of: Skip kunit tests when arm64+ACPI doesn't populate root node

A root node is required to apply DT overlays. A root node is usually
present after commit 7b937cc243e5 ("of: Create of_root if no dtb
provided by firmware"), except for on arm64 systems booted with ACPI
tables. In that case, the root node is intentionally not populated
because it would "allow DT devices to be instantiated atop an ACPI base
system"[1].

Introduce an OF function that skips the kunit test if the root node
isn't populated. Limit the test to when both CONFIG_ARM64 and
CONFIG_ACPI are set, because otherwise the lack of a root node is a bug.
Make the function private and take a kunit test parameter so that it
can't be abused to test for the presence of the root node in non-test
code.

Use this function to skip tests that require the root node. Currently
that's the DT tests and any tests that apply overlays.

Reported-by: Guenter Roeck <linux@roeck-us.net>
Closes: https://lore.kernel.org/r/6cd337fb-38f0-41cb-b942-5844b84433db@roeck-us.net
Link: https://lore.kernel.org/r/Zd4dQpHO7em1ji67@FVFF77S0Q05N.cambridge.arm.com
Fixes: 893ecc6d2d61 ("of: Add KUnit test to confirm DTB is loaded")
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20241009204133.1169931-1-sboyd@kernel.org
Signed-off-by: Rob Herring (Arm) <robh@kernel.org>

diff --git a/drivers/of/of_kunit_helpers.c b/drivers/of/of_kunit_helpers.c
index 287d6c91bb3721fb592f758fb917fe34cdfc28da..7b3ed5a382aaa562a07a13c30111fbda602f46a9 100644 (file)
--- a/drivers/of/of_kunit_helpers.c
+++ b/drivers/of/of_kunit_helpers.c
@@ -10,6 +10,19 @@
 #include <kunit/test.h>
 #include <kunit/resource.h>
 
+#include "of_private.h"
+
+/**
+ * of_root_kunit_skip() - Skip test if the root node isn't populated
+ * @test: test to skip if the root node isn't populated
+ */
+void of_root_kunit_skip(struct kunit *test)
+{
+       if (IS_ENABLED(CONFIG_ARM64) && IS_ENABLED(CONFIG_ACPI) && !of_root)
+               kunit_skip(test, "arm64+acpi doesn't populate a root node");
+}
+EXPORT_SYMBOL_GPL(of_root_kunit_skip);
+
 #if defined(CONFIG_OF_OVERLAY) && defined(CONFIG_OF_EARLY_FLATTREE)
 
 static void of_overlay_fdt_apply_kunit_exit(void *ovcs_id)
@@ -36,6 +49,8 @@ int of_overlay_fdt_apply_kunit(struct kunit *test, void *overlay_fdt,
        int ret;
        int *copy_id;
 
+       of_root_kunit_skip(test);
+
        copy_id = kunit_kmalloc(test, sizeof(*copy_id), GFP_KERNEL);
        if (!copy_id)
                return -ENOMEM;

diff --git a/drivers/of/of_private.h b/drivers/of/of_private.h
index 04aa2a91f851acd9b2da47c5b53edb025b9a1f8f..c235d6c909a16a75b8e2995282abf5473532eb53 100644 (file)
--- a/drivers/of/of_private.h
+++ b/drivers/of/of_private.h
@@ -42,6 +42,9 @@ extern raw_spinlock_t devtree_lock;
 extern struct list_head aliases_lookup;
 extern struct kset *of_kset;
 
+struct kunit;
+extern void of_root_kunit_skip(struct kunit *test);
+
 #if defined(CONFIG_OF_DYNAMIC)
 extern int of_property_notify(int action, struct device_node *np,
                              struct property *prop, struct property *old_prop);

diff --git a/drivers/of/of_test.c b/drivers/of/of_test.c
index c85a258bc6ae64b83b76fdfb99533914b02ff8b3..b0557ded838fdf70f0b679c31ead38f501371304 100644 (file)
--- a/drivers/of/of_test.c
+++ b/drivers/of/of_test.c
@@ -7,6 +7,8 @@
 
 #include <kunit/test.h>
 
+#include "of_private.h"
+
 /*
  * Test that the root node "/" can be found by path.
  */
@@ -36,6 +38,7 @@ static struct kunit_case of_dtb_test_cases[] = {
 
 static int of_dtb_test_init(struct kunit *test)
 {
+       of_root_kunit_skip(test);
        if (!IS_ENABLED(CONFIG_OF_EARLY_FLATTREE))
                kunit_skip(test, "requires CONFIG_OF_EARLY_FLATTREE");
 

diff --git a/drivers/of/overlay_test.c b/drivers/of/overlay_test.c
index 19695bdf77bef4282c412776888fa1ea01439324..1f76d50fb16a5237989341b9ca50a7664a7b31be 100644 (file)
--- a/drivers/of/overlay_test.c
+++ b/drivers/of/overlay_test.c
@@ -11,6 +11,8 @@
 #include <kunit/of.h>
 #include <kunit/test.h>
 
+#include "of_private.h"
+
 static const char * const kunit_node_name = "kunit-test";
 static const char * const kunit_compatible = "test,empty";
 
@@ -62,6 +64,7 @@ static void of_overlay_apply_kunit_cleanup(struct kunit *test)
        struct device *dev;
        struct device_node *np;
 
+       of_root_kunit_skip(test);
        if (!IS_ENABLED(CONFIG_OF_EARLY_FLATTREE))
                kunit_skip(test, "requires CONFIG_OF_EARLY_FLATTREE for root node");