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, 28 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/sysfs-driver-pciback b/Documentation/ABI/testing/sysfs-driver-pciback
new file mode 100644
index 000000000..49f5fd0c8
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-driver-pciback
@@ -0,0 +1,28 @@
+What:           /sys/bus/pci/drivers/pciback/quirks
+Date:           Oct 2011
+KernelVersion:  3.1
+Contact:        xen-devel@lists.xenproject.org
+Description:
+                If the permissive attribute is set, then writing a string in
+                the format of DDDD:BB:DD.F-REG:SIZE:MASK will allow the guest
+                to write and read from the PCI device. That is Domain:Bus:
+                Device.Function-Register:Size:Mask (Domain is optional).
+                For example::
+
+                  #echo 00:19.0-E0:2:FF > /sys/bus/pci/drivers/pciback/quirks
+
+                will allow the guest to read and write to the configuration
+                register 0x0E.
+
+What:           /sys/bus/pci/drivers/pciback/allow_interrupt_control
+Date:           Jan 2020
+KernelVersion:  5.6
+Contact:        xen-devel@lists.xenproject.org
+Description:
+                List of devices which can have interrupt control flag (INTx,
+                MSI, MSI-X) set by a connected guest. It is meant to be set
+                only when the guest is a stubdomain hosting device model (qemu)
+                and the actual device is assigned to a HVM. It is not safe
+                (similar to permissive attribute) to set for a devices assigned
+                to a PV guest. The device is automatically removed from this
+                list when the connected pcifront terminates.