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, 78 insertions, 0 deletions

diff --git a/drivers/net/wireguard/main.c b/drivers/net/wireguard/main.c
new file mode 100644
index 000000000..a00671b58
--- /dev/null
+++ b/drivers/net/wireguard/main.c
@@ -0,0 +1,78 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ */
+
+#include "version.h"
+#include "device.h"
+#include "noise.h"
+#include "queueing.h"
+#include "ratelimiter.h"
+#include "netlink.h"
+
+#include <uapi/linux/wireguard.h>
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <net/genetlink.h>
+#include <net/rtnetlink.h>
+
+static int __init wg_mod_init(void)
+{
+	int ret;
+
+	ret = wg_allowedips_slab_init();
+	if (ret < 0)
+		goto err_allowedips;
+
+#ifdef DEBUG
+	ret = -ENOTRECOVERABLE;
+	if (!wg_allowedips_selftest() || !wg_packet_counter_selftest() ||
+	    !wg_ratelimiter_selftest())
+		goto err_peer;
+#endif
+	wg_noise_init();
+
+	ret = wg_peer_init();
+	if (ret < 0)
+		goto err_peer;
+
+	ret = wg_device_init();
+	if (ret < 0)
+		goto err_device;
+
+	ret = wg_genetlink_init();
+	if (ret < 0)
+		goto err_netlink;
+
+	pr_info("WireGuard " WIREGUARD_VERSION " loaded. See www.wireguard.com for information.\n");
+	pr_info("Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.\n");
+
+	return 0;
+
+err_netlink:
+	wg_device_uninit();
+err_device:
+	wg_peer_uninit();
+err_peer:
+	wg_allowedips_slab_uninit();
+err_allowedips:
+	return ret;
+}
+
+static void __exit wg_mod_exit(void)
+{
+	wg_genetlink_uninit();
+	wg_device_uninit();
+	wg_peer_uninit();
+	wg_allowedips_slab_uninit();
+}
+
+module_init(wg_mod_init);
+module_exit(wg_mod_exit);
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("WireGuard secure network tunnel");
+MODULE_AUTHOR("Jason A. Donenfeld <Jason@zx2c4.com>");
+MODULE_VERSION(WIREGUARD_VERSION);
+MODULE_ALIAS_RTNL_LINK(KBUILD_MODNAME);
+MODULE_ALIAS_GENL_FAMILY(WG_GENL_NAME);