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, 98 insertions, 0 deletions

diff --git a/scripts/include/hashtable.h b/scripts/include/hashtable.h
new file mode 100644
index 000000000..45abcb12b
--- /dev/null
+++ b/scripts/include/hashtable.h
@@ -0,0 +1,98 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef HASHTABLE_H
+#define HASHTABLE_H
+
+#include "array_size.h"
+#include "list.h"
+
+#define HASH_SIZE(name) (ARRAY_SIZE(name))
+
+#define HASHTABLE_DECLARE(name, size)		struct hlist_head name[size]
+
+#define HASHTABLE_DEFINE(name, size)						\
+	HASHTABLE_DECLARE(name, size) =						\
+			{ [0 ... ((size) - 1)] = HLIST_HEAD_INIT }
+
+#define hash_head(table, key)		(&(table)[(key) % HASH_SIZE(table)])
+
+static inline void __hash_init(struct hlist_head *ht, unsigned int sz)
+{
+	unsigned int i;
+
+	for (i = 0; i < sz; i++)
+		INIT_HLIST_HEAD(&ht[i]);
+}
+
+/**
+ * hash_init - initialize a hash table
+ * @table: hashtable to be initialized
+ *
+ * This has to be a macro since HASH_SIZE() will not work on pointers since
+ * it calculates the size during preprocessing.
+ */
+#define hash_init(table) __hash_init(table, HASH_SIZE(table))
+
+/**
+ * hash_add - add an object to a hashtable
+ * @table: hashtable to add to
+ * @node: the &struct hlist_node of the object to be added
+ * @key: the key of the object to be added
+ */
+#define hash_add(table, node, key)						\
+	hlist_add_head(node, hash_head(table, key))
+
+/**
+ * hash_del - remove an object from a hashtable
+ * @node: &struct hlist_node of the object to remove
+ */
+static inline void hash_del(struct hlist_node *node)
+{
+	hlist_del_init(node);
+}
+
+/**
+ * hash_for_each - iterate over a hashtable
+ * @table: hashtable to iterate
+ * @obj: the type * to use as a loop cursor for each entry
+ * @member: the name of the hlist_node within the struct
+ */
+#define hash_for_each(table, obj, member)				\
+	for (int _bkt = 0; _bkt < HASH_SIZE(table); _bkt++)		\
+		hlist_for_each_entry(obj, &table[_bkt], member)
+
+/**
+ * hash_for_each_safe - iterate over a hashtable safe against removal of
+ * hash entry
+ * @table: hashtable to iterate
+ * @obj: the type * to use as a loop cursor for each entry
+ * @tmp: a &struct hlist_node used for temporary storage
+ * @member: the name of the hlist_node within the struct
+ */
+#define hash_for_each_safe(table, obj, tmp, member)			\
+	for (int _bkt = 0; _bkt < HASH_SIZE(table); _bkt++)		\
+		hlist_for_each_entry_safe(obj, tmp, &table[_bkt], member)
+
+/**
+ * hash_for_each_possible - iterate over all possible objects hashing to the
+ * same bucket
+ * @table: hashtable to iterate
+ * @obj: the type * to use as a loop cursor for each entry
+ * @member: the name of the hlist_node within the struct
+ * @key: the key of the objects to iterate over
+ */
+#define hash_for_each_possible(table, obj, member, key)			\
+	hlist_for_each_entry(obj, hash_head(table, key), member)
+
+/**
+ * hash_for_each_possible_safe - iterate over all possible objects hashing to the
+ * same bucket safe against removals
+ * @table: hashtable to iterate
+ * @obj: the type * to use as a loop cursor for each entry
+ * @tmp: a &struct hlist_node used for temporary storage
+ * @member: the name of the hlist_node within the struct
+ * @key: the key of the objects to iterate over
+ */
+#define hash_for_each_possible_safe(table, obj, tmp, member, key)	\
+	hlist_for_each_entry_safe(obj, tmp, hash_head(table, key), member)
+
+#endif /* HASHTABLE_H */