fix(errata): workaround for Cortex-A78 erratum 2395406
Cortex-A78 erratum 2395406 is a cat B erratum that applies to revisions
r0p0 - r1p2 and is still open. The workaround is to set bit[40] of
CPUACTLR2 which will disable folding of demand requests into older
prefetches with L2 miss requests outstanding.
SDEN can be found here:
https://developer.arm.com/documentation/SDEN1401784
Signed-off-by: John Powell <john.powell@arm.com>
Change-Id: If06f988f05f925c2a4bed3e6a9414b6acdfec894
diff --git a/docs/design/cpu-specific-build-macros.rst b/docs/design/cpu-specific-build-macros.rst
index 2a47abe..1ad662f 100644
--- a/docs/design/cpu-specific-build-macros.rst
+++ b/docs/design/cpu-specific-build-macros.rst
@@ -300,6 +300,10 @@
CPU. This needs to be enabled for revisions r0p0, r1p0, r1p1, and r1p2, and
it is still open.
+- ``ERRATA_A78_2395406``: This applies errata 2395406 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/lib/cpus/aarch64/cortex_a78.S b/lib/cpus/aarch64/cortex_a78.S
index 53eaa26..be94e91 100644
--- a/lib/cpus/aarch64/cortex_a78.S
+++ b/lib/cpus/aarch64/cortex_a78.S
@@ -295,6 +295,34 @@
b cpu_rev_var_ls
endfunc check_errata_2376745
+/* --------------------------------------------------
+ * Errata Workaround for Cortex A78 Errata 2395406.
+ * 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_2395406_wa
+ /* Check revision. */
+ mov x17, x30
+ bl check_errata_2395406
+ cbz x0, 1f
+
+ /* Apply the workaround. */
+ mrs x1, CORTEX_A78_ACTLR2_EL1
+ orr x1, x1, #BIT(40)
+ msr CORTEX_A78_ACTLR2_EL1, x1
+1:
+ ret x17
+endfunc errata_a78_2395406_wa
+
+func check_errata_2395406
+ /* Applies to r0p0, r0p1, r1p1, and r1p2 */
+ mov x1, #CPU_REV(1, 2)
+ b cpu_rev_var_ls
+endfunc check_errata_2395406
+
func check_errata_cve_2022_23960
#if WORKAROUND_CVE_2022_23960
mov x0, #ERRATA_APPLIES
@@ -353,6 +381,11 @@
bl errata_a78_2376745_wa
#endif
+#if ERRATA_A78_2395406
+ mov x0, x18
+ bl errata_a78_2395406_wa
+#endif
+
#if ENABLE_AMU
/* Make sure accesses from EL0/EL1 and EL2 are not trapped to EL3 */
mrs x0, actlr_el3
@@ -424,6 +457,7 @@
report_errata ERRATA_A78_2132060, cortex_a78, 2132060
report_errata ERRATA_A78_2242635, cortex_a78, 2242635
report_errata ERRATA_A78_2376745, cortex_a78, 2376745
+ report_errata ERRATA_A78_2395406, cortex_a78, 2395406
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 6a3bc17..9185fa1 100644
--- a/lib/cpus/cpu-ops.mk
+++ b/lib/cpus/cpu-ops.mk
@@ -337,6 +337,10 @@
# to revisions r0p0, r1p0, r1p1, and r1p2 of the A78 cpu. It is still open.
ERRATA_A78_2376745 ?=0
+# Flag to apply erratum 2395406 workaround during reset. This erratum applies
+# to revisions r0p0, r1p0, r1p1, and r1p2 of the A78 cpu. It is still open.
+ERRATA_A78_2395406 ?=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
@@ -850,6 +854,10 @@
$(eval $(call assert_boolean,ERRATA_A78_2376745))
$(eval $(call add_define,ERRATA_A78_2376745))
+# Process ERRATA_A78_2395406 flag
+$(eval $(call assert_boolean,ERRATA_A78_2395406))
+$(eval $(call add_define,ERRATA_A78_2395406))
+
# Process ERRATA_A78_AE_1941500 flag
$(eval $(call assert_boolean,ERRATA_A78_AE_1941500))
$(eval $(call add_define,ERRATA_A78_AE_1941500))