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, 49 insertions, 0 deletions

diff --git a/net/dsa/Makefile b/net/dsa/Makefile
new file mode 100644
index 000000000..d15bcf5c6
--- /dev/null
+++ b/net/dsa/Makefile
@@ -0,0 +1,49 @@
+# SPDX-License-Identifier: GPL-2.0
+
+# the stubs are built-in whenever DSA is built-in or module
+ifdef CONFIG_NET_DSA
+obj-y := stubs.o
+endif
+
+# the core
+obj-$(CONFIG_NET_DSA) += dsa_core.o
+dsa_core-y += \
+	conduit.o \
+	devlink.o \
+	dsa.o \
+	netlink.o \
+	port.o \
+	switch.o \
+	tag.o \
+	tag_8021q.o \
+	trace.o \
+	user.o
+
+# tagging formats
+obj-$(CONFIG_NET_DSA_TAG_AR9331) += tag_ar9331.o
+obj-$(CONFIG_NET_DSA_TAG_BRCM_COMMON) += tag_brcm.o
+obj-$(CONFIG_NET_DSA_TAG_DSA_COMMON) += tag_dsa.o
+obj-$(CONFIG_NET_DSA_TAG_GSWIP) += tag_gswip.o
+obj-$(CONFIG_NET_DSA_TAG_HELLCREEK) += tag_hellcreek.o
+obj-$(CONFIG_NET_DSA_TAG_KSZ) += tag_ksz.o
+obj-$(CONFIG_NET_DSA_TAG_LAN9303) += tag_lan9303.o
+obj-$(CONFIG_NET_DSA_TAG_MT7628) += tag_mt7628.o
+obj-$(CONFIG_NET_DSA_TAG_MTK) += tag_mtk.o
+obj-$(CONFIG_NET_DSA_TAG_MXL_862XX) += tag_mxl862xx.o
+obj-$(CONFIG_NET_DSA_TAG_MXL_GSW1XX) += tag_mxl-gsw1xx.o
+obj-$(CONFIG_NET_DSA_TAG_NETC) += tag_netc.o
+obj-$(CONFIG_NET_DSA_TAG_NONE) += tag_none.o
+obj-$(CONFIG_NET_DSA_TAG_OCELOT) += tag_ocelot.o
+obj-$(CONFIG_NET_DSA_TAG_OCELOT_8021Q) += tag_ocelot_8021q.o
+obj-$(CONFIG_NET_DSA_TAG_QCA) += tag_qca.o
+obj-$(CONFIG_NET_DSA_TAG_RTL4_A) += tag_rtl4_a.o
+obj-$(CONFIG_NET_DSA_TAG_RTL8_4) += tag_rtl8_4.o
+obj-$(CONFIG_NET_DSA_TAG_RZN1_A5PSW) += tag_rzn1_a5psw.o
+obj-$(CONFIG_NET_DSA_TAG_SJA1105) += tag_sja1105.o
+obj-$(CONFIG_NET_DSA_TAG_TRAILER) += tag_trailer.o
+obj-$(CONFIG_NET_DSA_TAG_VSC73XX_8021Q) += tag_vsc73xx_8021q.o
+obj-$(CONFIG_NET_DSA_TAG_XRS700X) += tag_xrs700x.o
+obj-$(CONFIG_NET_DSA_TAG_YT921X) += tag_yt921x.o
+
+# for tracing framework to find trace.h
+CFLAGS_trace.o := -I$(src)