fix(cpus): workaround for Cortex-A720 erratum 3699561
Cortex-A720 erratum 3699561 that applies to all revisions <= r0p2
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/SDEN-2439421/latest/
Change-Id: I7ea3aaf3e7bf6b4f3648f6872e505a41247b14ba
Signed-off-by: Govindraj Raja <govindraj.raja@arm.com>
diff --git a/docs/design/cpu-specific-build-macros.rst b/docs/design/cpu-specific-build-macros.rst
index 47fa955..34fa2e9 100644
--- a/docs/design/cpu-specific-build-macros.rst
+++ b/docs/design/cpu-specific-build-macros.rst
@@ -982,6 +982,10 @@
Cortex-A720 CPU. This needs to be enabled for revisions r0p0 and r0p1.
It is fixed in r0p2.
+- ``ERRATA_A720_3699561``: This applies errata 3699561 workaround to
+ Cortex-A720 CPU. This needs to be enabled for revisions r0p0, r0p1
+ and r0p2. It is still open.
+
DSU Errata Workarounds
----------------------
diff --git a/include/lib/cpus/aarch64/cortex_a720.h b/include/lib/cpus/aarch64/cortex_a720.h
index 129c1ee..670438f 100644
--- a/include/lib/cpus/aarch64/cortex_a720.h
+++ b/include/lib/cpus/aarch64/cortex_a720.h
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2021-2024, Arm Limited. All rights reserved.
+ * Copyright (c) 2021-2025, Arm Limited. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
@@ -38,4 +38,8 @@
#define CORTEX_A720_CPUPWRCTLR_EL1 S3_0_C15_C2_7
#define CORTEX_A720_CPUPWRCTLR_EL1_CORE_PWRDN_BIT U(1)
+#ifndef __ASSEMBLER__
+long check_erratum_cortex_a720_3699561(long cpu_rev);
+#endif /* __ASSEMBLER__ */
+
#endif /* CORTEX_A720_H */
diff --git a/lib/cpus/aarch64/cortex_a720.S b/lib/cpus/aarch64/cortex_a720.S
index 9befb36..ab2c12f 100644
--- a/lib/cpus/aarch64/cortex_a720.S
+++ b/lib/cpus/aarch64/cortex_a720.S
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2021-2024, Arm Limited. All rights reserved.
+ * Copyright (c) 2021-2025, Arm Limited. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
@@ -22,6 +22,8 @@
#error "Cortex A720 supports only AArch64. Compile with CTX_INCLUDE_AARCH32_REGS=0"
#endif
+.global check_erratum_cortex_a720_3699561
+
#if WORKAROUND_CVE_2022_23960
wa_cve_2022_23960_bhb_vector_table CORTEX_A720_BHB_LOOP_COUNT, cortex_a720
#endif /* WORKAROUND_CVE_2022_23960 */
@@ -72,6 +74,10 @@
check_erratum_chosen cortex_a720, CVE(2022, 23960), WORKAROUND_CVE_2022_23960
+add_erratum_entry cortex_a720, ERRATUM(3699561), ERRATA_A720_3699561, NO_APPLY_AT_RESET
+
+check_erratum_ls cortex_a720, ERRATUM(3699561), CPU_REV(0, 2)
+
cpu_reset_func_start cortex_a720
/* Disable speculative loads */
msr SSBS, xzr
diff --git a/lib/cpus/cpu-ops.mk b/lib/cpus/cpu-ops.mk
index 0e5e24c..68a50fc 100644
--- a/lib/cpus/cpu-ops.mk
+++ b/lib/cpus/cpu-ops.mk
@@ -1010,12 +1010,17 @@
# to revisions r0p0 and r0p1. It is fixed in r0p2.
CPU_FLAG_LIST += ERRATA_A720_2940794
+# Flag to apply erratum 3699561 workaround during context save/restore of
+# ICH_VMCR_EL2 reg. This erratum applies to revisions r0p0, r0p1, r0p2 of
+# the Cortex-A720 cpu and is still open.
+CPU_FLAG_LIST += ERRATA_A720_3699561
+
# Flag to apply DSU erratum 798953. This erratum applies to DSUs revision r0p0.
# Applying the workaround results in higher DSU power consumption on idle.
CPU_FLAG_LIST += ERRATA_DSU_798953
# Flag to apply DSU erratum 936184. This erratum applies to DSUs containing
-# the ACP interface and revision < r2p0. Applying the workaround results in
+# the ACP interface and revision < r0p0. Applying the workaround results in
# higher DSU power consumption on idle.
CPU_FLAG_LIST += ERRATA_DSU_936184
diff --git a/lib/cpus/errata_common.c b/lib/cpus/errata_common.c
index 08f8786..e5d14d5 100644
--- a/lib/cpus/errata_common.c
+++ b/lib/cpus/errata_common.c
@@ -12,6 +12,7 @@
#include <cortex_a520.h>
#include <cortex_a710.h>
#include <cortex_a715.h>
+#include <cortex_a720.h>
#include <cortex_x4.h>
#include <lib/cpus/cpu_ops.h>
#include <lib/cpus/errata.h>
@@ -60,6 +61,13 @@
break;
#endif /* ERRATA_A715_3699560 */
+#if ERRATA_A720_3699561
+ case EXTRACT_PARTNUM(CORTEX_A720_MIDR):
+ if (check_erratum_cortex_a720_3699561(cpu_get_rev_var()) == ERRATA_APPLIES)
+ return true;;
+ break;
+#endif /* ERRATA_A720_3699561 */
+
default:
break;
}