From: Marc Zyngier <[email protected]>

commit c1fbec4ac0d701f350a581941d35643d5a9cd184 upstream.

As we are about to disable the vdso for compat tasks in some circumstances,
let's allow a workaround descriptor to express exactly that.

Signed-off-by: Marc Zyngier <[email protected]>
Acked-by: Mark Rutland <[email protected]>
Cc: [email protected]
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Will Deacon <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

---
 arch/arm64/include/asm/arch_timer.h  |    1 +
 drivers/clocksource/arm_arch_timer.c |    3 +++
 2 files changed, 4 insertions(+)

--- 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 *,
--- a/drivers/clocksource/arm_arch_timer.c
+++ b/drivers/clocksource/arm_arch_timer.c
@@ -566,6 +566,9 @@ void arch_timer_enable_workaround(const
        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;
        }
 }
 


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