[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH 3/4] xen: arm: add barrier before sev in smp_spin_table_cpu_up
On Mon, 2014-03-17 at 13:52 +0000, Ian Campbell wrote: > This ensures that the writeq to the release address has occurred. > > In reality there is a dsb() in the iounmap() (in the eventual write_pte()) but > make it explicit. > > The ARMv8 ARM recommends that sev() is usually accompanied by a dsb(), the > only other uses are in the v7 spinlock code which includes a dsb() already. Thinking about this some more the dsb() in the ioumap is logical and it is reasonable to rely on it. This also satisfies the need for a dsb before the sev. So I intend to just drop this patch for the next iteration. > > Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx> > --- > v2: typos in the commit message > --- > xen/arch/arm/arm64/smpboot.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/xen/arch/arm/arm64/smpboot.c b/xen/arch/arm/arm64/smpboot.c > index 9146476..8e2ecf2 100644 > --- a/xen/arch/arm/arm64/smpboot.c > +++ b/xen/arch/arm/arm64/smpboot.c > @@ -36,6 +36,7 @@ static int __init smp_spin_table_cpu_up(int cpu) > > iounmap(release); > > + dsb(); /* Ensure that the write to cpu_release_addr has occurred. */ > sev(); > > return cpu_up_send_sgi(cpu); _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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