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    SubjectRe: [PATCH 0/3] clone64() and unshare64() system calls
    H. Peter Anvin [] wrote:
    > wrote:
    >> This is a resend of the patch set Cedric had sent earlier. I ported
    >> the patch set to 2.6.25-rc8-mm1 and tested on x86 and x86_64.
    >> ---
    >> We have run out of the 32 bits in clone_flags !
    >> This patchset introduces 2 new system calls which support 64bit
    >> clone-flags.
    >> long sys_clone64(unsigned long flags_high, unsigned long flags_low,
    >> unsigned long newsp);
    >> long sys_unshare64(unsigned long flags_high, unsigned long
    >> flags_low);
    >> The current version of clone64() does not support CLONE_PARENT_SETTID and
    >> CLONE_CHILD_CLEARTID because we would exceed the 6 registers limit of some
    >> arches. It's possible to get around this limitation but we might not
    >> need it as we already have clone()
    > I really dislike this interface.
    > If you're going to make it a 64-bit pass it in as a 64-bit number, instead
    > of breaking it into two numbers.

    Maybe I am missing your point. The glibc interface could take a 64bit
    parameter, but don't we need to pass 32-bit values into the system call
    on 32 bit systems ?

    > Better yet, IMO, would be to pass a pointer to a structure like:
    > struct shared {
    > unsigned long nwords;
    > unsigned long flags[];
    > };
    > ... which can be expanded indefinitely.

    Yes, this was discussed before in the context of Pavel Emelyanov's patch

    along with sys_indirect(). While there was no consensus, it looked like
    adding a new system call was better than open ended interfaces.

     \ /
      Last update: 2008-04-10 03:11    [W:0.022 / U:7.780 seconds]
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