[PATCH 0/1] ACPI / PCI: Fix "Operation not permitted" error reading sysfs acpi_index and label files.

[PATCH 0/1] ACPI / PCI: Fix "Operation not permitted" error reading sysfs acpi_index and label files.

[Simone Gotti]

Hi everyone,

starting from kernel 3.14 I noticed that the on board interfaces names on a Dell
PowerEdge E420 where renamed (by udev net_id internal) from eno1/eno2 to
enp2s0f0/enp2s0f1.

The root cause is that reading from the exported sysfs informations (acpi_index
and label) from drivers/pci/pci-label.c returns an "Operation not permitted"
error.

This machine supports PCI firmware specification 3.1 so the acpi methods are
preferred over the smbios one.

Debugging the problem I noticed that the call to the _DSM method returned the
second element with ACPI_TYPE_BUFFER type instead of ACPI_TYPE_STRING as
expected. The commit that forced this check is:

commit 1d0fcef732832432aee47cb75bf4a2cb3107be64 Author: Jiang Liu
<jiang.liu@linux.intel.com> Date:   Thu Dec 19 20:38:13 2013 +0800

    ACPI / PCI: replace open-coded _DSM code with helper functions

Previously the elements' types weren't checked and an ACPI_TYPE_BUFFER for the
second element was accepted.

The disassembled _DSM acpi method uses the ASL Unicode() macro that returns an
unicode string contained in a buffer.

Additionaly I noticed that an ascii string (as it should be the one of type
ACPI_TYPE_STRING) will be wrongly converted to utf8 from
dsm_label_utf16s_to_utf8s as it expects an utf16 string (I reproduced this
problem with a modified DSDT that returned an acpi string as label).

I don't have the PCI firmware specification so I don't know if an Unicode string
is correct or the bios is not compliant but I'm assuming this is possible. If
so, the following patch tries to fix this.


Thanks a lot.


Simone Gotti (1):
  Fix "Operation not permitted" error reading sysfs acpi_index and label
    files.

 drivers/pci/pci-label.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

-- 
2.0.0

[PATCH 1/1] ACPI / PCI: Fix "Operation not permitted" error reading sysfs acpi_index and label files.

[Simone Gotti]

If the _DSM method returns an unicode string then the acpi type is not
ACPI_TYPE_STRING but ACPI_TYPE_BUFFER.

Before commit 1d0fcef732832432aee47cb75bf4a2cb3107be64 the dsm_get_label
function wasn't checking the second element type and it was correctly working only with
ACPI_TYPE_BUFFER as the call to dsm_label_utf16s_to_utf8s will return bad
encoding for an ascii string.

Also fix dsm_label_utf16s_to_utf8s to use acpi_object->buffer instead of
acpi_object->string.

This fixes changed onboard interfaces names generated by udev net_id internal as
reading from the acpi_index file returned "Operation not permitted" error.

Signed-off-by: Simone Gotti <simone.gotti@gmail.com>
---
 drivers/pci/pci-label.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/drivers/pci/pci-label.c b/drivers/pci/pci-label.c
index a3fbe20..2ab1b47 100644
--- a/drivers/pci/pci-label.c
+++ b/drivers/pci/pci-label.c
@@ -161,8 +161,8 @@ enum acpi_attr_enum {
 static void dsm_label_utf16s_to_utf8s(union acpi_object *obj, char *buf)
 {
 	int len;
-	len = utf16s_to_utf8s((const wchar_t *)obj->string.pointer,
-			      obj->string.length,
+	len = utf16s_to_utf8s((const wchar_t *)obj->buffer.pointer,
+			      obj->buffer.length,
 			      UTF16_LITTLE_ENDIAN,
 			      buf, PAGE_SIZE);
 	buf[len] = '\n';
@@ -187,16 +187,22 @@ static int dsm_get_label(struct device *dev, char *buf,
 	tmp = obj->package.elements;
 	if (obj->type == ACPI_TYPE_PACKAGE && obj->package.count == 2 &&
 	    tmp[0].type == ACPI_TYPE_INTEGER &&
-	    tmp[1].type == ACPI_TYPE_STRING) {
+	    (tmp[1].type == ACPI_TYPE_STRING ||
+	     tmp[1].type == ACPI_TYPE_BUFFER)) {
 		/*
 		 * The second string element is optional even when
 		 * this _DSM is implemented; when not implemented,
 		 * this entry must return a null string.
 		 */
-		if (attr == ACPI_ATTR_INDEX_SHOW)
+		if (attr == ACPI_ATTR_INDEX_SHOW) {
 			scnprintf(buf, PAGE_SIZE, "%llu\n", tmp->integer.value);
-		else if (attr == ACPI_ATTR_LABEL_SHOW)
-			dsm_label_utf16s_to_utf8s(tmp + 1, buf);
+		} else if (attr == ACPI_ATTR_LABEL_SHOW) {
+			if (tmp[1].type == ACPI_TYPE_STRING)
+				scnprintf(buf, PAGE_SIZE, "%s\n",
+					  tmp[1].string.pointer);
+			else if (tmp[1].type == ACPI_TYPE_BUFFER)
+				dsm_label_utf16s_to_utf8s(tmp + 1, buf);
+		}
 		len = strlen(buf) > 0 ? strlen(buf) : -1;
 	}
 
-- 
2.0.0

Re: [PATCH 1/1] ACPI / PCI: Fix "Operation not permitted" error reading sysfs acpi_index and label files.

[Jiang Liu]

Hi Simone,
	Thanks for fixing this, you may add
Reviewed-by: Jiang Liu <jiang.liu@linux.intel.com>

On 2014/6/18 22:55, Simone Gotti wrote:
> If the _DSM method returns an unicode string then the acpi type is not
> ACPI_TYPE_STRING but ACPI_TYPE_BUFFER.
> 
> Before commit 1d0fcef732832432aee47cb75bf4a2cb3107be64 the dsm_get_label
> function wasn't checking the second element type and it was correctly working only with
> ACPI_TYPE_BUFFER as the call to dsm_label_utf16s_to_utf8s will return bad
> encoding for an ascii string.
> 
> Also fix dsm_label_utf16s_to_utf8s to use acpi_object->buffer instead of
> acpi_object->string.
> 
> This fixes changed onboard interfaces names generated by udev net_id internal as
> reading from the acpi_index file returned "Operation not permitted" error.
> 
> Signed-off-by: Simone Gotti <simone.gotti@gmail.com>
> ---
>  drivers/pci/pci-label.c | 18 ++++++++++++------
>  1 file changed, 12 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/pci/pci-label.c b/drivers/pci/pci-label.c
> index a3fbe20..2ab1b47 100644
> --- a/drivers/pci/pci-label.c
> +++ b/drivers/pci/pci-label.c
> @@ -161,8 +161,8 @@ enum acpi_attr_enum {
>  static void dsm_label_utf16s_to_utf8s(union acpi_object *obj, char *buf)
>  {
>  	int len;
> -	len = utf16s_to_utf8s((const wchar_t *)obj->string.pointer,
> -			      obj->string.length,
> +	len = utf16s_to_utf8s((const wchar_t *)obj->buffer.pointer,
> +			      obj->buffer.length,
>  			      UTF16_LITTLE_ENDIAN,
>  			      buf, PAGE_SIZE);
>  	buf[len] = '\n';
> @@ -187,16 +187,22 @@ static int dsm_get_label(struct device *dev, char *buf,
>  	tmp = obj->package.elements;
>  	if (obj->type == ACPI_TYPE_PACKAGE && obj->package.count == 2 &&
>  	    tmp[0].type == ACPI_TYPE_INTEGER &&
> -	    tmp[1].type == ACPI_TYPE_STRING) {
> +	    (tmp[1].type == ACPI_TYPE_STRING ||
> +	     tmp[1].type == ACPI_TYPE_BUFFER)) {
>  		/*
>  		 * The second string element is optional even when
>  		 * this _DSM is implemented; when not implemented,
>  		 * this entry must return a null string.
>  		 */
> -		if (attr == ACPI_ATTR_INDEX_SHOW)
> +		if (attr == ACPI_ATTR_INDEX_SHOW) {
>  			scnprintf(buf, PAGE_SIZE, "%llu\n", tmp->integer.value);
> -		else if (attr == ACPI_ATTR_LABEL_SHOW)
> -			dsm_label_utf16s_to_utf8s(tmp + 1, buf);
> +		} else if (attr == ACPI_ATTR_LABEL_SHOW) {
> +			if (tmp[1].type == ACPI_TYPE_STRING)
> +				scnprintf(buf, PAGE_SIZE, "%s\n",
> +					  tmp[1].string.pointer);
> +			else if (tmp[1].type == ACPI_TYPE_BUFFER)
> +				dsm_label_utf16s_to_utf8s(tmp + 1, buf);
> +		}
>  		len = strlen(buf) > 0 ? strlen(buf) : -1;
>  	}
>  
> 

Re: [PATCH 1/1] ACPI / PCI: Fix "Operation not permitted" error reading sysfs acpi_index and label files.

[Bjorn Helgaas]

On Wed, Jun 18, 2014 at 04:55:30PM +0200, Simone Gotti wrote:
> If the _DSM method returns an unicode string then the acpi type is not
> ACPI_TYPE_STRING but ACPI_TYPE_BUFFER.
> 
> Before commit 1d0fcef732832432aee47cb75bf4a2cb3107be64 the dsm_get_label
> function wasn't checking the second element type and it was correctly working only with
> ACPI_TYPE_BUFFER as the call to dsm_label_utf16s_to_utf8s will return bad
> encoding for an ascii string.
> 
> Also fix dsm_label_utf16s_to_utf8s to use acpi_object->buffer instead of
> acpi_object->string.
> 
> This fixes changed onboard interfaces names generated by udev net_id internal as
> reading from the acpi_index file returned "Operation not permitted" error.
> 
> Signed-off-by: Simone Gotti <simone.gotti@gmail.com>

Applied with Jiang's reviewed-by to pci/misc for v3.17.  I also added a
stable tag for v3.14+.  Thanks!

> ---
>  drivers/pci/pci-label.c | 18 ++++++++++++------
>  1 file changed, 12 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/pci/pci-label.c b/drivers/pci/pci-label.c
> index a3fbe20..2ab1b47 100644
> --- a/drivers/pci/pci-label.c
> +++ b/drivers/pci/pci-label.c
> @@ -161,8 +161,8 @@ enum acpi_attr_enum {
>  static void dsm_label_utf16s_to_utf8s(union acpi_object *obj, char *buf)
>  {
>  	int len;
> -	len = utf16s_to_utf8s((const wchar_t *)obj->string.pointer,
> -			      obj->string.length,
> +	len = utf16s_to_utf8s((const wchar_t *)obj->buffer.pointer,
> +			      obj->buffer.length,
>  			      UTF16_LITTLE_ENDIAN,
>  			      buf, PAGE_SIZE);
>  	buf[len] = '\n';
> @@ -187,16 +187,22 @@ static int dsm_get_label(struct device *dev, char *buf,
>  	tmp = obj->package.elements;
>  	if (obj->type == ACPI_TYPE_PACKAGE && obj->package.count == 2 &&
>  	    tmp[0].type == ACPI_TYPE_INTEGER &&
> -	    tmp[1].type == ACPI_TYPE_STRING) {
> +	    (tmp[1].type == ACPI_TYPE_STRING ||
> +	     tmp[1].type == ACPI_TYPE_BUFFER)) {
>  		/*
>  		 * The second string element is optional even when
>  		 * this _DSM is implemented; when not implemented,
>  		 * this entry must return a null string.
>  		 */
> -		if (attr == ACPI_ATTR_INDEX_SHOW)
> +		if (attr == ACPI_ATTR_INDEX_SHOW) {
>  			scnprintf(buf, PAGE_SIZE, "%llu\n", tmp->integer.value);
> -		else if (attr == ACPI_ATTR_LABEL_SHOW)
> -			dsm_label_utf16s_to_utf8s(tmp + 1, buf);
> +		} else if (attr == ACPI_ATTR_LABEL_SHOW) {
> +			if (tmp[1].type == ACPI_TYPE_STRING)
> +				scnprintf(buf, PAGE_SIZE, "%s\n",
> +					  tmp[1].string.pointer);
> +			else if (tmp[1].type == ACPI_TYPE_BUFFER)
> +				dsm_label_utf16s_to_utf8s(tmp + 1, buf);
> +		}
>  		len = strlen(buf) > 0 ? strlen(buf) : -1;
>  	}
>  
> -- 
> 2.0.0
> 
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