Newer Thinkpads have a feature called MAC Address Pass-through.
This patch provides a sysfs interface that userspace can use
to get this auxiliary mac address.
Signed-off-by: Fernando Eckhardt Valle <[email protected]>
---
Changes in v5:
- Repeated code deleted.
- Adjusted offset of a strscpy().
Changes in v4:
- strscpy() in all string copies.
Changes in v3:
- Added null terminator to auxmac string when copying auxiliary
mac address value.
Changes in v2:
- Added documentation.
- All handling of the auxmac value is done in the _init function.
---
.../admin-guide/laptops/thinkpad-acpi.rst | 20 +++++
drivers/platform/x86/thinkpad_acpi.c | 81 +++++++++++++++++++
2 files changed, 101 insertions(+)
diff --git a/Documentation/admin-guide/laptops/thinkpad-acpi.rst b/Documentation/admin-guide/laptops/thinkpad-acpi.rst
index e27a1c3f6..98d304010 100644
--- a/Documentation/admin-guide/laptops/thinkpad-acpi.rst
+++ b/Documentation/admin-guide/laptops/thinkpad-acpi.rst
@@ -53,6 +53,7 @@ detailed description):
- Lap mode sensor
- Setting keyboard language
- WWAN Antenna type
+ - Auxmac
A compatibility table by model and feature is maintained on the web
site, http://ibm-acpi.sf.net/. I appreciate any success or failure
@@ -1511,6 +1512,25 @@ Currently 2 antenna types are supported as mentioned below:
The property is read-only. If the platform doesn't have support the sysfs
class is not created.
+Auxmac
+------
+
+sysfs: auxmac
+
+Some newer Thinkpads have a feature called MAC Address Pass-through. This
+feature is implemented by the system firmware to provide a system unique MAC,
+that can override a dock or USB ethernet dongle MAC, when connected to a
+network. This property enables user-space to easily determine the MAC address
+if the feature is enabled.
+
+The values of this auxiliary MAC are:
+
+ cat /sys/devices/platform/thinkpad_acpi/auxmac
+
+If the feature is disabled, the value will be 'disabled'.
+
+This property is read-only.
+
Adaptive keyboard
-----------------
diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
index d70c89d32..2324ebb46 100644
--- a/drivers/platform/x86/thinkpad_acpi.c
+++ b/drivers/platform/x86/thinkpad_acpi.c
@@ -10785,6 +10785,82 @@ static struct ibm_struct dprc_driver_data = {
.name = "dprc",
};
+/*
+ * Auxmac
+ *
+ * This auxiliary mac address is enabled in the bios through the
+ * MAC Address Pass-through feature. In most cases, there are three
+ * possibilities: Internal Mac, Second Mac, and disabled.
+ *
+ */
+
+#define AUXMAC_LEN 12
+#define AUXMAC_START 9
+#define AUXMAC_STRLEN 22
+#define AUXMAC_BEGIN_MARKER 8
+#define AUXMAC_END_MARKER 21
+
+static char auxmac[AUXMAC_LEN + 1];
+
+static int auxmac_init(struct ibm_init_struct *iibm)
+{
+ acpi_status status;
+ struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
+ union acpi_object *obj;
+
+ status = acpi_evaluate_object(NULL, "\\MACA", NULL, &buffer);
+
+ if (ACPI_FAILURE(status))
+ return -ENODEV;
+
+ obj = buffer.pointer;
+
+ if (obj->type != ACPI_TYPE_STRING || obj->string.length != AUXMAC_STRLEN) {
+ pr_info("Invalid buffer for MAC address pass-through.\n");
+ goto auxmacinvalid;
+ }
+
+ if (obj->string.pointer[AUXMAC_BEGIN_MARKER] != '#' ||
+ obj->string.pointer[AUXMAC_END_MARKER] != '#') {
+ pr_info("Invalid header for MAC address pass-through.\n");
+ goto auxmacinvalid;
+ }
+
+ if (strncmp(obj->string.pointer + AUXMAC_START, "XXXXXXXXXXXX", AUXMAC_LEN) != 0)
+ strscpy(auxmac, obj->string.pointer + AUXMAC_START, AUXMAC_LEN + 1);
+ else
+ strscpy(auxmac, "disabled", AUXMAC_LEN);
+
+free:
+ kfree(obj);
+ return 0;
+
+auxmacinvalid:
+ strscpy(auxmac, "unavailable", AUXMAC_LEN);
+ goto free;
+}
+
+static struct ibm_struct auxmac_data = {
+ .name = "auxmac",
+};
+
+static ssize_t auxmac_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ return sysfs_emit(buf, "%s\n", auxmac);
+}
+static DEVICE_ATTR_RO(auxmac);
+
+static struct attribute *auxmac_attributes[] = {
+ &dev_attr_auxmac.attr,
+ NULL
+};
+
+static const struct attribute_group auxmac_attr_group = {
+ .attrs = auxmac_attributes,
+};
+
/* --------------------------------------------------------------------- */
static struct attribute *tpacpi_driver_attributes[] = {
@@ -10843,6 +10919,7 @@ static const struct attribute_group *tpacpi_groups[] = {
&proxsensor_attr_group,
&kbdlang_attr_group,
&dprc_attr_group,
+ &auxmac_attr_group,
NULL,
};
@@ -11414,6 +11491,10 @@ static struct ibm_init_struct ibms_init[] __initdata = {
.init = tpacpi_dprc_init,
.data = &dprc_driver_data,
},
+ {
+ .init = auxmac_init,
+ .data = &auxmac_data,
+ },
};
static int __init set_ibm_param(const char *val, const struct kernel_param *kp)
--
2.25.1
Hi,
It looks like I just reviewed an old version, reviewing this version now ...
On 9/25/23 20:41, Fernando Eckhardt Valle wrote:
> Newer Thinkpads have a feature called MAC Address Pass-through.
> This patch provides a sysfs interface that userspace can use
> to get this auxiliary mac address.
>
> Signed-off-by: Fernando Eckhardt Valle <[email protected]>
> ---
> Changes in v5:
> - Repeated code deleted.
> - Adjusted offset of a strscpy().
> Changes in v4:
> - strscpy() in all string copies.
> Changes in v3:
> - Added null terminator to auxmac string when copying auxiliary
> mac address value.
> Changes in v2:
> - Added documentation.
> - All handling of the auxmac value is done in the _init function.
> ---
> .../admin-guide/laptops/thinkpad-acpi.rst | 20 +++++
> drivers/platform/x86/thinkpad_acpi.c | 81 +++++++++++++++++++
> 2 files changed, 101 insertions(+)
>
> diff --git a/Documentation/admin-guide/laptops/thinkpad-acpi.rst b/Documentation/admin-guide/laptops/thinkpad-acpi.rst
> index e27a1c3f6..98d304010 100644
> --- a/Documentation/admin-guide/laptops/thinkpad-acpi.rst
> +++ b/Documentation/admin-guide/laptops/thinkpad-acpi.rst
> @@ -53,6 +53,7 @@ detailed description):
> - Lap mode sensor
> - Setting keyboard language
> - WWAN Antenna type
> + - Auxmac
>
> A compatibility table by model and feature is maintained on the web
> site, http://ibm-acpi.sf.net/. I appreciate any success or failure
> @@ -1511,6 +1512,25 @@ Currently 2 antenna types are supported as mentioned below:
> The property is read-only. If the platform doesn't have support the sysfs
> class is not created.
>
> +Auxmac
> +------
> +
> +sysfs: auxmac
> +
> +Some newer Thinkpads have a feature called MAC Address Pass-through. This
> +feature is implemented by the system firmware to provide a system unique MAC,
> +that can override a dock or USB ethernet dongle MAC, when connected to a
> +network. This property enables user-space to easily determine the MAC address
> +if the feature is enabled.
> +
> +The values of this auxiliary MAC are:
> +
> + cat /sys/devices/platform/thinkpad_acpi/auxmac
> +
> +If the feature is disabled, the value will be 'disabled'.
> +
> +This property is read-only.
> +
> Adaptive keyboard
> -----------------
>
> diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
> index d70c89d32..2324ebb46 100644
> --- a/drivers/platform/x86/thinkpad_acpi.c
> +++ b/drivers/platform/x86/thinkpad_acpi.c
> @@ -10785,6 +10785,82 @@ static struct ibm_struct dprc_driver_data = {
> .name = "dprc",
> };
>
> +/*
> + * Auxmac
> + *
> + * This auxiliary mac address is enabled in the bios through the
> + * MAC Address Pass-through feature. In most cases, there are three
> + * possibilities: Internal Mac, Second Mac, and disabled.
> + *
> + */
> +
> +#define AUXMAC_LEN 12
> +#define AUXMAC_START 9
> +#define AUXMAC_STRLEN 22
> +#define AUXMAC_BEGIN_MARKER 8
> +#define AUXMAC_END_MARKER 21
> +
> +static char auxmac[AUXMAC_LEN + 1];
> +
> +static int auxmac_init(struct ibm_init_struct *iibm)
> +{
> + acpi_status status;
> + struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
> + union acpi_object *obj;
> +
> + status = acpi_evaluate_object(NULL, "\\MACA", NULL, &buffer);
> +
> + if (ACPI_FAILURE(status))
> + return -ENODEV;
In this code path you don't initialize the "auxmac" buffer at all,
but your auxmac_attr_group does not have an is_visible callback,
so the auxmax sysfs attr will still show up.
Please add an is_visible callback and retuern 0 (not visible)
when auxmac[0] == 0; See existing is_visible code for some
examples.
> +
> + obj = buffer.pointer;
> +
> + if (obj->type != ACPI_TYPE_STRING || obj->string.length != AUXMAC_STRLEN) {
> + pr_info("Invalid buffer for MAC address pass-through.\n");
> + goto auxmacinvalid;
> + }
> +
> + if (obj->string.pointer[AUXMAC_BEGIN_MARKER] != '#' ||
> + obj->string.pointer[AUXMAC_END_MARKER] != '#') {
> + pr_info("Invalid header for MAC address pass-through.\n");
> + goto auxmacinvalid;
> + }
> +
> + if (strncmp(obj->string.pointer + AUXMAC_START, "XXXXXXXXXXXX", AUXMAC_LEN) != 0)
> + strscpy(auxmac, obj->string.pointer + AUXMAC_START, AUXMAC_LEN + 1);
Please use sizeof(auxmac) as last parameter to strscpy() here.
> + else
> + strscpy(auxmac, "disabled", AUXMAC_LEN);
Please use sizeof(auxmac) as last parameter to strscpy() here.
Also note how you pass 2 different dest-sizes for the same dest buffer before,
which looks weird ...
> +
> +free:
> + kfree(obj);
> + return 0;
> +
> +auxmacinvalid:
> + strscpy(auxmac, "unavailable", AUXMAC_LEN);
> + goto free;
> +}
I'm not liking the goto dance here, I would prefer:
kfree(obj);
return 0;
auxmacinvalid:
strscpy(auxmac, "unavailable", AUXMAC_LEN);
kfree(obj);
return 0;
It is quite normal for an error-exit path to repeat a kfree().
Note this is just a preference you keen keep this as is
if you want, but to me the goto free which jumps up looks
pretty weird.
Regards,
Hans
> +
> +static struct ibm_struct auxmac_data = {
> + .name = "auxmac",
> +};
> +
> +static ssize_t auxmac_show(struct device *dev,
> + struct device_attribute *attr,
> + char *buf)
> +{
> + return sysfs_emit(buf, "%s\n", auxmac);
> +}
> +static DEVICE_ATTR_RO(auxmac);
> +
> +static struct attribute *auxmac_attributes[] = {
> + &dev_attr_auxmac.attr,
> + NULL
> +};
> +
> +static const struct attribute_group auxmac_attr_group = {
> + .attrs = auxmac_attributes,
> +};
> +
> /* --------------------------------------------------------------------- */
>
> static struct attribute *tpacpi_driver_attributes[] = {
> @@ -10843,6 +10919,7 @@ static const struct attribute_group *tpacpi_groups[] = {
> &proxsensor_attr_group,
> &kbdlang_attr_group,
> &dprc_attr_group,
> + &auxmac_attr_group,
> NULL,
> };
>
> @@ -11414,6 +11491,10 @@ static struct ibm_init_struct ibms_init[] __initdata = {
> .init = tpacpi_dprc_init,
> .data = &dprc_driver_data,
> },
> + {
> + .init = auxmac_init,
> + .data = &auxmac_data,
> + },
> };
>
> static int __init set_ibm_param(const char *val, const struct kernel_param *kp)
Thanks for the review Hans, I'll send a new version with some adjustments.
> Note this is just a preference you keen keep this as is
> if you want,
I liked the Ilpo suggestion, with two 'gotos' is eliminated repeated code. If everything is ok, I prefer it this way.
Regards,
Fernando Valle
________________________________________
From: Hans de Goede <[email protected]>
Sent: Tuesday, September 26, 2023 7:23 AM
To: Fernando Eckhardt Valle (FIPT); [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]
Subject: Re: [PATCH v5] platform/x86: thinkpad_acpi: sysfs interface to auxmac
Hi,
It looks like I just reviewed an old version, reviewing this version now ...
On 9/25/23 20:41, Fernando Eckhardt Valle wrote:
> Newer Thinkpads have a feature called MAC Address Pass-through.
> This patch provides a sysfs interface that userspace can use
> to get this auxiliary mac address.
>
> Signed-off-by: Fernando Eckhardt Valle <[email protected]>
> ---
> Changes in v5:
> - Repeated code deleted.
> - Adjusted offset of a strscpy().
> Changes in v4:
> - strscpy() in all string copies.
> Changes in v3:
> - Added null terminator to auxmac string when copying auxiliary
> mac address value.
> Changes in v2:
> - Added documentation.
> - All handling of the auxmac value is done in the _init function.
> ---
> .../admin-guide/laptops/thinkpad-acpi.rst | 20 +++++
> drivers/platform/x86/thinkpad_acpi.c | 81 +++++++++++++++++++
> 2 files changed, 101 insertions(+)
>
> diff --git a/Documentation/admin-guide/laptops/thinkpad-acpi.rst b/Documentation/admin-guide/laptops/thinkpad-acpi.rst
> index e27a1c3f6..98d304010 100644
> --- a/Documentation/admin-guide/laptops/thinkpad-acpi.rst
> +++ b/Documentation/admin-guide/laptops/thinkpad-acpi.rst
> @@ -53,6 +53,7 @@ detailed description):
> - Lap mode sensor
> - Setting keyboard language
> - WWAN Antenna type
> + - Auxmac
>
> A compatibility table by model and feature is maintained on the web
> site, http://ibm-acpi.sf.net/. I appreciate any success or failure
> @@ -1511,6 +1512,25 @@ Currently 2 antenna types are supported as mentioned below:
> The property is read-only. If the platform doesn't have support the sysfs
> class is not created.
>
> +Auxmac
> +------
> +
> +sysfs: auxmac
> +
> +Some newer Thinkpads have a feature called MAC Address Pass-through. This
> +feature is implemented by the system firmware to provide a system unique MAC,
> +that can override a dock or USB ethernet dongle MAC, when connected to a
> +network. This property enables user-space to easily determine the MAC address
> +if the feature is enabled.
> +
> +The values of this auxiliary MAC are:
> +
> + cat /sys/devices/platform/thinkpad_acpi/auxmac
> +
> +If the feature is disabled, the value will be 'disabled'.
> +
> +This property is read-only.
> +
> Adaptive keyboard
> -----------------
>
> diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
> index d70c89d32..2324ebb46 100644
> --- a/drivers/platform/x86/thinkpad_acpi.c
> +++ b/drivers/platform/x86/thinkpad_acpi.c
> @@ -10785,6 +10785,82 @@ static struct ibm_struct dprc_driver_data = {
> .name = "dprc",
> };
>
> +/*
> + * Auxmac
> + *
> + * This auxiliary mac address is enabled in the bios through the
> + * MAC Address Pass-through feature. In most cases, there are three
> + * possibilities: Internal Mac, Second Mac, and disabled.
> + *
> + */
> +
> +#define AUXMAC_LEN 12
> +#define AUXMAC_START 9
> +#define AUXMAC_STRLEN 22
> +#define AUXMAC_BEGIN_MARKER 8
> +#define AUXMAC_END_MARKER 21
> +
> +static char auxmac[AUXMAC_LEN + 1];
> +
> +static int auxmac_init(struct ibm_init_struct *iibm)
> +{
> + acpi_status status;
> + struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
> + union acpi_object *obj;
> +
> + status = acpi_evaluate_object(NULL, "\\MACA", NULL, &buffer);
> +
> + if (ACPI_FAILURE(status))
> + return -ENODEV;
In this code path you don't initialize the "auxmac" buffer at all,
but your auxmac_attr_group does not have an is_visible callback,
so the auxmax sysfs attr will still show up.
Please add an is_visible callback and retuern 0 (not visible)
when auxmac[0] == 0; See existing is_visible code for some
examples.
> +
> + obj = buffer.pointer;
> +
> + if (obj->type != ACPI_TYPE_STRING || obj->string.length != AUXMAC_STRLEN) {
> + pr_info("Invalid buffer for MAC address pass-through.\n");
> + goto auxmacinvalid;
> + }
> +
> + if (obj->string.pointer[AUXMAC_BEGIN_MARKER] != '#' ||
> + obj->string.pointer[AUXMAC_END_MARKER] != '#') {
> + pr_info("Invalid header for MAC address pass-through.\n");
> + goto auxmacinvalid;
> + }
> +
> + if (strncmp(obj->string.pointer + AUXMAC_START, "XXXXXXXXXXXX", AUXMAC_LEN) != 0)
> + strscpy(auxmac, obj->string.pointer + AUXMAC_START, AUXMAC_LEN + 1);
Please use sizeof(auxmac) as last parameter to strscpy() here.
> + else
> + strscpy(auxmac, "disabled", AUXMAC_LEN);
Please use sizeof(auxmac) as last parameter to strscpy() here.
Also note how you pass 2 different dest-sizes for the same dest buffer before,
which looks weird ...
> +
> +free:
> + kfree(obj);
> + return 0;
> +
> +auxmacinvalid:
> + strscpy(auxmac, "unavailable", AUXMAC_LEN);
> + goto free;
> +}
I'm not liking the goto dance here, I would prefer:
kfree(obj);
return 0;
auxmacinvalid:
strscpy(auxmac, "unavailable", AUXMAC_LEN);
kfree(obj);
return 0;
It is quite normal for an error-exit path to repeat a kfree().
Note this is just a preference you keen keep this as is
if you want, but to me the goto free which jumps up looks
pretty weird.
Regards,
Hans
> +
> +static struct ibm_struct auxmac_data = {
> + .name = "auxmac",
> +};
> +
> +static ssize_t auxmac_show(struct device *dev,
> + struct device_attribute *attr,
> + char *buf)
> +{
> + return sysfs_emit(buf, "%s\n", auxmac);
> +}
> +static DEVICE_ATTR_RO(auxmac);
> +
> +static struct attribute *auxmac_attributes[] = {
> + &dev_attr_auxmac.attr,
> + NULL
> +};
> +
> +static const struct attribute_group auxmac_attr_group = {
> + .attrs = auxmac_attributes,
> +};
> +
> /* --------------------------------------------------------------------- */
>
> static struct attribute *tpacpi_driver_attributes[] = {
> @@ -10843,6 +10919,7 @@ static const struct attribute_group *tpacpi_groups[] = {
> &proxsensor_attr_group,
> &kbdlang_attr_group,
> &dprc_attr_group,
> + &auxmac_attr_group,
> NULL,
> };
>
> @@ -11414,6 +11491,10 @@ static struct ibm_init_struct ibms_init[] __initdata = {
> .init = tpacpi_dprc_init,
> .data = &dprc_driver_data,
> },
> + {
> + .init = auxmac_init,
> + .data = &auxmac_data,
> + },
> };
>
> static int __init set_ibm_param(const char *val, const struct kernel_param *kp)
Hi,
On 9/26/23 20:42, Fernando Eckhardt Valle (FIPT) wrote:
> Thanks for the review Hans, I'll send a new version with some adjustments.
>
>> Note this is just a preference you keen keep this as is
>> if you want,
> I liked the Ilpo suggestion, with two 'gotos' is eliminated repeated code. If everything is ok, I prefer it this way.
If you prefer the 2 goto solution from v5 then keeping it as is is fine.
Regards,
Hans
> ________________________________________
> From: Hans de Goede <[email protected]>
> Sent: Tuesday, September 26, 2023 7:23 AM
> To: Fernando Eckhardt Valle (FIPT); [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]
> Subject: Re: [PATCH v5] platform/x86: thinkpad_acpi: sysfs interface to auxmac
>
> Hi,
>
> It looks like I just reviewed an old version, reviewing this version now ...
>
> On 9/25/23 20:41, Fernando Eckhardt Valle wrote:
>> Newer Thinkpads have a feature called MAC Address Pass-through.
>> This patch provides a sysfs interface that userspace can use
>> to get this auxiliary mac address.
>>
>> Signed-off-by: Fernando Eckhardt Valle <[email protected]>
>> ---
>> Changes in v5:
>> - Repeated code deleted.
>> - Adjusted offset of a strscpy().
>> Changes in v4:
>> - strscpy() in all string copies.
>> Changes in v3:
>> - Added null terminator to auxmac string when copying auxiliary
>> mac address value.
>> Changes in v2:
>> - Added documentation.
>> - All handling of the auxmac value is done in the _init function.
>> ---
>> .../admin-guide/laptops/thinkpad-acpi.rst | 20 +++++
>> drivers/platform/x86/thinkpad_acpi.c | 81 +++++++++++++++++++
>> 2 files changed, 101 insertions(+)
>>
>> diff --git a/Documentation/admin-guide/laptops/thinkpad-acpi.rst b/Documentation/admin-guide/laptops/thinkpad-acpi.rst
>> index e27a1c3f6..98d304010 100644
>> --- a/Documentation/admin-guide/laptops/thinkpad-acpi.rst
>> +++ b/Documentation/admin-guide/laptops/thinkpad-acpi.rst
>> @@ -53,6 +53,7 @@ detailed description):
>> - Lap mode sensor
>> - Setting keyboard language
>> - WWAN Antenna type
>> + - Auxmac
>>
>> A compatibility table by model and feature is maintained on the web
>> site, http://ibm-acpi.sf.net/. I appreciate any success or failure
>> @@ -1511,6 +1512,25 @@ Currently 2 antenna types are supported as mentioned below:
>> The property is read-only. If the platform doesn't have support the sysfs
>> class is not created.
>>
>> +Auxmac
>> +------
>> +
>> +sysfs: auxmac
>> +
>> +Some newer Thinkpads have a feature called MAC Address Pass-through. This
>> +feature is implemented by the system firmware to provide a system unique MAC,
>> +that can override a dock or USB ethernet dongle MAC, when connected to a
>> +network. This property enables user-space to easily determine the MAC address
>> +if the feature is enabled.
>> +
>> +The values of this auxiliary MAC are:
>> +
>> + cat /sys/devices/platform/thinkpad_acpi/auxmac
>> +
>> +If the feature is disabled, the value will be 'disabled'.
>> +
>> +This property is read-only.
>> +
>> Adaptive keyboard
>> -----------------
>>
>> diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
>> index d70c89d32..2324ebb46 100644
>> --- a/drivers/platform/x86/thinkpad_acpi.c
>> +++ b/drivers/platform/x86/thinkpad_acpi.c
>> @@ -10785,6 +10785,82 @@ static struct ibm_struct dprc_driver_data = {
>> .name = "dprc",
>> };
>>
>> +/*
>> + * Auxmac
>> + *
>> + * This auxiliary mac address is enabled in the bios through the
>> + * MAC Address Pass-through feature. In most cases, there are three
>> + * possibilities: Internal Mac, Second Mac, and disabled.
>> + *
>> + */
>> +
>> +#define AUXMAC_LEN 12
>> +#define AUXMAC_START 9
>> +#define AUXMAC_STRLEN 22
>> +#define AUXMAC_BEGIN_MARKER 8
>> +#define AUXMAC_END_MARKER 21
>> +
>> +static char auxmac[AUXMAC_LEN + 1];
>> +
>> +static int auxmac_init(struct ibm_init_struct *iibm)
>> +{
>> + acpi_status status;
>> + struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
>> + union acpi_object *obj;
>> +
>> + status = acpi_evaluate_object(NULL, "\\MACA", NULL, &buffer);
>> +
>> + if (ACPI_FAILURE(status))
>> + return -ENODEV;
>
> In this code path you don't initialize the "auxmac" buffer at all,
> but your auxmac_attr_group does not have an is_visible callback,
> so the auxmax sysfs attr will still show up.
>
> Please add an is_visible callback and retuern 0 (not visible)
> when auxmac[0] == 0; See existing is_visible code for some
> examples.
>
>> +
>> + obj = buffer.pointer;
>> +
>> + if (obj->type != ACPI_TYPE_STRING || obj->string.length != AUXMAC_STRLEN) {
>> + pr_info("Invalid buffer for MAC address pass-through.\n");
>> + goto auxmacinvalid;
>> + }
>> +
>> + if (obj->string.pointer[AUXMAC_BEGIN_MARKER] != '#' ||
>> + obj->string.pointer[AUXMAC_END_MARKER] != '#') {
>> + pr_info("Invalid header for MAC address pass-through.\n");
>> + goto auxmacinvalid;
>> + }
>> +
>> + if (strncmp(obj->string.pointer + AUXMAC_START, "XXXXXXXXXXXX", AUXMAC_LEN) != 0)
>> + strscpy(auxmac, obj->string.pointer + AUXMAC_START, AUXMAC_LEN + 1);
>
> Please use sizeof(auxmac) as last parameter to strscpy() here.
>
>> + else
>> + strscpy(auxmac, "disabled", AUXMAC_LEN);
>
> Please use sizeof(auxmac) as last parameter to strscpy() here.
>
> Also note how you pass 2 different dest-sizes for the same dest buffer before,
> which looks weird ...
>
>
>> +
>> +free:
>> + kfree(obj);
>> + return 0;
>> +
>> +auxmacinvalid:
>> + strscpy(auxmac, "unavailable", AUXMAC_LEN);
>> + goto free;
>> +}
>
> I'm not liking the goto dance here, I would prefer:
>
> kfree(obj);
> return 0;
>
> auxmacinvalid:
> strscpy(auxmac, "unavailable", AUXMAC_LEN);
> kfree(obj);
> return 0;
>
> It is quite normal for an error-exit path to repeat a kfree().
>
> Note this is just a preference you keen keep this as is
> if you want, but to me the goto free which jumps up looks
> pretty weird.
>
> Regards,
>
> Hans
>
>
>
>> +
>> +static struct ibm_struct auxmac_data = {
>> + .name = "auxmac",
>> +};
>> +
>> +static ssize_t auxmac_show(struct device *dev,
>> + struct device_attribute *attr,
>> + char *buf)
>> +{
>> + return sysfs_emit(buf, "%s\n", auxmac);
>> +}
>> +static DEVICE_ATTR_RO(auxmac);
>> +
>> +static struct attribute *auxmac_attributes[] = {
>> + &dev_attr_auxmac.attr,
>> + NULL
>> +};
>> +
>> +static const struct attribute_group auxmac_attr_group = {
>> + .attrs = auxmac_attributes,
>> +};
>> +
>> /* --------------------------------------------------------------------- */
>>
>> static struct attribute *tpacpi_driver_attributes[] = {
>> @@ -10843,6 +10919,7 @@ static const struct attribute_group *tpacpi_groups[] = {
>> &proxsensor_attr_group,
>> &kbdlang_attr_group,
>> &dprc_attr_group,
>> + &auxmac_attr_group,
>> NULL,
>> };
>>
>> @@ -11414,6 +11491,10 @@ static struct ibm_init_struct ibms_init[] __initdata = {
>> .init = tpacpi_dprc_init,
>> .data = &dprc_driver_data,
>> },
>> + {
>> + .init = auxmac_init,
>> + .data = &auxmac_data,
>> + },
>> };
>>
>> static int __init set_ibm_param(const char *val, const struct kernel_param *kp)
>
>