Re: [RFC] platform/x86: hp-wmi: make hp_wmi_perform_query() work with certain devices

[Bedant Patnaik <bedant.patnaik@gmail.com>]

From: Bedant Patnaik <bedant.patnaik@gmail.com>
Date: Tue, 7 Jun 2022 23:16:05 +0530
Subject: [PATCH] platform/x86: hp-wmi: make hp_wmi_perform_query() work with
 certain devices

4b4967cbd2685f313411e6facf915fb2ae01d796 ("platform/x86: hp-wmi: Changing bios_args.data to be dynamically allocated")
broke WMI queries on some devices where the ACPI method HWMC unconditionally attempts to create Fields beyond the buffer
if the buffer is too small:
        CreateByteField (Arg1, 0x10, D008)
        CreateByteField (Arg1, 0x11, D009)
        CreateByteField (Arg1, 0x12, D010)
        CreateDWordField (Arg1, 0x10, D032)
        CreateField (Arg1, 0x80, 0x0400, D128)
In cases where args->data had zero length, ACPI BIOS Error (bug): AE_AML_BUFFER_LIMIT, Field [D008] at bit
offset/length 128/8 exceeds size of target Buffer (128 bits) (20211217/dsopcode-198) was obtained.
Fix: allocate at least 128 bytes for args->data

Tested on Omen 15 AMD (2020) board ID: 8786.

Signed-off-by: Bedant Patnaik <bedant.patnaik@gmail.com>
---
 drivers/platform/x86/hp-wmi.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/platform/x86/hp-wmi.c b/drivers/platform/x86/hp-wmi.c
index 667f94bba..7a54191f0 100644
--- a/drivers/platform/x86/hp-wmi.c
+++ b/drivers/platform/x86/hp-wmi.c
@@ -175,7 +175,7 @@ enum hp_thermal_profile_omen_v1 {
 enum hp_thermal_profile {
 	HP_THERMAL_PROFILE_PERFORMANCE	= 0x00,
 	HP_THERMAL_PROFILE_DEFAULT		= 0x01,
-	HP_THERMAL_PROFILE_COOL			= 0x02
+	HP_THERMAL_PROFILE_COOL			= 0x02,
 };
 
 #define IS_HWBLOCKED(x) ((x & HPWMI_POWER_FW_OR_HW) != HPWMI_POWER_FW_OR_HW)
@@ -297,8 +297,8 @@ static int hp_wmi_perform_query(int query, enum hp_wmi_command command,
 	if (WARN_ON(mid < 0))
 		return mid;
 
-	bios_args_size = struct_size(args, data, insize);
-	args = kmalloc(bios_args_size, GFP_KERNEL);
+	bios_args_size = max(struct_size(args, data, insize), struct_size(args, data, 128));
+	args = kzalloc(bios_args_size, GFP_KERNEL);
 	if (!args)
 		return -ENOMEM;
 
-- 
2.36.1