Thread (26 messages) 26 messages, 5 authors, 2024-01-24

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

From: David Gow <hidden>
Date: 2024-01-24 07:25:49
Also in: linux-devicetree, linux-kselftest, linux-patches, linux-um, lkml

On Tue, 23 Jan 2024 at 06:48, Stephen Boyd [off-list ref] wrote:
Quoting David Gow (2024-01-15 21:03:12)
quoted
On Sat, 13 Jan 2024 at 04:07, Stephen Boyd [off-list ref] wrote:
quoted
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+dt@kernel.org>
Cc: Frank Rowand <redacted>
Cc: David Gow <redacted>
Cc: Brendan Higgins <brendan.higgins@linux.dev>
Signed-off-by: Stephen Boyd <sboyd@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 <redacted>
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?
I admit, I only tested on UML, plus a quick check that the default
kunitconfig wasn't broken on anything else.

A further look is showing:
aarch64: PASSED
UML: PASSED
UML LLVM: PASSED
powerpc64: PASSED
m68k: FAILED
i386: FAILED
x86_64: FAILED
x86_64 KASAN: FAILED

The failures are all of the form:
[15:18:34] ============ of_have_populated_dt (2 subtests) =============
[15:18:34] # of_have_populated_dt_false_when_flag_set: ASSERTION FAILED at drivers/of/of_test.c:53
[15:18:34] Expected of_root is not null, but is
[15:18:34] [FAILED] of_have_populated_dt_false_when_flag_set
[15:18:34] # of_have_populated_dt_true_when_flag_clear: ASSERTION FAILED at drivers/of/of_test.c:70
[15:18:34] Expected of_root is not null, but is
[15:18:34] [FAILED] of_have_populated_dt_true_when_flag_clear
[15:18:34]     # module: of_test
[15:18:34] # of_have_populated_dt: pass:0 fail:2 skip:0 total:2
[15:18:34] # Totals: pass:0 fail:2 skip:0 total:2
[15:18:34] ============== [FAILED] of_have_populated_dt ===============
-- David
quoted hunk ↗ jump to hunk
----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
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