[PATCH 3/4] VFIO: PLATFORM: DEVTREE: Access property as a list of strings

From: Antonios Motakis
Date: Wed Aug 13 2014 - 07:05:42 EST


Certain device tree properties (e.g. the device node name, the compatible
string), are available as a list of strings (separated by the null
terminating character). Let the VFIO user query this type of properties.

Signed-off-by: Antonios Motakis <a.motakis@xxxxxxxxxxxxxxxxxxxxxx>
---
drivers/vfio/platform/devtree.c | 60 +++++++++++++++++++++++++++++++++++++++++
1 file changed, 60 insertions(+)

diff --git a/drivers/vfio/platform/devtree.c b/drivers/vfio/platform/devtree.c
index b8fd4138..80c60d4 100644
--- a/drivers/vfio/platform/devtree.c
+++ b/drivers/vfio/platform/devtree.c
@@ -61,6 +61,43 @@ static int devtree_get_prop_names(struct device_node *np, void __user *datap,
return ret;
}

+static int devtree_get_strings(struct device_node *np, char *name,
+ void __user *datap, unsigned long datasz)
+{
+ struct property *prop;
+ int len;
+
+ prop = of_find_property(np, name, &len);
+
+ if (!prop)
+ return -EINVAL;
+
+ if (len > datasz)
+ return -EAGAIN;
+
+ if (copy_to_user(datap, prop->value, len))
+ return -EFAULT;
+ else
+ return 0;
+}
+
+static int devtree_get_full_name(struct device_node *np, void __user *datap,
+ unsigned long datasz, int *lenp)
+{
+ int len = strlen(np->full_name) + 1;
+
+ if (lenp)
+ *lenp = len;
+
+ if (len > datasz)
+ return -EAGAIN;
+
+ if (copy_to_user(datap, np->full_name, len))
+ return -EFAULT;
+
+ return 0;
+}
+
long vfio_platform_devtree_ioctl(struct vfio_platform_device *vdev,
unsigned long arg)
{
@@ -68,6 +105,7 @@ long vfio_platform_devtree_ioctl(struct vfio_platform_device *vdev,
unsigned long minsz = offsetofend(struct vfio_devtree_info, length);
void __user *datap = (void __user *) arg + minsz;
unsigned long int datasz;
+ char *name;
int ret = -EINVAL;

if (!vfio_platform_has_devtree(vdev))
@@ -84,8 +122,30 @@ long vfio_platform_devtree_ioctl(struct vfio_platform_device *vdev,
if (info.type == VFIO_DEVTREE_PROP_NAMES) {
ret = devtree_get_prop_names(vdev->of_node, datap, datasz,
&info.length);
+ goto out;
}

+ name = kzalloc(datasz, GFP_KERNEL);
+ if (!name)
+ return -ENOMEM;
+ if (copy_from_user(name, datap, datasz))
+ return -EFAULT;
+
+ if (!of_find_property(vdev->of_node, name, &info.length)) {
+ /* special case full_name as a property that is not on the fdt,
+ * but we wish to return to the user as it includes the full
+ * path of the device */
+ if (!strcmp(name, "full_name") &&
+ (info.type == VFIO_DEVTREE_ARR_TYPE_STRING))
+ ret = devtree_get_full_name(vdev->of_node, datap,
+ datasz, &info.length);
+
+ } else if (info.type == VFIO_DEVTREE_ARR_TYPE_STRING)
+ ret = devtree_get_strings(vdev->of_node, name, datap, datasz);
+
+ kfree(name);
+
+out:
if (copy_to_user((void __user *)arg, &info, minsz))
ret = -EFAULT;

--
1.8.3.2

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