summaryrefslogtreecommitdiff
path: root/drivers/firmware
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/firmware')
-rw-r--r--drivers/firmware/efi/libstub/efi-stub-helper.c73
1 files changed, 73 insertions, 0 deletions
diff --git a/drivers/firmware/efi/libstub/efi-stub-helper.c b/drivers/firmware/efi/libstub/efi-stub-helper.c
index 29368ac69221..aded10662020 100644
--- a/drivers/firmware/efi/libstub/efi-stub-helper.c
+++ b/drivers/firmware/efi/libstub/efi-stub-helper.c
@@ -740,3 +740,76 @@ char *efi_convert_cmdline(efi_system_table_t *sys_table_arg,
*cmd_line_len = options_bytes;
return (char *)cmdline_addr;
}
+
+/*
+ * Handle calling ExitBootServices according to the requirements set out by the
+ * spec. Obtains the current memory map, and returns that info after calling
+ * ExitBootServices. The client must specify a function to perform any
+ * processing of the memory map data prior to ExitBootServices. A client
+ * specific structure may be passed to the function via priv. The client
+ * function may be called multiple times.
+ */
+efi_status_t efi_exit_boot_services(efi_system_table_t *sys_table_arg,
+ void *handle,
+ struct efi_boot_memmap *map,
+ void *priv,
+ efi_exit_boot_map_processing priv_func)
+{
+ efi_status_t status;
+
+ status = efi_get_memory_map(sys_table_arg, map);
+
+ if (status != EFI_SUCCESS)
+ goto fail;
+
+ status = priv_func(sys_table_arg, map, priv);
+ if (status != EFI_SUCCESS)
+ goto free_map;
+
+ status = efi_call_early(exit_boot_services, handle, *map->key_ptr);
+
+ if (status == EFI_INVALID_PARAMETER) {
+ /*
+ * The memory map changed between efi_get_memory_map() and
+ * exit_boot_services(). Per the UEFI Spec v2.6, Section 6.4:
+ * EFI_BOOT_SERVICES.ExitBootServices we need to get the
+ * updated map, and try again. The spec implies one retry
+ * should be sufficent, which is confirmed against the EDK2
+ * implementation. Per the spec, we can only invoke
+ * get_memory_map() and exit_boot_services() - we cannot alloc
+ * so efi_get_memory_map() cannot be used, and we must reuse
+ * the buffer. For all practical purposes, the headroom in the
+ * buffer should account for any changes in the map so the call
+ * to get_memory_map() is expected to succeed here.
+ */
+ *map->map_size = *map->buff_size;
+ status = efi_call_early(get_memory_map,
+ map->map_size,
+ *map->map,
+ map->key_ptr,
+ map->desc_size,
+ map->desc_ver);
+
+ /* exit_boot_services() was called, thus cannot free */
+ if (status != EFI_SUCCESS)
+ goto fail;
+
+ status = priv_func(sys_table_arg, map, priv);
+ /* exit_boot_services() was called, thus cannot free */
+ if (status != EFI_SUCCESS)
+ goto fail;
+
+ status = efi_call_early(exit_boot_services, handle, *map->key_ptr);
+ }
+
+ /* exit_boot_services() was called, thus cannot free */
+ if (status != EFI_SUCCESS)
+ goto fail;
+
+ return EFI_SUCCESS;
+
+free_map:
+ efi_call_early(free_pool, *map->map);
+fail:
+ return status;
+}