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/*
* Copyright (c) 2017-2018, ARM Limited and Contributors. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include <arch.h>
#include <arch_helpers.h>
#include <pubsub.h>
#include <sve.h>
int sve_supported(void)
{
uint64_t features;
features = read_id_aa64pfr0_el1() >> ID_AA64PFR0_SVE_SHIFT;
return (features & ID_AA64PFR0_SVE_MASK) == 1;
}
static void *disable_sve_hook(const void *arg)
{
uint64_t cptr;
if (!sve_supported())
return (void *)-1;
/*
* Disable SVE, SIMD and FP access for the Secure world.
* As the SIMD/FP registers are part of the SVE Z-registers, any
* use of SIMD/FP functionality will corrupt the SVE registers.
* Therefore it is necessary to prevent use of SIMD/FP support
* in the Secure world as well as SVE functionality.
*/
cptr = read_cptr_el3();
cptr = (cptr | TFP_BIT) & ~(CPTR_EZ_BIT);
write_cptr_el3(cptr);
/*
* No explicit ISB required here as ERET to switch to Secure
* world covers it
*/
return 0;
}
static void *enable_sve_hook(const void *arg)
{
uint64_t cptr;
if (!sve_supported())
return (void *)-1;
/*
* Enable SVE, SIMD and FP access for the Non-secure world.
*/
cptr = read_cptr_el3();
cptr = (cptr | CPTR_EZ_BIT) & ~(TFP_BIT);
write_cptr_el3(cptr);
/*
* No explicit ISB required here as ERET to switch to Non-secure
* world covers it
*/
return 0;
}
void sve_enable(int el2_unused)
{
uint64_t cptr;
if (!sve_supported())
return;
#if CTX_INCLUDE_FPREGS
/*
* CTX_INCLUDE_FPREGS is not supported on SVE enabled systems.
*/
assert(0);
#endif
/*
* Update CPTR_EL3 to enable access to SVE functionality for the
* Non-secure world.
* NOTE - assumed that CPTR_EL3.TFP is set to allow access to
* the SIMD, floating-point and SVE support.
*
* CPTR_EL3.EZ: Set to 1 to enable access to SVE functionality
* in the Non-secure world.
*/
cptr = read_cptr_el3();
cptr |= CPTR_EZ_BIT;
write_cptr_el3(cptr);
/*
* Need explicit ISB here to guarantee that update to ZCR_ELx
* and CPTR_EL2.TZ do not result in trap to EL3.
*/
isb();
/*
* Ensure lower ELs have access to full vector length.
*/
write_zcr_el3(ZCR_EL3_LEN_MASK);
if (el2_unused) {
/*
* Update CPTR_EL2 to enable access to SVE functionality
* for Non-secure world, EL2 and Non-secure EL1 and EL0.
* NOTE - assumed that CPTR_EL2.TFP is set to allow
* access to the SIMD, floating-point and SVE support.
*
* CPTR_EL2.TZ: Set to 0 to enable access to SVE support
* for EL2 and Non-secure EL1 and EL0.
*/
cptr = read_cptr_el2();
cptr &= ~(CPTR_EL2_TZ_BIT);
write_cptr_el2(cptr);
/*
* Ensure lower ELs have access to full vector length.
*/
write_zcr_el2(ZCR_EL2_LEN_MASK);
}
/*
* No explicit ISB required here as ERET to switch to
* Non-secure world covers it.
*/
}
SUBSCRIBE_TO_EVENT(cm_exited_normal_world, disable_sve_hook);
SUBSCRIBE_TO_EVENT(cm_entering_normal_world, enable_sve_hook);
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