Merge "fix(errata): workaround for Neoverse-N2 erratum 2376738" into integration

docs/design/cpu-specific-build-macros.rst

@@ -516,6 +516,10 @@ For Neoverse N2, the following errata build flags are defined :
 -  ``ERRATA_N2_2280757``: This applies errata 2280757 workaround to Neoverse-N2
    CPU. This needs to be enabled for revision r0p0 of the CPU and is still open.
 
+-  ``ERRATA_N2_2376738``: This applies errata 2376738 workaround to Neoverse-N2
+   CPU. This needs to be enabled for revision r0p0 of the CPU, it is fixed in
+   r0p1.
+
 -  ``ERRATA_N2_2388450``: This applies errata 2388450 workaround to Neoverse-N2
    CPU. This needs to be enabled for revision r0p0 of the CPU, it is fixed in
    r0p1.

include/lib/cpus/aarch64/neoverse_n2.h

@@ -37,6 +37,7 @@
  * CPU Auxiliary Control register 2 specific definitions.
  ******************************************************************************/
 #define NEOVERSE_N2_CPUACTLR2_EL1			S3_0_C15_C1_1
+#define NEOVERSE_N2_CPUACTLR2_EL1_BIT_0			(ULL(1) << 0)
 #define NEOVERSE_N2_CPUACTLR2_EL1_BIT_2			(ULL(1) << 2)
 #define NEOVERSE_N2_CPUACTLR2_EL1_BIT_40		(ULL(1) << 40)
 

lib/cpus/aarch64/neoverse_n2.S

@@ -338,6 +338,38 @@ func check_errata_2280757
 	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 @@ func neoverse_n2_reset_func
 	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 @@ func neoverse_n2_errata_report
 	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

lib/cpus/cpu-ops.mk

@@ -572,6 +572,10 @@ ERRATA_N2_2242400	?=0
 # 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 add_define,ERRATA_N2_2242400))
 $(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))