linux/arch/arm64/include/asm/vdso/clocksource.h
Marc Zyngier 97884ca8c2 arm64: Introduce a way to disable the 32bit vdso
We have a class of errata (grouped under the ARM64_WORKAROUND_1418040
banner) that force the trapping of counter access from 32bit EL0.

We would normally disable the whole vdso for such defect, except that
it would disable it for 64bit userspace as well, which is a shame.

Instead, add a new vdso_clock_mode, which signals that the vdso
isn't usable for compat tasks.  This gets checked in the new
vdso_clocksource_ok() helper, now provided for the 32bit vdso.

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/20200706163802.1836732-2-maz@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
2020-07-08 21:57:51 +01:00

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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __ASM_VDSOCLOCKSOURCE_H
#define __ASM_VDSOCLOCKSOURCE_H
#define VDSO_ARCH_CLOCKMODES \
/* vdso clocksource for both 32 and 64bit tasks */ \
VDSO_CLOCKMODE_ARCHTIMER, \
/* vdso clocksource for 64bit tasks only */ \
VDSO_CLOCKMODE_ARCHTIMER_NOCOMPAT
#endif