TFTF tests for v8.6 AMU enhancements (FEAT_AMUv1p1)

Not much can be done with the new AMU offsets running at EL2 (virtual
offsets apply at EL0 and EL1) but we can make sure they are being saved
and restored properly, so that's what this patch does.

Signed-off-by: John Powell <john.powell@arm.com>
Change-Id: I5aef85021e875be2109bb9bd7cdbdbe31580394e
diff --git a/lib/extensions/amu/aarch64/amu_helpers.S b/lib/extensions/amu/aarch64/amu_helpers.S
index 061f3fd..b15daf3 100644
--- a/lib/extensions/amu/aarch64/amu_helpers.S
+++ b/lib/extensions/amu/aarch64/amu_helpers.S
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017-2020, Arm Limited. All rights reserved.
+ * Copyright (c) 2017-2021, Arm Limited. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -11,6 +11,12 @@
 	.globl	amu_group0_cnt_read_internal
 	.globl	amu_group1_cnt_read_internal
 
+	/* FEAT_AMUv1p1 virtualisation offset register functions */
+	.globl	amu_group0_voffset_read_internal
+	.globl	amu_group0_voffset_write_internal
+	.globl	amu_group1_voffset_read_internal
+	.globl	amu_group1_voffset_write_internal
+
 /*
  * uint64_t amu_group0_cnt_read_internal(int idx);
  *
@@ -86,3 +92,169 @@
 	read	AMEVCNTR1E_EL0		/* index 14 */
 	read	AMEVCNTR1F_EL0		/* index 15 */
 endfunc amu_group1_cnt_read_internal
+
+/*
+ * Accessor functions for virtual offset registers added with FEAT_AMUv1p1
+ */
+
+/*
+ * uint64_t amu_group0_voffset_read_internal(int idx);
+ *
+ * Given `idx`, read the corresponding AMU virtual offset register
+ * and return it in `x0`.
+ */
+func amu_group0_voffset_read_internal
+	adr	x1, 1f
+#if ENABLE_ASSERTIONS
+	/*
+	 * It can be dangerous to call this function with an
+	 * out of bounds index.  Ensure `idx` is valid.
+	 */
+	tst	x0, #~3
+	ASM_ASSERT(eq)
+	/* Make sure idx != 1 since AMEVCNTVOFF01_EL2 does not exist */
+	cmp	x0, #1
+	ASM_ASSERT(ne)
+#endif
+	/*
+	 * Given `idx` calculate address of mrs/ret instruction pair
+	 * in the table below.
+	 */
+	add	x1, x1, x0, lsl #3	/* each mrs/ret sequence is 8 bytes */
+#if ENABLE_BTI
+	add	x1, x1, x0, lsl #2	/* + "bti j" instruction */
+#endif
+	br	x1
+
+1:	read	AMEVCNTVOFF00_EL2	/* index 0 */
+	.skip	8			/* AMEVCNTVOFF01_EL2 does not exist */
+#if ENABLE_BTI
+	.skip	4			/* Extra space for BTI instruction. */
+#endif
+	read	AMEVCNTVOFF02_EL2	/* index 2 */
+	read	AMEVCNTVOFF03_EL2	/* index 3 */
+endfunc amu_group0_voffset_read_internal
+
+/*
+ * void amu_group0_voffset_write_internal(int idx, uint64_t val);
+ *
+ * Given `idx`, write `val` to the corresponding AMU virtual offset register.
+ */
+func amu_group0_voffset_write_internal
+	adr	x2, 1f
+#if ENABLE_ASSERTIONS
+	/*
+	 * It can be dangerous to call this function with an
+	 * out of bounds index.  Ensure `idx` is valid.
+	 */
+	tst	x0, #~3
+	ASM_ASSERT(eq)
+	/* Make sure idx != 1 since AMEVCNTVOFF01_EL2 does not exist */
+	cmp	x0, #1
+	ASM_ASSERT(ne)
+#endif
+	/*
+	 * Given `idx` calculate address of mrs/ret instruction pair
+	 * in the table below.
+	 */
+	add	x2, x2, x0, lsl #3	/* each msr/ret sequence is 8 bytes */
+#if ENABLE_BTI
+	add	x2, x2, x0, lsl #2	/* + "bti j" instruction */
+#endif
+	br	x2
+
+1:	write	AMEVCNTVOFF00_EL2	/* index 0 */
+	.skip	8			/* AMEVCNTVOFF01_EL2 does not exist */
+#if ENABLE_BTI
+	.skip	4			/* Extra space for BTI instruction. */
+#endif
+	write	AMEVCNTVOFF02_EL2	/* index 2 */
+	write	AMEVCNTVOFF03_EL2	/* index 3 */
+endfunc amu_group0_voffset_write_internal
+
+/*
+ * uint64_t amu_group1_voffset_read_internal(int idx);
+ *
+ * Given `idx`, read the corresponding AMU virtual offset register
+ * and return it in `x0`.
+ */
+func amu_group1_voffset_read_internal
+	adr	x1, 1f
+#if ENABLE_ASSERTIONS
+	/*
+	 * It can be dangerous to call this function with an
+	 * out of bounds index.  Ensure `idx` is valid.
+	 */
+	tst	x0, #~0xF
+	ASM_ASSERT(eq)
+#endif
+	/*
+	 * Given `idx` calculate address of mrs/ret instruction pair
+	 * in the table below.
+	 */
+	add	x1, x1, x0, lsl #3	/* each mrs/ret sequence is 8 bytes */
+#if ENABLE_BTI
+	add	x1, x1, x0, lsl #2	/* + "bti j" instruction */
+#endif
+	br	x1
+
+1:	read	AMEVCNTVOFF10_EL2	/* index 0 */
+	read	AMEVCNTVOFF11_EL2	/* index 1 */
+	read	AMEVCNTVOFF12_EL2	/* index 2 */
+	read	AMEVCNTVOFF13_EL2	/* index 3 */
+	read	AMEVCNTVOFF14_EL2	/* index 4 */
+	read	AMEVCNTVOFF15_EL2	/* index 5 */
+	read	AMEVCNTVOFF16_EL2	/* index 6 */
+	read	AMEVCNTVOFF17_EL2	/* index 7 */
+	read	AMEVCNTVOFF18_EL2	/* index 8 */
+	read	AMEVCNTVOFF19_EL2	/* index 9 */
+	read	AMEVCNTVOFF1A_EL2	/* index 10 */
+	read	AMEVCNTVOFF1B_EL2	/* index 11 */
+	read	AMEVCNTVOFF1C_EL2	/* index 12 */
+	read	AMEVCNTVOFF1D_EL2	/* index 13 */
+	read	AMEVCNTVOFF1E_EL2	/* index 14 */
+	read	AMEVCNTVOFF1F_EL2	/* index 15 */
+endfunc amu_group1_voffset_read_internal
+
+/*
+ * void amu_group1_voffset_write_internal(int idx, uint64_t val);
+ *
+ * Given `idx`, write `val` to the corresponding AMU virtual offset register.
+ */
+func amu_group1_voffset_write_internal
+	adr	x2, 1f
+#if ENABLE_ASSERTIONS
+	/*
+	 * It can be dangerous to call this function with an
+	 * out of bounds index.  Ensure `idx` is valid.
+	 */
+	tst	x0, #~0xF
+	ASM_ASSERT(eq)
+#endif
+	/*
+	 * Given `idx` calculate address of mrs/ret instruction pair
+	 * in the table below.
+	 */
+	add	x2, x2, x0, lsl #3	/* each msr/ret sequence is 8 bytes */
+#if ENABLE_BTI
+	add	x2, x2, x0, lsl #2	/* + "bti j" instruction */
+#endif
+	br	x2
+
+1:	write	AMEVCNTVOFF10_EL2	/* index 0 */
+	write	AMEVCNTVOFF11_EL2	/* index 1 */
+	write	AMEVCNTVOFF12_EL2	/* index 2 */
+	write	AMEVCNTVOFF13_EL2	/* index 3 */
+	write	AMEVCNTVOFF14_EL2	/* index 4 */
+	write	AMEVCNTVOFF15_EL2	/* index 5 */
+	write	AMEVCNTVOFF16_EL2	/* index 6 */
+	write	AMEVCNTVOFF17_EL2	/* index 7 */
+	write	AMEVCNTVOFF18_EL2	/* index 8 */
+	write	AMEVCNTVOFF19_EL2	/* index 9 */
+	write	AMEVCNTVOFF1A_EL2	/* index 10 */
+	write	AMEVCNTVOFF1B_EL2	/* index 11 */
+	write	AMEVCNTVOFF1C_EL2	/* index 12 */
+	write	AMEVCNTVOFF1D_EL2	/* index 13 */
+	write	AMEVCNTVOFF1E_EL2	/* index 14 */
+	write	AMEVCNTVOFF1F_EL2	/* index 15 */
+endfunc amu_group1_voffset_write_internal