AMU: Implement support for aarch64

The `ENABLE_AMU` build option can be used to enable the
architecturally defined AMU counters.  At present, there is no support
for the auxiliary counter group.

Change-Id: I7ea0c0a00327f463199d1b0a481f01dadb09d312
Signed-off-by: Dimitris Papastamos <dimitris.papastamos@arm.com>

bl31/bl31.mk

@@ -50,6 +50,10 @@ ifeq (${ENABLE_SPE_FOR_LOWER_ELS},1)
 BL31_SOURCES		+=	lib/extensions/spe/spe.c
 endif
 
+ifeq (${ENABLE_AMU},1)
+BL31_SOURCES		+=	lib/extensions/amu/aarch64/amu.c
+endif
+
 BL31_LINKERFILE		:=	bl31/bl31.ld.S
 
 # Flag used to indicate if Crash reporting via console should be included

docs/user-guide.rst

@@ -322,8 +322,9 @@ Common build options
    details.
 
 -  ``ENABLE_AMU``: Boolean option to enable Activity Monitor Unit extensions.
-   Currently this option only applies for platforms that include a v8.2 processor
-   with AMU implemented. Default is 0.
+   This is an optional architectural feature available on v8.4 onwards. Some
+   v8.2 implementations also implement an AMU and this option can be used to
+   enable this feature on those systems as well. Default is 0.
 
 -  ``ENABLE_ASSERTIONS``: This option controls whether or not calls to ``assert()``
    are compiled out. For debug builds, this option defaults to 1, and calls to

include/lib/aarch64/arch.h

@@ -110,6 +110,9 @@
 #define ID_AA64PFR0_EL1_SHIFT	U(4)
 #define ID_AA64PFR0_EL2_SHIFT	U(8)
 #define ID_AA64PFR0_EL3_SHIFT	U(12)
+#define ID_AA64PFR0_AMU_SHIFT	U(44)
+#define ID_AA64PFR0_AMU_LENGTH	U(4)
+#define ID_AA64PFR0_AMU_MASK	U(0xf)
 #define ID_AA64PFR0_ELX_MASK	U(0xf)
 
 /* ID_AA64DFR0_EL1.PMS definitions (for ARMv8.2+) */
@@ -295,6 +298,7 @@
 
 /* CPTR_EL3 definitions */
 #define TCPAC_BIT		(U(1) << 31)
+#define TAM_BIT			(U(1) << 30)
 #define TTA_BIT			(U(1) << 20)
 #define TFP_BIT			(U(1) << 10)
 #define CPTR_EL3_RESET_VAL	U(0x0)
@@ -302,6 +306,7 @@
 /* CPTR_EL2 definitions */
 #define CPTR_EL2_RES1		((U(1) << 13) | (U(1) << 12) | (U(0x3ff)))
 #define CPTR_EL2_TCPAC_BIT	(U(1) << 31)
+#define CPTR_EL2_TAM_BIT	(U(1) << 30)
 #define CPTR_EL2_TTA_BIT	(U(1) << 20)
 #define CPTR_EL2_TFP_BIT	(U(1) << 10)
 #define CPTR_EL2_RESET_VAL	CPTR_EL2_RES1
@@ -610,4 +615,28 @@
  ******************************************************************************/
 #define PMBLIMITR_EL1		S3_0_C9_C10_0
 
+/*******************************************************************************
+ * Definitions for system register interface to AMU for ARMv8.4 onwards
+ ******************************************************************************/
+#define AMCR_EL0		S3_3_C13_C2_0
+#define AMCFGR_EL0		S3_3_C13_C2_1
+#define AMCGCR_EL0		S3_3_C13_C2_2
+#define AMUSERENR_EL0		S3_3_C13_C2_3
+#define AMCNTENCLR0_EL0		S3_3_C13_C2_4
+#define AMCNTENSET0_EL0		S3_3_C13_C2_5
+#define AMCNTENCLR1_EL0		S3_3_C13_C3_0
+#define AMCNTENSET1_EL0		S3_3_C13_C3_1
+
+/* Activity Monitor Group 0 Event Counter Registers */
+#define AMEVCNTR00_EL0		S3_3_C13_C4_0
+#define AMEVCNTR01_EL0		S3_3_C13_C4_1
+#define AMEVCNTR02_EL0		S3_3_C13_C4_2
+#define AMEVCNTR03_EL0		S3_3_C13_C4_3
+
+/* Activity Monitor Group 0 Event Type Registers */
+#define AMEVTYPER00_EL0		S3_3_C13_C6_0
+#define AMEVTYPER01_EL0		S3_3_C13_C6_1
+#define AMEVTYPER02_EL0		S3_3_C13_C6_2
+#define AMEVTYPER03_EL0		S3_3_C13_C6_3
+
 #endif /* __ARCH_H__ */

include/lib/aarch64/arch_helpers.h

@@ -322,6 +322,11 @@ DEFINE_RENAME_SYSREG_WRITE_FUNC(icc_eoir0_el1, ICC_EOIR0_EL1)
 DEFINE_RENAME_SYSREG_WRITE_FUNC(icc_eoir1_el1, ICC_EOIR1_EL1)
 DEFINE_RENAME_SYSREG_WRITE_FUNC(icc_sgi0r_el1, ICC_SGI0R_EL1)
 
+DEFINE_RENAME_SYSREG_RW_FUNCS(amcntenclr0_el0, AMCNTENCLR0_EL0)
+DEFINE_RENAME_SYSREG_RW_FUNCS(amcntenset0_el0, AMCNTENSET0_EL0)
+DEFINE_RENAME_SYSREG_RW_FUNCS(amcntenclr1_el0, AMCNTENCLR1_EL0)
+DEFINE_RENAME_SYSREG_RW_FUNCS(amcntenset1_el0, AMCNTENSET1_EL0)
+
 DEFINE_RENAME_SYSREG_RW_FUNCS(pmblimitr_el1, PMBLIMITR_EL1)
 
 #define IS_IN_EL(x) \

include/lib/extensions/amu.h

@@ -0,0 +1,15 @@
+/*
+ * Copyright (c) 2017, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef __AMU_H__
+#define __AMU_H__
+
+/* Enable all group 0 counters */
+#define AMU_GROUP0_COUNTERS_MASK	0xf
+
+void amu_enable(int el2_unused);
+
+#endif /* __AMU_H__ */

lib/el3_runtime/aarch64/context_mgmt.c

@@ -4,6 +4,7 @@
  * SPDX-License-Identifier: BSD-3-Clause
  */
 
+#include <amu.h>
 #include <arch.h>
 #include <arch_helpers.h>
 #include <assert.h>
@@ -220,6 +221,10 @@ static void enable_extensions_nonsecure(int el2_unused)
 #if ENABLE_SPE_FOR_LOWER_ELS
 	spe_enable(el2_unused);
 #endif
+
+#if ENABLE_AMU
+	amu_enable(el2_unused);
+#endif
 #endif
 }
 

lib/extensions/amu/aarch64/amu.c

@@ -0,0 +1,40 @@
+/*
+ * Copyright (c) 2017, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <amu.h>
+#include <arch.h>
+#include <arch_helpers.h>
+
+void amu_enable(int el2_unused)
+{
+	uint64_t features;
+
+	features = read_id_aa64pfr0_el1() >> ID_AA64PFR0_AMU_SHIFT;
+	if ((features & ID_AA64PFR0_AMU_MASK) == 1) {
+		uint64_t v;
+
+		if (el2_unused) {
+			/*
+			 * CPTR_EL2.TAM: Set to zero so any accesses to
+			 * the Activity Monitor registers do not trap to EL2.
+			 */
+			v = read_cptr_el2();
+			v &= ~CPTR_EL2_TAM_BIT;
+			write_cptr_el2(v);
+		}
+
+		/*
+		 * CPTR_EL3.TAM: Set to zero so that any accesses to
+		 * the Activity Monitor registers do not trap to EL3.
+		 */
+		v = read_cptr_el3();
+		v &= ~TAM_BIT;
+		write_cptr_el3(v);
+
+		/* Enable group 0 counters */
+		write_amcntenset0_el0(AMU_GROUP0_COUNTERS_MASK);
+	}
+}