Re: [PATCH 6/6] of: Add KUnit test to confirm DTB is loaded

[Stephen Boyd]

Quoting David Gow (2024-01-15 21:03:12)
> On Sat, 13 Jan 2024 at 04:07, Stephen Boyd <sb...@kernel.org> wrote:
> >
> > Add a KUnit test that confirms a DTB has been loaded, i.e. there is a
> > root node, and that the of_have_populated_dt() API works properly.
> >
> > Cc: Rob Herring <robh...@kernel.org>
> > Cc: Frank Rowand <frowand.l...@gmail.com>
> > Cc: David Gow <david...@google.com>
> > Cc: Brendan Higgins <brendan.higg...@linux.dev>
> > Signed-off-by: Stephen Boyd <sb...@kernel.org>
> > ---
> 
> I won't pretend to be a devicetree expert, but this looks good to me
> from a KUnit point of view, and passes comfortably here.
> 
> checkpatch seems to have one complaint about the kconfig help text.
> Personally, I think the brief description is fine.
> 
> Reviewed-by: David Gow <david...@google.com>
> 

Thanks! I noticed that x86 has some devicetree init code. Did you happen
to try on an x86 kvm instance? Or only run on UML?

----8<----
diff --git a/arch/x86/kernel/devicetree.c b/arch/x86/kernel/devicetree.c
index afd09924094e..650752d112a6 100644
--- a/arch/x86/kernel/devicetree.c
+++ b/arch/x86/kernel/devicetree.c
@@ -283,22 +283,24 @@ void __init x86_flattree_get_config(void)
        u32 size, map_len;
        void *dt;
 
-       if (!initial_dtb)
-               return;
+       if (initial_dtb) {
+               map_len = max(PAGE_SIZE - (initial_dtb & ~PAGE_MASK), (u64)128);
 
-       map_len = max(PAGE_SIZE - (initial_dtb & ~PAGE_MASK), (u64)128);
+               dt = early_memremap(initial_dtb, map_len);
+               size = fdt_totalsize(dt);
+               if (map_len < size) {
+                       early_memunmap(dt, map_len);
+                       dt = early_memremap(initial_dtb, size);
+                       map_len = size;
+               }
 
-       dt = early_memremap(initial_dtb, map_len);
-       size = fdt_totalsize(dt);
-       if (map_len < size) {
-               early_memunmap(dt, map_len);
-               dt = early_memremap(initial_dtb, size);
-               map_len = size;
+               early_init_dt_verify(dt);
        }
 
-       early_init_dt_verify(dt);
        unflatten_and_copy_device_tree();
-       early_memunmap(dt, map_len);
+
+       if (initial_dtb)
+               early_memunmap(dt, map_len);
 }
 #endif