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    SubjectRe: [PATCH 08/10] x86-32: support atomic64_t on 386/486 UP/SMP
    On 02/18/2010 02:25 AM, Peter Zijlstra wrote:
    > On Wed, 2010-02-17 at 12:42 +0100, Luca Barbieri wrote:
    >> This patch makes atomic64 use either the generic implementation or
    >> the rewritten cmpxchg8b one just introduced by inserting a "call" to
    >> either, using the alternatives system to dynamically switch the calls.
    >>
    >> This allows to use atomic64_t on 386/486 which lack cmpxchg8b
    >
    > IIRC we dropped <i586 SMP support, and since we don't have a PMU on
    > those chips atomic64_t doesn't need to be NMI safe, so a simple
    > UP-IRQ-disable implementation should suffice.

    ... which is what we have now, with the cmpxchg8b alternates emulation.

    -hpa

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



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