From: Marc Zyngier maz@kernel.org
commit 4b661d6133c5d3a7c9aca0b4ee5a78c7766eff3f upstream.
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.
Signed-off-by: Marc Zyngier maz@kernel.org Acked-by: Mark Rutland mark.rutland@arm.com Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20200706163802.1836732-4-maz@kernel.org Signed-off-by: Will Deacon will@kernel.org Signed-off-by: Marc Zyngier maz@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/clocksource/arm_arch_timer.c | 8 ++++++++ 1 file changed, 8 insertions(+)
--- a/drivers/clocksource/arm_arch_timer.c +++ b/drivers/clocksource/arm_arch_timer.c @@ -476,6 +476,14 @@ static const struct arch_timer_erratum_w .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 *,