linux/Documentation/arm64
Rob Herring 96d389ca10 arm64: Add workaround for Arm Cortex-A77 erratum 1508412
On Cortex-A77 r0p0 and r1p0, a sequence of a non-cacheable or device load
and a store exclusive or PAR_EL1 read can cause a deadlock.

The workaround requires a DMB SY before and after a PAR_EL1 register
read. In addition, it's possible an interrupt (doing a device read) or
KVM guest exit could be taken between the DMB and PAR read, so we
also need a DMB before returning from interrupt and before returning to
a guest.

A deadlock is still possible with the workaround as KVM guests must also
have the workaround. IOW, a malicious guest can deadlock an affected
systems.

This workaround also depends on a firmware counterpart to enable the h/w
to insert DMB SY after load and store exclusive instructions. See the
errata document SDEN-1152370 v10 [1] for more information.

[1] https://static.docs.arm.com/101992/0010/Arm_Cortex_A77_MP074_Software_Developer_Errata_Notice_v10.pdf

Signed-off-by: Rob Herring <robh@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Julien Thierry <julien.thierry.kdev@gmail.com>
Cc: kvmarm@lists.cs.columbia.edu
Link: https://lore.kernel.org/r/20201028182839.166037-2-robh@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
2020-10-29 12:56:01 +00:00
..
acpi_object_usage.rst Documentation: arm64/acpi_object_usage: drop duplicate words 2020-07-05 14:37:45 -06:00
amu.rst Documentation: Chinese translation of Documentation/arm64/amu.rst 2020-09-28 15:24:24 -06:00
arm-acpi.rst arm64: Replace HTTP links with HTTPS ones 2020-07-23 14:04:37 -06:00
booting.rst A fair amount of stuff this time around, dominated by yet another massive 2020-06-01 15:45:27 -07:00
cpu-feature-registers.rst arm64: mte: Add Memory Tagging Extension documentation 2020-09-04 12:46:07 +01:00
elf_hwcaps.rst arm64: mte: Add Memory Tagging Extension documentation 2020-09-04 12:46:07 +01:00
hugetlbpage.rst Documentation: Chinese translation of Documentation/arm64/hugetlbpage.rst 2020-10-21 15:15:17 -06:00
index.rst As hoped, things calmed down for docs this cycle; fewer changes and almost 2020-10-12 16:21:29 -07:00
kasan-offsets.sh arm64: kasan: Switch to using KASAN_SHADOW_OFFSET 2019-08-09 11:17:11 +01:00
legacy_instructions.rst docs: arm64: convert docs to ReST and rename to .rst 2019-06-14 14:20:27 -06:00
memory-tagging-extension.rst arm64: mte: Document that user PSTATE.TCO is ignored by kernel uaccess 2020-10-28 17:50:39 +00:00
memory.rst docs: arm64: fix trivial spelling enought to enough in memory.rst 2020-02-20 10:03:14 +00:00
perf.rst docs: arm64: convert perf.txt to ReST format 2020-06-19 14:09:39 -06:00
pointer-authentication.rst docs: arm64: convert docs to ReST and rename to .rst 2019-06-14 14:20:27 -06:00
silicon-errata.rst arm64: Add workaround for Arm Cortex-A77 erratum 1508412 2020-10-29 12:56:01 +00:00
sve.rst It's been a busy cycle for documentation - hopefully the busiest for a 2020-08-04 22:47:54 -07:00
tagged-address-abi.rst mm: Avoid creating virtual address aliases in brk()/mmap()/mremap() 2020-02-20 10:03:14 +00:00
tagged-pointers.rst arm64: Relax Documentation/arm64/tagged-pointers.rst 2019-08-27 18:16:20 +01:00