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, 99 insertions, 0 deletions

diff --git a/Documentation/userspace-api/dcdbas.rst b/Documentation/userspace-api/dcdbas.rst
new file mode 100644
index 000000000..309cc57a7
--- /dev/null
+++ b/Documentation/userspace-api/dcdbas.rst
@@ -0,0 +1,99 @@
+===================================
+Dell Systems Management Base Driver
+===================================
+
+Overview
+========
+
+The Dell Systems Management Base Driver provides a sysfs interface for
+systems management software such as Dell OpenManage to perform system
+management interrupts and host control actions (system power cycle or
+power off after OS shutdown) on certain Dell systems.
+
+Dell OpenManage requires this driver on the following Dell PowerEdge systems:
+300, 1300, 1400, 400SC, 500SC, 1500SC, 1550, 600SC, 1600SC, 650, 1655MC,
+700, and 750.  Other Dell software such as the open source libsmbios project
+is expected to make use of this driver, and it may include the use of this
+driver on other Dell systems.
+
+The Dell libsmbios project aims towards providing access to as much BIOS
+information as possible.  See http://linux.dell.com/libsmbios/main/ for
+more information about the libsmbios project.
+
+
+System Management Interrupt
+===========================
+
+On some Dell systems, systems management software must access certain
+management information via a system management interrupt (SMI).  The SMI data
+buffer must reside in 32-bit address space, and the physical address of the
+buffer is required for the SMI.  The driver maintains the memory required for
+the SMI and provides a way for the application to generate the SMI.
+The driver creates the following sysfs entries for systems management
+software to perform these system management interrupts::
+
+	/sys/devices/platform/dcdbas/smi_data
+	/sys/devices/platform/dcdbas/smi_data_buf_phys_addr
+	/sys/devices/platform/dcdbas/smi_data_buf_size
+	/sys/devices/platform/dcdbas/smi_request
+
+Systems management software must perform the following steps to execute
+a SMI using this driver:
+
+1) Lock smi_data.
+2) Write system management command to smi_data.
+3) Write "1" to smi_request to generate a calling interface SMI or
+   "2" to generate a raw SMI.
+4) Read system management command response from smi_data.
+5) Unlock smi_data.
+
+
+Host Control Action
+===================
+
+Dell OpenManage supports a host control feature that allows the administrator
+to perform a power cycle or power off of the system after the OS has finished
+shutting down.  On some Dell systems, this host control feature requires that
+a driver perform a SMI after the OS has finished shutting down.
+
+The driver creates the following sysfs entries for systems management software
+to schedule the driver to perform a power cycle or power off host control
+action after the system has finished shutting down:
+
+/sys/devices/platform/dcdbas/host_control_action
+/sys/devices/platform/dcdbas/host_control_smi_type
+/sys/devices/platform/dcdbas/host_control_on_shutdown
+
+Dell OpenManage performs the following steps to execute a power cycle or
+power off host control action using this driver:
+
+1) Write host control action to be performed to host_control_action.
+2) Write type of SMI that driver needs to perform to host_control_smi_type.
+3) Write "1" to host_control_on_shutdown to enable host control action.
+4) Initiate OS shutdown.
+   (Driver will perform host control SMI when it is notified that the OS
+   has finished shutting down.)
+
+
+Host Control SMI Type
+=====================
+
+The following table shows the value to write to host_control_smi_type to
+perform a power cycle or power off host control action:
+
+=================== =====================
+PowerEdge System    Host Control SMI Type
+=================== =====================
+      300             HC_SMITYPE_TYPE1
+     1300             HC_SMITYPE_TYPE1
+     1400             HC_SMITYPE_TYPE2
+      500SC           HC_SMITYPE_TYPE2
+     1500SC           HC_SMITYPE_TYPE2
+     1550             HC_SMITYPE_TYPE2
+      600SC           HC_SMITYPE_TYPE2
+     1600SC           HC_SMITYPE_TYPE2
+      650             HC_SMITYPE_TYPE2
+     1655MC           HC_SMITYPE_TYPE2
+      700             HC_SMITYPE_TYPE3
+      750             HC_SMITYPE_TYPE3
+=================== =====================