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    SubjectRe: 32-bit syscalls from 64-bit process on x86-64?
    On Fri, 2004-12-03 at 07:15 +0100, Andi Kleen wrote:
    > int 0x80 from 64bit will call 32bit syscalls.

    Hm, that's not what I found. If I run int 0x80 with [re]ax=1, I get
    exit with a 32-bit process and write with a 64-bit one.

    > But some things
    > will not work properly, e.g. signals because they test the 32bit
    > flag in the task_struct. So you would still get 64bit signal frames.

    OK, I can deal with that, since signals are never directly delivered to
    the client.

    > There are some other such tests, but they probably wont affect you.
    > There were some plans at one point to allow to toggle the flag
    > using personality or prctl, but so far it hasn't been implemented.
    > There is also no way to do 64bit calls from a 32bit executable.

    What about my idea of using distinct ranges of syscall numbers to
    disambiguate them?


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