Unbound devices may race with calling this function causing the mutex
to stay locked. This failure mode should have released the mutex too.
Signed-off-by: Mario Limonciello <mario.limonciello@dell.com>
Signed-off-by: Darren Hart (VMware) <dvhart@infradead.org>
It's important for the driver to provide a R/W ioctl to ensure that
two competing userspace processes don't race to provide or read each
others data.
This userspace character device will be used to perform SMBIOS calls
from any applications.
It provides an ioctl that will allow passing the WMI calling
interface buffer between userspace and kernel space.
This character device is intended to deprecate the dcdbas kernel module
and the interface that it provides to userspace.
To perform an SMBIOS IOCTL call using the character device userspace will
perform a read() on the the character device. The WMI bus will provide
a u64 variable containing the necessary size of the IOCTL buffer.
The API for interacting with this interface is defined in documentation
as well as the WMI uapi header provides the format of the structures.
Not all userspace requests will be accepted. The dell-smbios filtering
functionality will be used to prevent access to certain tokens and calls.
All whitelisted commands and tokens are now shared out to userspace so
applications don't need to define them in their own headers.
Signed-off-by: Mario Limonciello <mario.limonciello@dell.com>
Reviewed-by: Edward O'Callaghan <quasisec@google.com>
Signed-off-by: Darren Hart (VMware) <dvhart@infradead.org>
The dell-smbios stack only currently uses an SMI interface which grants
direct access to physical memory to the firmware SMM methods via a pointer.
This dispatcher driver adds a WMI-ACPI interface that is detected by WMI
probe and preferred over the SMI interface in dell-smbios.
Changing this to operate over WMI-ACPI will use an ACPI OperationRegion
for a buffer of data storage when SMM calls are performed.
This is a safer approach to use in kernel drivers as the SMM will
only have access to that OperationRegion.
Signed-off-by: Mario Limonciello <mario.limonciello@dell.com>
Reviewed-by: Edward O'Callaghan <quasisec@google.com>
Signed-off-by: Darren Hart (VMware) <dvhart@infradead.org>
Mario Limonciello