Re: [RFC PATCH v1 08/21] RISC-V: ACPI: RHCT: Add function to get CBO block sizes

[Andy Shevchenko]

On Thu, Aug 03, 2023 at 11:29:03PM +0530, Sunil V L wrote:
> CBO related block size in ACPI is provided by RHCT. Add
> support to read the CMO node in RHCT to get this information.

...

> +	if (!table) {

Why not positive conditional?

> +		rhct = (struct acpi_table_rhct *)acpi_get_rhct();
> +		if (!rhct)
> +			return -ENOENT;
> +	} else {
> +		rhct = (struct acpi_table_rhct *)table;
> +	}

...

> +	end = ACPI_ADD_PTR(struct acpi_rhct_node_header, rhct, rhct->header.length);

> +

Blank line here is not needed.

> +	for (node = ACPI_ADD_PTR(struct acpi_rhct_node_header, rhct, rhct->node_offset);
> +	     node < end;
> +	     node = ACPI_ADD_PTR(struct acpi_rhct_node_header, node, node->length)) {

> +			for (int i = 0; i < hart_info->num_offsets; i++) {
> +				ref_node = ACPI_ADD_PTR(struct acpi_rhct_node_header,
> +							rhct, hart_info_node_offset[i]);
> +				if (ref_node->type == ACPI_RHCT_NODE_TYPE_CMO) {
> +					cmo_node = ACPI_ADD_PTR(struct acpi_rhct_cmo_node,
> +								ref_node, size_hdr);
> +					if (cbom_size)
> +						*cbom_size = 1 << cmo_node->cbom_size;
> +
> +					if (cboz_size)
> +						*cboz_size = 1 << cmo_node->cboz_size;
> +
> +					if (cbop_size)
> +						*cbop_size = 1 << cmo_node->cbop_size;

BIT() in all three cases?

But how you guarantee it will not overflow? I mean who prevents cboX_size to be
bigger than 30 (note also that 31 in your case is Undefined Behaviour in
accordance with the C standard).

> +					return 0;
> +				}
> +			}

> +	}

-- 
With Best Regards,
Andy Shevchenko