fix(cpus): workaround for Cortex-X2 erratum 1916945
Cortex-X2 erratum 1916945 is a Cat B erratum that applies to
revisions r0p0 and r1p0 and is fixed in r2p0.
The workaround is to set CPUECTLR_EL1[8]. This has a small
performance impact (<0.5%).
SDEN documentation:
https://developer.arm.com/documentation/SDEN-1775100/latest
Change-Id: If810b1d0a07c43b3e1aa70d2ec88c1dcfa6f735f
Signed-off-by: John Powell <john.powell@arm.com>
diff --git a/docs/design/cpu-specific-build-macros.rst b/docs/design/cpu-specific-build-macros.rst
index 9978202..9c55077 100644
--- a/docs/design/cpu-specific-build-macros.rst
+++ b/docs/design/cpu-specific-build-macros.rst
@@ -744,6 +744,10 @@
- ``ERRATA_X2_1901946``: This applies errata 1901946 workaround to Cortex-X2
CPU. This needs to be enabled only for r1p0, it is fixed in r2p0.
+- ``ERRATA_X2_1916945``: This applies errata 1916945 workaround to Cortex-X2
+ CPU. This needs to be enabled for revisions r0p0 and r1p0, it is fixed in
+ r2p0.
+
- ``ERRATA_X2_2002765``: This applies errata 2002765 workaround to Cortex-X2
CPU. This needs to be enabled for revisions r0p0, r1p0, and r2p0 of the CPU,
it is still open.
diff --git a/lib/cpus/aarch64/cortex_x2.S b/lib/cpus/aarch64/cortex_x2.S
index 30a1bde..28bff36 100644
--- a/lib/cpus/aarch64/cortex_x2.S
+++ b/lib/cpus/aarch64/cortex_x2.S
@@ -37,6 +37,12 @@
check_erratum_range cortex_x2, ERRATUM(1901946), CPU_REV(1, 0), CPU_REV(1, 0)
+workaround_reset_start cortex_x2, ERRATUM(1916945), ERRATA_X2_1916945
+ sysreg_bit_set CORTEX_X2_CPUECTLR_EL1, BIT(8)
+workaround_reset_end cortex_x2, ERRATUM(1916945)
+
+check_erratum_ls cortex_x2, ERRATUM(1916945), CPU_REV(1, 0)
+
workaround_reset_start cortex_x2, ERRATUM(2002765), ERRATA_X2_2002765
ldr x0, =0x6
msr S3_6_C15_C8_0, x0 /* CPUPSELR_EL3 */
diff --git a/lib/cpus/cpu-ops.mk b/lib/cpus/cpu-ops.mk
index fa49b73..8916b16 100644
--- a/lib/cpus/cpu-ops.mk
+++ b/lib/cpus/cpu-ops.mk
@@ -746,6 +746,10 @@
# only to revision r1p0 of the Cortex-X2 cpu, it is fixed in r2p0.
CPU_FLAG_LIST += ERRATA_X2_1901946
+# Flag to apply erratum 1916945 workaround during reset. This erratum applies
+# to revisions r0p0 and r1p0 of the Cortex-X2 cpu, it is fixed in r2p0.
+CPU_FLAG_LIST += ERRATA_X2_1916945
+
# Flag to apply erratum 2002765 workaround during reset. This erratum applies
# to revisions r0p0, r1p0, and r2p0 of the Cortex-X2 cpu and is still open.
CPU_FLAG_LIST += ERRATA_X2_2002765