efi/arm: Revert deferred unmap of early memmap mapping

Commit:

  3ea86495aef2 ("efi/arm: preserve early mapping of UEFI memory map longer for BGRT")

deferred the unmap of the early mapping of the UEFI memory map to
accommodate the ACPI BGRT code, which looks up the memory type that
backs the BGRT table to validate it against the requirements of the UEFI spec.

Unfortunately, this causes problems on ARM, which does not permit
early mappings to persist after paging_init() is called, resulting
in a WARN() splat. Since we don't support the BGRT table on ARM anway,
let's revert ARM to the old behaviour, which is to take down the
early mapping at the end of efi_init().

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Fixes: 3ea86495aef2 ("efi/arm: preserve early mapping of UEFI memory ...")
Link: http://lkml.kernel.org/r/20181114175544.12860-3-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/drivers/firmware/efi/arm-init.c b/drivers/firmware/efi/arm-init.c
index 388a929baf95d1e1107ab4b0ab20516dea3cfdf7..1a6a77df8a5e8aea45f3cbc2bac9c5d0883b0edb 100644 (file)
--- a/drivers/firmware/efi/arm-init.c
+++ b/drivers/firmware/efi/arm-init.c
@@ -265,6 +265,10 @@ void __init efi_init(void)
                                    (params.mmap & ~PAGE_MASK)));
 
        init_screen_info();
+
+       /* ARM does not permit early mappings to persist across paging_init() */
+       if (IS_ENABLED(CONFIG_ARM))
+               efi_memmap_unmap();
 }
 
 static int __init register_gop_device(void)

diff --git a/drivers/firmware/efi/arm-runtime.c b/drivers/firmware/efi/arm-runtime.c
index 922cfb813109a3c14a88a0bb054a09534e813ec9..a00934d263c519a9d476a57a5bb2388c6041b810 100644 (file)
--- a/drivers/firmware/efi/arm-runtime.c
+++ b/drivers/firmware/efi/arm-runtime.c
@@ -110,7 +110,7 @@ static int __init arm_enable_runtime_services(void)
 {
        u64 mapsize;
 
-       if (!efi_enabled(EFI_BOOT) || !efi_enabled(EFI_MEMMAP)) {
+       if (!efi_enabled(EFI_BOOT)) {
                pr_info("EFI services will not be available.\n");
                return 0;
        }

diff --git a/drivers/firmware/efi/memmap.c b/drivers/firmware/efi/memmap.c
index fa2904fb841fe459a6562b9fea237c5213fa97be..38b686c67b177da4875b9174c0f50ca165c6b2d4 100644 (file)
--- a/drivers/firmware/efi/memmap.c
+++ b/drivers/firmware/efi/memmap.c
@@ -118,6 +118,9 @@ int __init efi_memmap_init_early(struct efi_memory_map_data *data)
 
 void __init efi_memmap_unmap(void)
 {
+       if (!efi_enabled(EFI_MEMMAP))
+               return;
+
        if (!efi.memmap.late) {
                unsigned long size;