[PATCH v6 05/12] platform/x86: alienware-wmi-wmax: Improve platform profile probe

Kurt Borja
2025-03-13T14:30:22Z

Get and store the AWCC system description in alienware_awcc_setup()
instead of awcc_platform_profile_probe() and add a check for integer
overflows to avoid misbehaviors.

While at it, replace set_bit() with it's non-atomic version __set_bit()
because `choices` belong to this thread only.

Reviewed-by: Armin Wolf <W_Armin@gmx.de>
Signed-off-by: Kurt Borja <kuurtb@gmail.com>
---
drivers/platform/x86/dell/alienware-wmi-wmax.c | 61 +++++++++++++++++++-------
1 file changed, 46 insertions(+), 15 deletions(-)

diff --git a/drivers/platform/x86/dell/alienware-wmi-wmax.c b/drivers/platform/x86/dell/alienware-wmi-wmax.c
index a8a13779793abbcc8d1263474cac6227d524a6f5..0530f25b956f73f47c0354f40dac2910448c894e 100644
--- a/drivers/platform/x86/dell/alienware-wmi-wmax.c
+++ b/drivers/platform/x86/dell/alienware-wmi-wmax.c
@@ -38,6 +38,9 @@
/* Some IDs have a BIT(8) flag that we ignore */
#define AWCC_RESOURCE_ID_MASK GENMASK(7, 0)

+/* Arbitrary limit based on supported models */
+#define AWCC_MAX_RES_COUNT 16
+
static bool force_platform_profile;
module_param_unsafe(force_platform_profile, bool, 0);
MODULE_PARM_DESC(force_platform_profile, "Forces auto-detecting thermal profiles without checking if WMI thermal backend is available");
@@ -212,6 +215,17 @@ struct wmax_u32_args {

struct awcc_priv {
struct wmi_device *wdev;
+ union {
+ u32 system_description;
+ struct {
+ u8 fan_count;
+ u8 temp_count;
+ u8 unknown_count;
+ u8 profile_count;
+ };
+ u8 res_count[4];
+ };
+
struct device *ppdev;
u8 supported_profiles[PLATFORM_PROFILE_LAST];
};
@@ -624,37 +638,40 @@ static int awcc_platform_profile_probe(void *drvdata, unsigned long *choices)
enum platform_profile_option profile;
struct awcc_priv *priv = drvdata;
enum awcc_thermal_profile mode;
- u8 sys_desc[4];
- u32 first_mode;
+ u8 id, offset = 0;
u32 out_data;
int ret;
- u8 id;

- ret = awcc_thermal_information(priv->wdev, AWCC_OP_GET_SYSTEM_DESCRIPTION,
- 0, (u32 *) &sys_desc);
- if (ret < 0)
- return ret;
-
- first_mode = sys_desc[0] + sys_desc[1];
-
- for (u32 i = 0; i < sys_desc[3]; i++) {
- ret = awcc_op_get_resource_id(priv->wdev, i + first_mode, &out_data);
+ /*
+ * Thermal profile IDs are listed last at offset
+ * fan_count + temp_count + unknown_count
+ */
+ for (unsigned int i = 0; i < ARRAY_SIZE(priv->res_count) - 1; i++)
+ offset += priv->res_count[i];

+ for (unsigned int i = 0; i < priv->profile_count; i++) {
+ ret = awcc_op_get_resource_id(priv->wdev, i + offset, &out_data);
if (ret == -EIO)
return ret;

+ /*
+ * Some devices report an incorrect number of thermal profiles
+ * so the resource ID list may end prematurely
+ */
if (ret == -EBADRQC)
break;

id = FIELD_GET(AWCC_RESOURCE_ID_MASK, out_data);
- if (!is_awcc_thermal_profile_id(id))
+ if (!is_awcc_thermal_profile_id(id)) {
+ dev_dbg(&priv->wdev->dev, "Unmapped thermal profile ID 0x%02x\n", id);
continue;
+ }

mode = FIELD_GET(AWCC_THERMAL_MODE_MASK, id);
profile = awcc_mode_to_platform_profile[mode];
priv->supported_profiles[profile] = id;

- set_bit(profile, choices);
+ __set_bit(profile, choices);
}

if (bitmap_empty(choices, PLATFORM_PROFILE_LAST))
@@ -664,7 +681,7 @@ static int awcc_platform_profile_probe(void *drvdata, unsigned long *choices)
priv->supported_profiles[PLATFORM_PROFILE_PERFORMANCE] =
AWCC_THERMAL_MODE_GMODE;

- set_bit(PLATFORM_PROFILE_PERFORMANCE, choices);
+ __set_bit(PLATFORM_PROFILE_PERFORMANCE, choices);
}

return 0;
@@ -695,6 +712,20 @@ static int alienware_awcc_setup(struct wmi_device *wdev)
if (!priv)
return -ENOMEM;

+ ret = awcc_thermal_information(wdev, AWCC_OP_GET_SYSTEM_DESCRIPTION,
+ 0, &priv->system_description);
+ if (ret < 0)
+ return ret;
+
+ /* Sanity check */
+ for (unsigned int i = 0; i < ARRAY_SIZE(priv->res_count); i++) {
+ if (priv->res_count[i] > AWCC_MAX_RES_COUNT) {
+ dev_err(&wdev->dev, "Malformed system description: 0x%08x\n",
+ priv->system_description);
+ return -ENXIO;
+ }
+ }
+
priv->wdev = wdev;
dev_set_drvdata(&wdev->dev, priv);

--
2.48.1