On 13/12/2021 17.44, Javier Martinez Canillas wrote:
Hello Hector,
On Sun, Dec 12, 2021 at 7:24 AM Hector Martin <marcan@xxxxxxxxx> wrote:
This code is required for both simplefb and simpledrm, so let's move it
into the OF core instead of having it as an ad-hoc initcall in the
drivers.
Acked-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
Signed-off-by: Hector Martin <marcan@xxxxxxxxx>
---
drivers/of/platform.c | 4 ++++
drivers/video/fbdev/simplefb.c | 21 +--------------------
2 files changed, 5 insertions(+), 20 deletions(-)
This is indeed a much better approach than what I suggested. I just
have one comment.
diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index b3faf89744aa..793350028906 100644
--- a/drivers/of/platform.c
+++ b/drivers/of/platform.c
@@ -540,6 +540,10 @@ static int __init of_platform_default_populate_init(void)
of_node_put(node);
}
+ node = of_get_compatible_child(of_chosen, "simple-framebuffer");
You have to check if the node variable is NULL here.
+ of_platform_device_create(node, NULL, NULL);
Otherwise this could lead to a NULL pointer dereference if debug
output is enabled (the node->full_name is printed).
Where is it printed? I thought I might need a NULL check, but this code
was suggested verbatim by Rob in v2 without the NULL check and digging
through I found that the NULL codepath is safe.
of_platform_device_create calls of_platform_device_create_pdata
directly, and:
static struct platform_device *of_platform_device_create_pdata(
struct device_node *np,
const char *bus_id,
void *platform_data,
struct device *parent)
{
struct platform_device *dev;
if (!of_device_is_available(np) ||
of_node_test_and_set_flag(np, OF_POPULATED))
return NULL;
of_device_is_available takes a global spinlock and then calls
__of_device_is_available, and that does:
static bool __of_device_is_available(const struct device_node *device)
{
const char *status;
int statlen;
if (!device)
return false;
... so I don't see how this can do anything but immediately return false
if node is NULL.
--
Hector Martin (marcan@xxxxxxxxx)
Public Key: https://mrcn.st/pub
