UIO: Add alignment warnings for uio-mem
This patch adds an "offset" attribute for UIO mappings. It shows the
difference between the actual start address of the memory and the start
address of the page.
Signed-off-by: Hans J. Koch <hjk@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/uio/uio.c b/drivers/uio/uio.c
index 9ac22c7..557e73e 100644
--- a/drivers/uio/uio.c
+++ b/drivers/uio/uio.c
@@ -67,6 +67,11 @@
return sprintf(buf, "0x%lx\n", mem->size);
}
+static ssize_t map_offset_show(struct uio_mem *mem, char *buf)
+{
+ return sprintf(buf, "0x%lx\n", mem->addr & ~PAGE_MASK);
+}
+
struct uio_sysfs_entry {
struct attribute attr;
ssize_t (*show)(struct uio_mem *, char *);
@@ -77,10 +82,13 @@
__ATTR(addr, S_IRUGO, map_addr_show, NULL);
static struct uio_sysfs_entry size_attribute =
__ATTR(size, S_IRUGO, map_size_show, NULL);
+static struct uio_sysfs_entry offset_attribute =
+ __ATTR(offset, S_IRUGO, map_offset_show, NULL);
static struct attribute *attrs[] = {
&addr_attribute.attr,
&size_attribute.attr,
+ &offset_attribute.attr,
NULL, /* need to NULL terminate the list of attributes */
};