1 files changed, 117 insertions, 0 deletions
diff --git a/lib/extensions/pauth/pauth_helpers.S b/lib/extensions/pauth/pauth_helpers.S
new file mode 100644
index 00000000..c6808de5
--- /dev/null
+++ b/lib/extensions/pauth/pauth_helpers.S
@@ -0,0 +1,117 @@
+/*
+ * Copyright (c) 2019, Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <arch.h>
+#include <asm_macros.S>
+#include <lib/el3_runtime/cpu_data.h>
+
+	.global	pauth_init_enable_el1
+	.global	pauth_disable_el1
+	.global	pauth_init_enable_el3
+	.global	pauth_disable_el3
+	.globl	pauth_load_bl31_apiakey
+
+/* -------------------------------------------------------------
+ * Program APIAKey_EL1 and enable pointer authentication in EL1
+ * -------------------------------------------------------------
+ */
+func pauth_init_enable_el1
+	stp	x29, x30, [sp, #-16]!
+
+	/* Initialize platform key */
+	bl	plat_init_apkey
+
+	/* Program instruction key A used by the Trusted Firmware */
+	msr	APIAKeyLo_EL1, x0
+	msr	APIAKeyHi_EL1, x1
+
+	/* Enable pointer authentication */
+	mrs	x0, sctlr_el1
+	orr	x0, x0, #SCTLR_EnIA_BIT
+
+#if ENABLE_BTI
+	 /* Enable PAC branch type compatibility */
+	bic	x0, x0, #(SCTLR_BT0_BIT | SCTLR_BT1_BIT)
+#endif
+	msr	sctlr_el1, x0
+	isb
+
+	ldp	x29, x30, [sp], #16
+	ret
+endfunc pauth_init_enable_el1
+
+/* -------------------------------------------------------------
+ * Disable pointer authentication in EL3
+ * -------------------------------------------------------------
+ */
+func pauth_disable_el1
+	mrs	x0, sctlr_el1
+	bic	x0, x0, #SCTLR_EnIA_BIT
+	msr	sctlr_el1, x0
+	isb
+	ret
+endfunc pauth_disable_el1
+
+/* -------------------------------------------------------------
+ * Program APIAKey_EL1 and enable pointer authentication in EL3
+ * -------------------------------------------------------------
+ */
+func pauth_init_enable_el3
+	stp	x29, x30, [sp, #-16]!
+
+	/* Initialize platform key */
+	bl	plat_init_apkey
+
+	/* Program instruction key A used by the Trusted Firmware */
+	msr	APIAKeyLo_EL1, x0
+	msr	APIAKeyHi_EL1, x1
+
+	/* Enable pointer authentication */
+	mrs	x0, sctlr_el3
+	orr	x0, x0, #SCTLR_EnIA_BIT
+
+#if ENABLE_BTI
+	 /* Enable PAC branch type compatibility */
+	bic	x0, x0, #SCTLR_BT_BIT
+#endif
+	msr	sctlr_el3, x0
+	isb
+
+	ldp	x29, x30, [sp], #16
+	ret
+endfunc pauth_init_enable_el3
+
+/* -------------------------------------------------------------
+ * Disable pointer authentication in EL3
+ * -------------------------------------------------------------
+ */
+func pauth_disable_el3
+	mrs	x0, sctlr_el3
+	bic	x0, x0, #SCTLR_EnIA_BIT
+	msr	sctlr_el3, x0
+	isb
+	ret
+endfunc pauth_disable_el3
+
+/* -------------------------------------------------------------
+ * The following function strictly follows the AArch64 PCS
+ * to use x9-x17 (temporary caller-saved registers) to load
+ * the APIAKey_EL1 used by the firmware.
+ * -------------------------------------------------------------
+ */
+func pauth_load_bl31_apiakey
+	/* tpidr_el3 contains the address of cpu_data structure */
+	mrs	x9, tpidr_el3
+
+	/* Load apiakey from cpu_data */
+	ldp	x10, x11, [x9, #CPU_DATA_APIAKEY_OFFSET]
+
+	/* Program instruction key A */
+	msr	APIAKeyLo_EL1, x10
+	msr	APIAKeyHi_EL1, x11
+	isb
+	ret
+endfunc pauth_load_bl31_apiakey