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 12 void trf_init_el3(void) 13 { 14 u_register_t val; 15 16 /* 17 * MDCR_EL3.TTRF = b0 18 * Allow access of trace filter control registers from NS-EL2 19 * and NS-EL1 when NS-EL2 is implemented but not used 20 */ 21 val = read_mdcr_el3(); 22 val &= ~MDCR_TTRF_BIT; 23 write_mdcr_el3(val); 24 } 25 26 void trf_init_el2_unused(void) 27 { 28 /* 29 * MDCR_EL2.TTRF: Set to zero so that access to Trace 30 * Filter Control register TRFCR_EL1 at EL1 is not 31 * trapped to EL2. This bit is RES0 in versions of 32 * the architecture earlier than ARMv8.4. 33 * 34 */ 35 write_mdcr_el2(read_mdcr_el2() & ~MDCR_EL2_TTRF); 36 } 37