Workaround for Cortex A78 erratum 1941498
Cortex A78 erratum 1941498 is a Cat B erratum that applies to revisions
r0p0, r1p0, and r1p1. The workaround is to set bit 8 in the ECTLR_EL1
register, there is a small performance cost (<0.5%) for setting this bit.
SDEN can be found here:
https://documentation-service.arm.com/static/5fb66157ca04df4095c1cc2e
Signed-off-by: John Powell <john.powell@arm.com>
Change-Id: I959cee8e3d46c1b84ff5e4409ce5945e459cc6a9
diff --git a/lib/cpus/aarch64/cortex_a78.S b/lib/cpus/aarch64/cortex_a78.S
index 9914f12..ef760ed 100644
--- a/lib/cpus/aarch64/cortex_a78.S
+++ b/lib/cpus/aarch64/cortex_a78.S
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2019-2020, ARM Limited. All rights reserved.
+ * Copyright (c) 2019-2021, ARM Limited. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
@@ -31,7 +31,7 @@
bl check_errata_1688305
cbz x0, 1f
mrs x1, CORTEX_A78_ACTLR2_EL1
- orr x1, x1, CORTEX_A78_ACTLR2_EL1_BIT_1
+ orr x1, x1, #CORTEX_A78_ACTLR2_EL1_BIT_1
msr CORTEX_A78_ACTLR2_EL1, x1
isb
1:
@@ -44,6 +44,34 @@
b cpu_rev_var_ls
endfunc check_errata_1688305
+ /* --------------------------------------------------
+ * Errata Workaround for Cortex A78 Errata #1941498.
+ * This applies to revisions r0p0, r1p0, and r1p1.
+ * x0: variant[4:7] and revision[0:3] of current cpu.
+ * Shall clobber: x0-x17
+ * --------------------------------------------------
+ */
+func errata_a78_1941498_wa
+ /* Compare x0 against revision <= r1p1 */
+ mov x17, x30
+ bl check_errata_1941498
+ cbz x0, 1f
+
+ /* Set bit 8 in ECTLR_EL1 */
+ mrs x1, CORTEX_A78_CPUECTLR_EL1
+ orr x1, x1, #CORTEX_A78_CPUECTLR_EL1_BIT_8
+ msr CORTEX_A78_CPUECTLR_EL1, x1
+ isb
+1:
+ ret x17
+endfunc errata_a78_1941498_wa
+
+func check_errata_1941498
+ /* Check for revision <= r1p1, might need to be updated later. */
+ mov x1, #0x11
+ b cpu_rev_var_ls
+endfunc check_errata_1941498
+
/* -------------------------------------------------
* The CPU Ops reset function for Cortex-A78
* -------------------------------------------------
@@ -58,6 +86,11 @@
bl errata_a78_1688305_wa
#endif
+#if ERRATA_A78_1941498
+ mov x0, x18
+ bl errata_a78_1941498_wa
+#endif
+
#if ENABLE_AMU
/* Make sure accesses from EL0/EL1 and EL2 are not trapped to EL3 */
mrs x0, actlr_el3
@@ -113,6 +146,7 @@
* checking functions of each errata.
*/
report_errata ERRATA_A78_1688305, cortex_a78, 1688305
+ report_errata ERRATA_A78_1941498, cortex_a78, 1941498
ldp x8, x30, [sp], #16
ret
diff --git a/lib/cpus/cpu-ops.mk b/lib/cpus/cpu-ops.mk
index da0157f..b7dec0b 100644
--- a/lib/cpus/cpu-ops.mk
+++ b/lib/cpus/cpu-ops.mk
@@ -1,5 +1,5 @@
#
-# Copyright (c) 2014-2020, ARM Limited and Contributors. All rights reserved.
+# Copyright (c) 2014-2021, ARM Limited and Contributors. All rights reserved.
# Copyright (c) 2020, NVIDIA Corporation. All rights reserved.
#
# SPDX-License-Identifier: BSD-3-Clause
@@ -294,6 +294,10 @@
# to revisions r0p0 - r1p0 of the A78 cpu.
ERRATA_A78_1688305 ?=0
+# Flag to apply erratum 1941498 workaround during reset. This erratum applies
+# to revisions r0p0, r1p0, and r1p1 of the A78 cpu.
+ERRATA_A78_1941498 ?=0
+
# Flag to apply T32 CLREX workaround during reset. This erratum applies
# only to r0p0 and r1p0 of the Neoverse N1 cpu.
ERRATA_N1_1043202 ?=0
@@ -575,6 +579,10 @@
$(eval $(call assert_boolean,ERRATA_A78_1688305))
$(eval $(call add_define,ERRATA_A78_1688305))
+# Process ERRATA_A78_1941498 flag
+$(eval $(call assert_boolean,ERRATA_A78_1941498))
+$(eval $(call add_define,ERRATA_A78_1941498))
+
# Process ERRATA_N1_1043202 flag
$(eval $(call assert_boolean,ERRATA_N1_1043202))
$(eval $(call add_define,ERRATA_N1_1043202))