fix(cpus): workaround for Neoverse-N2 erratum 2388450
Neoverse-N2 erratum 2388450 is a cat B erratum that applies to
revision r0p0 and is fixed in r0p1. The workaround is to set
bit[40] of CPUACTLR2_EL1 to disable folding of demand requests into
older prefetches with L2 miss requests outstanding.
SDEN can be found here:
https://developer.arm.com/documentation/SDEN1982442/latest
Change-Id: I6dd949c79cea8dbad322e569aa5de86cf8cf9639
Signed-off-by: Daniel Boulby <daniel.boulby@arm.com>
diff --git a/lib/cpus/aarch64/neoverse_n2.S b/lib/cpus/aarch64/neoverse_n2.S
index 5b796dc..fae3be2 100644
--- a/lib/cpus/aarch64/neoverse_n2.S
+++ b/lib/cpus/aarch64/neoverse_n2.S
@@ -338,6 +338,36 @@
b cpu_rev_var_ls
endfunc check_errata_2280757
+/* --------------------------------------------------
+ * Errata Workaround for Neoverse N2 Erratum 2388450.
+ * 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_2388450_wa
+ /* Check revision. */
+ mov x17, x30
+ bl check_errata_2388450
+ cbz x0, 1f
+
+ /*Set bit 40 in ACTLR2_EL1 */
+ mrs x1, NEOVERSE_N2_CPUACTLR2_EL1
+ orr x1, x1, #NEOVERSE_N2_CPUACTLR2_EL1_BIT_40
+ msr NEOVERSE_N2_CPUACTLR2_EL1, x1
+ isb
+1:
+ ret x17
+endfunc errata_n2_2388450_wa
+
+func check_errata_2388450
+ /* Applies to r0p0, fixed in r0p1 */
+ mov x1, #0x00
+ b cpu_rev_var_ls
+endfunc check_errata_2388450
+
func check_errata_cve_2022_23960
#if WORKAROUND_CVE_2022_23960
mov x0, #ERRATA_APPLIES
@@ -417,6 +447,11 @@
bl errata_n2_2280757_wa
#endif
+#if ERRATA_N2_2388450
+ mov x0, x18
+ bl errata_n2_2388450_wa
+#endif
+
#if ENABLE_AMU
/* Make sure accesses from EL0/EL1 and EL2 are not trapped to EL3 */
mrs x0, cptr_el3
@@ -496,6 +531,7 @@
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_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 6d49dab..5eecdd6 100644
--- a/lib/cpus/cpu-ops.mk
+++ b/lib/cpus/cpu-ops.mk
@@ -556,6 +556,10 @@
# to revision r0p0 of the Neoverse N2 cpu and is still open.
ERRATA_N2_2280757 ?=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
+
# Flag to apply erratum 2002765 workaround during reset. This erratum applies
# to revisions r0p0, r1p0, and r2p0 of the Cortex-X2 cpu and is still open.
ERRATA_X2_2002765 ?=0
@@ -1103,6 +1107,10 @@
$(eval $(call assert_boolean,ERRATA_N2_2280757))
$(eval $(call add_define,ERRATA_N2_2280757))
+# Process ERRATA_N2_2388450 flag
+$(eval $(call assert_boolean,ERRATA_N2_2388450))
+$(eval $(call add_define,ERRATA_N2_2388450))
+
# Process ERRATA_X2_2002765 flag
$(eval $(call assert_boolean,ERRATA_X2_2002765))
$(eval $(call add_define,ERRATA_X2_2002765))