fix(errata): workaround for Neoverse-N2 erratum 2376738
Neoverse-N2 erratum 2376738 is a Cat B erratum that applies
to revision r0p0 of the CPU. It is fixed in r0p1. The workaround
is to set CPUACTLR2_EL1[0] to 1 to force PLDW/PFRM ST to
behave like PLD/PRFM LD and not cause invalidations to other
PE caches.
SDEN can be found here:
https://developer.arm.com/documentation/SDEN1982442/latest
Signed-off-by: Akram Ahmad <Akram.Ahmad@arm.com>
Change-Id: I4ad4434f9b7210244e67046d9657d218857dced5
diff --git a/lib/cpus/aarch64/neoverse_n2.S b/lib/cpus/aarch64/neoverse_n2.S
index fae3be2..a807b63 100644
--- a/lib/cpus/aarch64/neoverse_n2.S
+++ b/lib/cpus/aarch64/neoverse_n2.S
@@ -338,6 +338,38 @@
b cpu_rev_var_ls
endfunc check_errata_2280757
+
+/* --------------------------------------------------
+ * Errata Workaround for Neoverse N2 Erratum 2376738.
+ * This applies to revision r0p0 of Neoverse N2,
+ * fixed in r0p1.
+ * Inputs:
+ * x0: variant[4:7] and revision[0:3] of current CPU.
+ * Shall clobber: x0-x1, x17
+ * --------------------------------------------------
+ */
+func errata_n2_2376738_wa
+ mov x17, x30
+ bl check_errata_2376738
+ cbz x0, 1f
+
+ /* Set CPUACTLR2_EL1[0] to 1 to force PLDW/PFRM
+ * ST to behave like PLD/PFRM LD and not cause
+ * invalidations to other PE caches.
+ */
+ mrs x1, NEOVERSE_N2_CPUACTLR2_EL1
+ orr x1, x1, NEOVERSE_N2_CPUACTLR2_EL1_BIT_0
+ msr NEOVERSE_N2_CPUACTLR2_EL1, x1
+1:
+ ret x17
+endfunc errata_n2_2376738_wa
+
+func check_errata_2376738
+ /* Applies to r0p0, fixed in r0p1 */
+ mov x1, 0x00
+ b cpu_rev_var_ls
+endfunc check_errata_2376738
+
/* --------------------------------------------------
* Errata Workaround for Neoverse N2 Erratum 2388450.
* This applies to revision r0p0 of Neoverse N2,
@@ -447,6 +479,11 @@
bl errata_n2_2280757_wa
#endif
+#if ERRATA_N2_2376738
+ mov x0, x18
+ bl errata_n2_2376738_wa
+#endif
+
#if ERRATA_N2_2388450
mov x0, x18
bl errata_n2_2388450_wa
@@ -531,6 +568,7 @@
report_errata ERRATA_N2_2138958, neoverse_n2, 2138958
report_errata ERRATA_N2_2242400, neoverse_n2, 2242400
report_errata ERRATA_N2_2280757, neoverse_n2, 2280757
+ report_errata ERRATA_N2_2376738, neoverse_n2, 2376738
report_errata ERRATA_N2_2388450, neoverse_n2, 2388450
report_errata WORKAROUND_CVE_2022_23960, neoverse_n2, cve_2022_23960
report_errata ERRATA_DSU_2313941, neoverse_n2, dsu_2313941
diff --git a/lib/cpus/cpu-ops.mk b/lib/cpus/cpu-ops.mk
index 2ed1c6d..3e5e92a 100644
--- a/lib/cpus/cpu-ops.mk
+++ b/lib/cpus/cpu-ops.mk
@@ -572,6 +572,10 @@
# to revision r0p0 of the Neoverse N2 cpu and is still open.
ERRATA_N2_2280757 ?=0
+# Flag to apply erratum 2376738 workaround during reset. This erratum applies
+# to revision r0p0 of the Neoverse N2 cpu, it is fixed in r0p1.
+ERRATA_N2_2376738 ?=0
+
# Flag to apply erratum 2388450 workaround during reset. This erratum applies
# to revision r0p0 of the Neoverse N2 cpu, it is fixed in r0p1.
ERRATA_N2_2388450 ?=0
@@ -1143,6 +1147,10 @@
$(eval $(call assert_boolean,ERRATA_N2_2280757))
$(eval $(call add_define,ERRATA_N2_2280757))
+# Process ERRATA_N2_2376738 flag
+$(eval $(call assert_boolean,ERRATA_N2_2376738))
+$(eval $(call add_define,ERRATA_N2_2376738))
+
# Process ERRATA_N2_2388450 flag
$(eval $(call assert_boolean,ERRATA_N2_2388450))
$(eval $(call add_define,ERRATA_N2_2388450))