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/*
* Copyright (c) 2018, ARM Limited and Contributors. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include <common/debug.h>
#include <common/runtime_svc.h>
#include <lib/cpus/errata_report.h>
#include <lib/cpus/wa_cve_2017_5715.h>
#include <lib/cpus/wa_cve_2018_3639.h>
#include <lib/smccc.h>
#include <services/arm_arch_svc.h>
#include <smccc_helpers.h>
static int32_t smccc_version(void)
{
return MAKE_SMCCC_VERSION(SMCCC_MAJOR_VERSION, SMCCC_MINOR_VERSION);
}
static int32_t smccc_arch_features(u_register_t arg)
{
switch (arg) {
case SMCCC_VERSION:
case SMCCC_ARCH_FEATURES:
return SMC_OK;
#if WORKAROUND_CVE_2017_5715
case SMCCC_ARCH_WORKAROUND_1:
if (check_wa_cve_2017_5715() == ERRATA_NOT_APPLIES)
return 1;
return 0; /* ERRATA_APPLIES || ERRATA_MISSING */
#endif
#if WORKAROUND_CVE_2018_3639
case SMCCC_ARCH_WORKAROUND_2: {
#if DYNAMIC_WORKAROUND_CVE_2018_3639
unsigned long long ssbs;
/*
* Firmware doesn't have to carry out dynamic workaround if the
* PE implements architectural Speculation Store Bypass Safe
* (SSBS) feature.
*/
ssbs = (read_id_aa64pfr0_el1() >> ID_AA64PFR1_EL1_SSBS_SHIFT) &
ID_AA64PFR1_EL1_SSBS_MASK;
/*
* If architectural SSBS is available on this PE, no firmware
* mitigation via SMCCC_ARCH_WORKAROUND_2 is required.
*/
if (ssbs != SSBS_UNAVAILABLE)
return 1;
/*
* On a platform where at least one CPU requires
* dynamic mitigation but others are either unaffected
* or permanently mitigated, report the latter as not
* needing dynamic mitigation.
*/
if (wa_cve_2018_3639_get_disable_ptr() == NULL)
return 1;
/*
* If we get here, this CPU requires dynamic mitigation
* so report it as such.
*/
return 0;
#else
/* Either the CPUs are unaffected or permanently mitigated */
return SMCCC_ARCH_NOT_REQUIRED;
#endif
}
#endif
/* Fallthrough */
default:
return SMC_UNK;
}
}
/*
* Top-level Arm Architectural Service SMC handler.
*/
static uintptr_t arm_arch_svc_smc_handler(uint32_t smc_fid,
u_register_t x1,
u_register_t x2,
u_register_t x3,
u_register_t x4,
void *cookie,
void *handle,
u_register_t flags)
{
switch (smc_fid) {
case SMCCC_VERSION:
SMC_RET1(handle, smccc_version());
case SMCCC_ARCH_FEATURES:
SMC_RET1(handle, smccc_arch_features(x1));
#if WORKAROUND_CVE_2017_5715
case SMCCC_ARCH_WORKAROUND_1:
/*
* The workaround has already been applied on affected PEs
* during entry to EL3. On unaffected PEs, this function
* has no effect.
*/
SMC_RET0(handle);
#endif
#if WORKAROUND_CVE_2018_3639
case SMCCC_ARCH_WORKAROUND_2:
/*
* The workaround has already been applied on affected PEs
* requiring dynamic mitigation during entry to EL3.
* On unaffected or statically mitigated PEs, this function
* has no effect.
*/
SMC_RET0(handle);
#endif
default:
WARN("Unimplemented Arm Architecture Service Call: 0x%x \n",
smc_fid);
SMC_RET1(handle, SMC_UNK);
}
}
/* Register Standard Service Calls as runtime service */
DECLARE_RT_SVC(
arm_arch_svc,
OEN_ARM_START,
OEN_ARM_END,
SMC_TYPE_FAST,
NULL,
arm_arch_svc_smc_handler
);
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