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, 77 insertions, 0 deletions

diff --git a/arch/xtensa/Makefile b/arch/xtensa/Makefile
new file mode 100644
index 000000000..4c14a0217
--- /dev/null
+++ b/arch/xtensa/Makefile
@@ -0,0 +1,77 @@
+#
+# This file is subject to the terms and conditions of the GNU General Public
+# License.  See the file "COPYING" in the main directory of this archive
+# for more details.
+#
+# Copyright (C) 2001 - 2005  Tensilica Inc.
+# Copyright (C) 2014 Cadence Design Systems Inc.
+#
+# This file is included by the global makefile so that you can add your own
+# architecture-specific flags and dependencies.
+
+# Core configuration.
+# (Use VAR=<xtensa_config> to use another default compiler.)
+
+variant-y := $(CONFIG_XTENSA_VARIANT_NAME)
+
+VARIANT = $(variant-y)
+
+ifneq ($(VARIANT),)
+  ifdef cross_compiling
+    ifndef CROSS_COMPILE
+      CROSS_COMPILE = xtensa_$(VARIANT)-
+    endif
+  endif
+endif
+
+# Platform configuration
+
+platform-$(CONFIG_XTENSA_PLATFORM_XT2000)	:= xt2000
+platform-$(CONFIG_XTENSA_PLATFORM_ISS)		:= iss
+platform-$(CONFIG_XTENSA_PLATFORM_XTFPGA)	:= xtfpga
+
+# temporarily until string.h is fixed
+KBUILD_CFLAGS += -ffreestanding -D__linux__
+KBUILD_CFLAGS += -pipe -mlongcalls -mtext-section-literals
+KBUILD_CFLAGS += $(call cc-option,-mforce-no-pic,)
+KBUILD_CFLAGS += $(call cc-option,-mno-serialize-volatile,)
+KBUILD_CFLAGS += $(call cc-option,-mno-fdpic,)
+ifneq ($(CONFIG_KERNEL_ABI_CALL0),)
+KBUILD_CFLAGS += -mabi=call0
+KBUILD_AFLAGS += -mabi=call0
+endif
+
+KBUILD_AFLAGS += -mlongcalls -mtext-section-literals
+KBUILD_AFLAGS += $(call cc-option,-mno-fdpic,)
+
+KBUILD_LDFLAGS += -m elf32xtensa
+
+ifneq ($(CONFIG_LD_NO_RELAX),)
+KBUILD_LDFLAGS += --no-relax
+endif
+
+CHECKFLAGS += -D$(if $(CONFIG_CPU_BIG_ENDIAN),__XTENSA_EB__,__XTENSA_EL__)
+
+vardirs := $(patsubst %,arch/xtensa/variants/%/,$(variant-y))
+plfdirs := $(patsubst %,arch/xtensa/platforms/%/,$(platform-y))
+
+KBUILD_CPPFLAGS += $(patsubst %,-I$(srctree)/%include,$(vardirs) $(plfdirs))
+
+KBUILD_DEFCONFIG := iss_defconfig
+
+libs-y		+= arch/xtensa/lib/
+
+boot		:= arch/xtensa/boot
+
+all Image zImage uImage xipImage: vmlinux
+	$(Q)$(MAKE) $(build)=$(boot) $@
+
+archheaders:
+	$(Q)$(MAKE) $(build)=arch/xtensa/kernel/syscalls all
+
+define archhelp
+  @echo '* Image       - Kernel ELF image with reset vector'
+  @echo '* zImage      - Compressed kernel image (arch/xtensa/boot/images/zImage.*)'
+  @echo '* uImage      - U-Boot wrapped image'
+  @echo '  xipImage    - XIP image'
+endef