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    SubjectRe: x86: get rid of the insane TIF_ABI_PENDING bit
    On 02/15/2010 08:17 AM, Oleg Nesterov wrote:
    >> +
    >> + /* Prepare the first "return" to user space */
    >> + current_thread_info()->status |= TS_COMPAT;
    >
    > Can't understand why we need TS_COMPAT. I assume this is correct,
    > this was copied from flush_thread().
    >
    > What TS_COMPAT actually means? I thought it just means "the task
    > is inside 32-bit syscall".
    >
    > If a 64bit task execs a 32bit app, can't this TS_COMPAT break, say,
    > syscall_get_arguments() ?
    >
    > Just curious, I don't really understand COMPAT issues anyway.
    >

    I suspect the purpose of TS_COMPAT is actually so you can ptrace() the
    newly exec'd process (and see it as a 32-bit process!) before it returns
    to userspace. The comment, obviously, is wrong -- that again refers to
    TIF_IA32.

    -hpa

    --
    H. Peter Anvin, Intel Open Source Technology Center
    I work for Intel. I don't speak on their behalf.



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