blob: 8c1c42180c4afaa2872bae39d3749e12b78a4420 [file] [log] [blame]
/*
* Copyright (c) 2021-2024, 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(cpu_context_t *ctx)
{
el3_state_t *state = get_el3state_ctx(ctx);
u_register_t mdcr_el3_val = read_ctx_reg(state, CTX_MDCR_EL3);
/*
* MDCR_EL3.NSTBE = 0b0
* Trace Buffer owning Security state is Non-secure state. If FEAT_RME
* is not implemented, this field is RES0.
*
* 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).
*/
mdcr_el3_val |= MDCR_NSTB(MDCR_NSTB_EL1);
mdcr_el3_val &= ~(MDCR_NSTBE_BIT);
write_ctx_reg(state, CTX_MDCR_EL3, mdcr_el3_val);
}
void trbe_disable(cpu_context_t *ctx)
{
el3_state_t *state = get_el3state_ctx(ctx);
u_register_t mdcr_el3_val = read_ctx_reg(state, CTX_MDCR_EL3);
/*
* MDCR_EL3.NSTBE = 0b0
* Trace Buffer owning Security state is secure state. If FEAT_RME
* is not implemented, this field is RES0.
*
* MDCR_EL3.NSTB = 0b00
* Clear these bits to disable access of trace buffer control registers
* from lower ELs in any security state.
*/
mdcr_el3_val &= ~(MDCR_NSTB(MDCR_NSTB_EL1));
mdcr_el3_val &= ~(MDCR_NSTBE_BIT);
write_ctx_reg(state, CTX_MDCR_EL3, mdcr_el3_val);
}
void trbe_init_el2_unused(void)
{
/*
* MDCR_EL2.E2TB: Set to zero so that the trace Buffer
* owning exception level is NS-EL1 and, tracing is
* prohibited at NS-EL2. These bits are RES0 when
* FEAT_TRBE is not implemented.
*/
write_mdcr_el2(read_mdcr_el2() & ~MDCR_EL2_E2TB(MDCR_EL2_E2TB_EL1));
}
static void *trbe_drain_trace_buffers_hook(const void *arg __unused)
{
if (is_feat_trbe_supported()) {
/*
* 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);