• Matt Fleming's avatar
    x86/efi: Hoist page table switching code into efi_call_virt() · c9f2a9a6
    Matt Fleming authored
    This change is a prerequisite for pending patches that switch to
    a dedicated EFI page table, instead of using 'trampoline_pgd'
    which shares PGD entries with 'swapper_pg_dir'. The pending
    patches make it impossible to dereference the runtime service
    function pointer without first switching %cr3.
    
    It's true that we now have duplicated switching code in
    efi_call_virt() and efi_call_phys_{prolog,epilog}() but we are
    sacrificing code duplication for a little more clarity and the
    ease of writing the page table switching code in C instead of
    asm.
    Signed-off-by: default avatarMatt Fleming <matt@codeblueprint.co.uk>
    Reviewed-by: default avatarBorislav Petkov <bp@suse.de>
    Acked-by: default avatarBorislav Petkov <bp@suse.de>
    Cc: Andrew Morton <akpm@linux-foundation.org>
    Cc: Andy Lutomirski <luto@amacapital.net>
    Cc: Andy Lutomirski <luto@kernel.org>
    Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
    Cc: Borislav Petkov <bp@alien8.de>
    Cc: Brian Gerst <brgerst@gmail.com>
    Cc: Dave Jones <davej@codemonkey.org.uk>
    Cc: Denys Vlasenko <dvlasenk@redhat.com>
    Cc: H. Peter Anvin <hpa@zytor.com>
    Cc: Linus Torvalds <torvalds@linux-foundation.org>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
    Cc: Stephen Smalley <sds@tycho.nsa.gov>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Cc: Toshi Kani <toshi.kani@hp.com>
    Cc: linux-efi@vger.kernel.org
    Link: http://lkml.kernel.org/r/1448658575-17029-5-git-send-email-matt@codeblueprint.co.ukSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
    c9f2a9a6
efi_stub_64.S 1.11 KB