Unverified Commit 6d6d0641 authored by Clément Léger's avatar Clément Léger Committed by Palmer Dabbelt
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riscv: sbi: add FWFT extension interface 



This SBI extensions enables supervisor mode to control feature that are
under M-mode control (For instance, Svadu menvcfg ADUE bit, Ssdbltrp
DTE, etc). Add an interface to set local features for a specific cpu
mask as well as for the online cpu mask.

Signed-off-by: default avatarClément Léger <cleger@rivosinc.com>
Reviewed-by: default avatarAndrew Jones <ajones@ventanamicro.com>
Reviewed-by: default avatarAtish Patra <atishp@rivosinc.com>
Link: https://lore.kernel.org/r/20250523101932.1594077-5-cleger@rivosinc.com


Signed-off-by: default avatarPalmer Dabbelt <palmer@dabbelt.com>
parent 99cf5b7c

arch/riscv/include/asm/sbi.h

+17 −0
Original line number Diff line number Diff line
@@ -503,6 +503,23 @@ int sbi_remote_hfence_vvma_asid(const struct cpumask *cpu_mask, 
				unsigned long asid);

long sbi_probe_extension(int ext);



int sbi_fwft_set(u32 feature, unsigned long value, unsigned long flags);

int sbi_fwft_set_cpumask(const cpumask_t *mask, u32 feature,

			 unsigned long value, unsigned long flags);

/**

 * sbi_fwft_set_online_cpus() - 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.

 */

static inline int sbi_fwft_set_online_cpus(u32 feature, unsigned long value,

					   unsigned long flags)

{

	return sbi_fwft_set_cpumask(cpu_online_mask, feature, value, flags);

}



/* Check if current SBI specification version is 0.1 or not */

static inline int sbi_spec_is_0_1(void)

{

arch/riscv/kernel/sbi.c

+57 −0
Original line number Diff line number Diff line
@@ -299,6 +299,63 @@ static int __sbi_rfence_v02(int fid, const struct cpumask *cpu_mask, 
	return 0;

}



struct fwft_set_req {

	u32 feature;

	unsigned long value;

	unsigned long flags;

	atomic_t error;

};



static void cpu_sbi_fwft_set(void *arg)

{

	struct fwft_set_req *req = arg;

	int ret;



	ret = sbi_fwft_set(req->feature, req->value, req->flags);

	if (ret)

		atomic_set(&req->error, ret);

}



/**

 * sbi_fwft_set() - Set a feature on the local hart

 * @feature: The feature ID 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;

}



/**

 * sbi_fwft_set_cpumask() - Set a feature for the specified cpumask

 * @mask: CPU mask of cpus that need the feature to be set

 * @feature: The feature ID 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_cpumask(const cpumask_t *mask, u32 feature,

			       unsigned long value, unsigned long flags)

{

	struct fwft_set_req req = {

		.feature = feature,

		.value = value,

		.flags = flags,

		.error = ATOMIC_INIT(0),

	};



	if (feature & SBI_FWFT_GLOBAL_FEATURE_BIT)

		return -EINVAL;



	on_each_cpu_mask(mask, cpu_sbi_fwft_set, &req, 1);



	return atomic_read(&req.error);

}



/**

 * sbi_set_timer() - Program the timer for next timer event.

 * @stime_value: The value after which next timer event should fire.