1 /*
2  * Copyright (c) 2017-2018, ARM Limited and Contributors. All rights reserved.
3  *
4  * SPDX-License-Identifier: BSD-3-Clause
5  */
6 
7 #include <stdbool.h>
8 
9 #include <arch.h>
10 #include <arch_helpers.h>
11 #include <lib/el3_runtime/pubsub.h>
12 #include <lib/extensions/spe.h>
13 
psb_csync(void)14 static inline void psb_csync(void)
15 {
16 	/*
17 	 * The assembler does not yet understand the psb csync mnemonic
18 	 * so use the equivalent hint instruction.
19 	 */
20 	__asm__ volatile("hint #17");
21 }
22 
spe_supported(void)23 bool spe_supported(void)
24 {
25 	uint64_t features;
26 
27 	features = read_id_aa64dfr0_el1() >> ID_AA64DFR0_PMS_SHIFT;
28 	return (features & ID_AA64DFR0_PMS_MASK) > 0ULL;
29 }
30 
spe_enable(bool el2_unused)31 void spe_enable(bool el2_unused)
32 {
33 	uint64_t v;
34 
35 	if (!spe_supported())
36 		return;
37 
38 	if (el2_unused) {
39 		/*
40 		 * MDCR_EL2.TPMS (ARM v8.2): Do not trap statistical
41 		 * profiling controls to EL2.
42 		 *
43 		 * MDCR_EL2.E2PB (ARM v8.2): SPE enabled in Non-secure
44 		 * state. Accesses to profiling buffer controls at
45 		 * Non-secure EL1 are not trapped to EL2.
46 		 */
47 		v = read_mdcr_el2();
48 		v &= ~MDCR_EL2_TPMS;
49 		v |= MDCR_EL2_E2PB(MDCR_EL2_E2PB_EL1);
50 		write_mdcr_el2(v);
51 	}
52 
53 	/*
54 	 * MDCR_EL2.NSPB (ARM v8.2): SPE enabled in Non-secure state
55 	 * and disabled in secure state. Accesses to SPE registers at
56 	 * S-EL1 generate trap exceptions to EL3.
57 	 */
58 	v = read_mdcr_el3();
59 	v |= MDCR_NSPB(MDCR_NSPB_EL1);
60 	write_mdcr_el3(v);
61 }
62 
spe_disable(void)63 void spe_disable(void)
64 {
65 	uint64_t v;
66 
67 	if (!spe_supported())
68 		return;
69 
70 	/* Drain buffered data */
71 	psb_csync();
72 	dsbnsh();
73 
74 	/* Disable profiling buffer */
75 	v = read_pmblimitr_el1();
76 	v &= ~(1ULL << 0);
77 	write_pmblimitr_el1(v);
78 	isb();
79 }
80 
spe_drain_buffers_hook(const void * arg)81 static void *spe_drain_buffers_hook(const void *arg)
82 {
83 	if (!spe_supported())
84 		return (void *)-1;
85 
86 	/* Drain buffered data */
87 	psb_csync();
88 	dsbnsh();
89 
90 	return (void *)0;
91 }
92 
93 SUBSCRIBE_TO_EVENT(cm_entering_secure_world, spe_drain_buffers_hook);
94