FreeBSD/Linux Kernel Cross Reference
sys/dev/psci/smccc.c

     /*-
      * SPDX-License-Identifier: BSD-2-Clause
      *
      * Copyright (c) 2018 Andrew Turner
      *
      * This software was developed by SRI International and the University of
      * Cambridge Computer Laboratory under DARPA/AFRL contract FA8750-10-C-0237
      * ("CTSRD"), as part of the DARPA CRASH research programme.
      *
     * Redistribution and use in source and binary forms, with or without
     * modification, are permitted provided that the following conditions
     * are met:
     * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     */
    
    #include "opt_acpi.h"
    #include "opt_platform.h"
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD$");
    
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/kernel.h>
    
    #include <dev/psci/psci.h>
    #include <dev/psci/smccc.h>
    
    #define SMCCC_VERSION_1_0       0x10000
    
    /* Assume 1.0 until we detect a later version */
    static uint32_t smccc_version = SMCCC_VERSION_1_0;
    
    static void
    smccc_init(void *dummy)
    {
            int32_t features;
            uint32_t ret;
    
            features = psci_features(SMCCC_VERSION);
            if (features != PSCI_RETVAL_NOT_SUPPORTED) {
                    ret = psci_call(SMCCC_VERSION, 0, 0, 0);
                    /* This should always be the case as we checked it above */
                    if (ret > 0)
                            smccc_version = ret;
            }
    
            if (bootverbose) {
                    printf("Found SMCCC version %u.%u\n",
                        SMCCC_VERSION_MAJOR(smccc_version),
                        SMCCC_VERSION_MINOR(smccc_version));
            }
    }
    SYSINIT(smccc_start, SI_SUB_CONFIGURE, SI_ORDER_ANY, smccc_init, NULL);
    
    int32_t
    smccc_arch_features(uint32_t smccc_func_id)
    {
    
            if (smccc_version == SMCCC_VERSION_1_0)
                    return (PSCI_RETVAL_NOT_SUPPORTED);
    
            return (psci_call(SMCCC_ARCH_FEATURES, smccc_func_id, 0, 0));
    }
    
    /*
     * The SMCCC handler for Spectre variant 2: Branch target injection.
     * (CVE-2017-5715)
     */
    int
    smccc_arch_workaround_1(void)
    {
    
            KASSERT(smccc_version != SMCCC_VERSION_1_0,
                ("SMCCC arch workaround 1 called with an invalid SMCCC interface"));
            return (psci_call(SMCCC_ARCH_WORKAROUND_1, 0, 0, 0));
    }
    
    int
    smccc_arch_workaround_2(int enable)
    {
    
            KASSERT(smccc_version != SMCCC_VERSION_1_0,
               ("SMCCC arch workaround 2 called with an invalid SMCCC interface"));
           return (psci_call(SMCCC_ARCH_WORKAROUND_2, enable, 0, 0));
   }

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