1 /* 2 * Copyright (c) 2021-2024, 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_enable(cpu_context_t * ctx)12void trf_enable(cpu_context_t *ctx) 13 { 14 el3_state_t *state = get_el3state_ctx(ctx); 15 u_register_t mdcr_el3_val = read_ctx_reg(state, CTX_MDCR_EL3); 16 17 /* 18 * MDCR_EL3.STE = b0 19 * Trace prohibited in Secure state unless overridden by the 20 * IMPLEMENTATION DEFINED authentication interface. 21 * 22 * MDCR_EL3.TTRF = b0 23 * Allow access of trace filter control registers from NS-EL2 24 * and NS-EL1 when NS-EL2 is implemented but not used 25 */ 26 mdcr_el3_val &= ~(MDCR_STE_BIT | MDCR_TTRF_BIT); 27 write_ctx_reg(state, CTX_MDCR_EL3, mdcr_el3_val); 28 } 29 trf_init_el2_unused(void)30void 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