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: Jorge Lopez <jorge.lopez2@xxxxxx>
---
Based on the latest platform-drivers-x86.git/for-next
---
drivers/platform/x86/hp-wmi.c | 59 ++++++++++++++++++++++-------------
1 file changed, 38 insertions(+), 21 deletions(-)
diff --git a/drivers/platform/x86/hp-wmi.c b/drivers/platform/x86/hp-wmi.c
index ecf2a3a8ed78..95a95535aea0 100644
--- a/drivers/platform/x86/hp-wmi.c
+++ b/drivers/platform/x86/hp-wmi.c
@@ -86,12 +86,17 @@ 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[0];
};
enum hp_wmi_commandtype {
@@ -259,34 +264,39 @@ static int hp_wmi_perform_query(int query, enum hp_wmi_command command,
int mid;
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 };
+ union acpi_object *obj = NULL;
+ size_t bios_args_size = sizeof(struct bios_args) + insize;
+ struct bios_args *args = NULL;
+ struct acpi_buffer input;
struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
int ret = 0;
- mid = encode_outsize_for_pvsz(outsize);
- if (WARN_ON(mid < 0))
- return mid;
+ args = kmalloc(bios_args_size, GFP_KERNEL);
+ if (!args)
+ return -ENOMEM;
- if (WARN_ON(insize > sizeof(args.data)))
- return -EINVAL;
- memcpy(&args.data[0], buffer, insize);
+ input.length = bios_args_size;
+ input.pointer = args;
- wmi_evaluate_method(HPWMI_BIOS_GUID, 0, mid, &input, &output);
+ mid = encode_outsize_for_pvsz(outsize);
+ if (WARN_ON(mid < 0)) {
+ ret = mid;
+ goto out_free;
+ }
- obj = output.pointer;
+ memcpy(args->data, buffer, insize);
- if (!obj)
- return -EINVAL;
+ args->signature = 0x55434553;
+ args->command = command;
+ args->commandtype = query;
+ args->datasize = insize;
- if (obj->type != ACPI_TYPE_BUFFER) {
+ 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;
}
@@ -301,6 +311,12 @@ static int hp_wmi_perform_query(int query, enum hp_wmi_command command,
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;
+ }
+
/* Ignore output data of zero size */
if (!outsize)
goto out_free;
@@ -311,6 +327,7 @@ static int hp_wmi_perform_query(int query, enum hp_wmi_command command,
out_free:
kfree(obj);
+ kfree(args);
return ret;
}
--
2.25.1
