• Matt Fleming's avatar
    efi: Add efi_memmap_init_late() for permanent EFI memmap · dca0f971
    Matt Fleming authored
    Drivers need a way to access the EFI memory map at runtime. ARM and
    arm64 currently provide this by remapping the EFI memory map into the
    vmalloc space before setting up the EFI virtual mappings.
    x86 does not provide this functionality which has resulted in the code
    in efi_mem_desc_lookup() where it will manually map individual EFI
    memmap entries if the memmap has already been torn down on x86,
       * If a driver calls this after efi_free_boot_services,
       * ->map will be NULL, and the target may also not be mapped.
       * So just always get our own virtual map on the CPU.
      md = early_memremap(p, sizeof (*md));
    There isn't a good reason for not providing a permanent EFI memory map
    for runtime queries, especially since the EFI regions are not mapped
    into the standard kernel page tables.
    Tested-by: Dave Young <dyoung@redhat.com> [kexec/kdump]
    Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> [arm]
    Acked-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
    Cc: Leif Lindholm <leif.lindholm@linaro.org>
    Cc: Peter Jones <pjones@redhat.com>
    Cc: Borislav Petkov <bp@alien8.de>
    Cc: Mark Rutland <mark.rutland@arm.com>
    Signed-off-by: default avatarMatt Fleming <matt@codeblueprint.co.uk>