1744ad974Sjohpow01 /* 2*985b6a6bSBoyan Karatotev * Copyright (c) 2022-2025, Arm Limited. All rights reserved. 3744ad974Sjohpow01 * 4744ad974Sjohpow01 * SPDX-License-Identifier: BSD-3-Clause 5744ad974Sjohpow01 */ 6744ad974Sjohpow01 7744ad974Sjohpow01 #include <arch.h> 81298f2f1SJayanth Dodderi Chidanand #include <arch_features.h> 9744ad974Sjohpow01 #include <arch_helpers.h> 1060d330dcSBoyan Karatotev #include <lib/extensions/brbe.h> 11744ad974Sjohpow01 brbe_enable(cpu_context_t * ctx)12123002f9SJayanth Dodderi Chidanandvoid brbe_enable(cpu_context_t *ctx) 13744ad974Sjohpow01 { 14123002f9SJayanth Dodderi Chidanand el3_state_t *state = get_el3state_ctx(ctx); 15123002f9SJayanth Dodderi Chidanand u_register_t mdcr_el3_val = read_ctx_reg(state, CTX_MDCR_EL3); 16744ad974Sjohpow01 17744ad974Sjohpow01 /* 18744ad974Sjohpow01 * MDCR_EL3.SBRBE = 0b01 19744ad974Sjohpow01 * Allows BRBE usage in non-secure world and prohibited in 20*985b6a6bSBoyan Karatotev * secure world. This is relied on by SMCCC_ARCH_FEATURE_AVAILABILITY. 219890eab5SBoyan Karatotev * 229890eab5SBoyan Karatotev * MDCR_EL3.{E3BREW, E3BREC} = 0b00 239890eab5SBoyan Karatotev * Branch recording at EL3 is disabled 24744ad974Sjohpow01 */ 25fc7dca72SBoyan Karatotev mdcr_el3_val &= ~((MDCR_SBRBE(MDCR_SBRBE_ALL)) | MDCR_E3BREW_BIT | MDCR_E3BREC_BIT); 26fc7dca72SBoyan Karatotev mdcr_el3_val |= (MDCR_SBRBE(MDCR_SBRBE_NS)); 27123002f9SJayanth Dodderi Chidanand write_ctx_reg(state, CTX_MDCR_EL3, mdcr_el3_val); 28744ad974Sjohpow01 } 29