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, 163 insertions, 0 deletions

diff --git a/lib/ubsan.h b/lib/ubsan.h
new file mode 100644
index 000000000..b37e22374
--- /dev/null
+++ b/lib/ubsan.h
@@ -0,0 +1,163 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LIB_UBSAN_H
+#define _LIB_UBSAN_H
+
+/*
+ * ABI defined by Clang's UBSAN enum SanitizerHandler:
+ * https://github.com/llvm/llvm-project/blob/release/16.x/clang/lib/CodeGen/CodeGenFunction.h#L113
+ */
+enum ubsan_checks {
+	ubsan_add_overflow,
+	ubsan_builtin_unreachable,
+	ubsan_cfi_check_fail,
+	ubsan_divrem_overflow,
+	ubsan_dynamic_type_cache_miss,
+	ubsan_float_cast_overflow,
+	ubsan_function_type_mismatch,
+	ubsan_implicit_conversion,
+	ubsan_invalid_builtin,
+	ubsan_invalid_objc_cast,
+	ubsan_load_invalid_value,
+	ubsan_missing_return,
+	ubsan_mul_overflow,
+	ubsan_negate_overflow,
+	ubsan_nullability_arg,
+	ubsan_nullability_return,
+	ubsan_nonnull_arg,
+	ubsan_nonnull_return,
+	ubsan_out_of_bounds,
+	ubsan_pointer_overflow,
+	ubsan_shift_out_of_bounds,
+	ubsan_sub_overflow,
+	ubsan_type_mismatch,
+	ubsan_alignment_assumption,
+	ubsan_vla_bound_not_positive,
+};
+
+enum {
+	type_kind_int = 0,
+	type_kind_float = 1,
+	type_unknown = 0xffff
+};
+
+struct type_descriptor {
+	u16 type_kind;
+	u16 type_info;
+	char type_name[];
+};
+
+struct source_location {
+	const char *file_name;
+	union {
+		unsigned long reported;
+		struct {
+			u32 line;
+			u32 column;
+		};
+	};
+};
+
+struct overflow_data {
+	struct source_location location;
+	struct type_descriptor *type;
+};
+
+struct implicit_conversion_data {
+	struct source_location location;
+	struct type_descriptor *from_type;
+	struct type_descriptor *to_type;
+	unsigned char type_check_kind;
+};
+
+struct type_mismatch_data {
+	struct source_location location;
+	struct type_descriptor *type;
+	unsigned long alignment;
+	unsigned char type_check_kind;
+};
+
+struct type_mismatch_data_v1 {
+	struct source_location location;
+	struct type_descriptor *type;
+	unsigned char log_alignment;
+	unsigned char type_check_kind;
+};
+
+struct type_mismatch_data_common {
+	struct source_location *location;
+	struct type_descriptor *type;
+	unsigned long alignment;
+	unsigned char type_check_kind;
+};
+
+struct nonnull_arg_data {
+	struct source_location location;
+	struct source_location attr_location;
+	int arg_index;
+};
+
+struct out_of_bounds_data {
+	struct source_location location;
+	struct type_descriptor *array_type;
+	struct type_descriptor *index_type;
+};
+
+struct shift_out_of_bounds_data {
+	struct source_location location;
+	struct type_descriptor *lhs_type;
+	struct type_descriptor *rhs_type;
+};
+
+struct unreachable_data {
+	struct source_location location;
+};
+
+struct invalid_value_data {
+	struct source_location location;
+	struct type_descriptor *type;
+};
+
+struct alignment_assumption_data {
+	struct source_location location;
+	struct source_location assumption_location;
+	struct type_descriptor *type;
+};
+
+#if defined(CONFIG_ARCH_SUPPORTS_INT128)
+typedef __int128 s_max;
+typedef unsigned __int128 u_max;
+#else
+typedef s64 s_max;
+typedef u64 u_max;
+#endif
+
+/*
+ * When generating Runtime Calls, Clang doesn't respect the -mregparm=3
+ * option used on i386: https://github.com/llvm/llvm-project/issues/89670
+ * Fix this for earlier Clang versions by forcing the calling convention
+ * to use non-register arguments.
+ */
+#if defined(CONFIG_X86_32) && \
+    defined(CONFIG_CC_IS_CLANG) && CONFIG_CLANG_VERSION < 190000
+# define ubsan_linkage asmlinkage
+#else
+# define ubsan_linkage
+#endif
+
+void ubsan_linkage __ubsan_handle_add_overflow(void *data, void *lhs, void *rhs);
+void ubsan_linkage __ubsan_handle_sub_overflow(void *data, void *lhs, void *rhs);
+void ubsan_linkage __ubsan_handle_mul_overflow(void *data, void *lhs, void *rhs);
+void ubsan_linkage __ubsan_handle_negate_overflow(void *_data, void *old_val);
+void ubsan_linkage __ubsan_handle_divrem_overflow(void *_data, void *lhs, void *rhs);
+void ubsan_linkage __ubsan_handle_implicit_conversion(void *_data, void *lhs, void *rhs);
+void ubsan_linkage __ubsan_handle_type_mismatch(struct type_mismatch_data *data, void *ptr);
+void ubsan_linkage __ubsan_handle_type_mismatch_v1(void *_data, void *ptr);
+void ubsan_linkage __ubsan_handle_out_of_bounds(void *_data, void *index);
+void ubsan_linkage __ubsan_handle_shift_out_of_bounds(void *_data, void *lhs, void *rhs);
+void ubsan_linkage __ubsan_handle_builtin_unreachable(void *_data);
+void ubsan_linkage __ubsan_handle_load_invalid_value(void *_data, void *val);
+void ubsan_linkage __ubsan_handle_alignment_assumption(void *_data, unsigned long ptr,
+						       unsigned long align,
+						       unsigned long offset);
+
+#endif