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    SubjectRe: [PATCH 2/2] x86: Allow disabling of sys_iopl, sys_ioperm
    On Thu, Jul 14, 2011 at 1:37 PM, H. Peter Anvin <> wrote:
    > On 07/14/2011 01:34 PM, Mike Waychison wrote:
    >> In some build environments, it is useful to allow disabling of IO
    >> accesses to hardware, without having to rely on CAP_SYS_RAWIO (which is
    >> already overloaded to mean many other things).  One way that userland
    >> has access to IO accesses is via the iopl(2) and ioperm(2) system calls.
    >> Allow disabling of these system calls from ever being available via a
    >> configuration option, X86_SYS_IOPL.   This is implemented by simply
    >> stubbing out the system calls and having them return ENOSYS when their
    >> functionality is disabled.
    >> Note that we default this option to 'y', so that existing kernel configs
    >> will continue to support sys_iopl and sys_ioperm as before.
    > Wouldn't it be more useful for this to be a sysctl?  In particular, like
    > many similar things it probably should be a lockable sysctl (three
    > states: enabled, disabled, and locked-disabled).
    > Making it a compile-time option I'm very skeptical to.

    Are there existing examples of this already in the tree?
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      Last update: 2011-07-14 22:41    [W:0.021 / U:14.000 seconds]
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