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    SubjectRe: [PATCH] x86: export 'pcibios_enabled'
    On Wed, Mar 14, 2012 at 11:21:37AM +0000, Alan Cox wrote:
    > You can use set_memory_x() to mark memory executable (and _nx to set it back).
    >
    NO I can't, if I set_memory_x and don't set pcibios_enabled = 1, then
    static_protections will still failed because pcibios_enabled == 0,
    and I don't want to use set_memory_x, because I don't want to give the user
    of uvesafb that feeling "I will lost BIOS NX protection if I choice uvesafb."

    > If you really need to know if NX is being used then the check
    >
    > if (__supported_pte_mask & PTE_NX)
    >
    > will do the trick and the variable is exported.
    I don't understand what do you mean, do you means CONFIG_X86_PAE for 32? Or CONFIG_X86_64?
    when NX is being used, the pci bios is NX or not also depend on
    ACPI.ACPI on or off all will influnce the code path in pci_arch_init,
    decide the set_bios_x have chance to execute or not.See
    https://lkml.org/lkml/2011/11/16/84

    By the way _PAGE_NX instead of PTE_NX, right?

    > I'd suggest however you wrap that in a cpu_has_nx() type macro somewhere
    > in the arch headers.
    >
    The same above.

    > If you go poking around pcibios values you are going to get burned if
    > someone is ever bored enough to make NX and PCIBIOS work together
    > differently.
    >
    Indeed according to 5bd5a452662bc37c54fb6828db1a3faf87e6511c, who bring me
    the trouble, check the pcibios_enabled is the only simple and good way to
    resolve the Oops I meet.

    If you really don't want it, and if I am not all wrong about your "helper method",
    you means you want export the below:
    int check_pcibios_enabled()?
    See https://lkml.org/lkml/2012/2/26/124

    Thanks.



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