Previous patches enable SetVariableRT using a volatile storage backend
using EFI_RUNTIME_SERVICES_DATA allocared memory. Since there's no
recommendation from the spec on how to notify the OS, add a volatile
EFI variable that contains the filename relative to the ESP. OS'es
can use that file and update it at runtime
$~ efivar -p -n b2ac5fc9-92b7-4acd-aeac-11e818c3130c-RTStorageVolatile
GUID: b2ac5fc9-92b7-4acd-aeac-11e818c3130c
Name: "RTStorageVolatile"
Attributes:
Boot Service Access
Runtime Service Access
Value:
00000000 75 62 6f 6f 74 65 66 69 2e 76 61 72 00 |ubootefi.var. |
Signed-off-by: Ilias Apalodimas <ilias.apalodi...@linaro.org>
---
include/efi_loader.h | 4 ++++
lib/efi_loader/efi_runtime.c | 4 ----
lib/efi_loader/efi_variable.c | 20 ++++++++++++++++++++
3 files changed, 24 insertions(+), 4 deletions(-)
diff --git a/include/efi_loader.h b/include/efi_loader.h
index 7daca0afba2b..25551fe18948 100644
--- a/include/efi_loader.h
+++ b/include/efi_loader.h
@@ -159,6 +159,10 @@ static inline void efi_set_bootdev(const char *dev, const
char *devnr,
#define EFICONFIG_AUTO_GENERATED_ENTRY_GUID \
EFI_GUID(0x8108ac4e, 0x9f11, 0x4d59, \
0x85, 0x0e, 0xe2, 0x1a, 0x52, 0x2c, 0x59, 0xb2)
+#define U_BOOT_EFI_RT_VAR_FILE_GUID \
+ EFI_GUID(0xb2ac5fc9, 0x92b7, 0x4acd, \
+ 0xae, 0xac, 0x11, 0xe8, 0x18, 0xc3, 0x13, 0x0c)
+
/* Use internal device tree when starting UEFI application */
#define EFI_FDT_USE_INTERNAL NULL
diff --git a/lib/efi_loader/efi_runtime.c b/lib/efi_loader/efi_runtime.c
index 8ebbea7e5c69..d898ba6c268f 100644
--- a/lib/efi_loader/efi_runtime.c
+++ b/lib/efi_loader/efi_runtime.c
@@ -127,10 +127,6 @@ efi_status_t efi_init_runtime_supported(void)
EFI_RT_SUPPORTED_SET_VIRTUAL_ADDRESS_MAP |
EFI_RT_SUPPORTED_CONVERT_POINTER;
- if (IS_ENABLED(CONFIG_EFI_RT_VOLATILE_STORE))
- rt_table->runtime_services_supported |=
- EFI_RT_SUPPORTED_SET_VARIABLE;
-
/*
* This value must be synced with efi_runtime_detach_list
* as well as efi_runtime_services.
diff --git a/lib/efi_loader/efi_variable.c b/lib/efi_loader/efi_variable.c
index f79041e6bedd..f97c8c57f75c 100644
--- a/lib/efi_loader/efi_variable.c
+++ b/lib/efi_loader/efi_variable.c
@@ -554,6 +554,26 @@ if (IS_ENABLED(CONFIG_EFI_RT_VOLATILE_STORE)) {
*/
void efi_variables_boot_exit_notify(void)
{
+ const efi_guid_t efi_guid_efi_rt_var_file = U_BOOT_EFI_RT_VAR_FILE_GUID;
+ const efi_guid_t rt_prop_guid = EFI_RT_PROPERTIES_TABLE_GUID;
+ efi_status_t ret;
+
+ if (IS_ENABLED(CONFIG_EFI_RT_VOLATILE_STORE)) {
+ struct efi_rt_properties_table *rt_prop =
+ efi_get_configuration_table(&rt_prop_guid);
+
+ ret = efi_set_variable_int(u"RTStorageVolatile",
+ &efi_guid_efi_rt_var_file,
+ EFI_VARIABLE_BOOTSERVICE_ACCESS |
+ EFI_VARIABLE_RUNTIME_ACCESS |
+ EFI_VARIABLE_READ_ONLY,
+ sizeof(EFI_VAR_FILE_NAME),
+ EFI_VAR_FILE_NAME, false);
+ if (ret != EFI_SUCCESS)
+ rt_prop->runtime_services_supported |=
~EFI_RT_SUPPORTED_SET_VARIABLE;
+ else
+ log_err("Can't RTStorage. SetVariableRT won't be
available\n");
+ }
/* Switch variable services functions to runtime version */
efi_runtime_services.get_variable = efi_get_variable_runtime;
efi_runtime_services.get_next_variable_name =
--
2.37.2
