HardenedBSD/sys/x86/linux/linux_vdso_gettc_x86.inc
Warner Losh 4d846d260e spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD
The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of BSD-2-Clause.

Discussed with:		pfg
MFC After:		3 days
Sponsored by:		Netflix
2023-05-12 10:44:03 -06:00

152 lines
3.6 KiB
C++

/*-
* SPDX-License-Identifier: BSD-2-Clause
*
* Copyright (c) 2012 Konstantin Belousov <kib@FreeBSD.org>
* Copyright (c) 2016, 2017, 2019 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.
*/
static inline u_int
rdtsc_low(const struct vdso_timehands *th)
{
u_int rv;
__asm __volatile("rdtsc; shrd %%cl, %%edx, %0"
: "=a" (rv) : "c" (th->th_x86_shift) : "edx");
return (rv);
}
static inline u_int
rdtscp_low(const struct vdso_timehands *th)
{
u_int rv;
__asm __volatile("rdtscp; movl %%edi,%%ecx; shrd %%cl, %%edx, %0"
: "=a" (rv) : "D" (th->th_x86_shift) : "ecx", "edx");
return (rv);
}
static u_int
rdtsc_low_mb_lfence(const struct vdso_timehands *th)
{
lfence();
return (rdtsc_low(th));
}
static u_int
rdtsc_low_mb_mfence(const struct vdso_timehands *th)
{
mfence();
return (rdtsc_low(th));
}
static u_int
rdtsc_low_mb_none(const struct vdso_timehands *th)
{
return (rdtsc_low(th));
}
static u_int
rdtsc32_mb_lfence(void)
{
lfence();
return (rdtsc32());
}
static u_int
rdtsc32_mb_mfence(void)
{
mfence();
return (rdtsc32());
}
static u_int
rdtsc32_mb_none(void)
{
return (rdtsc32());
}
static u_int
rdtscp32_(void)
{
return (rdtscp32());
}
struct tsc_selector_tag {
u_int (*ts_rdtsc32)(void);
u_int (*ts_rdtsc_low)(const struct vdso_timehands *);
};
static const struct tsc_selector_tag tsc_selector[] = {
[0] = { /* Intel, LFENCE */
.ts_rdtsc32 = rdtsc32_mb_lfence,
.ts_rdtsc_low = rdtsc_low_mb_lfence,
},
[1] = { /* AMD, MFENCE */
.ts_rdtsc32 = rdtsc32_mb_mfence,
.ts_rdtsc_low = rdtsc_low_mb_mfence,
},
[2] = { /* No SSE2 */
.ts_rdtsc32 = rdtsc32_mb_none,
.ts_rdtsc_low = rdtsc_low_mb_none,
},
[3] = { /* RDTSCP */
.ts_rdtsc32 = rdtscp32_,
.ts_rdtsc_low = rdtscp_low,
},
};
static u_int
__vdso_gettc_rdtsc_low(const struct vdso_timehands *th)
{
return (tsc_selector[kern_tsc_selector].ts_rdtsc_low(th));
}
static u_int
__vdso_gettc_rdtsc32(void)
{
return (tsc_selector[kern_tsc_selector].ts_rdtsc32());
}
int
__vdso_gettc(const struct vdso_timehands *th, u_int *tc)
{
switch (th->th_algo) {
case VDSO_TH_ALGO_X86_TSC:
*tc = th->th_x86_shift > 0 ? __vdso_gettc_rdtsc_low(th) :
__vdso_gettc_rdtsc32();
return (0);
case VDSO_TH_ALGO_X86_HPET:
/* TODO */
default:
return (ENOSYS);
}
}