linux/arch/arm64
Scott Wood f6dc1576cd arm64: arch_timer: Work around QorIQ Erratum A-008585
Erratum A-008585 says that the ARM generic timer counter "has the
potential to contain an erroneous value for a small number of core
clock cycles every time the timer value changes".  Accesses to TVAL
(both read and write) are also affected due to the implicit counter
read.  Accesses to CVAL are not affected.

The workaround is to reread TVAL and count registers until successive
reads return the same value.  Writes to TVAL are replaced with an
equivalent write to CVAL.

The workaround is to reread TVAL and count registers until successive reads
return the same value, and when writing TVAL to retry until counter
reads before and after the write return the same value.

The workaround is enabled if the fsl,erratum-a008585 property is found in
the timer node in the device tree.  This can be overridden with the
clocksource.arm_arch_timer.fsl-a008585 boot parameter, which allows KVM
users to enable the workaround until a mechanism is implemented to
automatically communicate this information.

This erratum can be found on LS1043A and LS2080A.

Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Scott Wood <oss@buserror.net>
[will: renamed read macro to reflect that it's not usually unstable]
Signed-off-by: Will Deacon <will.deacon@arm.com>
2016-09-23 17:19:25 +01:00
..
boot ARM: SoC fixes 2016-08-11 14:14:23 -07:00
configs arm64: defconfig: enable CONFIG_LOCALVERSION_AUTO 2016-08-12 19:08:48 +01:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2016-03-17 11:22:54 -07:00
include arm64: arch_timer: Work around QorIQ Erratum A-008585 2016-09-23 17:19:25 +01:00
kernel arm64: migrate exception table users off module.h and onto extable.h 2016-09-20 09:36:21 +01:00
kvm arm64/kvm: use alternative auto-nop 2016-09-12 10:46:07 +01:00
lib arm64: use alternative auto-nop 2016-09-12 10:46:07 +01:00
mm arm64: migrate exception table users off module.h and onto extable.h 2016-09-20 09:36:21 +01:00
net arm64: bpf: optimize LD_ABS, LD_IND 2016-06-10 23:11:50 -07:00
xen arm/xen: add support for vm_assist hypercall 2016-07-06 10:42:14 +01:00
Kconfig arm64/numa: support HAVE_SETUP_PER_CPU_AREA 2016-09-09 14:59:09 +01:00
Kconfig.debug arm64: always enable DEBUG_RODATA and remove the Kconfig option 2016-08-26 10:13:41 +01:00
Kconfig.platforms arm64: remove redundant "select HAVE_CLK" 2016-08-22 10:00:48 +01:00
Makefile arm64: Set UTS_MACHINE in the Makefile 2016-08-31 12:31:38 +01:00