Merge "fix(errata-abi): add support for handling split workarounds" into integration

include/lib/cpus/aarch64/cpu_macros.S

@@ -235,10 +235,11 @@
  * _chosen:
  *	Compile time flag on whether the erratum is included
  *
- * _apply_at_reset:
+ * _split_wa:
- *	Whether the erratum should be automatically applied at reset
+ *	Flag that indicates whether an erratum has split workaround or not.
+ *	Default value is 0.
  */
-.macro add_erratum_entry _cpu:req, _cve:req, _id:req, _chosen:req
+.macro add_erratum_entry _cpu:req, _cve:req, _id:req, _chosen:req, _split_wa=0
 #if REPORT_ERRATA || ERRATA_ABI_SUPPORT
 	.pushsection .rodata.errata_entries
 		.align	3
@@ -250,7 +251,8 @@
 		/* Will fit CVEs with up to 10 character in the ID field */
 		.word	\_id
 		.hword	\_cve
-		.byte	\_chosen
+		/* bit magic that appends chosen field based on _split_wa */
+		.byte	((\_chosen * 0b11) & ((\_split_wa << 1) | \_chosen))
 		.byte	0x0 /* alignment */
 	.popsection
 #endif
@@ -276,14 +278,20 @@
  * _chosen:
  *	Compile time flag on whether the erratum is included
  *
+ * _split_wa:
+ *	Flag that indicates whether an erratum has split workaround or not.
+ *	Default value is 0.
+ *
  * in body:
  *	clobber x0 to x7 (please only use those)
  *	argument x7 - cpu_rev_var
  *
  * _wa clobbers: x0-x8 (PCS compliant)
  */
-.macro workaround_reset_start _cpu:req, _cve:req, _id:req, _chosen:req
+.macro workaround_reset_start _cpu:req, _cve:req, _id:req, \
-	add_erratum_entry \_cpu, \_cve, \_id, \_chosen
+	_chosen:req, _split_wa=0
+
+	add_erratum_entry \_cpu, \_cve, \_id, \_chosen, \_split_wa
 
 	.if \_chosen
 		/* put errata directly into the reset function */

include/lib/cpus/errata.h

@@ -42,6 +42,12 @@ struct erratum_entry {
 	uint32_t id;
 	/* Denote CVEs with their year or errata with 0 */
 	uint16_t cve;
+	/*
+	 * a bitfield:
+	 * bit 0 - denotes if the erratum is enabled in build.
+	 * bit 1 - denotes if the erratum workaround is split and
+	 * 	   also needs to be implemented at a lower EL.
+	 */
 	uint8_t chosen;
 	uint8_t _alignment;
 } __packed;
@@ -96,4 +102,11 @@ bool errata_ich_vmcr_el2_applies(void);
 /* Macro to get CPU revision code for checking errata version compatibility. */
 #define CPU_REV(r, p)		((r << 4) | p)
 
+/* Used for errata that have split workaround */
+#define SPLIT_WA			1
+
+/* chosen bitfield entries */
+#define WA_ENABLED_MASK			BIT(0)
+#define SPLIT_WA_MASK			BIT(1)
+
 #endif /* ERRATA_H */

lib/cpus/aarch64/neoverse_n1.S

@@ -116,7 +116,7 @@ workaround_reset_end neoverse_n1, ERRATUM(1315703)
 
 check_erratum_ls neoverse_n1, ERRATUM(1315703), CPU_REV(3, 0)
 
-workaround_reset_start neoverse_n1, ERRATUM(1542419), ERRATA_N1_1542419
+workaround_reset_start neoverse_n1, ERRATUM(1542419), ERRATA_N1_1542419, SPLIT_WA
 	/* Apply instruction patching sequence */
 	ldr	x0, =0x0
 	msr	CPUPSELR_EL3, x0

services/std_svc/errata_abi/errata_abi_main.c

@@ -197,8 +197,11 @@ int32_t verify_errata_implemented(uint32_t errata_id, uint32_t forward_flag)
 	while ((entry <= end) && (ret_val == EM_UNKNOWN_ERRATUM)) {
 		if (entry->id == errata_id) {
 			if (entry->check_func(rev_var)) {
-				if (entry->chosen)
+				if (entry->chosen & WA_ENABLED_MASK)
-					return EM_HIGHER_EL_MITIGATION;
+					if (entry->chosen & SPLIT_WA_MASK)
+						return EM_AFFECTED;
+					else
+						return EM_HIGHER_EL_MITIGATION;
 				else
 					return EM_AFFECTED;
 			}