The ACPI PRM address space handler calls efi_call_virt_pointer() to
execute PRM firmware code, but doing so is only permitted when the EFI
runtime environment is available. Otherwise, such calls are guaranteed
to result in a crash, and must therefore be avoided.
Cc: <stable@xxxxxxxxxxxxxxx>
Cc: "Rafael J. Wysocki" <rafael@xxxxxxxxxx>
Cc: Len Brown <lenb@xxxxxxxxxx>
Cc: linux-acpi@xxxxxxxxxxxxxxx
Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx>
---
drivers/acpi/prmt.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/drivers/acpi/prmt.c b/drivers/acpi/prmt.c
index 998101cf16e47145..74f924077866ae69 100644
--- a/drivers/acpi/prmt.c
+++ b/drivers/acpi/prmt.c
@@ -236,6 +236,11 @@ static acpi_status acpi_platformrt_space_handler(u32 function,
efi_status_t status;
struct prm_context_buffer context;
+ if (!efi_enabled(EFI_RUNTIME_SERVICES)) {
+ pr_err("PRM: EFI runtime services unavailable\n");
+ return AE_NOT_IMPLEMENTED;
+ }
+
/*
* The returned acpi_status will always be AE_OK. Error values will be
* saved in the first byte of the PRM message buffer to be used by ASL.
--
2.39.0
