1/*-
2 * Copyright (c) 2012 Konstantin Belousov <kib@FreeBSD.org>
3 * Copyright (c) 2016 The FreeBSD Foundation
4 * All rights reserved.
5 *
6 * Portions of this software were developed by Konstantin Belousov
7 * under sponsorship from the FreeBSD Foundation.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 *    notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 *    notice, this list of conditions and the following disclaimer in the
16 *    documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30
31#include <sys/cdefs.h>
32__FBSDID("$FreeBSD$");
33
34#include <sys/param.h>
35#include "namespace.h"
36#include <sys/elf.h>
37#include <sys/fcntl.h>
38#include <sys/mman.h>
39#include <sys/time.h>
40#include <sys/vdso.h>
41#include <errno.h>
42#include <string.h>
43#include <unistd.h>
44#include "un-namespace.h"
45#include <machine/cpufunc.h>
46#include <machine/specialreg.h>
47#include <dev/acpica/acpi_hpet.h>
48#include "libc_private.h"
49
50static void
51lfence_mb(void)
52{
53#if defined(__i386__)
54	static int lfence_works = -1;
55	u_int cpuid_supported, p[4];
56
57	if (lfence_works == -1) {
58		__asm __volatile(
59		    "	pushfl\n"
60		    "	popl	%%eax\n"
61		    "	movl    %%eax,%%ecx\n"
62		    "	xorl    $0x200000,%%eax\n"
63		    "	pushl	%%eax\n"
64		    "	popfl\n"
65		    "	pushfl\n"
66		    "	popl    %%eax\n"
67		    "	xorl    %%eax,%%ecx\n"
68		    "	je	1f\n"
69		    "	movl	$1,%0\n"
70		    "	jmp	2f\n"
71		    "1:	movl	$0,%0\n"
72		    "2:\n"
73		    : "=r" (cpuid_supported) : : "eax", "ecx", "cc");
74		if (cpuid_supported) {
75			__asm __volatile(
76			    "	pushl	%%ebx\n"
77			    "	cpuid\n"
78			    "	movl	%%ebx,%1\n"
79			    "	popl	%%ebx\n"
80			    : "=a" (p[0]), "=r" (p[1]), "=c" (p[2]), "=d" (p[3])
81			    :  "0" (0x1));
82			lfence_works = (p[3] & CPUID_SSE2) != 0;
83		} else
84			lfence_works = 0;
85	}
86	if (lfence_works == 1)
87		lfence();
88#elif defined(__amd64__)
89	lfence();
90#else
91#error "arch"
92#endif
93}
94
95static u_int
96__vdso_gettc_rdtsc_low(const struct vdso_timehands *th)
97{
98	u_int rv;
99
100	lfence_mb();
101	__asm __volatile("rdtsc; shrd %%cl, %%edx, %0"
102	    : "=a" (rv) : "c" (th->th_x86_shift) : "edx");
103	return (rv);
104}
105
106static u_int
107__vdso_rdtsc32(void)
108{
109
110	lfence_mb();
111	return (rdtsc32());
112}
113
114static char *hpet_dev_map = NULL;
115static uint32_t hpet_idx = 0xffffffff;
116
117static void
118__vdso_init_hpet(uint32_t u)
119{
120	static const char devprefix[] = "/dev/hpet";
121	char devname[64], *c, *c1, t;
122	int fd;
123
124	c1 = c = stpcpy(devname, devprefix);
125	u = hpet_idx;
126	do {
127		*c++ = u % 10 + '0';
128		u /= 10;
129	} while (u != 0);
130	*c = '\0';
131	for (c--; c1 != c; c1++, c--) {
132		t = *c1;
133		*c1 = *c;
134		*c = t;
135	}
136	fd = _open(devname, O_RDONLY);
137	if (fd == -1) {
138		hpet_dev_map = MAP_FAILED;
139		return;
140	}
141	if (hpet_dev_map != NULL && hpet_dev_map != MAP_FAILED)
142		munmap(hpet_dev_map, PAGE_SIZE);
143	hpet_dev_map = mmap(NULL, PAGE_SIZE, PROT_READ, MAP_SHARED, fd, 0);
144	_close(fd);
145}
146
147#pragma weak __vdso_gettc
148int
149__vdso_gettc(const struct vdso_timehands *th, u_int *tc)
150{
151	uint32_t tmp;
152
153	switch (th->th_algo) {
154	case VDSO_TH_ALGO_X86_TSC:
155		*tc = th->th_x86_shift > 0 ? __vdso_gettc_rdtsc_low(th) :
156		    __vdso_rdtsc32();
157		return (0);
158	case VDSO_TH_ALGO_X86_HPET:
159		tmp = th->th_x86_hpet_idx;
160		if (hpet_dev_map == NULL || tmp != hpet_idx) {
161			hpet_idx = tmp;
162			__vdso_init_hpet(hpet_idx);
163		}
164		if (hpet_dev_map == MAP_FAILED)
165			return (ENOSYS);
166		*tc = *(volatile uint32_t *)(hpet_dev_map + HPET_MAIN_COUNTER);
167		return (0);
168	default:
169		return (ENOSYS);
170	}
171}
172
173#pragma weak __vdso_gettimekeep
174int
175__vdso_gettimekeep(struct vdso_timekeep **tk)
176{
177
178	return (_elf_aux_info(AT_TIMEKEEP, tk, sizeof(*tk)));
179}
180