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.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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