fix(cpus): workaround for Cortex-X3 erratum 3827463
Cortex-X3 erratum 3827463 is a Cat B erratum that applies to
r0p0, r1p0 and r1p1. It is fixed in r1p2.
This erratum can be avoided by setting CPUACTLR_EL1[1]
prior to enabling MMU. This bit will disable a branch predictor
power savings feature. Disabling this power feature
results in negligible power movement and no performance impact.
SDEN Documentation:
https://developer.arm.com/documentation/SDEN-2055130/latest/
Signed-off-by: Arvind Ram Prakash <arvind.ramprakash@arm.com>
Change-Id: I1d4a2b9641400d8b9061f7cb32a8312c3995613e
diff --git a/docs/design/cpu-specific-build-macros.rst b/docs/design/cpu-specific-build-macros.rst
index 4ba8a43..c9213c9 100644
--- a/docs/design/cpu-specific-build-macros.rst
+++ b/docs/design/cpu-specific-build-macros.rst
@@ -844,6 +844,10 @@
CPU. This needs to be enabled only for revisions r0p0, r1p0, r1p1 and r1p2
of the CPU and it is still open.
+- ``ERRATA_X3_3827463``: This applies errata 3827463 workaround to Cortex-X3
+ CPU. This needs to be enabled only for revisions r0p0, r1p0 and r1p1 of
+ the CPU. It is fixed in r1p2.
+
For Cortex-X4, the following errata build flags are defined :
- ``ERRATA_X4_2701112``: This applies erratum 2701112 workaround to Cortex-X4
diff --git a/lib/cpus/aarch64/cortex_x3.S b/lib/cpus/aarch64/cortex_x3.S
index 3058778..a166e0f 100644
--- a/lib/cpus/aarch64/cortex_x3.S
+++ b/lib/cpus/aarch64/cortex_x3.S
@@ -106,6 +106,12 @@
check_erratum_ls cortex_x3, ERRATUM(3701769), CPU_REV(1, 2)
+workaround_reset_start cortex_x3, ERRATUM(3827463), ERRATA_X3_3827463
+ sysreg_bit_set CORTEX_X3_CPUACTLR_EL1, BIT(1)
+workaround_reset_end cortex_x3, ERRATUM(3827463)
+
+check_erratum_ls cortex_x3, ERRATUM(3827463), CPU_REV(1, 1)
+
workaround_reset_start cortex_x3, CVE(2022, 23960), WORKAROUND_CVE_2022_23960
#if IMAGE_BL31
override_vector_table wa_cve_vbar_cortex_x3
diff --git a/lib/cpus/cpu-ops.mk b/lib/cpus/cpu-ops.mk
index 1a1d444..5dbbb9e 100644
--- a/lib/cpus/cpu-ops.mk
+++ b/lib/cpus/cpu-ops.mk
@@ -850,6 +850,10 @@
# to revisions r0p0, r1p0, r1p1, r1p2 of the Cortex-X3 cpu and is still open.
CPU_FLAG_LIST += ERRATA_X3_3692984
+# Flag to apply erratum 3827463 workaround on reset. This erratum applies
+# to revisions r0p0, r1p0 and r1p1 of the Cortex-X3 cpu. It is fixed in r1p2.
+CPU_FLAG_LIST += ERRATA_X3_3827463
+
# Flag to apply erratum 2701112 workaround for platforms that do not use an
# Arm interconnect IP. This erratum applies to revisions r0p0 of the Cortex-X4
# cpu and is fixed in r0p1.