objtool: Validate disassembler headers in libopcodes probegrafted

commit 3f2de814c059 ("objtool: Fix libopcodes linking with static libraries")
tested for libopcodes availability by linking a test snippet with a forward
declaration of disassemble_init_for_target().

However, testing symbol linkage with an extern declaration only verifies
the presence of the library (.so/.a) and bypasses checking for development
headers (binutils-dev). On systems where libopcodes is present without
development headers installed, the probe succeeds, enabling BUILD_DISAS.
Subsequent compilation of objtool then fails:

  fatal error: 'bfd.h' file not found
    113 | #include <bfd.h>

Additionally, the probe invokes $(HOSTCC) without $(HOSTCFLAGS), ignoring
any sysroot or include flags specified for the host compiler.

Fix this by including <bfd.h> and <dis-asm.h> directly in the test snippet,
passing $(HOSTCFLAGS) so host compiler options are respected, and defining
PACKAGE="objtool" to satisfy the configuration check in <bfd.h>.

Fixes: 3f2de814c059 ("objtool: Fix libopcodes linking with static libraries")
Fixes: 436326bc525d ("objtool: fix build failure due to missing libopcodes check")
Reported-by: Alice Ryhl <aliceryhl@google.com>
Assisted-by: Antigravity:Gemini-Next
Signed-off-by: Ulises Mendez Martinez <umendez@google.com>
Link: https://patch.msgid.link/20260904150710.2997558-1-umendez@google.com
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>

1 files changed, 178 insertions, 0 deletions

diff --git a/drivers/of/of_test.c b/drivers/of/of_test.c
new file mode 100644
index 000000000..8bba5a72c
--- /dev/null
+++ b/drivers/of/of_test.c
@@ -0,0 +1,178 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * KUnit tests for OF APIs
+ */
+#include <linux/ioport.h>
+#include <linux/module.h>
+#include <linux/of.h>
+
+#include <kunit/test.h>
+
+#include "of_private.h"
+
+/*
+ * Test that the root node "/" can be found by path.
+ */
+static void of_dtb_root_node_found_by_path(struct kunit *test)
+{
+	struct device_node *np;
+
+	np = of_find_node_by_path("/");
+	KUNIT_EXPECT_NOT_ERR_OR_NULL(test, np);
+	of_node_put(np);
+}
+
+/*
+ * Test that the 'of_root' global variable is always populated when DT code is
+ * enabled. Remove this test once of_root is removed from global access.
+ */
+static void of_dtb_root_node_populates_of_root(struct kunit *test)
+{
+	KUNIT_EXPECT_NOT_ERR_OR_NULL(test, of_root);
+}
+
+static struct kunit_case of_dtb_test_cases[] = {
+	KUNIT_CASE(of_dtb_root_node_found_by_path),
+	KUNIT_CASE(of_dtb_root_node_populates_of_root),
+	{}
+};
+
+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");
+
+	return 0;
+}
+
+/*
+ * Test suite to confirm a DTB is loaded.
+ */
+static struct kunit_suite of_dtb_suite = {
+	.name = "of_dtb",
+	.test_cases = of_dtb_test_cases,
+	.init = of_dtb_test_init,
+};
+
+struct of_address_resource_bounds_case {
+	u64 start;
+	u64 size;
+	int ret;
+
+	u64 res_start;
+	u64 res_end;
+};
+
+static void of_address_resource_bounds_case_desc(const struct of_address_resource_bounds_case *p,
+						 char *name)
+{
+	snprintf(name, KUNIT_PARAM_DESC_SIZE, "start=0x%016llx,size=0x%016llx", p->start, p->size);
+}
+
+static const struct of_address_resource_bounds_case of_address_resource_bounds_cases[] = {
+	{
+		.start = 0,
+		.size = 0,
+		.ret = 0,
+		.res_start = 0,
+		.res_end = -1,
+	},
+	{
+		.start = 0,
+		.size = 0x1000,
+		.ret = 0,
+		.res_start = 0,
+		.res_end = 0xfff,
+	},
+	{
+		.start = 0x1000,
+		.size = 0,
+		.ret = 0,
+		.res_start = 0x1000,
+		.res_end = 0xfff,
+	},
+	{
+		.start = 0x1000,
+		.size = 0x1000,
+		.ret = 0,
+		.res_start = 0x1000,
+		.res_end = 0x1fff,
+	},
+	{
+		.start = 1,
+		.size = RESOURCE_SIZE_MAX,
+		.ret = 0,
+		.res_start = 1,
+		.res_end = RESOURCE_SIZE_MAX,
+	},
+	{
+		.start = RESOURCE_SIZE_MAX,
+		.size = 1,
+		.ret = 0,
+		.res_start = RESOURCE_SIZE_MAX,
+		.res_end = RESOURCE_SIZE_MAX,
+	},
+	{
+		.start = 2,
+		.size = RESOURCE_SIZE_MAX,
+		.ret = -EOVERFLOW,
+	},
+	{
+		.start = RESOURCE_SIZE_MAX,
+		.size = 2,
+		.ret = -EOVERFLOW,
+	},
+	{
+		.start = ULL(0x100000000),
+		.size = 1,
+		.ret = sizeof(resource_size_t) > sizeof(u32) ? 0 : -EOVERFLOW,
+		.res_start = ULL(0x100000000),
+		.res_end = ULL(0x100000000),
+	},
+	{
+		.start = 0x1000,
+		.size = 0xffffffff,
+		.ret = sizeof(resource_size_t) > sizeof(u32) ? 0 : -EOVERFLOW,
+		.res_start = 0x1000,
+		.res_end = ULL(0x100000ffe),
+	},
+};
+
+KUNIT_ARRAY_PARAM(of_address_resource_bounds,
+		  of_address_resource_bounds_cases, of_address_resource_bounds_case_desc);
+
+static void of_address_resource_bounds(struct kunit *test)
+{
+	const struct of_address_resource_bounds_case *param = test->param_value;
+	struct resource r; /* Intentionally uninitialized */
+	int ret;
+
+	if (!IS_ENABLED(CONFIG_OF_ADDRESS))
+		kunit_skip(test, "CONFIG_OF_ADDRESS not enabled\n");
+
+	ret = __of_address_resource_bounds(&r, param->start, param->size);
+	KUNIT_EXPECT_EQ(test, param->ret, ret);
+	if (ret == 0) {
+		KUNIT_EXPECT_EQ(test, (resource_size_t)param->res_start, r.start);
+		KUNIT_EXPECT_EQ(test, (resource_size_t)param->res_end, r.end);
+		KUNIT_EXPECT_EQ(test, param->size, resource_size(&r));
+	}
+}
+
+static struct kunit_case of_address_test_cases[] = {
+	KUNIT_CASE_PARAM(of_address_resource_bounds, of_address_resource_bounds_gen_params),
+	{}
+};
+
+static struct kunit_suite of_address_suite = {
+	.name = "of_address",
+	.test_cases = of_address_test_cases,
+};
+
+kunit_test_suites(
+	&of_dtb_suite, &of_address_suite,
+);
+MODULE_DESCRIPTION("KUnit tests for OF APIs");
+MODULE_IMPORT_NS("EXPORTED_FOR_KUNIT_TESTING");
+MODULE_LICENSE("GPL");