The EliteDesk 800 G6 stores a raw WMI string within the ACPI object in its BIOS corresponding to one instance of HPBIOS_PlatformEvents.Name. This is evidently a valid way of representing a WMI data item as far as the Microsoft ACPI-WMI mapper is concerned, but is preventing the driver from loading. This seems quite rare, but add support for such strings. Treating this as a quirk pretty much means adding that support anyway. Also clean up an oversight in update_numeric_sensor_from_wobj() in which the result of hp_wmi_strdup() was being used without error checking. Reported-by: Lukasz Stelmach <l.stelmach@xxxxxxxxxxx> Closes: https://lore.kernel.org/linux-hwmon/7850a0bd-60e7-88f8-1d6c-0bb0e3234fdc@xxxxxxxxxxxx/ Signed-off-by: James Seo <james@xxxxxxxxxx> --- Changes v1->v2: * Remove DMI-based workaround logic * Add full support for raw WMI strings - Improve UTF-16 validation and conversion for the general case - Support such strings if they occur in HPBIOS_BIOSEvent objects * Only use the result of hp_wmi_strdup() in update_numeric_sensor_from_wobj() if the call succeeded History: v1: https://lore.kernel.org/linux-hwmon/20231103181931.677796-1-james@xxxxxxxxxx/ --- drivers/hwmon/hp-wmi-sensors.c | 127 ++++++++++++++++++++++++++++----- 1 file changed, 111 insertions(+), 16 deletions(-) diff --git a/drivers/hwmon/hp-wmi-sensors.c b/drivers/hwmon/hp-wmi-sensors.c index 17ae62f88bbf..bdd7ca163593 100644 --- a/drivers/hwmon/hp-wmi-sensors.c +++ b/drivers/hwmon/hp-wmi-sensors.c @@ -17,6 +17,8 @@ * Available: https://github.com/linuxhw/ACPI * [4] P. Rohár, "bmfdec - Decompile binary MOF file (BMF) from WMI buffer", * 2017. [Online]. Available: https://github.com/pali/bmfdec + * [5] Microsoft Corporation, "Driver-Defined WMI Data Items", 2017. [Online]. + * Available: https://learn.microsoft.com/en-us/windows-hardware/drivers/kernel/driver-defined-wmi-data-items */ #include <linux/acpi.h> @@ -24,6 +26,7 @@ #include <linux/hwmon.h> #include <linux/jiffies.h> #include <linux/mutex.h> +#include <linux/nls.h> #include <linux/units.h> #include <linux/wmi.h> @@ -395,6 +398,50 @@ struct hp_wmi_sensors { struct mutex lock; /* Lock polling WMI and driver state changes. */ }; +static bool is_raw_wmi_string(const u8 *pointer, u32 length) +{ + const u16 *ptr; + u16 len; + + /* WMI strings are length-prefixed UTF-16 [5]. */ + if (length <= sizeof(*ptr)) + return false; + + length -= sizeof(*ptr); + ptr = (const u16 *)pointer; + len = *ptr; + + return len <= length && !(len & 1); +} + +static char *convert_raw_wmi_string(const u8 *buf) +{ + const wchar_t *src; + unsigned cps; + unsigned len; + char *dst; + int i; + + src = (const wchar_t *)buf; + + /* Count UTF-16 code points. Exclude trailing null padding. */ + cps = *src / sizeof(*src); + while (cps && !src[cps]) + cps--; + + /* Each code point becomes up to 3 UTF-8 characters. */ + len = min(cps * 3, HP_WMI_MAX_STR_SIZE - 1); + + dst = kmalloc((len + 1) * sizeof(*dst), GFP_KERNEL); + if (!dst) + return NULL; + + i = utf16s_to_utf8s(++src, cps, UTF16_LITTLE_ENDIAN, dst, len); + dst[i] = '\0'; + + return dst; +} + /* hp_wmi_strdup - devm_kstrdup, but length-limited */ static char *hp_wmi_strdup(struct device *dev, const char *src) { @@ -412,6 +459,23 @@ static char *hp_wmi_strdup(struct device *dev, const char *src) return dst; } +/* hp_wmi_wstrdup - hp_wmi_strdup, but for a raw WMI string */ +static char *hp_wmi_wstrdup(struct device *dev, const u8 *buf) +{ + char *src; + char *dst; + + src = convert_raw_wmi_string(buf); + if (!src) + return NULL; + + dst = hp_wmi_strdup(dev, strim(src)); /* Note: Copy is trimmed. */ + + kfree(src); + + return dst; +} + /* * hp_wmi_get_wobj - poll WMI for a WMI object instance * @guid: WMI object GUID @@ -462,8 +526,14 @@ static int check_wobj(const union acpi_object *wobj, for (prop = 0; prop <= last_prop; prop++) { type = elements[prop].type; valid_type = property_map[prop]; - if (type != valid_type) + if (type != valid_type) { + if (type == ACPI_TYPE_BUFFER && + valid_type == ACPI_TYPE_STRING && + is_raw_wmi_string(elements[prop].buffer.pointer, + elements[prop].buffer.length)) + continue; return -EINVAL; + } } return 0; @@ -480,7 +550,9 @@ static int extract_acpi_value(struct device *dev, break; case ACPI_TYPE_STRING: - *out_string = hp_wmi_strdup(dev, strim(element->string.pointer)); + *out_string = element->type == ACPI_TYPE_BUFFER ? + hp_wmi_wstrdup(dev, element->buffer.pointer) : + hp_wmi_strdup(dev, strim(element->string.pointer)); if (!*out_string) return -ENOMEM; break; @@ -861,7 +933,9 @@ update_numeric_sensor_from_wobj(struct device *dev, { const union acpi_object *elements; const union acpi_object *element; - const char *string; + const char *new_string; + char *trimmed; + char *string; bool is_new; int offset; u8 size; @@ -885,11 +959,21 @@ update_numeric_sensor_from_wobj(struct device *dev, offset = is_new ? size - 1 : -2; element = &elements[HP_WMI_PROPERTY_CURRENT_STATE + offset]; - string = strim(element->string.pointer); - - if (strcmp(string, nsensor->current_state)) { - devm_kfree(dev, nsensor->current_state); - nsensor->current_state = hp_wmi_strdup(dev, string); + string = element->type == ACPI_TYPE_BUFFER ? + convert_raw_wmi_string(element->buffer.pointer) : + element->string.pointer; + + if (string) { + trimmed = strim(string); + if (strcmp(trimmed, nsensor->current_state)) { + new_string = hp_wmi_strdup(dev, trimmed); + if (new_string) { + devm_kfree(dev, nsensor->current_state); + nsensor->current_state = new_string; + } + } + if (element->type == ACPI_TYPE_BUFFER) + kfree(string); } /* Old variant: -2 (not -1) because it lacks the Size property. */ @@ -996,11 +1080,15 @@ static int check_event_wobj(const union acpi_object *wobj) HP_WMI_EVENT_PROPERTY_STATUS); } -static int populate_event_from_wobj(struct hp_wmi_event *event, +static int populate_event_from_wobj(struct device *dev, + struct hp_wmi_event *event, union acpi_object *wobj) { int prop = HP_WMI_EVENT_PROPERTY_NAME; union acpi_object *element; + acpi_object_type type; + char *string; + u32 value; int err; err = check_event_wobj(wobj); @@ -1009,20 +1097,24 @@ static int populate_event_from_wobj(struct hp_wmi_event *event, element = wobj->package.elements; - /* Extracted strings are NOT device-managed copies. */ - for (; prop <= HP_WMI_EVENT_PROPERTY_CATEGORY; prop++, element++) { + type = hp_wmi_event_property_map[prop]; + + err = extract_acpi_value(dev, element, type, &value, &string); + if (err) + return err; + switch (prop) { case HP_WMI_EVENT_PROPERTY_NAME: - event->name = strim(element->string.pointer); + event->name = string; break; case HP_WMI_EVENT_PROPERTY_DESCRIPTION: - event->description = strim(element->string.pointer); + event->description = string; break; case HP_WMI_EVENT_PROPERTY_CATEGORY: - event->category = element->integer.value; + event->category = value; break; default: @@ -1511,8 +1603,8 @@ static void hp_wmi_notify(u32 value, void *context) struct acpi_buffer out = { ACPI_ALLOCATE_BUFFER, NULL }; struct hp_wmi_sensors *state = context; struct device *dev = &state->wdev->dev; + struct hp_wmi_event event = {}; struct hp_wmi_info *fan_info; - struct hp_wmi_event event; union acpi_object *wobj; acpi_status err; int event_type; @@ -1546,7 +1638,7 @@ static void hp_wmi_notify(u32 value, void *context) wobj = out.pointer; - err = populate_event_from_wobj(&event, wobj); + err = populate_event_from_wobj(dev, &event, wobj); if (err) { dev_warn(dev, "Bad event data (ACPI type %d)\n", wobj->type); goto out_free_wobj; @@ -1577,6 +1669,9 @@ static void hp_wmi_notify(u32 value, void *context) out_free_wobj: kfree(wobj); + devm_kfree(dev, event.name); + devm_kfree(dev, event.description); + out_unlock: mutex_unlock(&state->lock); } base-commit: 0f564130e5c76f1e5cf0008924f6a6cd138929d9 -- 2.39.2
