linux-kernel - Re: [PATCH v2.1 3/8] ACPI: bus: Split _OSC evaluation out of acpi_run

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Message-ID: <20251223111813.00000d67@huawei.com>
Date: Tue, 23 Dec 2025 11:18:13 +0000
From: Jonathan Cameron <jonathan.cameron@...wei.com>
To: "Rafael J. Wysocki" <rafael@...nel.org>, Linux ACPI
	<linux-acpi@...r.kernel.org>, LKML <linux-kernel@...r.kernel.org>
CC: Linux PCI <linux-pci@...r.kernel.org>, Bjorn Helgaas <helgaas@...nel.org>,
	Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>, Hans de Goede
	<hansg@...nel.org>, Mario Limonciello <mario.limonciello@....com>
Subject: Re: [PATCH v2.1 3/8] ACPI: bus: Split _OSC evaluation out of
 acpi_run_osc()

On Mon, 22 Dec 2025 20:14:16 +0100
"Rafael J. Wysocki" <rafael@...nel.org> wrote:

> From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> 
> Split a function for evaluating _OSC called acpi_eval_osc() out of
> acpi_run_osc() to facilitate subsequent changes and add some more
> parameters sanity checks to the latter.
> 
> No intentional functional impact.
> 
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Hi Rafael,

There is a little bit of reformatting / whitespace cleanup in here
that makes it a tiny bit harder to review than if that had been
done separately.  Not worth a respin though.

Reviewed-by: Jonathan Cameron <jonathan.cameron@...wei.com>
> ---
> 
> v1 -> v2.1:
>    * Fix typo in the changelog (Jonathan).
>    * Use at_least to enforce compiler checking of in_params[] size instead of
>      using "static" directly (Jonathan).
> 
> ---
>  drivers/acpi/bus.c |   91 ++++++++++++++++++++++++++++++-----------------------
>  1 file changed, 53 insertions(+), 38 deletions(-)
> 
> --- a/drivers/acpi/bus.c
> +++ b/drivers/acpi/bus.c
> @@ -196,52 +196,67 @@ static void acpi_dump_osc_data(acpi_hand
>  			 OSC_INVALID_REVISION_ERROR | \
>  			 OSC_CAPABILITIES_MASK_ERROR)
>  
> -acpi_status acpi_run_osc(acpi_handle handle, struct acpi_osc_context *context)
> +static int acpi_eval_osc(acpi_handle handle, guid_t *guid, int rev,
> +			 struct acpi_buffer *cap,
> +			 union acpi_object in_params[at_least 4],
> +			 struct acpi_buffer *output)
>  {
> -	u32 errors, *capbuf = context->cap.pointer;
> -	acpi_status status;
>  	struct acpi_object_list input;
> -	union acpi_object in_params[4];
>  	union acpi_object *out_obj;
> -	guid_t guid;
> -	struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
> -
> -	if (!context)
> -		return AE_ERROR;
> -	if (guid_parse(context->uuid_str, &guid))
> -		return AE_ERROR;
> -	context->ret.length = ACPI_ALLOCATE_BUFFER;
> -	context->ret.pointer = NULL;
> +	acpi_status status;
>  
> -	/* Setting up input parameters */
> -	input.count = 4;
> +	in_params[0].type = ACPI_TYPE_BUFFER;
> +	in_params[0].buffer.length = sizeof(*guid);
> +	in_params[0].buffer.pointer = (u8 *)guid;
> +	in_params[1].type = ACPI_TYPE_INTEGER;
> +	in_params[1].integer.value = rev;
> +	in_params[2].type = ACPI_TYPE_INTEGER;
> +	in_params[2].integer.value = cap->length / sizeof(u32);
> +	in_params[3].type = ACPI_TYPE_BUFFER;
> +	in_params[3].buffer.length = cap->length;
> +	in_params[3].buffer.pointer = cap->pointer;
>  	input.pointer = in_params;
> -	in_params[0].type 		= ACPI_TYPE_BUFFER;
> -	in_params[0].buffer.length 	= 16;
> -	in_params[0].buffer.pointer	= (u8 *)&guid;
> -	in_params[1].type 		= ACPI_TYPE_INTEGER;
> -	in_params[1].integer.value 	= context->rev;
> -	in_params[2].type 		= ACPI_TYPE_INTEGER;
> -	in_params[2].integer.value	= context->cap.length/sizeof(u32);
> -	in_params[3].type		= ACPI_TYPE_BUFFER;
> -	in_params[3].buffer.length 	= context->cap.length;
> -	in_params[3].buffer.pointer 	= context->cap.pointer;
Not sure I'd have made this formatting change in here because it
'might' have hidden real functional changes from reviewers.

> -
> -	status = acpi_evaluate_object(handle, "_OSC", &input, &output);
> -	if (ACPI_FAILURE(status))
> -		return status;
> +	input.count = 4;
>  
> -	if (!output.length)
> -		return AE_NULL_OBJECT;
> +	output->length = ACPI_ALLOCATE_BUFFER;
> +	output->pointer = NULL;
>  
> -	out_obj = output.pointer;
> -	if (out_obj->type != ACPI_TYPE_BUFFER
> -		|| out_obj->buffer.length != context->cap.length) {
> -		acpi_dump_osc_data(handle, &guid, context->rev, &context->cap);
> -		acpi_handle_debug(handle, "_OSC: evaluation returned wrong type");
> -		status = AE_TYPE;
> -		goto out_kfree;
> +	status = acpi_evaluate_object(handle, "_OSC", &input, output);
> +	if (ACPI_FAILURE(status) || !output->length)
> +		return -ENODATA;
> +
> +	out_obj = output->pointer;
> +	if (out_obj->type != ACPI_TYPE_BUFFER ||
> +	    out_obj->buffer.length != cap->length) {
> +		acpi_handle_debug(handle, "Invalid _OSC return buffer\n");
> +		acpi_dump_osc_data(handle, guid, rev, cap);
> +		ACPI_FREE(out_obj);
> +		return -ENODATA;
>  	}
> +
> +	return 0;
> +}