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, 129 insertions, 0 deletions

diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig
new file mode 100644
index 000000000..50697cc3b
--- /dev/null
+++ b/drivers/of/Kconfig
@@ -0,0 +1,129 @@
+# SPDX-License-Identifier: GPL-2.0
+config DTC
+	bool
+
+config GENERIC_BUILTIN_DTB
+	bool
+
+config BUILTIN_DTB_ALL
+	bool
+
+menuconfig OF
+	bool "Device Tree and Open Firmware support"
+	help
+	  This option enables the device tree infrastructure.
+	  It is automatically selected by platforms that need it or can
+	  be enabled manually for unittests, overlays or
+	  compile-coverage.
+
+if OF
+
+config OF_UNITTEST
+	bool "Device Tree runtime unit tests"
+	depends on OF_EARLY_FLATTREE
+	select IRQ_DOMAIN
+	select OF_RESOLVE
+	help
+	  This option builds in test cases for the device tree infrastructure
+	  that are executed once at boot time, and the results dumped to the
+	  console.
+
+	  This option should only be enabled for a development kernel. The tests
+	  will taint the kernel with TAINT_TEST. The tests will cause ERROR and
+	  WARNING messages to print on the console. The tests will cause stack
+	  traces to print on the console.  It is possible that the tests will
+	  leave the devicetree in a corrupted state.
+
+	  The unittest output will be verbose.  Copy the output to a file
+	  via capturing the console output or via the dmesg command.  Process
+	  this file with scripts/dtc/of_unittest_expect to reduce the
+	  verbosity, test whether expected output is present, and to
+	  summarize the results.
+
+	  If unsure, say N here. This option is not safe to enable.
+
+config OF_KUNIT_TEST
+	tristate "Devicetree KUnit Test" if !KUNIT_ALL_TESTS
+	depends on KUNIT
+	default KUNIT_ALL_TESTS
+	help
+	  This option builds KUnit unit tests for device tree infrastructure.
+
+	  If unsure, say N here, but this option is safe to enable.
+
+config OF_ALL_DTBS
+	bool "Build all Device Tree Blobs"
+	depends on COMPILE_TEST
+	select DTC
+	help
+	  This option builds all possible Device Tree Blobs (DTBs) for the
+	  current architecture.
+
+	  If unsure, say N here, but this option is safe to enable.
+
+config OF_FLATTREE
+	bool
+	select DTC
+	select LIBFDT
+	select CRC32
+
+config OF_EARLY_FLATTREE
+	def_bool OF && !(SPARC || ALPHA || HEXAGON || M68K || PARISC || S390)
+	select DMA_DECLARE_COHERENT if HAS_DMA && HAS_IOMEM
+	select OF_FLATTREE
+
+config OF_PROMTREE
+	bool
+
+config OF_KOBJ
+	def_bool SYSFS
+
+# Hardly any platforms need this.  It is safe to select, but only do so if you
+# need it.
+config OF_DYNAMIC
+	bool "Support for dynamic device trees" if OF_UNITTEST
+	select OF_KOBJ
+	help
+	  On some platforms, the device tree can be manipulated at runtime.
+	  While this option is selected automatically on such platforms, you
+	  can enable it manually to improve device tree unit test coverage.
+
+config OF_ADDRESS
+	def_bool y
+	depends on !SPARC && (HAS_IOMEM || UML)
+
+config OF_IRQ
+	def_bool y
+	depends on !SPARC && IRQ_DOMAIN
+
+config OF_RESERVED_MEM
+	def_bool OF_EARLY_FLATTREE
+
+config OF_RESOLVE
+	bool
+
+config OF_OVERLAY
+	bool "Device Tree overlays"
+	select OF_DYNAMIC
+	select OF_FLATTREE
+	select OF_RESOLVE
+	help
+	  Overlays are a method to dynamically modify part of the kernel's
+	  device tree with dynamically loaded data.
+	  While this option is selected automatically when needed, you can
+	  enable it manually to improve device tree unit test coverage.
+
+config OF_OVERLAY_KUNIT_TEST
+	tristate "Device Tree overlay KUnit tests" if !KUNIT_ALL_TESTS
+	depends on KUNIT
+	default KUNIT_ALL_TESTS
+	select DTC
+	help
+	  This option builds KUnit unit tests for the device tree overlay code.
+
+	  If unsure, say N here, but this option is safe to enable.
+
+config OF_NUMA
+	bool
+
+endif # OF