path: root/Documentation/arm64
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authorRob Herring <robh@kernel.org>2020-10-28 13:28:39 -0500
committerWill Deacon <will@kernel.org>2020-10-29 12:56:01 +0000
commit96d389ca10110d7eefb46feb6af9a0c6832f78f5 (patch)
tree100d4c5967acc6b8eab520466073417b4e3b52fa /Documentation/arm64
parentarm64: Add part number for Arm Cortex-A77 (diff)
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>
Diffstat (limited to 'Documentation/arm64')
1 files changed, 2 insertions, 0 deletions
diff --git a/Documentation/arm64/silicon-errata.rst b/Documentation/arm64/silicon-errata.rst
index d3587805de64..719510247292 100644
--- a/Documentation/arm64/silicon-errata.rst
+++ b/Documentation/arm64/silicon-errata.rst
@@ -90,6 +90,8 @@ stable kernels.
| ARM | Cortex-A76 | #1463225 | ARM64_ERRATUM_1463225 |
+| ARM | Cortex-A77 | #1508412 | ARM64_ERRATUM_1508412 |
| ARM | Neoverse-N1 | #1188873,1418040| ARM64_ERRATUM_1418040 |
| ARM | Neoverse-N1 | #1349291 | N/A |