arm-trusted-firmware/lib/extensions/trbe/trbe.c
Jayanth Dodderi Chidanand 47c681b7d7 feat(trbe): add trbe under feature detection mechanism
This change adds "FEAT_TRBE" to be part of feature detection mechanism.

Previously feature enablement flags were of boolean type, containing
either 0 or 1. With the introduction of feature detection procedure
we now support three states for feature enablement build flags(0 to 2).

Accordingly, "ENABLE_TRBE_FOR_NS" flag is now modified from boolean
to numeric type to align with the feature detection.

Change-Id: I53d3bc8dc2f6eac63feef22dfd627f3a48480afc
Signed-off-by: Jayanth Dodderi Chidanand <jayanthdodderi.chidanand@arm.com>
2022-06-06 11:43:14 +01:00

55 lines
1.2 KiB
C

/*
* 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);