Subject: Re: [PATCH v14 10/44] arm64: RMI: Add support for SRO

From: Aneesh Kumar K.V <[email-masked]>
Date: Thu, 14 May 2026 13:31:08 +0530

Steven Price <[email-masked]> writes:

> +unsigned long rmi_sro_execute(struct rmi_sro_state *sro, gfp_t gfp)
> +{
> +	unsigned long sro_handle;
> +	struct arm_smccc_1_2_regs regs;
> +	struct arm_smccc_1_2_regs *regs_in = &sro->regs;
> +
> +	rmi_smccc_invoke(regs_in, &regs);
> +
> +	sro_handle = regs.a1;
> +
> +	while (RMI_RETURN_STATUS(regs.a0) == RMI_INCOMPLETE) {
> +		bool can_cancel = RMI_RETURN_CAN_CANCEL(regs.a0);
> +		int ret;
> +
> +		switch (RMI_RETURN_MEMREQ(regs.a0)) {
> +		case RMI_OP_MEM_REQ_NONE:
> +			regs = (struct arm_smccc_1_2_regs){
> +				SMC_RMI_OP_CONTINUE, sro_handle, 0
> +			};
> +			rmi_smccc_invoke(&regs, &regs);
> +			break;
> +		case RMI_OP_MEM_REQ_DONATE:
> +			ret = rmi_sro_donate(sro, sro_handle, regs.a2, &regs,
> +					     gfp);
> +			break;
> +		case RMI_OP_MEM_REQ_RECLAIM:
> +			ret = rmi_sro_reclaim(sro, sro_handle, &regs);
> +			break;
> +		default:
> +			ret = WARN_ON(1);
> +			break;
> +		}
> +
> +		if (ret) {
> +			if (can_cancel) {
> +				/*
> +				 * FIXME: Handle cancelling properly!
> +				 *
> +				 * If the operation has failed due to memory
> +				 * allocation failure then the information on
> +				 * the memory allocation should be saved, so
> +				 * that the allocation can be repeated outside
> +				 * of any context which prevented the
> +				 * allocation.
> +				 */
> +			}
> +			if (WARN_ON(ret))
> +				return ret;
> +		}
> +	}
> +
> +	return regs.a0;
> +}

Can you also add support to return x1,x2 etc

This would help things like

static int rmi_rtt_dev_unmap(unsigned long rd_phys,
		unsigned long base, unsigned long top,
		unsigned long *out_ipa, unsigned long *out_desc,
		unsigned long *rmi_ret)
{
	unsigned long flags = RMI_ADDR_TYPE_SINGLE;
	struct rmi_sro_state *sro __free(sro) =
		rmi_sro_init(SMC_RMI_RTT_DEV_UNMAP, rd_phys, base, top, flags, NULL);
	if (!sro)
		return -ENOMEM;

	*rmi_ret = rmi_sro_execute(sro);
	if (*rmi_ret)
		return 0;

	*out_ipa = sro->regs.a1;
	*out_desc = sro->regs.a2;

	return 0;
}

-aneesh