On Wed, Oct 10, 2018 at 1:49 AM Frank Rowand [off-list ref] wrote:

On 10/09/18 23:04, frowand.list@gmail.com wrote:

quoted

From: Frank Rowand <redacted>


"of: overlay: use prop add changeset entry for property in new nodes"
fixed a problem where an 'update property' changeset entry was
created for properties contained in nodes added by a changeset.
The fix was to use an 'add property' changeset entry.

This exposed more bugs in the apply overlay code.  The properties
'name', 'phandle', and 'linux,phandle' were filtered out by
add_changeset_property() as special properties.  Change the filter
to be only for existing nodes, not newly added nodes.

The second bug is that the 'name' property does not exist in the
newest FDT version, and has to be constructed from the node's
full_name.  Construct an 'add property' changeset entry for
newly added nodes.

Signed-off-by: Frank Rowand <redacted>
---


Hi Alan,

Thanks for reporting the problem with missing node names.

I was able to replicate the problem, and have created this preliminary
version of a patch to fix the problem.

I have not extensively reviewed the patch yet, but would appreciate
if you can confirm this fixes your problem.

I created this patch as patch 17 of the series, but have also
applied it as patch 05.1, immediately after patch 05/16, and
built the kernel, booted, and verified name and phandle for
one of the nodes in a unittest overlay for both cases.  So
minimal testing so far on my part.

I have not verified whether the series builds and boots after
each of patches 06..16 if this patch is applied as patch 05.1.

There is definitely more work needed for me to complete this
patch because it allocates some more memory, but does not yet
free it when the overlay is released.

-Frank


 drivers/of/overlay.c | 72 ++++++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 67 insertions(+), 5 deletions(-)

diff --git a/drivers/of/overlay.c b/drivers/of/overlay.c
index 0b0904f44bc7..9746cea2aa91 100644
--- a/drivers/of/overlay.c
+++ b/drivers/of/overlay.c

@@ -301,10 +301,11 @@ static int add_changeset_property(struct overlay_changeset *ovcs,
      struct property *new_prop = NULL, *prop;
      int ret = 0;

-     if (!of_prop_cmp(overlay_prop->name, "name") ||
-         !of_prop_cmp(overlay_prop->name, "phandle") ||
-         !of_prop_cmp(overlay_prop->name, "linux,phandle"))
-             return 0;
+     if (target->in_livetree)
+             if (!of_prop_cmp(overlay_prop->name, "name") ||
+                 !of_prop_cmp(overlay_prop->name, "phandle") ||
+                 !of_prop_cmp(overlay_prop->name, "linux,phandle"))
+                     return 0;

This is a big hammer patch.

Nobody should waste time reviewing this patch.

I wasn't clear if you still could use the testing so I did re-run my
test.  This patch adds back some of the missing properties, but the
the kobject names aren't set as dev_name() returns NULL:

* without this patch some of_node properties don't show up in sysfs:
root@arria10:~# ls
/sys/bus/platform/drivers/altera_freeze_br/ff200450.\<NULL\>/of_node
clocks            compatible        interrupt-parent  interrupts        reg

* with this patch, the of_node properties phandle and name are back:
root@arria10:~#  ls
/sys/bus/platform/drivers/altera_freeze_br/ff200450.\<NULL\>/of_node
clocks            compatible        interrupt-parent  interrupts
 name              phandle           reg

root@arria10:~# cat
/sys/bus/platform/drivers/altera_freeze_br/ff200450.\<NULL\>/of_node/name
freeze_controllerroot@arria10:~#  ("freeze_controller" w/o the \n so
the name is correct)

* with or without the patch I see the behavior I reported yesterday,
kobj names are NULL.
root@arria10:~# ls /sys/bus/platform/drivers/altera_freeze_br/
bind             ff200450.<NULL>  uevent           unbind

root@arria10:~# ls /sys/bus/platform/drivers/altera_gpio/
bind             ff200010.<NULL>  ff200020.<NULL>  ff200030.<NULL>
uevent           unbind

Alan

Alan

The following part should not be needed (though the above section might have
to become _slightly_ more complex).

-Frank

quoted

      if (target->in_livetree)
              prop = of_find_property(target->np, overlay_prop->name, NULL);

@@ -443,10 +444,13 @@ static int build_changeset_next_level(struct overlay_changeset *ovcs,
              struct target *target, const struct device_node *overlay_node)
 {
      struct device_node *child;
-     struct property *prop;
+     struct property *prop, *name_prop;
+     bool has_name = false;
      int ret;

      for_each_property_of_node(overlay_node, prop) {
+             if (!strcmp(prop->name, "name"))
+                     has_name = true;
              ret = add_changeset_property(ovcs, target, prop, 0);
              if (ret) {
                      pr_debug("Failed to apply prop @%pOF/%s, err=%d\n",

@@ -455,6 +459,57 @@ static int build_changeset_next_level(struct overlay_changeset *ovcs,
              }
      }

+     /*
+      * With FDT version 0x10 we may not have the name property,
+      * recreate it here from the unit name if absent
+      */
+
+     if (!has_name) {
+             const char *p = target->np->full_name, *ps = p, *pa = NULL;
+             int len;
+
+             /*
+              * zzz
+              * TODO: stash name_prop on a list in ovcs, to be freed
+              * after overlay removed
+              */
+
+             while (*p) {
+                     if ((*p) == '@')
+                             pa = p;
+                     else if ((*p) == '/')
+                             ps = p + 1;
+                     p++;
+             }
+
+             if (pa < ps)
+                     pa = p;
+             len = (pa - ps) + 1;
+
+             name_prop = kmalloc(sizeof(*name_prop), GFP_KERNEL);
+             if (!name_prop)
+                     return -ENOMEM;
+
+             name_prop->name = kstrdup("name", GFP_KERNEL);
+             name_prop->value = kmalloc(len, GFP_KERNEL);
+             if (!name_prop->name || !name_prop->value) {
+                     ret = -ENOMEM;
+                     goto err_free_name_prop;
+             }
+
+             memcpy(name_prop->value, ps, len - 1);
+             ((char *)name_prop->value)[len - 1] = 0;
+
+             name_prop->length = strlen(name_prop->value) + 1;
+
+             ret = add_changeset_property(ovcs, target, name_prop, 0);
+             if (ret) {
+                     pr_debug("Failed to apply name_prop @%pOF/%s, err=%d\n",
+                              target->np, name_prop->name, ret);
+                     goto err_free_name_prop;
+             }
+     }
+
      for_each_child_of_node(overlay_node, child) {
              ret = add_changeset_node(ovcs, target, child);
              if (ret) {

@@ -466,6 +521,13 @@ static int build_changeset_next_level(struct overlay_changeset *ovcs,
      }

      return 0;
+
+err_free_name_prop:
+     kfree(name_prop->name);
+     kfree(name_prop->value);
+     kfree(name_prop);
+     return ret;
+
 }

 /*