platform/x86: dell-smbios-wmi: Stop using WMI chardev

The WMI chardev API will be removed in the near future.
Reimplement the necessary bits used by this driver so
that userspace software depending on it does no break.

Signed-off-by: Armin Wolf <W_Armin@gmx.de>
Link: https://lore.kernel.org/r/20231210202443.646427-5-W_Armin@gmx.de
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

platform/x86: dell-smbios-wmi: Use devm_get_free_pages()

Use devres version of __get_free_pages() to simplify the
error handling code.

Signed-off-by: Armin Wolf <W_Armin@gmx.de>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20231210202443.646427-4-W_Armin@gmx.de
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

platform/x86: dell-smbios-wmi: Add missing kfree in error-exit from run_smbios_call

As pointed out be Kees Cook if we return -EIO because the
obj->type != ACPI_TYPE_BUFFER, then we must kfree the
output buffer before the return.

Fixes: 1a258e670434 ("platform/x86: dell-smbios-wmi: Add new WMI dispatcher driver")
Reported-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20210826140822.71198-1-hdegoede@redhat.com

platform/x86: dell-smbios-wmi: Avoid false-positive memcpy() warning

In preparation for FORTIFY_SOURCE performing compile-time and run-time
field bounds checking for memcpy(), memmove(), and memset(), avoid
intentionally writing across neighboring fields.

Since all the size checking has already happened, use input.pointer
(void *) so memcpy() doesn't get confused about how much is being
written.

Avoids this false-positive warning when run-time memcpy() strict
bounds checking is enabled:

memcpy: detected field-spanning write (size 4096) of single field (size 36)
WARNING: CPU: 0 PID: 357 at drivers/platform/x86/dell/dell-smbios-wmi.c:74 run_smbios_call+0x110/0x1e0 [dell_smbios]

Cc: Hans de Goede <hdegoede@redhat.com>
Cc: Mark Gross <mgross@linux.intel.com>
Cc: Mario Limonciello <mario.limonciello@dell.com>
Cc: "Pali Rohár" <pali@kernel.org>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
Cc: Dell.Client.Kernel@dell.com
Cc: platform-driver-x86@vger.kernel.org
Reported-by: Andy Lavr <andy.lavr@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20210825160749.3891090-1-keescook@chromium.org
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

platform/x86: dell-smbios-wmi: Fix oops on rmmod dell_smbios

init_dell_smbios_wmi() only registers the dell_smbios_wmi_driver on systems
where the Dell WMI interface is supported. While exit_dell_smbios_wmi()
unregisters it unconditionally, this leads to the following oops:

[ 175.722921] ------------[ cut here ]------------
[ 175.722925] Unexpected driver unregister!
[ 175.722939] WARNING: CPU: 1 PID: 3630 at drivers/base/driver.c:194 driver_unregister+0x38/0x40
...
[ 175.723089] Call Trace:
[ 175.723094] cleanup_module+0x5/0xedd [dell_smbios]
...
[ 175.723148] ---[ end trace 064c34e1ad49509d ]---

Make the unregister happen on the same condition the register happens
to fix this.

Cc: Mario Limonciello <mario.limonciello@outlook.com>
Fixes: 1a258e670434 ("platform/x86: dell-smbios-wmi: Add new WMI dispatcher driver")
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Mario Limonciello <mario.limonciello@outlook.com>
Reviewed-by: Mark Gross <mgross@linux.intel.com>
Link: https://lore.kernel.org/r/20210518125027.21824-1-hdegoede@redhat.com

platform/x86: wmi: Make remove callback return void

The driver core ignores the return value of struct bus_type::remove()
(and so wmi_dev_remove()) because there is only little that can be done.

To simplify the quest to make this function return void, let struct
wmi_driver::remove() return void, too. All implementers of this callback
return 0 already and this way it should be obvious to driver authors
that returning an error code is a bad idea.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Pali Rohár <pali@kernel.org>
Link: https://lore.kernel.org/r/20210301160404.1677064-1-u.kleine-koenig@pengutronix.de
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

platform/x86: Move all dell drivers to their own subdirectory

A user without a Dell system doesn't need to pick any of these
drivers.

Users with a Dell system can enable this submenu and all drivers
behind it will be enabled.

Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mario Limonciello <mario.limonciello@dell.com>
Link: https://lore.kernel.org/r/20210203195832.2950605-1-mario.limonciello@dell.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>