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![Brooks Davis](/assets/img/avatar_default.png)
Remove core system call implementations and documentation to lib/libsys and lib/libsys/<arch> from lib/libc/sys and lib/libc/<arch>/<sys>. Update paths to allow libc to find them in their new home. Reviewed by: kib, emaste, imp Pull Request: https://github.com/freebsd/freebsd-src/pull/908
197 lines
5 KiB
C
197 lines
5 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause
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*
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* Copyright (c) 2012 Konstantin Belousov <kib@FreeBSD.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/elf.h>
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#include <sys/time.h>
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#include <sys/vdso.h>
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#include <errno.h>
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#include <stdbool.h>
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#include <strings.h>
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#include <time.h>
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#include <machine/atomic.h>
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#include "libc_private.h"
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static int
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tc_delta(const struct vdso_timehands *th, u_int *delta)
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{
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int error;
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u_int tc;
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error = __vdso_gettc(th, &tc);
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if (error == 0)
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*delta = (tc - th->th_offset_count) & th->th_counter_mask;
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return (error);
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}
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/*
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* Calculate the absolute or boot-relative time from the
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* machine-specific fast timecounter and the published timehands
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* structure read from the shared page.
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*
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* The lockless reading scheme is similar to the one used to read the
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* in-kernel timehands, see sys/kern/kern_tc.c:binuptime(). This code
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* is based on the kernel implementation.
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*/
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static int
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binuptime(struct bintime *bt, struct vdso_timekeep *tk, bool abs)
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{
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struct vdso_timehands *th;
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uint32_t curr, gen;
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uint64_t scale, x;
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u_int delta, scale_bits;
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int error;
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do {
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if (!tk->tk_enabled)
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return (ENOSYS);
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curr = atomic_load_acq_32(&tk->tk_current);
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th = &tk->tk_th[curr];
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gen = atomic_load_acq_32(&th->th_gen);
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*bt = th->th_offset;
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error = tc_delta(th, &delta);
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if (error == EAGAIN)
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continue;
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if (error != 0)
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return (error);
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scale = th->th_scale;
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#ifdef _LP64
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scale_bits = flsl(scale);
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#else
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scale_bits = flsll(scale);
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#endif
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if (__predict_false(scale_bits + fls(delta) > 63)) {
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x = (scale >> 32) * delta;
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scale &= 0xffffffff;
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bt->sec += x >> 32;
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bintime_addx(bt, x << 32);
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}
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bintime_addx(bt, scale * delta);
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if (abs)
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bintime_add(bt, &th->th_boottime);
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/*
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* Ensure that the load of th_offset is completed
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* before the load of th_gen.
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*/
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atomic_thread_fence_acq();
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} while (curr != tk->tk_current || gen == 0 || gen != th->th_gen);
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return (0);
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}
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static int
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getnanouptime(struct bintime *bt, struct vdso_timekeep *tk)
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{
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struct vdso_timehands *th;
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uint32_t curr, gen;
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do {
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if (!tk->tk_enabled)
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return (ENOSYS);
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curr = atomic_load_acq_32(&tk->tk_current);
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th = &tk->tk_th[curr];
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gen = atomic_load_acq_32(&th->th_gen);
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*bt = th->th_offset;
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/*
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* Ensure that the load of th_offset is completed
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* before the load of th_gen.
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*/
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atomic_thread_fence_acq();
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} while (curr != tk->tk_current || gen == 0 || gen != th->th_gen);
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return (0);
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}
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static struct vdso_timekeep *tk;
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#pragma weak __vdso_gettimeofday
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int
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__vdso_gettimeofday(struct timeval *tv, struct timezone *tz)
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{
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struct bintime bt;
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int error;
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if (tz != NULL)
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return (ENOSYS);
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if (tk == NULL) {
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error = __vdso_gettimekeep(&tk);
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if (error != 0 || tk == NULL)
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return (ENOSYS);
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}
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if (tk->tk_ver != VDSO_TK_VER_CURR)
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return (ENOSYS);
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error = binuptime(&bt, tk, true);
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if (error != 0)
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return (error);
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bintime2timeval(&bt, tv);
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return (0);
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}
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#pragma weak __vdso_clock_gettime
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int
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__vdso_clock_gettime(clockid_t clock_id, struct timespec *ts)
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{
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struct bintime bt;
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int error;
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if (tk == NULL) {
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error = _elf_aux_info(AT_TIMEKEEP, &tk, sizeof(tk));
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if (error != 0 || tk == NULL)
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return (ENOSYS);
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}
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if (tk->tk_ver != VDSO_TK_VER_CURR)
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return (ENOSYS);
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switch (clock_id) {
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case CLOCK_REALTIME:
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case CLOCK_REALTIME_PRECISE:
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case CLOCK_REALTIME_FAST:
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case CLOCK_SECOND:
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error = binuptime(&bt, tk, true);
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break;
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case CLOCK_MONOTONIC:
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case CLOCK_MONOTONIC_PRECISE:
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case CLOCK_UPTIME:
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case CLOCK_UPTIME_PRECISE:
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error = binuptime(&bt, tk, false);
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break;
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case CLOCK_MONOTONIC_FAST:
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case CLOCK_UPTIME_FAST:
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error = getnanouptime(&bt, tk);
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break;
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default:
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error = ENOSYS;
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break;
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}
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if (error != 0)
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return (error);
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bintime2timespec(&bt, ts);
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if (clock_id == CLOCK_SECOND)
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ts->tv_nsec = 0;
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return (0);
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}
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