fix(cpus): workaround for Cortex-A78 erratum 2779479
Cortex-A78 erratum 2779479 is a Cat B erratum that applies to
all revisions <= r1p2 and is still open.
The workaround is to set the CPUACTLR3_EL1[47] bit to 1. Setting this
bit might have a small impact on power and negligible impact
on performance.
SDEN documentation:
https://developer.arm.com/documentation/SDEN1401784/latest
Change-Id: I3779fd1eff3017c5961ffa101b357918070b3b36
Signed-off-by: Sona Mathew <SonaRebecca.Mathew@arm.com>
diff --git a/docs/design/cpu-specific-build-macros.rst b/docs/design/cpu-specific-build-macros.rst
index 8a8445d..4ae4e54 100644
--- a/docs/design/cpu-specific-build-macros.rst
+++ b/docs/design/cpu-specific-build-macros.rst
@@ -321,6 +321,10 @@
CPU. This needs to be enabled for revisions r0p0, r1p0, r1p1, and r1p2, and
it is still open.
+- ``ERRATA_A78_2779479``: This applies erratum 2779479 workaround to Cortex-A78
+ CPU. This needs to be enabled for revisions r0p0, r1p0, r1p1 and r1p2 and
+ it is still open.
+
For Cortex-A78 AE, the following errata build flags are defined :
- ``ERRATA_A78_AE_1941500`` : This applies errata 1941500 workaround to
diff --git a/include/lib/cpus/aarch64/cortex_a78.h b/include/lib/cpus/aarch64/cortex_a78.h
index 31da99e..fb325b6 100644
--- a/include/lib/cpus/aarch64/cortex_a78.h
+++ b/include/lib/cpus/aarch64/cortex_a78.h
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2019-2022, ARM Limited. All rights reserved.
+ * Copyright (c) 2019-2023, ARM Limited. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
@@ -40,6 +40,8 @@
#define CORTEX_A78_ACTLR2_EL1_BIT_2 (ULL(1) << 2)
#define CORTEX_A78_ACTLR2_EL1_BIT_40 (ULL(1) << 40)
+#define CORTEX_A78_ACTLR3_EL1 S3_0_C15_C1_2
+
/*******************************************************************************
* CPU Activity Monitor Unit register specific definitions.
******************************************************************************/
diff --git a/lib/cpus/aarch64/cortex_a78.S b/lib/cpus/aarch64/cortex_a78.S
index 38f58bb..a3932e8 100644
--- a/lib/cpus/aarch64/cortex_a78.S
+++ b/lib/cpus/aarch64/cortex_a78.S
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2019-2022, ARM Limited. All rights reserved.
+ * Copyright (c) 2019-2023, ARM Limited. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
@@ -351,6 +351,35 @@
b cpu_rev_var_ls
endfunc check_errata_2772019
+/* ----------------------------------------------------
+ * Errata Workaround for Cortex A78 Errata 2779479.
+ * This applies to revisions r0p0, r1p0, r1p1, and r1p2.
+ * It is still open.
+ * x0: variant[4:7] and revision[0:3] of current cpu.
+ * Shall clobber: x0-x1, x17
+ * ----------------------------------------------------
+ */
+func errata_a78_2779479_wa
+ /* Check revision. */
+ mov x17, x30
+ bl check_errata_2779479
+ cbz x0, 1f
+
+ /* Apply the workaround */
+ mrs x1, CORTEX_A78_ACTLR3_EL1
+ orr x1, x1, #BIT(47)
+ msr CORTEX_A78_ACTLR3_EL1, x1
+
+1:
+ ret x17
+endfunc errata_a78_2779479_wa
+
+func check_errata_2779479
+ /* Applies to r0p0, r1p0, r1p1, r1p2 */
+ mov x1, #CPU_REV(1, 2)
+ b cpu_rev_var_ls
+endfunc check_errata_2779479
+
func check_errata_cve_2022_23960
#if WORKAROUND_CVE_2022_23960
mov x0, #ERRATA_APPLIES
@@ -414,6 +443,11 @@
bl errata_a78_2395406_wa
#endif
+#if ERRATA_A78_2779479
+ mov x0, x18
+ bl errata_a78_2779479_wa
+#endif
+
#if ENABLE_AMU
/* Make sure accesses from EL0/EL1 and EL2 are not trapped to EL3 */
mrs x0, actlr_el3
@@ -493,6 +527,7 @@
report_errata ERRATA_A78_2376745, cortex_a78, 2376745
report_errata ERRATA_A78_2395406, cortex_a78, 2395406
report_errata ERRATA_A78_2772019, cortex_a78, 2772019
+ report_errata ERRATA_A78_2779479, cortex_a78, 2779479
report_errata WORKAROUND_CVE_2022_23960, cortex_a78, cve_2022_23960
ldp x8, x30, [sp], #16
diff --git a/lib/cpus/cpu-ops.mk b/lib/cpus/cpu-ops.mk
index c9b4447..ae6baa7 100644
--- a/lib/cpus/cpu-ops.mk
+++ b/lib/cpus/cpu-ops.mk
@@ -362,6 +362,10 @@
# open.
ERRATA_A78_2772019 ?=0
+# Flag to apply erratum 2779479 workaround during reset. This erratum applies
+# to revision r0p0, r1p0, r1p1 and r1p2 of the A78 cpu. It is still open.
+ERRATA_A78_2779479 ?=0
+
# Flag to apply erratum 1941500 workaround during reset. This erratum applies
# to revisions r0p0 and r0p1 of the A78 AE cpu. It is still open.
ERRATA_A78_AE_1941500 ?=0
@@ -1030,6 +1034,10 @@
$(eval $(call assert_boolean,ERRATA_A78_2772019))
$(eval $(call add_define,ERRATA_A78_2772019))
+# Process ERRATA_A78_2779479 flag
+$(eval $(call assert_boolean,ERRATA_A78_2779479))
+$(eval $(call add_define,ERRATA_A78_2779479))
+
# Process ERRATA_A78_AE_1941500 flag
$(eval $(call assert_boolean,ERRATA_A78_AE_1941500))
$(eval $(call add_define,ERRATA_A78_AE_1941500))