1 /*
2  * Copyright (c) 2021-2023, Arm Limited. All rights reserved.
3  *
4  * SPDX-License-Identifier: BSD-3-Clause
5  */
6 
7 #include <arch.h>
8 #include <arch_features.h>
9 #include <arch_helpers.h>
10 #include <lib/extensions/trf.h>
11 
trf_init_el3(void)12 void trf_init_el3(void)
13 {
14 	u_register_t val;
15 
16 	/*
17 	 * MDCR_EL3.STE = b0
18 	 * Trace prohibited in Secure state unless overridden by the
19 	 * IMPLEMENTATION DEFINED authentication interface.
20 	 *
21 	 * MDCR_EL3.TTRF = b0
22 	 * Allow access of trace filter control registers from NS-EL2
23 	 * and NS-EL1 when NS-EL2 is implemented but not used
24 	 */
25 	val = read_mdcr_el3();
26 	val &= ~(MDCR_STE_BIT | MDCR_TTRF_BIT);
27 	write_mdcr_el3(val);
28 }
29 
trf_init_el2_unused(void)30 void trf_init_el2_unused(void)
31 {
32 	/*
33 	 * MDCR_EL2.TTRF: Set to zero so that access to Trace
34 	 *  Filter Control register TRFCR_EL1 at EL1 is not
35 	 *  trapped to EL2. This bit is RES0 in versions of
36 	 *  the architecture earlier than ARMv8.4.
37 	 *
38 	 */
39 	write_mdcr_el2(read_mdcr_el2() & ~MDCR_EL2_TTRF);
40 }
41