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/*
* Copyright (c) 2021-2022, Arm Limited. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include <arch.h>
#include <arch_features.h>
#include <arch_helpers.h>
#include <lib/el3_runtime/pubsub.h>
#include <lib/extensions/trbe.h>
static void tsb_csync(void)
{
/*
* The assembler does not yet understand the tsb csync mnemonic
* so use the equivalent hint instruction.
*/
__asm__ volatile("hint #18");
}
void trbe_enable(void)
{
uint64_t val;
if (is_feat_trbe_present()) {
/*
* MDCR_EL3.NSTB = 0b11
* Allow access of trace buffer control registers from NS-EL1
* and NS-EL2, tracing is prohibited in Secure and Realm state
* (if implemented).
*/
val = read_mdcr_el3();
val |= MDCR_NSTB(MDCR_NSTB_EL1);
write_mdcr_el3(val);
}
}
static void *trbe_drain_trace_buffers_hook(const void *arg __unused)
{
if (is_feat_trbe_present()) {
/*
* Before switching from normal world to secure world
* the trace buffers need to be drained out to memory. This is
* required to avoid an invalid memory access when TTBR is switched
* for entry to S-EL1.
*/
tsb_csync();
dsbnsh();
}
return (void *)0;
}
SUBSCRIBE_TO_EVENT(cm_entering_secure_world, trbe_drain_trace_buffers_hook);
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