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path: root/drivers/firmware/efi/efi-stub-helper.c
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Diffstat (limited to 'drivers/firmware/efi/efi-stub-helper.c')
-rw-r--r--drivers/firmware/efi/efi-stub-helper.c30
1 files changed, 30 insertions, 0 deletions
diff --git a/drivers/firmware/efi/efi-stub-helper.c b/drivers/firmware/efi/efi-stub-helper.c
index 1bf439be9138..a168dd20511f 100644
--- a/drivers/firmware/efi/efi-stub-helper.c
+++ b/drivers/firmware/efi/efi-stub-helper.c
@@ -11,6 +11,10 @@
*/
#define EFI_READ_CHUNK_SIZE (1024 * 1024)
+/* error code which can't be mistaken for valid address */
+#define EFI_ERROR (~0UL)
+
+
struct file_info {
efi_file_handle_t *handle;
u64 size;
@@ -83,6 +87,32 @@ fail:
return status;
}
+
+static unsigned long __init get_dram_base(efi_system_table_t *sys_table_arg)
+{
+ efi_status_t status;
+ unsigned long map_size;
+ unsigned long membase = EFI_ERROR;
+ struct efi_memory_map map;
+ efi_memory_desc_t *md;
+
+ status = efi_get_memory_map(sys_table_arg, (efi_memory_desc_t **)&map.map,
+ &map_size, &map.desc_size, NULL, NULL);
+ if (status != EFI_SUCCESS)
+ return membase;
+
+ map.map_end = map.map + map_size;
+
+ for_each_efi_memory_desc(&map, md)
+ if (md->attribute & EFI_MEMORY_WB)
+ if (membase > md->phys_addr)
+ membase = md->phys_addr;
+
+ efi_call_early(free_pool, map.map);
+
+ return membase;
+}
+
/*
* Allocate at the highest possible address that is not above 'max'.
*/