On Mon, Jul 06, 2020 at 05:38:01PM +0100, Marc Zyngier wrote:
> ARM64_WORKAROUND_1418040 requires that AArch32 EL0 accesses to
> the virtual counter register are trapped and emulated by the kernel.
> This makes the vdso pretty pointless, and in some cases livelock
> prone.
>
> Provide a workaround entry that limits the vdso to 64bit tasks.
>
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
Acked-by: Mark Rutland <mark.rutland@xxxxxxx>
Mark.
> ---
> drivers/clocksource/arm_arch_timer.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
> index a8e4fb429f52..6c3e84180146 100644
> --- a/drivers/clocksource/arm_arch_timer.c
> +++ b/drivers/clocksource/arm_arch_timer.c
> @@ -480,6 +480,14 @@ static const struct arch_timer_erratum_workaround ool_workarounds[] = {
> .set_next_event_virt = erratum_set_next_event_tval_virt,
> },
> #endif
> +#ifdef CONFIG_ARM64_ERRATUM_1418040
> + {
> + .match_type = ate_match_local_cap_id,
> + .id = (void *)ARM64_WORKAROUND_1418040,
> + .desc = "ARM erratum 1418040",
> + .disable_compat_vdso = true,
> + },
> +#endif
> };
>
> typedef bool (*ate_match_fn_t)(const struct arch_timer_erratum_workaround *,
> --
> 2.27.0
>
