lkml.org 
[lkml]   [2000]   [Feb]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    Subject[patch] vsyscall feature

    On Tue, 22 Feb 2000, Dean Gaudet wrote:

    > out of curiosity, has the fast syscall and fast gettimeofday stuff
    > with the nifty kernel-supplied code page made it into the
    > kernel/glibc/etc?

    nope, 2.5 stuff. You can check out the 2.3.32 patch (which has a working
    purely-user-space times() syscall) at:

    http://www.redhat.com/~mingo/vsyscall-2.3.32-F4

    Documentation/syscall.txt has the design:

    +
    + 'x86 Virtual System Call Interface', Ingo Molnar <mingo@redhat.com>
    +
    + The point is to have an extensible system call interface. The kernel
    + provides a generic entry point, which is a readonly user-visible page
    + range. User-space does not know about the internals of this entry
    + point, it's a simple generic function call.
    +

    there are several 'trampoline pages' (both data and code) which are
    'dual-mapped': kernel-space has a read-write mapping to the data page,
    user-space only has a read-only mapping. This is how sys_times() works.

    it's in the prototype stage, but pretty promising IMO, will post a
    finished patch once the 2.5 is branched off.

    -- mingo


    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.rutgers.edu
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2005-03-22 13:56    [W:0.027 / U:0.156 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site