fix(security): workaround for CVE-2022-23960

Implements the loop workaround for Cortex Makalu/Makalu-ELP/Hunter
and Neoverse Demeter/Poseidon.

Signed-off-by: Bipin Ravi <bipin.ravi@arm.com>
Change-Id: If5f6689b662ecac92491e0c0902df4270051ce5b
diff --git a/include/lib/cpus/aarch64/cortex_hunter.h b/include/lib/cpus/aarch64/cortex_hunter.h
index 8b59fd9..24bd217 100644
--- a/include/lib/cpus/aarch64/cortex_hunter.h
+++ b/include/lib/cpus/aarch64/cortex_hunter.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021, Arm Limited. All rights reserved.
+ * Copyright (c) 2021-2022, Arm Limited. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -9,6 +9,9 @@
 
 #define CORTEX_HUNTER_MIDR					U(0x410FD810)
 
+/* Cortex Hunter loop count for CVE-2022-23960 mitigation */
+#define CORTEX_HUNTER_BHB_LOOP_COUNT				U(132)
+
 /*******************************************************************************
  * CPU Extended Control register specific definitions
  ******************************************************************************/
diff --git a/include/lib/cpus/aarch64/cortex_makalu.h b/include/lib/cpus/aarch64/cortex_makalu.h
index 4e0dc86..ee59657 100644
--- a/include/lib/cpus/aarch64/cortex_makalu.h
+++ b/include/lib/cpus/aarch64/cortex_makalu.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021, Arm Limited. All rights reserved.
+ * Copyright (c) 2021-2022, Arm Limited. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -9,6 +9,9 @@
 
 #define CORTEX_MAKALU_MIDR					U(0x410FD4D0)
 
+/* Cortex Makalu loop count for CVE-2022-23960 mitigation */
+#define CORTEX_MAKALU_BHB_LOOP_COUNT				U(38)
+
 /*******************************************************************************
  * CPU Extended Control register specific definitions
  ******************************************************************************/
diff --git a/include/lib/cpus/aarch64/cortex_makalu_elp_arm.h b/include/lib/cpus/aarch64/cortex_makalu_elp_arm.h
index a0d788e..9ed5ee3 100644
--- a/include/lib/cpus/aarch64/cortex_makalu_elp_arm.h
+++ b/include/lib/cpus/aarch64/cortex_makalu_elp_arm.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021, Arm Limited. All rights reserved.
+ * Copyright (c) 2021-2022, Arm Limited. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -9,6 +9,9 @@
 
 #define CORTEX_MAKALU_ELP_ARM_MIDR				U(0x410FD4E0)
 
+/* Cortex Makalu ELP loop count for CVE-2022-23960 mitigation */
+#define CORTEX_MAKALU_ELP_ARM_BHB_LOOP_COUNT			U(132)
+
 /*******************************************************************************
  * CPU Extended Control register specific definitions
  ******************************************************************************/
diff --git a/include/lib/cpus/aarch64/neoverse_demeter.h b/include/lib/cpus/aarch64/neoverse_demeter.h
index 230ed66..f1afae7 100644
--- a/include/lib/cpus/aarch64/neoverse_demeter.h
+++ b/include/lib/cpus/aarch64/neoverse_demeter.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021, Arm Limited. All rights reserved.
+ * Copyright (c) 2021-2022, Arm Limited. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -9,6 +9,9 @@
 
 #define NEOVERSE_DEMETER_MIDR				U(0x410FD4F0)
 
+/* Neoverse Demeter loop count for CVE-2022-23960 mitigation */
+#define NEOVERSE_DEMETER_BHB_LOOP_COUNT			U(132)
+
 /*******************************************************************************
  * CPU Extended Control register specific definitions
  ******************************************************************************/
diff --git a/include/lib/cpus/aarch64/neoverse_poseidon.h b/include/lib/cpus/aarch64/neoverse_poseidon.h
index 0a8b1d1..798ecd1 100644
--- a/include/lib/cpus/aarch64/neoverse_poseidon.h
+++ b/include/lib/cpus/aarch64/neoverse_poseidon.h
@@ -10,6 +10,9 @@
 
 #define NEOVERSE_POSEIDON_MIDR                      		U(0x410FD830)
 
+/* Neoverse Poseidon loop count for CVE-2022-23960 mitigation */
+#define NEOVERSE_POSEIDON_BHB_LOOP_COUNT			U(132)
+
 /*******************************************************************************
  * CPU Extended Control register specific definitions.
  ******************************************************************************/
diff --git a/lib/cpus/aarch64/cortex_hunter.S b/lib/cpus/aarch64/cortex_hunter.S
index 2ab4296..973637e 100644
--- a/lib/cpus/aarch64/cortex_hunter.S
+++ b/lib/cpus/aarch64/cortex_hunter.S
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021, Arm Limited. All rights reserved.
+ * Copyright (c) 2021-2022, Arm Limited. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -10,6 +10,7 @@
 #include <cortex_hunter.h>
 #include <cpu_macros.S>
 #include <plat_macros.S>
+#include "wa_cve_2022_23960_bhb_vector.S"
 
 /* Hardware handled coherency */
 #if HW_ASSISTED_COHERENCY == 0
@@ -21,9 +22,32 @@
 #error "Cortex Hunter supports only AArch64. Compile with CTX_INCLUDE_AARCH32_REGS=0"
 #endif
 
+#if WORKAROUND_CVE_2022_23960
+        wa_cve_2022_23960_bhb_vector_table CORTEX_HUNTER_BHB_LOOP_COUNT, cortex_hunter
+#endif /* WORKAROUND_CVE_2022_23960 */
+
+func check_errata_cve_2022_23960
+#if WORKAROUND_CVE_2022_23960
+	mov	x0, #ERRATA_APPLIES
+#else
+	mov	x0, #ERRATA_MISSING
+#endif
+	ret
+endfunc check_errata_cve_2022_23960
+
 func cortex_hunter_reset_func
 	/* Disable speculative loads */
 	msr	SSBS, xzr
+
+#if IMAGE_BL31 && WORKAROUND_CVE_2022_23960
+	/*
+	 * The Cortex Hunter generic vectors are overridden to apply errata
+	 * mitigation on exception entry from lower ELs.
+	 */
+	adr	x0, wa_cve_vbar_cortex_hunter
+	msr	vbar_el3, x0
+#endif /* IMAGE_BL31 && WORKAROUND_CVE_2022_23960 */
+
 	isb
 	ret
 endfunc cortex_hunter_reset_func
@@ -49,6 +73,18 @@
  * Errata printing function for Cortex Hunter. Must follow AAPCS.
  */
 func cortex_hunter_errata_report
+	stp	x8, x30, [sp, #-16]!
+
+	bl	cpu_get_rev_var
+	mov	x8, x0
+
+	/*
+	 * Report all errata. The revision-variant information is passed to
+	 * checking functions of each errata.
+	 */
+	report_errata WORKAROUND_CVE_2022_23960, cortex_hunter, cve_2022_23960
+
+	ldp	x8, x30, [sp], #16
 	ret
 endfunc cortex_hunter_errata_report
 #endif
diff --git a/lib/cpus/aarch64/cortex_makalu.S b/lib/cpus/aarch64/cortex_makalu.S
index 98c7d6d..7603210 100644
--- a/lib/cpus/aarch64/cortex_makalu.S
+++ b/lib/cpus/aarch64/cortex_makalu.S
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021, Arm Limited. All rights reserved.
+ * Copyright (c) 2021-2022, Arm Limited. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -10,6 +10,7 @@
 #include <cortex_makalu.h>
 #include <cpu_macros.S>
 #include <plat_macros.S>
+#include "wa_cve_2022_23960_bhb_vector.S"
 
 /* Hardware handled coherency */
 #if HW_ASSISTED_COHERENCY == 0
@@ -21,9 +22,32 @@
 #error "Cortex Makalu supports only AArch64. Compile with CTX_INCLUDE_AARCH32_REGS=0"
 #endif
 
+#if WORKAROUND_CVE_2022_23960
+	wa_cve_2022_23960_bhb_vector_table CORTEX_MAKALU_BHB_LOOP_COUNT, cortex_makalu
+#endif /* WORKAROUND_CVE_2022_23960 */
+
+func check_errata_cve_2022_23960
+#if WORKAROUND_CVE_2022_23960
+	mov     x0, #ERRATA_APPLIES
+#else
+	mov     x0, #ERRATA_MISSING
+#endif
+	ret
+endfunc check_errata_cve_2022_23960
+
 func cortex_makalu_reset_func
 	/* Disable speculative loads */
 	msr	SSBS, xzr
+
+#if IMAGE_BL31 && WORKAROUND_CVE_2022_23960
+	/*
+	 * The Cortex Makalu generic vectors are overridden to apply errata
+	 * mitigation on exception entry from lower ELs.
+	 */
+        adr	x0, wa_cve_vbar_cortex_makalu
+        msr	vbar_el3, x0
+#endif /* IMAGE_BL31 && WORKAROUND_CVE_2022_23960 */
+
 	isb
 	ret
 endfunc cortex_makalu_reset_func
@@ -49,6 +73,18 @@
  * Errata printing function for Cortex Makalu. Must follow AAPCS.
  */
 func cortex_makalu_errata_report
+	stp	x8, x30, [sp, #-16]!
+
+	bl	cpu_get_rev_var
+	mov	x8, x0
+
+	/*
+	 * Report all errata. The revision-variant information is passed to
+	 * checking functions of each errata.
+	 */
+	report_errata WORKAROUND_CVE_2022_23960, cortex_makalu, cve_2022_23960
+
+	ldp     x8, x30, [sp], #16
 	ret
 endfunc cortex_makalu_errata_report
 #endif
diff --git a/lib/cpus/aarch64/cortex_makalu_elp_arm.S b/lib/cpus/aarch64/cortex_makalu_elp_arm.S
index fbbf205..f4d2df0 100644
--- a/lib/cpus/aarch64/cortex_makalu_elp_arm.S
+++ b/lib/cpus/aarch64/cortex_makalu_elp_arm.S
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021, Arm Limited. All rights reserved.
+ * Copyright (c) 2021-2022, Arm Limited. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -10,6 +10,7 @@
 #include <cortex_makalu_elp_arm.h>
 #include <cpu_macros.S>
 #include <plat_macros.S>
+#include "wa_cve_2022_23960_bhb_vector.S"
 
 /* Hardware handled coherency */
 #if HW_ASSISTED_COHERENCY == 0
@@ -21,6 +22,10 @@
 #error "Cortex Makalu ELP supports only AArch64. Compile with CTX_INCLUDE_AARCH32_REGS=0"
 #endif
 
+#if WORKAROUND_CVE_2022_23960
+	wa_cve_2022_23960_bhb_vector_table CORTEX_MAKALU_ELP_ARM_BHB_LOOP_COUNT, cortex_makalu_elp_arm
+#endif /* WORKAROUND_CVE_2022_23960 */
+
 	/* ----------------------------------------------------
 	 * HW will do the cache maintenance while powering down
 	 * ----------------------------------------------------
@@ -37,22 +42,53 @@
 	ret
 endfunc cortex_makalu_elp_arm_core_pwr_dwn
 
+func check_errata_cve_2022_23960
+#if WORKAROUND_CVE_2022_23960
+	mov	x0, #ERRATA_APPLIES
+#else
+	mov	x0, #ERRATA_MISSING
+#endif
+	ret
+endfunc check_errata_cve_2022_23960
+
+func cortex_makalu_elp_arm_reset_func
+	/* Disable speculative loads */
+	msr	SSBS, xzr
+
+#if IMAGE_BL31 && WORKAROUND_CVE_2022_23960
+	/*
+	 * The Cortex Makalu ELP generic vectors are overridden to apply
+	 * errata mitigation on exception entry from lower ELs.
+         */
+	adr	x0, wa_cve_vbar_cortex_makalu_elp_arm
+	msr	vbar_el3, x0
+#endif /* IMAGE_BL31 && WORKAROUND_CVE_2022_23960 */
+
+	isb
+	ret
+endfunc cortex_makalu_elp_arm_reset_func
+
 #if REPORT_ERRATA
 /*
  * Errata printing function for Cortex Makalu ELP. Must follow AAPCS.
  */
 func cortex_makalu_elp_arm_errata_report
+	stp	x8, x30, [sp, #-16]!
+
+	bl	cpu_get_rev_var
+	mov	x8, x0
+
+	/*
+	 * Report all errata. The revision-variant information is passed to
+	 * checking functions of each errata.
+	 */
+	report_errata WORKAROUND_CVE_2022_23960, cortex_makalu_elp_arm, cve_2022_23960
+
+	ldp	x8, x30, [sp], #16
 	ret
 endfunc cortex_makalu_elp_arm_errata_report
 #endif
 
-func cortex_makalu_elp_arm_reset_func
-	/* Disable speculative loads */
-	msr	SSBS, xzr
-	isb
-	ret
-endfunc cortex_makalu_elp_arm_reset_func
-
 	/* ---------------------------------------------
 	 * This function provides Cortex Makalu ELP-
 	 * specific register information for crash
diff --git a/lib/cpus/aarch64/neoverse_demeter.S b/lib/cpus/aarch64/neoverse_demeter.S
index f43c18b..41cb4ee 100644
--- a/lib/cpus/aarch64/neoverse_demeter.S
+++ b/lib/cpus/aarch64/neoverse_demeter.S
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021, Arm Limited. All rights reserved.
+ * Copyright (c) 2021-2022, Arm Limited. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -10,6 +10,7 @@
 #include <neoverse_demeter.h>
 #include <cpu_macros.S>
 #include <plat_macros.S>
+#include "wa_cve_2022_23960_bhb_vector.S"
 
 /* Hardware handled coherency */
 #if HW_ASSISTED_COHERENCY == 0
@@ -21,6 +22,10 @@
 #error "Neoverse Demeter supports only AArch64. Compile with CTX_INCLUDE_AARCH32_REGS=0"
 #endif
 
+#if WORKAROUND_CVE_2022_23960
+	wa_cve_2022_23960_bhb_vector_table NEOVERSE_DEMETER_BHB_LOOP_COUNT, neoverse_demeter
+#endif /* WORKAROUND_CVE_2022_23960 */
+
 	/* ----------------------------------------------------
 	 * HW will do the cache maintenance while powering down
 	 * ----------------------------------------------------
@@ -37,22 +42,52 @@
 	ret
 endfunc neoverse_demeter_core_pwr_dwn
 
+func check_errata_cve_2022_23960
+#if WORKAROUND_CVE_2022_23960
+	mov	x0, #ERRATA_APPLIES
+#else
+	mov	x0, #ERRATA_MISSING
+#endif
+	ret
+endfunc check_errata_cve_2022_23960
+
+func neoverse_demeter_reset_func
+	/* Disable speculative loads */
+	msr	SSBS, xzr
+
+#if IMAGE_BL31 && WORKAROUND_CVE_2022_23960
+	/*
+	 * The Neoverse Demeter vectors are overridden to apply
+	 * errata mitigation on exception entry from lower ELs.
+	 */
+	adr	x0, wa_cve_vbar_neoverse_demeter
+	msr	vbar_el3, x0
+#endif /* IMAGE_BL31 && WORKAROUND_CVE_2022_23960 */
+	isb
+	ret
+endfunc neoverse_demeter_reset_func
+
 #if REPORT_ERRATA
 /*
  * Errata printing function for Neoverse Demeter. Must follow AAPCS.
  */
 func neoverse_demeter_errata_report
+	stp	x8, x30, [sp, #-16]!
+
+	bl	cpu_get_rev_var
+	mov	x8, x0
+
+	/*
+	 * Report all errata. The revision-variant information is passed to
+	 * checking functions of each errata.
+	 */
+	report_errata WORKAROUND_CVE_2022_23960, neoverse_demeter, cve_2022_23960
+
+	ldp	x8, x30, [sp], #16
 	ret
 endfunc neoverse_demeter_errata_report
 #endif
 
-func neoverse_demeter_reset_func
-	/* Disable speculative loads */
-	msr	SSBS, xzr
-	isb
-	ret
-endfunc neoverse_demeter_reset_func
-
 	/* ---------------------------------------------
 	 * This function provides Neoverse Demeter-
 	 * specific register information for crash
diff --git a/lib/cpus/aarch64/neoverse_poseidon.S b/lib/cpus/aarch64/neoverse_poseidon.S
index 43a93aa..030293d 100644
--- a/lib/cpus/aarch64/neoverse_poseidon.S
+++ b/lib/cpus/aarch64/neoverse_poseidon.S
@@ -10,6 +10,7 @@
 #include <neoverse_poseidon.h>
 #include <cpu_macros.S>
 #include <plat_macros.S>
+#include "wa_cve_2022_23960_bhb_vector.S"
 
 /* Hardware handled coherency */
 #if HW_ASSISTED_COHERENCY == 0
@@ -21,6 +22,10 @@
 #error "Neoverse Poseidon supports only AArch64. Compile with CTX_INCLUDE_AARCH32_REGS=0"
 #endif
 
+#if WORKAROUND_CVE_2022_23960
+	wa_cve_2022_23960_bhb_vector_table NEOVERSE_POSEIDON_BHB_LOOP_COUNT, neoverse_poseidon
+#endif /* WORKAROUND_CVE_2022_23960 */
+
 	/* ---------------------------------------------
 	 * HW will do the cache maintenance while powering down
 	 * ---------------------------------------------
@@ -37,22 +42,53 @@
 	ret
 endfunc neoverse_poseidon_core_pwr_dwn
 
+func check_errata_cve_2022_23960
+#if WORKAROUND_CVE_2022_23960
+	mov	x0, #ERRATA_APPLIES
+#else
+	mov	x0, #ERRATA_MISSING
+#endif
+	ret
+endfunc check_errata_cve_2022_23960
+
+func neoverse_poseidon_reset_func
+	/* Disable speculative loads */
+	msr	SSBS, xzr
+
+#if IMAGE_BL31 && WORKAROUND_CVE_2022_23960
+	/*
+	 * The Neoverse Poseidon generic vectors are overridden to apply
+	 * errata mitigation on exception entry from lower ELs.
+	 */
+	adr	x0, wa_cve_vbar_neoverse_poseidon
+	msr	vbar_el3, x0
+#endif /* IMAGE_BL31 && WORKAROUND_CVE_2022_23960 */
+
+	isb
+	ret
+endfunc neoverse_poseidon_reset_func
+
 #if REPORT_ERRATA
 	/*
 	 * Errata printing function for Neoverse Poseidon. Must follow AAPCS.
 	 */
 func neoverse_poseidon_errata_report
+	stp	x8, x30, [sp, #-16]!
+
+	bl	cpu_get_rev_var
+	mov	x8, x0
+
+	/*
+	 * Report all errata. The revision-variant information is passed to
+	 * checking functions of each errata.
+	 */
+	report_errata WORKAROUND_CVE_2022_23960, neoverse_poseidon, cve_2022_23960
+
+	ldp	x8, x30, [sp], #16
 	ret
 endfunc neoverse_poseidon_errata_report
 #endif
 
-func neoverse_poseidon_reset_func
-	/* Disable speculative loads */
-	msr	SSBS, xzr
-	isb
-	ret
-endfunc neoverse_poseidon_reset_func
-
 	/* ---------------------------------------------
 	 * This function provides Neoverse-Poseidon specific
 	 * register information for crash reporting.