-
Bjorn Helgaas authored
An SHPC can be operated either by platform firmware or by the OS. The OS uses a host bridge ACPI _OSC method to negotiate for control of SHPC. If firmware wants to prevent an OS from operating an SHPC, it must supply an _OSC method that declines to grant SHPC ownership to the OS. If acpi_pci_find_root() returns NULL, it means there's no ACPI host bridge device (PNP0A03 or PNP0A08) and hence no _OSC method, so the OS is always allowed to manage the SHPC. Fix a NULL pointer dereference when CONFIG_ACPI=y but the current hardware/firmware platform doesn't support ACPI. In that case, acpi_get_hp_hw_control_from_firmware() is implemented but acpi_pci_find_root() returns NULL. Fixes: 90cc0c3c ("PCI: shpchp: Add shpchp_is_native()") Link: https://lkml.kernel.org/r/20180621164715.28160-1-marc.zyngier@arm.comReported-by:
Marc Zyngier <marc.zyngier@arm.com> Tested-by:
Marc Zyngier <marc.zyngier@arm.com> Signed-off-by:
Bjorn Helgaas <bhelgaas@google.com> Reviewed-by:
Mika Westerberg <mika.westerberg@linux.intel.com>
6f6f4246