ACPI / PCI: Fix sysfs acpi_index and label errors

Fix errors in handling "device label" _DSM return values.

If _DSM returns a Unicode string, the ACPI type is ACPI_TYPE_BUFFER, not
ACPI_TYPE_STRING.  Fix dsm_label_utf16s_to_utf8s() to convert UTF-16 from
acpi_object->buffer instead of acpi_object->string.

Prior to v3.14, we accepted Unicode labels (ACPI_TYPE_BUFFER return
values).  But after 1d0fcef73283, we accepted only ASCII (ACPI_TYPE_STRING)
(and we incorrectly tried to convert those ASCII labels from UTF-16 to
UTF-8).

Rejecting Unicode labels made us return -EPERM when reading sysfs
"acpi_index" or "label" files, which in turn caused on-board network
interfaces on a Dell PowerEdge E420 to be renamed (by udev net_id internal)
from eno1/eno2 to enp2s0f0/enp2s0f1.

Fix this by accepting either ACPI_TYPE_STRING (and treating it as ASCII) or
ACPI_TYPE_BUFFER (and converting from UTF-16 to UTF-8).

[bhelgaas: changelog]
Fixes: 1d0fcef73283 ("ACPI / PCI: replace open-coded _DSM code with helper functions")
Signed-off-by: Simone Gotti <simone.gotti@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Jiang Liu <jiang.liu@linux.intel.com>
CC: stable@vger.kernel.org	# v3.14+

diff --git a/drivers/pci/pci-label.c b/drivers/pci/pci-label.c
index a3fbe20..2ab1b47 100644 (file)
--- 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;
        }