Commit Graph

7 Commits

Author SHA1 Message Date
Colin Ian King 10a2032d7a platform/x86: dell-smbios-wmi: make function dell_smbios_wmi_call static
The function dell_smbios_wmi_call is local to the source and does not
need to be in global scope, so make it static.

Cleans up sparse warning:
symbol 'dell_smbios_wmi_call' was not declared. Should it be static?

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Mario Limonciello <mario.limonciello@dell.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
2018-07-02 16:48:22 +03:00
Mario Limonciello 25d47027e1 platform/x86: dell-smbios: Link all dell-smbios-* modules together
Some race conditions were raised due to dell-smbios and its backends
not being ready by the time that a consumer would call one of the
exported methods.

To avoid this problem, guarantee that all initialization has been
done by linking them all together and running init for them all.

As part of this change the Kconfig needs to be adjusted so that
CONFIG_DELL_SMBIOS_SMM and CONFIG_DELL_SMBIOS_WMI are boolean
rather than modules.

CONFIG_DELL_SMBIOS is a visually selectable option again and both
CONFIG_DELL_SMBIOS_WMI and CONFIG_DELL_SMBIOS_SMM are optional.

Signed-off-by: Mario Limonciello <mario.limonciello@dell.com>
[dvhart: Update prompt and help text for DELL_SMBIOS_* backends]
Signed-off-by: Darren Hart (VMware) <dvhart@infradead.org>
2018-03-09 09:35:42 -08:00
Mario Limonciello 4255c30fe8 platform/x86: dell-smbios-wmi: Disable userspace interface if missing hotfix
The Dell SMBIOS WMI interface will fail for some more complex calls unless
a WMI hotfix has been included.  Most platforms have this fix available in
a maintenance BIOS release.  In the case the driver is loaded on a
platform without this fix, disable the userspace interface.

A hotfix indicator is present in the dell-wmi-descriptor that represents
whether or not more complex calls will work properly.

"Simple" calls such as those used by dell-laptop and dell-wmi will continue
to work properly so dell-smbios-wmi should not be blocked from binding and
being used as the dell-smbios dispatcher.

Suggested-by: Girish Prakash <girish.prakash@dell.com>
Signed-off-by: Mario Limonciello <mario.limonciello@dell.com>
Signed-off-by: Darren Hart (VMware) <dvhart@infradead.org>
2017-11-20 12:38:43 -08:00
Mario Limonciello 868b8d33f9 platform/x86: dell-*wmi*: Relay failed initial probe to dependent drivers
dell-wmi and dell-smbios-wmi are dependent upon dell-wmi-descriptor
finishing probe successfully to probe themselves.

Currently if dell-wmi-descriptor fails probing in a non-recoverable way
(such as invalid header) dell-wmi and dell-smbios-wmi will continue to
try to redo probing due to deferred probing.

To solve this have the dependent drivers query the dell-wmi-descriptor
driver whether the descriptor has been determined valid. The possible
results are:
-ENODEV: Descriptor GUID missing from WMI bus
-EPROBE_DEFER: Descriptor not yet probed, dependent driver should wait
 and use deferred probing
< 0: Descriptor probed, invalid.  Dependent driver should return an
 error.
0: Successful descriptor probe, dependent driver can continue

Successful descriptor probe still doesn't mean that the descriptor driver
is necessarily bound at the time of initialization of dependent driver.
Userspace can unbind the driver, so all methods used from driver
should still be verified to return success values otherwise deferred
probing be used.

Signed-off-by: Mario Limonciello <mario.limonciello@dell.com>
Reviewed-by: Pali Rohár <pali.rohar@gmail.com>
Signed-off-by: Darren Hart (VMware) <dvhart@infradead.org>
2017-11-16 17:45:26 -08:00
Mario Limonciello 307ab2a99d platform/x86: dell-smbios-wmi: release mutex lock on WMI call failure
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>
2017-11-08 12:58:37 -08:00
Mario Limonciello f2645fa317 platform/x86: dell-smbios-wmi: introduce userspace interface
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>
2017-11-03 16:34:00 -07:00
Mario Limonciello 1a258e6704 platform/x86: dell-smbios-wmi: Add new WMI dispatcher driver
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>
2017-11-03 16:33:59 -07:00