Re: [PATCH v20 4/9] firmware: arm_rmm: Add support for SRO

[Suzuki K Poulose]

On 30/09/2026 14:15, Catalin Marinas wrote:
> On Tue, Sep 29, 2026 at 11:16:18PM +0100, Suzuki K Poulose wrote:
> > +static int rmi_sro_donate_contig(struct rmi_sro_state *sro,
> > +				 unsigned long sro_handle,
> > +				 unsigned long donatereq,
> > +				 struct arm_smccc_1_2_regs *out_regs,
> > +				 gfp_t gfp)
> > +{
> > +	unsigned long block_size_fld = RMI_DONATE_BLOCK_SIZE(donatereq);
> > +	unsigned long block_size = rmi_addr_block_size_to_bytes(block_size_fld);
> > +	unsigned long count = RMI_DONATE_COUNT(donatereq);
> > +	unsigned long state = RMI_DONATE_STATE(donatereq);
> > +	unsigned long size = block_size * count;
> > +	unsigned long addr_range;
> > +	unsigned long donated_size;
> > +	int ret;
> > +	void *virt;
> > +	phys_addr_t phys;
> > +
> > +	/*
> > +	 * The RMM specification requires contiguous allocations are always a
> > +	 * power of 2
> > +	 */
> > +	if (WARN_ON_ONCE(!is_power_of_2(size)))
> > +		return -EINVAL;
> > +	/*
> > +	 * RMM clamps the Maximum value of RmiOpMemDonateReq:count to prevent
> > +	 * overflow in the RMI_ADDR_RANGE_COUNT field.
> > +	 */
> > +	if (WARN_ON_ONCE(count > (BIT(PAGE_SHIFT - 2) - 1)))
> > +		return -EINVAL;
>
> Nit: it might be easier to read as FIELD_MAX(RMI_ADDR_RANGE_COUNT_MASK)
> as that's what we want to limit it to.

Thanks, that is neat. I will update this.

> Reviewed-by: Catalin Marinas <catalin.marinas@xxxxxxx>
>
> (Sashiko seems to have more findings but the rest looks alright to me)

I have updated the code to address the issues.

Thanks Catalin.

Suzuki