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    SubjectRe: export of sys_call_table
    Alan,

    Would it be possible to put a secondary call table behind
    the call gate wrappered in sys_ni_syscall that a module
    could register against. Is it merely the fact that the
    call gate table itself must be static? A secondary table
    and a mechanism to register against the secondary table with
    kernel locks taken behind the call gate would be trivial,
    I think.

    Does that sound like the best way to go about it?

    --brian

    On Thu, 03 Oct 2002, Alan Cox wrote:

    > On Thu, 2002-10-03 at 22:39, Brian F. G. Bidulock wrote:
    > > I see that RH, in their infinite wisdom, have seen fit to remove
    > > the export of sys_call_table in 8.0 kernels breaking any loadable
    > > modules that wish to implement non-implemented system calls such
    > > as LiS's or iBCS implementation of putmsg/getmsg.
    >
    > Overwriting syscall table entries is not safe. Its not safe because
    > there is no locking mechanism, and its not safe because of the pentium
    > III errata.
    >
    > > Until now, loadable modules have been able to just overwrite
    > > the non implemented point in the sys_call_table when they load
    > > and putting it back when they unload. There is no mechanism
    > > for registering system calls.
    >
    > Not actually safely implementable. The right way to do this is a
    > relevant 2.5 question. In general however you shouldnt need to register
    > syscalls because the upper layer interfaces already exist (the LiS stuff
    > is an example otherwise I grant).
    >
    > Alan
    >
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    --
    Brian F. G. Bidulock ¦ The reasonable man adapts himself to the ¦
    bidulock@openss7.org ¦ world; the unreasonable one persists in ¦
    http://www.openss7.org/ ¦ trying to adapt the world to himself. ¦
    ¦ Therefore all progress depends on the ¦
    ¦ unreasonable man. -- George Bernard Shaw ¦
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