[PATCH v4 4/5] efi/arm: map UEFI memory map even w/o runtime services enabled

From: AKASHI Takahiro
Date: Sun Jul 22 2018 - 21:59:47 EST


Under the current implementation, UEFI memory map will be mapped and made
available in virtual mappings only if runtime services are enabled.
But in a later patch, we want to use UEFI memory map in acpi_os_ioremap()
to create mappings of ACPI tables using memory attributes described in
UEFI memory map.
See the following commit:
arm64: acpi: fix alignment fault in accessing ACPI tables

So, as a first step, arm_enter_runtime_services() is modified, alongside
Ard's patch[1], so that UEFI memory map will not be freed even if
efi=noruntime.

[1] https://marc.info/?l=linux-efi&m=152930773507524&w=2

Signed-off-by: AKASHI Takahiro <takahiro.akashi@xxxxxxxxxx>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
---
drivers/firmware/efi/arm-runtime.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/firmware/efi/arm-runtime.c b/drivers/firmware/efi/arm-runtime.c
index 59a8c0ec94d5..a00934d263c5 100644
--- a/drivers/firmware/efi/arm-runtime.c
+++ b/drivers/firmware/efi/arm-runtime.c
@@ -117,6 +117,13 @@ static int __init arm_enable_runtime_services(void)

efi_memmap_unmap();

+ 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;
+ }
+
if (efi_runtime_disabled()) {
pr_info("EFI runtime services will be disabled.\n");
return 0;
@@ -129,13 +136,6 @@ static int __init arm_enable_runtime_services(void)

pr_info("Remapping and enabling EFI services.\n");

- 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 -ENOMEM;
- }
-
if (!efi_virtmap_init()) {
pr_err("UEFI virtual mapping missing or invalid -- runtime services will not be available\n");
return -ENOMEM;
--
2.18.0