1*54fd6939SJiyong Park /* 2*54fd6939SJiyong Park * Copyright (c) 2021, Arm Limited. All rights reserved. 3*54fd6939SJiyong Park * 4*54fd6939SJiyong Park * SPDX-License-Identifier: BSD-3-Clause 5*54fd6939SJiyong Park */ 6*54fd6939SJiyong Park 7*54fd6939SJiyong Park #include <arch.h> 8*54fd6939SJiyong Park #include <arch_helpers.h> 9*54fd6939SJiyong Park #include <lib/el3_runtime/pubsub.h> 10*54fd6939SJiyong Park #include <lib/extensions/trbe.h> 11*54fd6939SJiyong Park tsb_csync(void)12*54fd6939SJiyong Parkstatic void tsb_csync(void) 13*54fd6939SJiyong Park { 14*54fd6939SJiyong Park /* 15*54fd6939SJiyong Park * The assembler does not yet understand the tsb csync mnemonic 16*54fd6939SJiyong Park * so use the equivalent hint instruction. 17*54fd6939SJiyong Park */ 18*54fd6939SJiyong Park __asm__ volatile("hint #18"); 19*54fd6939SJiyong Park } 20*54fd6939SJiyong Park trbe_supported(void)21*54fd6939SJiyong Parkstatic bool trbe_supported(void) 22*54fd6939SJiyong Park { 23*54fd6939SJiyong Park uint64_t features; 24*54fd6939SJiyong Park 25*54fd6939SJiyong Park features = read_id_aa64dfr0_el1() >> ID_AA64DFR0_TRACEBUFFER_SHIFT; 26*54fd6939SJiyong Park return ((features & ID_AA64DFR0_TRACEBUFFER_MASK) == 27*54fd6939SJiyong Park ID_AA64DFR0_TRACEBUFFER_SUPPORTED); 28*54fd6939SJiyong Park } 29*54fd6939SJiyong Park trbe_enable(void)30*54fd6939SJiyong Parkvoid trbe_enable(void) 31*54fd6939SJiyong Park { 32*54fd6939SJiyong Park uint64_t val; 33*54fd6939SJiyong Park 34*54fd6939SJiyong Park if (trbe_supported()) { 35*54fd6939SJiyong Park /* 36*54fd6939SJiyong Park * MDCR_EL3.NSTB = 0b11 37*54fd6939SJiyong Park * Allow access of trace buffer control registers from NS-EL1 38*54fd6939SJiyong Park * and NS-EL2, tracing is prohibited in Secure and Realm state 39*54fd6939SJiyong Park * (if implemented). 40*54fd6939SJiyong Park */ 41*54fd6939SJiyong Park val = read_mdcr_el3(); 42*54fd6939SJiyong Park val |= MDCR_NSTB(MDCR_NSTB_EL1); 43*54fd6939SJiyong Park write_mdcr_el3(val); 44*54fd6939SJiyong Park } 45*54fd6939SJiyong Park } 46*54fd6939SJiyong Park trbe_drain_trace_buffers_hook(const void * arg __unused)47*54fd6939SJiyong Parkstatic void *trbe_drain_trace_buffers_hook(const void *arg __unused) 48*54fd6939SJiyong Park { 49*54fd6939SJiyong Park if (trbe_supported()) { 50*54fd6939SJiyong Park /* 51*54fd6939SJiyong Park * Before switching from normal world to secure world 52*54fd6939SJiyong Park * the trace buffers need to be drained out to memory. This is 53*54fd6939SJiyong Park * required to avoid an invalid memory access when TTBR is switched 54*54fd6939SJiyong Park * for entry to S-EL1. 55*54fd6939SJiyong Park */ 56*54fd6939SJiyong Park tsb_csync(); 57*54fd6939SJiyong Park dsbnsh(); 58*54fd6939SJiyong Park } 59*54fd6939SJiyong Park 60*54fd6939SJiyong Park return (void *)0; 61*54fd6939SJiyong Park } 62*54fd6939SJiyong Park 63*54fd6939SJiyong Park SUBSCRIBE_TO_EVENT(cm_entering_secure_world, trbe_drain_trace_buffers_hook); 64