fix(cpus): workaround for Cortex-X3 erratum 2779509

Cortex-X3 erratum 2779509 is a Cat B erratum that applies to
all revisions <= r1p1 and is fixed in r1p2. The workaround is
to set chicken bit CPUACTLR3_EL1[47], this might have a small
impact on power and has negligible impact on performance.

SDEN documentation:
https://developer.arm.com/documentation/2055130/latest

Change-Id: Id92dbae6f1f313b133ffaa018fbf9c078da55d75
Signed-off-by: Sona Mathew <sonarebecca.mathew@arm.com>

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

@@ -759,6 +759,10 @@ For Cortex-X3, the following errata build flags are defined :
   Cortex-X3 CPU. This needs to be enabled only for revisions r0p0, r1p0 and
   r1p1. It is fixed in r1p2.
 
+- ``ERRATA_X3_2779509``: This applies errata 2779509 workaround to Cortex-X3
+  CPU. This needs to be enabled only for revisions r0p0, r1p0 and r1p1 of the
+  CPU. It is fixed in r1p2.
+
 For Cortex-A510, the following errata build flags are defined :
 
 -  ``ERRATA_A510_1922240``: This applies errata 1922240 workaround to

include/lib/cpus/aarch64/cortex_x3.h

@@ -47,4 +47,10 @@
 #define CORTEX_X3_CPUECTLR2_EL1_PF_MODE_WIDTH	U(4)
 #define CORTEX_X3_CPUECTLR2_EL1_PF_MODE_CNSRV	ULL(0x9)
 
+/*******************************************************************************
+ * CPU Auxiliary Control register 3 specific definitions.
+ ******************************************************************************/
+#define CORTEX_X3_CPUACTLR3_EL1			S3_0_C15_C1_2
+#define CORTEX_X3_CPUACTLR3_EL1_BIT_47		(ULL(1) << 47)
+
 #endif /* CORTEX_X3_H */

lib/cpus/aarch64/cortex_x3.S

@@ -57,6 +57,13 @@ workaround_reset_end cortex_x3, ERRATUM(2742421)
 
 check_erratum_ls cortex_x3, ERRATUM(2742421), CPU_REV(1, 1)
 
+workaround_reset_start cortex_x3, ERRATUM(2779509), ERRATA_X3_2779509
+	/* Set CPUACTLR3_EL1 bit 47 */
+	sysreg_bit_set CORTEX_X3_CPUACTLR3_EL1, CORTEX_X3_CPUACTLR3_EL1_BIT_47
+workaround_reset_end cortex_x3, ERRATUM(2779509)
+
+check_erratum_ls cortex_x3, ERRATUM(2779509), CPU_REV(1, 1)
+
 workaround_reset_start cortex_x3, CVE(2022, 23960), WORKAROUND_CVE_2022_23960
 #if IMAGE_BL31
 	override_vector_table wa_cve_vbar_cortex_x3

lib/cpus/cpu-ops.mk

@@ -769,6 +769,10 @@ CPU_FLAG_LIST += ERRATA_X3_2615812
 # to revisions r0p0, r1p0 and r1p1 of the Cortex-X3 cpu, it is fixed in r1p2.
 CPU_FLAG_LIST += ERRATA_X3_2742421
 
+# Flag to apply erratum 2779509 workaround on reset. This erratum applies
+# to revisions r0p0, r1p0, r1p1 of the Cortex-X3 cpu, it is fixed in r1p2.
+CPU_FLAG_LIST += ERRATA_X3_2779509
+
 # Flag to apply erratum 1922240 workaround during reset. This erratum applies
 # to revision r0p0 of the Cortex-A510 cpu and is fixed in r0p1.
 CPU_FLAG_LIST += ERRATA_A510_1922240

services/std_svc/errata_abi/errata_abi_main.c

@@ -443,7 +443,8 @@ struct em_cpu_list cpu_list[] = {
 		[1] = {2313909, 0x00, 0x10, ERRATA_X3_2313909},
 		[2] = {2615812, 0x00, 0x11, ERRATA_X3_2615812},
 		[3] = {2742421, 0x00, 0x11, ERRATA_X3_2742421},
-		[4 ... ERRATA_LIST_END] = UNDEF_ERRATA,
+		[4] = {2779509, 0x00, 0x11, ERRATA_X3_2779509},
+		[5 ... ERRATA_LIST_END] = UNDEF_ERRATA,
 	}
 },
 #endif /* CORTEX_X3_H_INC */