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/*
* Copyright (c) 2021, Arm Limited and Contributors. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include <stdbool.h>
#include <arch.h>
#include <arch_helpers.h>
#include <common/debug.h>
#include <lib/el3_runtime/context_mgmt.h>
#include <lib/extensions/sme.h>
#include <lib/extensions/sve.h>
static bool feat_sme_supported(void)
{
uint64_t features;
features = read_id_aa64pfr1_el1() >> ID_AA64PFR1_EL1_SME_SHIFT;
return (features & ID_AA64PFR1_EL1_SME_MASK) != 0U;
}
static bool feat_sme_fa64_supported(void)
{
uint64_t features;
features = read_id_aa64smfr0_el1();
return (features & ID_AA64SMFR0_EL1_FA64_BIT) != 0U;
}
void sme_enable(cpu_context_t *context)
{
u_register_t reg;
u_register_t cptr_el3;
el3_state_t *state;
/* Make sure SME is implemented in hardware before continuing. */
if (!feat_sme_supported()) {
return;
}
/* Get the context state. */
state = get_el3state_ctx(context);
/* Enable SME in CPTR_EL3. */
reg = read_ctx_reg(state, CTX_CPTR_EL3);
reg |= ESM_BIT;
write_ctx_reg(state, CTX_CPTR_EL3, reg);
/* Set the ENTP2 bit in SCR_EL3 to enable access to TPIDR2_EL0. */
reg = read_ctx_reg(state, CTX_SCR_EL3);
reg |= SCR_ENTP2_BIT;
write_ctx_reg(state, CTX_SCR_EL3, reg);
/* Set CPTR_EL3.ESM bit so we can write SMCR_EL3 without trapping. */
cptr_el3 = read_cptr_el3();
write_cptr_el3(cptr_el3 | ESM_BIT);
/*
* Set the max LEN value and FA64 bit. This register is set up globally
* to be the least restrictive, then lower ELs can restrict as needed
* using SMCR_EL2 and SMCR_EL1.
*/
reg = SMCR_ELX_LEN_MASK;
if (feat_sme_fa64_supported()) {
VERBOSE("[SME] FA64 enabled\n");
reg |= SMCR_ELX_FA64_BIT;
}
write_smcr_el3(reg);
/* Reset CPTR_EL3 value. */
write_cptr_el3(cptr_el3);
/* Enable SVE/FPU in addition to SME. */
sve_enable(context);
}
void sme_disable(cpu_context_t *context)
{
u_register_t reg;
el3_state_t *state;
/* Make sure SME is implemented in hardware before continuing. */
if (!feat_sme_supported()) {
return;
}
/* Get the context state. */
state = get_el3state_ctx(context);
/* Disable SME, SVE, and FPU since they all share registers. */
reg = read_ctx_reg(state, CTX_CPTR_EL3);
reg &= ~ESM_BIT; /* Trap SME */
reg &= ~CPTR_EZ_BIT; /* Trap SVE */
reg |= TFP_BIT; /* Trap FPU/SIMD */
write_ctx_reg(state, CTX_CPTR_EL3, reg);
/* Disable access to TPIDR2_EL0. */
reg = read_ctx_reg(state, CTX_SCR_EL3);
reg &= ~SCR_ENTP2_BIT;
write_ctx_reg(state, CTX_SCR_EL3, reg);
}
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