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, 150 insertions, 0 deletions

diff --git a/Documentation/filesystems/api-summary.rst b/Documentation/filesystems/api-summary.rst
new file mode 100644
index 000000000..bd7e3d5db
--- /dev/null
+++ b/Documentation/filesystems/api-summary.rst
@@ -0,0 +1,150 @@
+=============================
+Linux Filesystems API summary
+=============================
+
+This section contains API-level documentation, mostly taken from the source
+code itself.
+
+The Linux VFS
+=============
+
+The Filesystem types
+--------------------
+
+.. kernel-doc:: include/linux/fs.h
+   :internal:
+
+The Directory Cache
+-------------------
+
+.. kernel-doc:: fs/dcache.c
+   :export:
+
+.. kernel-doc:: include/linux/dcache.h
+   :internal:
+
+Inode Handling
+--------------
+
+.. kernel-doc:: fs/inode.c
+   :export:
+
+.. kernel-doc:: fs/bad_inode.c
+   :export:
+
+Registration and Superblocks
+----------------------------
+
+.. kernel-doc:: fs/super.c
+   :export:
+
+File Locks
+----------
+
+.. kernel-doc:: fs/locks.c
+   :export:
+
+.. kernel-doc:: fs/locks.c
+   :internal:
+
+Other Functions
+---------------
+
+.. kernel-doc:: fs/mpage.c
+   :export:
+
+.. kernel-doc:: fs/namei.c
+   :export:
+
+.. kernel-doc:: fs/open.c
+   :export:
+
+.. kernel-doc:: block/bio.c
+   :export:
+
+.. kernel-doc:: fs/seq_file.c
+   :export:
+
+.. kernel-doc:: fs/filesystems.c
+   :export:
+
+.. kernel-doc:: fs/fs-writeback.c
+   :export:
+
+.. kernel-doc:: fs/anon_inodes.c
+   :export:
+
+.. kernel-doc:: fs/attr.c
+   :export:
+
+.. kernel-doc:: fs/d_path.c
+   :export:
+
+.. kernel-doc:: fs/dax.c
+   :export:
+
+.. kernel-doc:: fs/libfs.c
+   :export:
+
+.. kernel-doc:: fs/posix_acl.c
+   :export:
+
+.. kernel-doc:: fs/stat.c
+   :export:
+
+.. kernel-doc:: fs/sync.c
+   :export:
+
+.. kernel-doc:: fs/xattr.c
+   :export:
+
+.. kernel-doc:: fs/namespace.c
+   :export:
+
+The proc filesystem
+===================
+
+sysctl interface
+----------------
+
+.. kernel-doc:: kernel/sysctl.c
+   :export:
+
+proc filesystem interface
+-------------------------
+
+.. kernel-doc:: fs/proc/base.c
+   :internal:
+
+Events based on file descriptors
+================================
+
+.. kernel-doc:: fs/eventfd.c
+   :export:
+
+eventpoll (epoll) interfaces
+============================
+
+.. kernel-doc:: fs/eventpoll.c
+   :internal:
+
+The Filesystem for Exporting Kernel Objects
+===========================================
+
+.. kernel-doc:: fs/sysfs/file.c
+   :export:
+
+.. kernel-doc:: fs/sysfs/symlink.c
+   :export:
+
+The debugfs filesystem
+======================
+
+debugfs interface
+-----------------
+
+.. kernel-doc:: fs/debugfs/inode.c
+   :export:
+
+.. kernel-doc:: fs/debugfs/file.c
+   :export: