lkml.org 
[lkml]   [1998]   [Aug]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: copy_from_user() fixu
    On Tue, Aug 25, 1998 at 05:37:39PM +1000, Richard Gooch wrote:
    >
    > I can't sanitise the input: I don't know what pointer the application
    > will pass. Trapping SEGV is a performance bugger: I have to install a
    > signal handler before every pseudo-syscall and restore it afterwards
    > (my library can't steal signals).
    >

    What if we created a faster way to handle signals. This is something
    I'd like for other applications such as JIT-compilers. My idea for
    doing this is to map a page from kernel-memory into each process.
    This will be the exception-handler. Exceptions are caught directly in
    user-space (possible on i386). This code will decide whether the
    exception is "dangerous" (routed back to the kernel), or can be
    handled by the user.

    Similarly, installing a signal-handler could be done using a write to
    a special page.

    The reason I want this is to be able to implement fast read/write/exec
    barriers for GC and continuous compilers.

    astor

    --
    Alexander Kjeldaas, Guardian Networks AS, Trondheim, Norway
    http://www.guardian.no/

    -
    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.altern.org/andrebalsa/doc/lkml-faq.html

    \
     
     \ /
      Last update: 2005-03-22 13:44    [W:0.035 / U:0.372 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site