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, 55 insertions, 0 deletions

diff --git a/fs/befs/inode.c b/fs/befs/inode.c
new file mode 100644
index 000000000..791b46a6f
--- /dev/null
+++ b/fs/befs/inode.c
@@ -0,0 +1,55 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * inode.c
+ *
+ * Copyright (C) 2001 Will Dyson <will_dyson@pobox.com>
+ */
+
+#include <linux/fs.h>
+
+#include "befs.h"
+#include "inode.h"
+
+/*
+ * Validates the correctness of the befs inode
+ * Returns BEFS_OK if the inode should be used, otherwise
+ * returns BEFS_BAD_INODE
+ */
+int
+befs_check_inode(struct super_block *sb, befs_inode *raw_inode,
+		 befs_blocknr_t inode)
+{
+	u32 magic1 = fs32_to_cpu(sb, raw_inode->magic1);
+	befs_inode_addr ino_num = fsrun_to_cpu(sb, raw_inode->inode_num);
+	u32 flags = fs32_to_cpu(sb, raw_inode->flags);
+
+	/* check magic header. */
+	if (magic1 != BEFS_INODE_MAGIC1) {
+		befs_error(sb,
+			   "Inode has a bad magic header - inode = %lu",
+			   (unsigned long)inode);
+		return BEFS_BAD_INODE;
+	}
+
+	/*
+	 * Sanity check2: inodes store their own block address. Check it.
+	 */
+	if (inode != iaddr2blockno(sb, &ino_num)) {
+		befs_error(sb, "inode blocknr field disagrees with vfs "
+			   "VFS: %lu, Inode %lu", (unsigned long)
+			   inode, (unsigned long)iaddr2blockno(sb, &ino_num));
+		return BEFS_BAD_INODE;
+	}
+
+	/*
+	 * check flag
+	 */
+
+	if (!(flags & BEFS_INODE_IN_USE)) {
+		befs_error(sb, "inode is not used - inode = %lu",
+			   (unsigned long)inode);
+		return BEFS_BAD_INODE;
+	}
+
+	return BEFS_OK;
+}