[PATCH v2 3/4] efi/arm: map UEFI memory map earlier on boot

[AKASHI Takahiro]

Since arm_enter_runtime_services() was modified to always create a virtual
mapping of UEFI memory map in the previous patch, it is now renamed to
efi_enter_virtual_mode() and called earlier before acpi_load_tables()
in acpi_early_init().

This will allow us to use UEFI memory map in acpi_os_ioremap() to create
mappings of ACPI tables using memory attributes described in UEFI memory
map.

See a relevant commit:
    arm64: acpi: fix alignment fault in accessing ACPI tables

Signed-off-by: AKASHI Takahiro <takahiro.akashi@xxxxxxxxxx>
Cc: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
 drivers/firmware/efi/arm-runtime.c | 15 ++++++---------
 init/main.c                        |  3 +++
 2 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/firmware/efi/arm-runtime.c b/drivers/firmware/efi/arm-runtime.c
index 30ac5c82051e..566ef0a9edb5 100644
--- a/drivers/firmware/efi/arm-runtime.c
+++ b/drivers/firmware/efi/arm-runtime.c
@@ -106,46 +106,43 @@ static bool __init efi_virtmap_init(void)
  * non-early mapping of the UEFI system table and virtual mappings for all
  * EFI_MEMORY_RUNTIME regions.
  */
-static int __init arm_enable_runtime_services(void)
+void __init efi_enter_virtual_mode(void)
 {
 	u64 mapsize;
 
 	if (!efi_enabled(EFI_BOOT)) {
 		pr_info("EFI services will not be available.\n");
-		return 0;
+		return;
 	}
 
 	mapsize = efi.memmap.desc_size * efi.memmap.nr_map;
 
 	if (efi_memmap_init_late(efi.memmap.phys_map, mapsize)) {
 		pr_err("Failed to remap EFI memory map\n");
-		return 0;
+		return;
 	}
 
 	if (efi_runtime_disabled()) {
 		pr_info("EFI runtime services will be disabled.\n");
-		return 0;
+		return;
 	}
 
 	if (efi_enabled(EFI_RUNTIME_SERVICES)) {
 		pr_info("EFI runtime services access via paravirt.\n");
-		return 0;
+		return;
 	}
 
 	pr_info("Remapping and enabling EFI services.\n");
 
 	if (!efi_virtmap_init()) {
 		pr_err("UEFI virtual mapping missing or invalid -- runtime services will not be available\n");
-		return -ENOMEM;
+		return;
 	}
 
 	/* Set up runtime services function pointers */
 	efi_native_runtime_setup();
 	set_bit(EFI_RUNTIME_SERVICES, &efi.flags);
-
-	return 0;
 }
-early_initcall(arm_enable_runtime_services);
 
 void efi_virtmap_load(void)
 {
diff --git a/init/main.c b/init/main.c
index 3b4ada11ed52..532fc0d02353 100644
--- a/init/main.c
+++ b/init/main.c
@@ -694,6 +694,9 @@ asmlinkage __visible void __init start_kernel(void)
 	debug_objects_mem_init();
 	setup_per_cpu_pageset();
 	numa_policy_init();
+	if (IS_ENABLED(CONFIG_EFI) &&
+	    (IS_ENABLED(CONFIG_ARM64) || IS_ENABLED(CONFIG_ARM)))
+		efi_enter_virtual_mode();
 	acpi_early_init();
 	if (late_time_init)
 		late_time_init();
-- 
2.17.0