Commit 4b4967cb authored by Jorge Lopez's avatar Jorge Lopez Committed by Hans de Goede
Browse files

platform/x86: hp-wmi: Changing bios_args.data to be dynamically allocated 



The purpose of this patch is to remove 128 bytes buffer limitation
imposed in bios_args structure.

A limiting factor discovered during this investigation was the struct
bios_args.data size restriction.  The data member size limits all
possible WMI commands to those requiring buffer size of 128 bytes or
less. Several WMI commands and queries require a buffer size larger
than 128 bytes hence limiting current and feature supported by the
driver. It is for this reason, struct bios_args.data changed and is
dynamically allocated.  hp_wmi_perform_query function changed to
handle the memory allocation and release of any required buffer size.

All changes were validated on a HP ZBook Workstation notebook,
HP EliteBook x360, and HP EliteBook 850 G8.  Additional
validation was included in the test process to ensure no other
commands were incorrectly handled.

Signed-off-by: default avatarJorge Lopez <jorge.lopez2@hp.com>
Link: https://lore.kernel.org/r/20220310210853.28367-5-jorge.lopez2@hp.com


Reviewed-by: default avatarHans de Goede <hdegoede@redhat.com>
Signed-off-by: default avatarHans de Goede <hdegoede@redhat.com>
parent be9d73e6

drivers/platform/x86/hp-wmi.c

+33 −21
Original line number Diff line number Diff line
@@ -82,12 +82,17 @@ enum hp_wmi_event_ids { 
	HPWMI_BATTERY_CHARGE_PERIOD	= 0x10,

};



/*

 * struct bios_args buffer is dynamically allocated.  New WMI command types

 * were introduced that exceeds 128-byte data size.  Changes to handle

 * the data size allocation scheme were kept in hp_wmi_perform_qurey function.

 */

struct bios_args {

	u32 signature;

	u32 command;

	u32 commandtype;

	u32 datasize;

	u8 data[128];

	u8 data[];

};



enum hp_wmi_commandtype {
@@ -266,37 +271,43 @@ static inline int encode_outsize_for_pvsz(int outsize) 
static int hp_wmi_perform_query(int query, enum hp_wmi_command command,

				void *buffer, int insize, int outsize)

{

	int mid;

	struct acpi_buffer input, output = { ACPI_ALLOCATE_BUFFER, NULL };

	struct bios_return *bios_return;

	int actual_outsize;

	union acpi_object *obj;

	struct bios_args args = {

		.signature = 0x55434553,

		.command = command,

		.commandtype = query,

		.datasize = insize,

		.data = { 0 },

	};

	struct acpi_buffer input = { sizeof(struct bios_args), &args };

	struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };

	int ret = 0;

	union acpi_object *obj = NULL;

	struct bios_args *args = NULL;

	int mid, actual_outsize, ret;

	size_t bios_args_size;



	mid = encode_outsize_for_pvsz(outsize);

	if (WARN_ON(mid < 0))

		return mid;



	if (WARN_ON(insize > sizeof(args.data)))

		return -EINVAL;

	memcpy(&args.data[0], buffer, insize);

	bios_args_size = struct_size(args, data, insize);

	args = kmalloc(bios_args_size, GFP_KERNEL);

	if (!args)

		return -ENOMEM;



	wmi_evaluate_method(HPWMI_BIOS_GUID, 0, mid, &input, &output);

	input.length = bios_args_size;

	input.pointer = args;



	obj = output.pointer;

	args->signature = 0x55434553;

	args->command = command;

	args->commandtype = query;

	args->datasize = insize;

	memcpy(args->data, buffer, flex_array_size(args, data, insize));



	if (!obj)

		return -EINVAL;

	ret = wmi_evaluate_method(HPWMI_BIOS_GUID, 0, mid, &input, &output);

	if (ret)

		goto out_free;



	obj = output.pointer;

	if (!obj) {

		ret = -EINVAL;

		goto out_free;

	}



	if (obj->type != ACPI_TYPE_BUFFER) {

		pr_warn("query 0x%x returned an invalid object 0x%x\n", query, ret);

		ret = -EINVAL;

		goto out_free;

	}
@@ -321,6 +332,7 @@ static int hp_wmi_perform_query(int query, enum hp_wmi_command command, 


out_free:

	kfree(obj);

	kfree(args);

	return ret;

}