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, 66 insertions, 0 deletions

diff --git a/fs/dlm/util.c b/fs/dlm/util.c
new file mode 100644
index 000000000..f2bc401f3
--- /dev/null
+++ b/fs/dlm/util.c
@@ -0,0 +1,66 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/******************************************************************************
+*******************************************************************************
+**
+**  Copyright (C) 2005-2008 Red Hat, Inc.  All rights reserved.
+**
+**
+*******************************************************************************
+******************************************************************************/
+
+#include "dlm_internal.h"
+#include "rcom.h"
+#include "util.h"
+
+#define DLM_ERRNO_EDEADLK		35
+#define DLM_ERRNO_EBADR			53
+#define DLM_ERRNO_EBADSLT		57
+#define DLM_ERRNO_EPROTO		71
+#define DLM_ERRNO_EOPNOTSUPP		95
+#define DLM_ERRNO_ETIMEDOUT	       110
+#define DLM_ERRNO_EINPROGRESS	       115
+
+/* higher errno values are inconsistent across architectures, so select
+   one set of values for on the wire */
+
+int to_dlm_errno(int err)
+{
+	switch (err) {
+	case -EDEADLK:
+		return -DLM_ERRNO_EDEADLK;
+	case -EBADR:
+		return -DLM_ERRNO_EBADR;
+	case -EBADSLT:
+		return -DLM_ERRNO_EBADSLT;
+	case -EPROTO:
+		return -DLM_ERRNO_EPROTO;
+	case -EOPNOTSUPP:
+		return -DLM_ERRNO_EOPNOTSUPP;
+	case -ETIMEDOUT:
+		return -DLM_ERRNO_ETIMEDOUT;
+	case -EINPROGRESS:
+		return -DLM_ERRNO_EINPROGRESS;
+	}
+	return err;
+}
+
+int from_dlm_errno(int err)
+{
+	switch (err) {
+	case -DLM_ERRNO_EDEADLK:
+		return -EDEADLK;
+	case -DLM_ERRNO_EBADR:
+		return -EBADR;
+	case -DLM_ERRNO_EBADSLT:
+		return -EBADSLT;
+	case -DLM_ERRNO_EPROTO:
+		return -EPROTO;
+	case -DLM_ERRNO_EOPNOTSUPP:
+		return -EOPNOTSUPP;
+	case -DLM_ERRNO_ETIMEDOUT:
+		return -ETIMEDOUT;
+	case -DLM_ERRNO_EINPROGRESS:
+		return -EINPROGRESS;
+	}
+	return err;
+}