FreeBSD/Linux Kernel Cross Reference
sys/x86/linux/linux_vdso_selector_x86.c

     /*-
      * Copyright (c) 2012 Konstantin Belousov <kib@FreeBSD.org>
      * Copyright (c) 2016, 2017, 2019, 2021 The FreeBSD Foundation
      * Copyright (c) 2021 Dmitry Chagin <dchagin@FreeBSD.org>
      *
      * Portions of this software were developed by Konstantin Belousov
      * under sponsorship from the FreeBSD Foundation.
      *
      * 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 <sys/cdefs.h>
    __FBSDID("$FreeBSD$");
    
    #include <sys/param.h>
    #include <x86/cputypes.h>
    #include <x86/x86_var.h>
    #include <x86/specialreg.h>
    
    #include <machine/cpufunc.h>
    
    #include <x86/linux/linux_x86.h>
    
    int
    linux_vdso_tsc_selector_idx(void)
    {
            bool amd_cpu;
    
            if (cpu_feature == 0)
                    return (2);     /* should not happen due to RDTSC */
    
            amd_cpu = (cpu_vendor_id == CPU_VENDOR_AMD ||
                cpu_vendor_id == CPU_VENDOR_HYGON);
    
            if ((amd_feature & AMDID_RDTSCP) != 0)
                    return (3);
            if ((cpu_feature & CPUID_SSE2) == 0)
                    return (2);
            return (amd_cpu ? 1 : 0);
    }
    
    int
    linux_vdso_cpu_selector_idx(void)
    {
    
            if ((cpu_stdext_feature2 & CPUID_STDEXT2_RDPID) != 0)
                    return (LINUX_VDSO_CPU_RDPID);
    
            return ((amd_feature & AMDID_RDTSCP) == 0 ?
                LINUX_VDSO_CPU_DEFAULT : LINUX_VDSO_CPU_RDTSCP);
    }

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