Errata application is painful for performance. For a start, it's done
when the core has just come out of reset, which means branch predictors
and caches will be empty so a branch to a workaround function must be
fetched from memory and that round trip is very slow. Then it also runs
with the I-cache off, which means that the loop to iterate over the
workarounds must also be fetched from memory on each iteration.
We can remove both branches. First, we can simply apply every erratum
directly instead of defining a workaround function and jumping to it.
Currently, no errata that need to be applied at both reset and runtime,
with the same workaround function, exist. If the need arose in future,
this should be achievable with a reset + runtime wrapper combo.
Then, we can construct a function that applies each erratum linearly
instead of looping over the list. If this function is part of the reset
function, then the only "far" branches at reset will be for the checker
functions. Importantly, this mitigates the slowdown even when an erratum
is disabled.
The result is ~50% speedup on N1SDP and ~20% on AArch64 Juno on wakeup
from PSCI calls that end in powerdown. This is roughly back to the
baseline of v2.9, before the errata framework regressed on performance
(or a little better). It is important to note that there are other
slowdowns since then that remain unknown.
Change-Id: Ie4d5288a331b11fd648e5c4a0b652b74160b07b9
Signed-off-by: Boyan Karatotev <boyan.karatotev@arm.com>
Cortex-X925 erratum 2963999 that applies to r0p0 and is fixed in
r0p1.
In EL3, reads of MPIDR_EL1 and MIDR_EL1 might incorrectly virtualize
which register to return when reading the value of
MPIDR_EL1/VMPIDR_EL2 and MIDR_EL1/VPIDR_EL2, respectively.
The workaround is to do an ISB prior to an MRS read to either
MPIDR_EL1 and MIDR_EL1.
SDEN documentation:
https://developer.arm.com/documentation/109180/latest/
Change-Id: I447fd359ea32e1d274e1245886e1de57d14f082c
Signed-off-by: Govindraj Raja <govindraj.raja@arm.com>
Cortex-X925 erratum 3701747 that applies to r0p0, r0p1 and is still
Open.
The workaround is for EL3 software that performs context save/restore
on a change of Security state to use a value of SCR_EL3.NS when
accessing ICH_VMCR_EL2 that reflects the Security state that owns the
data being saved or restored.
SDEN documentation:
https://developer.arm.com/documentation/109180/latest/
Change-Id: I080296666f89276b3260686c2bdb8de63fc174c1
Signed-off-by: Govindraj Raja <govindraj.raja@arm.com>
This patch implements SMCCC_ARCH_WORKAROUND_4 and
allows discovery through SMCCC_ARCH_FEATURES.
This mechanism is enabled if CVE_2024_7881 [1] is enabled
by the platform. If CVE_2024_7881 mitigation
is implemented, the discovery call returns 0,
if not -1 (SMC_ARCH_CALL_NOT_SUPPORTED).
For more information about SMCCC_ARCH_WORKAROUND_4 [2], please
refer to the SMCCC Specification reference provided below.
[1]: https://developer.arm.com/Arm%20Security%20Center/Arm%20CPU%20Vulnerability%20CVE-2024-7881
[2]: https://developer.arm.com/documentation/den0028/latest
Signed-off-by: Arvind Ram Prakash <arvind.ramprakash@arm.com>
Change-Id: I1b1ffaa1f806f07472fd79d5525f81764d99bc79
Implements mitigation for CVE-2024-5660 that affects Cortex-X925
revisions r0p0, r0p1.
The workaround is to disable the hardware page aggregation at
EL3 by setting CPUECTLR_EL1[46] = 1'b1.
Public Documentation:
https://developer.arm.com/Arm%20Security%20Center/Arm%20CPU%20Vulnerability%20CVE-2024-5660
Change-Id: I9d5a07ca6b89b27d8876f4349eff2af26c962d8a
Signed-off-by: Sona Mathew <sonarebecca.mathew@arm.com>
Errata printing is done directly via generic_errata_report.
This commit removes the unused \_cpu\()_errata_report
functions for all cores, and removes errata_func from cpu_ops.
Change-Id: I04fefbde5f0ff63b1f1cd17c864557a14070d68c
Signed-off-by: Ryan Everett <ryan.everett@arm.com>
