fix(errata): workaround for Cortex-A710 erratum 2267065

Cortex-A710 erratum 2267065 is a Cat B erratum that applies to
revisions r0p0, r1p0 and r2p0 of the CPU. It is fixed in r2p1.
The workaround is to set CPUACTLR_EL1[22] to 1'b1. Setting
CPUACTLR_EL1[22] will cause the CFP instruction to invalidate
all branch predictor resources regardless of context.

SDEN can be found here:
https://developer.arm.com/documentation/SDEN1775101/latest

Signed-off-by: Bipin Ravi <bipin.ravi@arm.com>
Change-Id: Ia9085aaf9b2b6a2b25d03ab36bd3774839fac9aa

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

@@ -409,6 +409,10 @@ For Cortex-A710, the following errata build flags are defined :
    Cortex-A710 CPU. This needs to be enabled for revisions r0p0, r1p0 and r2p0
    of the CPU and is still open.
 
+-  ``ERRATA_A710_2267065``: This applies errata 2267065 workaround to
+   Cortex-A710 CPU. This needs to be enabled for revisions r0p0, r1p0 and r2p0
+   of the CPU and is fixed in r2p1.
+
 For Neoverse N2, the following errata build flags are defined :
 
 -  ``ERRATA_N2_2002655``: This applies errata 2002655 workaround to Neoverse-N2

include/lib/cpus/aarch64/cortex_a710.h

@@ -26,6 +26,7 @@
  ******************************************************************************/
 #define CORTEX_A710_CPUACTLR_EL1 				S3_0_C15_C1_0
 #define CORTEX_A710_CPUACTLR_EL1_BIT_46				(ULL(1) << 46)
+#define CORTEX_A710_CPUACTLR_EL1_BIT_22				(ULL(1) << 22)
 
 /*******************************************************************************
  * CPU Auxiliary Control register specific definitions.

lib/cpus/aarch64/cortex_a710.S

@@ -216,6 +216,35 @@ func check_errata_2058056
 	b	cpu_rev_var_ls
 endfunc check_errata_2058056
 
+/* --------------------------------------------------
+ * Errata Workaround for Cortex-A710 Erratum 2267065.
+ * This applies to revisions r0p0, r1p0 and r2p0.
+ * It is fixed in r2p1.
+ * Inputs:
+ * x0: variant[4:7] and revision[0:3] of current cpu.
+ * Shall clobber: x0-x1, x17
+ * --------------------------------------------------
+ */
+func errata_a710_2267065_wa
+	/* Compare x0 against revision r2p0 */
+	mov	x17, x30
+	bl	check_errata_2267065
+	cbz	x0, 1f
+
+	/* Apply instruction patching sequence */
+	mrs	x1, CORTEX_A710_CPUACTLR_EL1
+	orr	x1, x1, CORTEX_A710_CPUACTLR_EL1_BIT_22
+	msr	CORTEX_A710_CPUACTLR_EL1, x1
+1:
+	ret	x17
+endfunc errata_a710_2267065_wa
+
+func check_errata_2267065
+	/* Applies to r0p0, r1p0 and r2p0 */
+	mov	x1, #0x20
+	b	cpu_rev_var_ls
+endfunc check_errata_2267065
+
 	/* ----------------------------------------------------
 	 * HW will do the cache maintenance while powering down
 	 * ----------------------------------------------------
@@ -252,6 +281,7 @@ func cortex_a710_errata_report
 	report_errata ERRATA_A710_2017096, cortex_a710, 2017096
 	report_errata ERRATA_A710_2083908, cortex_a710, 2083908
 	report_errata ERRATA_A710_2058056, cortex_a710, 2058056
+	report_errata ERRATA_A710_2267065, cortex_a710, 2267065
 
 	ldp	x8, x30, [sp], #16
 	ret
@@ -296,6 +326,12 @@ func cortex_a710_reset_func
 	mov	x0, x18
 	bl	errata_a710_2058056_wa
 #endif
+
+#if ERRATA_A710_2267065
+	mov	x0, x18
+	bl	errata_a710_2267065_wa
+#endif
+
 	isb
 	ret	x19
 endfunc cortex_a710_reset_func

lib/cpus/cpu-ops.mk

@@ -495,6 +495,10 @@ ERRATA_A710_2055002	?=0
 # to revision r0p0, r1p0 and r2p0 of the Cortex-A710 cpu and is still open.
 ERRATA_A710_2017096	?=0
 
+# Flag to apply erratum 2267065 workaround during reset. This erratum applies
+# to revision r0p0, r1p0 and r2p0 of the Cortex-A710 cpu and is fixed in r2p1.
+ERRATA_A710_2267065	?=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
@@ -947,6 +951,10 @@ $(eval $(call add_define,ERRATA_A710_2055002))
 $(eval $(call assert_boolean,ERRATA_A710_2017096))
 $(eval $(call add_define,ERRATA_A710_2017096))
 
+# Process ERRATA_A710_2267065 flag
+$(eval $(call assert_boolean,ERRATA_A710_2267065))
+$(eval $(call add_define,ERRATA_A710_2267065))
+
 # Process ERRATA_X2_2002765 flag
 $(eval $(call assert_boolean,ERRATA_X2_2002765))
 $(eval $(call add_define,ERRATA_X2_2002765))