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    SubjectRe: [PATCH] x86-64: use EFI to deal with platform wall clock
    >>> On 15.05.12 at 14:47, Matthew Garrett <> wrote:
    > On Tue, May 15, 2012 at 01:18:19PM +0100, Jan Beulich wrote:
    >> Simply removing the #ifdef around the respective code isn't enough,
    >> however: The runtime code must not only be forced to be executable, it
    >> also must have a proper virtual address set (which on at least the
    >> system I'm testing on isn't the case for all necessary regions, or at
    >> least not as early as they're now being required).
    > I don't understand this. The get_time pointer won't be updated to the
    > virtual function until the end of efi_enter_virtual_mode, at which point
    > all runtime regions should have a virtual address mapped. We also call
    > runtime_code_page_mkexec() immediately after updating that pointer,
    > although maybe the order should be swapped. So I think the bug you're
    > fixing is not the bug you think you're fixing...

    I would have expected that things work that way, but they
    don't. In particular is the function in efi_64.c that's being
    modified here called from efi_call_phys_{pro,epi}log(), and at
    that point we can't expect virtual addresses to be uniformly
    set yet. So it's a physical call that requires the fixup done
    here, as efi_set_executable() simply expects ->virt_addr to
    be valid. I suspect that no physical calls other than
    phys_efi_set_virtual_address_map() were being done so far
    at all on 64-bit, hiding the problem.


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