Revision 2.8 of the UEFI spec introduces provisions for firmware to
advertise lack of support for certain runtime services at OS runtime.
Let's store this mask in struct efi for easy access.
Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx>
---
drivers/firmware/efi/efi.c | 27 ++++++++++-------
include/linux/efi.h | 31 ++++++++++++++++++++
2 files changed, 48 insertions(+), 10 deletions(-)
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 7dbe1487b111..703a019d81b4 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -34,6 +34,7 @@
#include <asm/early_ioremap.h>
struct efi __read_mostly efi = {
+ .runtime_supported_mask = EFI_RT_SUPPORTED_ALL,
.acpi = EFI_INVALID_TABLE_ADDR,
.acpi20 = EFI_INVALID_TABLE_ADDR,
.smbios = EFI_INVALID_TABLE_ADDR,
@@ -301,16 +302,22 @@ static int __init efisubsys_init(void)
if (!efi_enabled(EFI_BOOT))
return 0;
- /*
- * Since we process only one efi_runtime_service() at a time, an
- * ordered workqueue (which creates only one execution context)
- * should suffice all our needs.
- */
- efi_rts_wq = alloc_ordered_workqueue("efi_rts_wq", 0);
- if (!efi_rts_wq) {
- pr_err("Creating efi_rts_wq failed, EFI runtime services disabled.\n");
- clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
- return 0;
+ if (!efi_enabled(EFI_RUNTIME_SERVICES))
+ efi.runtime_supported_mask = 0;
+
+ if (efi.runtime_supported_mask) {
+ /*
+ * Since we process only one efi_runtime_service() at a time, an
+ * ordered workqueue (which creates only one execution context)
+ * should suffice for all our needs.
+ */
+ efi_rts_wq = alloc_ordered_workqueue("efi_rts_wq", 0);
+ if (!efi_rts_wq) {
+ pr_err("Creating efi_rts_wq failed, EFI runtime services disabled.\n");
+ clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
+ efi.runtime_supported_mask = 0;
+ return 0;
+ }
}
/* We register the efi directory at /sys/firmware/efi */
diff --git a/include/linux/efi.h b/include/linux/efi.h
index a0008e3d4e9d..57695f400044 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -523,6 +523,7 @@ typedef struct {
extern struct efi {
const efi_runtime_services_t *runtime; /* EFI runtime services table */
unsigned int runtime_version; /* Runtime services version */
+ unsigned int runtime_supported_mask;
unsigned long acpi; /* ACPI table (IA64 ext 0.71) */
unsigned long acpi20; /* ACPI table (ACPI 2.0) */
@@ -551,6 +552,26 @@ extern struct efi {
unsigned long flags;
} efi;
+#define EFI_RT_SUPPORTED_GET_TIME 0x0001
+#define EFI_RT_SUPPORTED_SET_TIME 0x0002
+#define EFI_RT_SUPPORTED_GET_WAKEUP_TIME 0x0004
+#define EFI_RT_SUPPORTED_SET_WAKEUP_TIME 0x0008
+#define EFI_RT_SUPPORTED_GET_VARIABLE 0x0010
+#define EFI_RT_SUPPORTED_GET_NEXT_VARIABLE_NAME 0x0020
+#define EFI_RT_SUPPORTED_SET_VARIABLE 0x0040
+#define EFI_RT_SUPPORTED_SET_VIRTUAL_ADDRESS_MAP 0x0080
+#define EFI_RT_SUPPORTED_CONVERT_POINTER 0x0100
+#define EFI_RT_SUPPORTED_GET_NEXT_HIGH_MONOTONIC_COUNT 0x0200
+#define EFI_RT_SUPPORTED_RESET_SYSTEM 0x0400
+#define EFI_RT_SUPPORTED_UPDATE_CAPSULE 0x0800
+#define EFI_RT_SUPPORTED_QUERY_CAPSULE_CAPABILITIES 0x1000
+#define EFI_RT_SUPPORTED_QUERY_VARIABLE_INFO 0x2000
+
+#define EFI_RT_SUPPORTED_ALL 0x3fff
+
+#define EFI_RT_SUPPORTED_TIME_SERVICES 0x000f
+#define EFI_RT_SUPPORTED_VARIABLE_SERVICES 0x0070
+
extern struct mm_struct efi_mm;
static inline int
@@ -761,6 +782,11 @@ static inline bool __pure efi_soft_reserve_enabled(void)
return IS_ENABLED(CONFIG_EFI_SOFT_RESERVE)
&& __efi_soft_reserve_enabled();
}
+
+static inline bool efi_rt_services_supported(unsigned int mask)
+{
+ return (efi.runtime_supported_mask & mask) == mask;
+}
#else
static inline bool efi_enabled(int feature)
{
@@ -779,6 +805,11 @@ static inline bool efi_soft_reserve_enabled(void)
{
return false;
}
+
+static inline bool efi_rt_services_supported(unsigned int mask)
+{
+ return false;
+}
#endif
extern int efi_status_to_err(efi_status_t status);
--
2.17.1
