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Commit f608a77e authored by Marc Zyngier's avatar Marc Zyngier Committed by Greg Kroah-Hartman
Browse files

arm64: arch_timer: Disable the compat vdso for cores affected by ARM64_WORKAROUND_1418040 



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: default avatarMarc Zyngier <maz@kernel.org>
Acked-by: default avatarMark 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: default avatarWill Deacon <will@kernel.org>
Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 86e3c7c7

drivers/clocksource/arm_arch_timer.c

+8 −0
Original line number Diff line number Diff line
@@ -476,6 +476,14 @@ 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 *,