efi_loader: Align runtime section to 64kb

The UEFI spec mandates that runtime sections are 64kb aligned to enable
support for 64kb page size OSs.

This patch ensures that we extend the runtime section to 64kb to be spec
compliant.

Signed-off-by: Alexander Graf <agraf@suse.de>

1 files changed, 17 insertions, 3 deletions

diff --git a/lib/efi_loader/efi_memory.c b/lib/efi_loader/efi_memory.c
index 5359118b4d..4bb517473e 100644
--- a/lib/efi_loader/efi_memory.c
+++ b/lib/efi_loader/efi_memory.c
@@ -11,6 +11,7 @@
 #include <mapmem.h>
 #include <watchdog.h>
 #include <linux/list_sort.h>
+#include <linux/sizes.h>
 
 DECLARE_GLOBAL_DATA_PTR;
 
@@ -602,6 +603,7 @@ __weak void efi_add_known_memory(void)
 static void add_u_boot_and_runtime(void)
 {
 	unsigned long runtime_start, runtime_end, runtime_pages;
+	unsigned long runtime_mask = EFI_PAGE_MASK;
 	unsigned long uboot_start, uboot_pages;
 	unsigned long uboot_stack_size = 16 * 1024 * 1024;
 
@@ -610,10 +612,22 @@ static void add_u_boot_and_runtime(void)
 	uboot_pages = (gd->ram_top - uboot_start) >> EFI_PAGE_SHIFT;
 	efi_add_memory_map(uboot_start, uboot_pages, EFI_LOADER_DATA, false);
 
-	/* Add Runtime Services */
-	runtime_start = (ulong)&__efi_runtime_start & ~EFI_PAGE_MASK;
+#if defined(__aarch64__)
+	/*
+	 * Runtime Services must be 64KiB aligned according to the
+	 * "AArch64 Platforms" section in the UEFI spec (2.7+).
+	 */
+
+	runtime_mask = SZ_64K - 1;
+#endif
+
+	/*
+	 * Add Runtime Services. We mark surrounding boottime code as runtime as
+	 * well to fulfill the runtime alignment constraints but avoid padding.
+	 */
+	runtime_start = (ulong)&__efi_runtime_start & ~runtime_mask;
 	runtime_end = (ulong)&__efi_runtime_stop;
-	runtime_end = (runtime_end + EFI_PAGE_MASK) & ~EFI_PAGE_MASK;
+	runtime_end = (runtime_end + runtime_mask) & ~runtime_mask;
 	runtime_pages = (runtime_end - runtime_start) >> EFI_PAGE_SHIFT;
 	efi_add_memory_map(runtime_start, runtime_pages,
 			   EFI_RUNTIME_SERVICES_CODE, false);