Differential D30900 Diff 91352 sys/x86/linux/linux_vdso_tsc_selector_x86.c

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sys/x86/linux/linux_vdso_tsc_selector_x86.c

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				/*-
				* Copyright (c) 2021 Dmitry Chagin <dchagin@FreeBSD.org>
				*
				* Redistribution and use in source and binary forms, with or without
				* modification, are permitted provided that the following conditions
				* are met:
				emasteUnsubmitted Not Done Inline Actions We can probably drop the `All rights reserved.` assuming kib agrees. For all Foundation copyrights it can be removed. emaste: We can probably drop the `All rights reserved.` assuming kib agrees. For all Foundation…
				* 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 <x86/linux/linux_x86.h>

				int
				linux_vdso_tsc_selector_idx()
				{
				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);
				}