On Tue, May 22, 2018 at 12:38:05PM +0200, Geert Uytterhoeven wrote:
> Hi Russell,
>
> On Wed, May 16, 2018 at 1:01 PM, Russell King
> <rmk+kernel@xxxxxxxxxxxxxxx> wrote:
> > When the branch predictor hardening is enabled, firmware must have set
> > the IBE bit in the auxiliary control register. If this bit has not
> > been set, the Spectre workarounds will not be functional.
> >
> > Add validation that this bit is set, and print a warning at alert level
> > if this is not the case.
> >
> > Signed-off-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxx>
>
> Thanks for your patch!
>
> > --- /dev/null
> > +++ b/arch/arm/mm/proc-v7-bugs.c
> > @@ -0,0 +1,29 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +#include <linux/kernel.h>
> > +#include <linux/smp.h>
> > +
> > +static __maybe_unused void cpu_v7_check_auxcr_set(u32 mask, const char *msg)
> > +{
> > + u32 aux_cr;
> > +
> > + asm("mrc p15, 0, %0, c1, c0, 1" : "=r" (aux_cr));
> > +
> > + if ((aux_cr & mask) != mask)
> > + pr_err("CPU%u: %s", smp_processor_id(), msg);
>
> pr_alert(), to match the patch description.
It was alert, but I've lowered it because I don't think it warrants
alert status. Maybe critical would be better? Shrug, this stuff is
rather subjective.
--
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
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