flags, + }; + + cpumask_copy(&req.mask, cpu_online_mask); + + /* We can not revert if features are locked */ + if (revert_on_fail && flags & SBI_FWFT_SET_FLAG_LOCK) + return -EINVAL; + + /* Reset value is the same for all cpus, read it once. */ + ret = sbi_fwft_get(feature, &prev_value); + if (ret) + return ret; + + /* Feature might already be set to the value we want */ + if (prev_value == value) + return 0; + + on_each_cpu_mask(&req.mask, cpu_sbi_fwft_set, &req, 1); + if (cpumask_equal(&req.mask, cpu_online_mask)) + return 0; + + pr_err("Failed to set feature %x for all online cpus, reverting\n", + feature); + + req.value = prev_value; + cpumask_copy(&tmp, &req.mask); + on_each_cpu_mask(&req.mask, cpu_sbi_fwft_set, &req, 1); + if (cpumask_equal(&req.mask, &tmp)) + return 0; + + return -EINVAL; +} + +/** + * sbi_fwft_all_cpus_set() - Set a feature on all online cpus + * @feature: The feature to be set + * @value: The feature value to be set + * @flags: FWFT feature set flags + * @revert_on_fail: true if feature value should be restored to it's orignal + * value on failure. + * + * Return: 0 on success, appropriate linux error code otherwise. + */ +int sbi_fwft_all_cpus_set(u32 feature, unsigned long value, unsigned long flags, + bool revert_on_fail) +{ + if (feature & SBI_FWFT_GLOBAL_FEATURE_BIT) + return sbi_fwft_set(feature, value, flags); + + return sbi_fwft_feature_local_set(feature, value, flags, + revert_on_fail); +} + /** * sbi_set_timer() - Program the timer for next timer event. * @stime_value: The value after which next timer event should fire.