On Mon, Jul 06, 2020 at 05:38:00PM +0100, Marc Zyngier wrote:
> As we are about to disable the vdso for compat tasks in some circumstances,
> let's allow a workaround descriptor to express exactly that.
>
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
Acked-by: Mark Rutland <mark.rutland@xxxxxxx>
Mark.
> ---
> arch/arm64/include/asm/arch_timer.h | 1 +
> drivers/clocksource/arm_arch_timer.c | 3 +++
> 2 files changed, 4 insertions(+)
>
> diff --git a/arch/arm64/include/asm/arch_timer.h b/arch/arm64/include/asm/arch_timer.h
> index 7ae54d7d333a..9f0ec21d6327 100644
> --- a/arch/arm64/include/asm/arch_timer.h
> +++ b/arch/arm64/include/asm/arch_timer.h
> @@ -58,6 +58,7 @@ struct arch_timer_erratum_workaround {
> u64 (*read_cntvct_el0)(void);
> int (*set_next_event_phys)(unsigned long, struct clock_event_device *);
> int (*set_next_event_virt)(unsigned long, struct clock_event_device *);
> + bool disable_compat_vdso;
> };
>
> DECLARE_PER_CPU(const struct arch_timer_erratum_workaround *,
> diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
> index ecf7b7db2d05..a8e4fb429f52 100644
> --- a/drivers/clocksource/arm_arch_timer.c
> +++ b/drivers/clocksource/arm_arch_timer.c
> @@ -566,6 +566,9 @@ void arch_timer_enable_workaround(const struct arch_timer_erratum_workaround *wa
> if (wa->read_cntvct_el0) {
> clocksource_counter.vdso_clock_mode = VDSO_CLOCKMODE_NONE;
> vdso_default = VDSO_CLOCKMODE_NONE;
> + } else if (wa->disable_compat_vdso && vdso_default != VDSO_CLOCKMODE_NONE) {
> + vdso_default = VDSO_CLOCKMODE_ARCHTIMER_NOCOMPAT;
> + clocksource_counter.vdso_clock_mode = vdso_default;
> }
> }
>
> --
> 2.27.0
>
