Add workaround for errata 764081 of Cortex-A75
Implicit Error Synchronization Barrier (IESB) might not be correctly
generated in Cortex-A75 r0p0. To prevent this, IESB are enabled at all
expection levels.
Change-Id: I2a1a568668a31e4f3f38d0fba1d632ad9939e5ad
Signed-off-by: Louis Mayencourt <louis.mayencourt@arm.com>
diff --git a/docs/cpu-specific-build-macros.rst b/docs/cpu-specific-build-macros.rst
index d417521..dbb1856 100644
--- a/docs/cpu-specific-build-macros.rst
+++ b/docs/cpu-specific-build-macros.rst
@@ -137,6 +137,11 @@
- ``ERRATA_A73_855423``: This applies errata 855423 workaround to Cortex-A73
CPU. This needs to be enabled only for revision <= r0p1 of the CPU.
+For Cortex-A75, the following errata build flags are defined :
+
+- ``ERRATA_A75_764081``: This applies errata 764081 workaround to Cortex-A75
+ CPU. This needs to be enabled only for revision r0p0 of the CPU.
+
DSU Errata Workarounds
----------------------
diff --git a/include/arch/aarch64/arch.h b/include/arch/aarch64/arch.h
index 76c3e27..45aa077 100644
--- a/include/arch/aarch64/arch.h
+++ b/include/arch/aarch64/arch.h
@@ -255,6 +255,7 @@
#define SCTLR_NTWE_BIT (ULL(1) << 18)
#define SCTLR_WXN_BIT (ULL(1) << 19)
#define SCTLR_UWXN_BIT (ULL(1) << 20)
+#define SCTLR_IESB_BIT (ULL(1) << 21)
#define SCTLR_E0E_BIT (ULL(1) << 24)
#define SCTLR_EE_BIT (ULL(1) << 25)
#define SCTLR_UCI_BIT (ULL(1) << 26)
diff --git a/lib/cpus/aarch64/cortex_a75.S b/lib/cpus/aarch64/cortex_a75.S
index e121b7d..8d04294 100644
--- a/lib/cpus/aarch64/cortex_a75.S
+++ b/lib/cpus/aarch64/cortex_a75.S
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2017-2018, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2017-2019, ARM Limited and Contributors. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
@@ -10,8 +10,46 @@
#include <cpuamu.h>
#include <cpu_macros.S>
+ /* --------------------------------------------------
+ * Errata Workaround for Cortex A75 Errata #764081.
+ * This applies only to revision r0p0 of Cortex A75.
+ * Inputs:
+ * x0: variant[4:7] and revision[0:3] of current cpu.
+ * Shall clobber: x0-x17
+ * --------------------------------------------------
+ */
+func errata_a75_764081_wa
+ /*
+ * Compare x0 against revision r0p0
+ */
+ mov x17, x30
+ bl check_errata_764081
+ cbz x0, 1f
+ mrs x1, sctlr_el3
+ orr x1, x1 ,#SCTLR_IESB_BIT
+ msr sctlr_el3, x1
+ isb
+1:
+ ret x17
+endfunc errata_a75_764081_wa
+
+func check_errata_764081
+ mov x1, #0x00
+ b cpu_rev_var_ls
+endfunc check_errata_764081
+
+ /* -------------------------------------------------
+ * The CPU Ops reset function for Cortex-A75.
+ * -------------------------------------------------
+ */
func cortex_a75_reset_func
mov x19, x30
+ bl cpu_get_rev_var
+
+#if ERRATA_A75_764081
+ bl errata_a75_764081_wa
+#endif
+
#if IMAGE_BL31 && WORKAROUND_CVE_2017_5715
cpu_check_csv2 x0, 1f
adr x0, wa_cve_2017_5715_bpiall_vbar
@@ -109,6 +147,7 @@
* Report all errata. The revision-variant information is passed to
* checking functions of each errata.
*/
+ report_errata ERRATA_A75_764081, cortex_a75, 764081
report_errata WORKAROUND_CVE_2017_5715, cortex_a75, cve_2017_5715
report_errata WORKAROUND_CVE_2018_3639, cortex_a75, cve_2018_3639
report_errata ERRATA_DSU_936184, cortex_a75, dsu_936184
diff --git a/lib/cpus/cpu-ops.mk b/lib/cpus/cpu-ops.mk
index a9c6fda..be7d3bd 100644
--- a/lib/cpus/cpu-ops.mk
+++ b/lib/cpus/cpu-ops.mk
@@ -123,6 +123,10 @@
# only to revision <= r0p1 of the Cortex A73 cpu.
ERRATA_A73_855423 ?=0
+# Flag to apply erratum 764081 workaround during reset. This erratum applies
+# only to revision <= r0p0 of the Cortex A75 cpu.
+ERRATA_A75_764081 ?=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 ?=1
@@ -196,6 +200,10 @@
$(eval $(call assert_boolean,ERRATA_A73_855423))
$(eval $(call add_define,ERRATA_A73_855423))
+# Process ERRATA_A75_764081 flag
+$(eval $(call assert_boolean,ERRATA_A75_764081))
+$(eval $(call add_define,ERRATA_A75_764081))
+
# Process ERRATA_N1_1043202 flag
$(eval $(call assert_boolean,ERRATA_N1_1043202))
$(eval $(call add_define,ERRATA_N1_1043202))
diff --git a/lib/el3_runtime/aarch64/context_mgmt.c b/lib/el3_runtime/aarch64/context_mgmt.c
index b956491..0a72aeb 100644
--- a/lib/el3_runtime/aarch64/context_mgmt.c
+++ b/lib/el3_runtime/aarch64/context_mgmt.c
@@ -173,6 +173,14 @@
| SCTLR_NTWI_BIT | SCTLR_NTWE_BIT;
}
+#if ERRATA_A75_764081
+ /*
+ * If workaround of errata 764081 for Cortex-A75 is used then set
+ * SCTLR_EL1.IESB to enable Implicit Error Synchronization Barrier.
+ */
+ sctlr_elx |= SCTLR_IESB_BIT;
+#endif
+
/*
* Store the initialised SCTLR_EL1 value in the cpu_context - SCTLR_EL2
* and other EL2 registers are set up by cm_prepare_ns_entry() as they
@@ -305,6 +313,14 @@
CTX_SCTLR_EL1);
sctlr_elx &= SCTLR_EE_BIT;
sctlr_elx |= SCTLR_EL2_RES1;
+#if ERRATA_A75_764081
+ /*
+ * If workaround of errata 764081 for Cortex-A75 is used
+ * then set SCTLR_EL2.IESB to enable Implicit Error
+ * Synchronization Barrier.
+ */
+ sctlr_elx |= SCTLR_IESB_BIT;
+#endif
write_sctlr_el2(sctlr_elx);
} else if (el_implemented(2) != EL_IMPL_NONE) {
el2_unused = true;