1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2021 Dmitry Chagin <dchagin@FreeBSD.org>
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28 #include <sys/elf.h>
29 #include <sys/errno.h>
30 #include <sys/proc.h>
31 #include <sys/stddef.h>
32 #define _KERNEL
33 #include <sys/vdso.h>
34 #undef _KERNEL
35 #include <stdbool.h>
36
37 #include <machine/atomic.h>
38 #include <machine/cpufunc.h>
39 #include <machine/stdarg.h>
40
41 #include <amd64/linux/linux.h>
42 #include <amd64/linux/linux_syscall.h>
43 #include <compat/linux/linux_errno.h>
44 #include <compat/linux/linux_time.h>
45
46 /* The kernel fixup this at vDSO install */
47 uintptr_t *kern_timekeep_base = NULL;
48 uint32_t kern_tsc_selector = 0;
49 uint32_t kern_cpu_selector = 0;
50
51 #include <x86/linux/linux_vdso_gettc_x86.inc>
52 #include <x86/linux/linux_vdso_getcpu_x86.inc>
53
54 /* for debug purpose */
55 static int
write(int fd,const void * buf,size_t size)56 write(int fd, const void *buf, size_t size)
57 {
58 int res;
59
60 __asm__ __volatile__
61 (
62 "syscall"
63 : "=a"(res)
64 : "a"(LINUX_SYS_linux_write), "D"(fd), "S"(buf), "d"(size)
65 : "cc", "rcx", "r11", "memory"
66 );
67 return (res);
68 }
69
70 static int
__vdso_clock_gettime_fallback(clockid_t clock_id,struct l_timespec * ts)71 __vdso_clock_gettime_fallback(clockid_t clock_id, struct l_timespec *ts)
72 {
73 int res;
74
75 __asm__ __volatile__
76 (
77 "syscall"
78 : "=a"(res)
79 : "a"(LINUX_SYS_linux_clock_gettime), "D"(clock_id), "S"(ts)
80 : "cc", "rcx", "r11", "memory"
81 );
82 return (res);
83 }
84
85 static int
__vdso_gettimeofday_fallback(l_timeval * tv,struct timezone * tz)86 __vdso_gettimeofday_fallback(l_timeval *tv, struct timezone *tz)
87 {
88 int res;
89
90 __asm__ __volatile__
91 (
92 "syscall"
93 : "=a"(res)
94 : "a"(LINUX_SYS_gettimeofday), "D"(tv), "S"(tz)
95 : "cc", "rcx", "r11", "memory"
96 );
97 return (res);
98 }
99
100 static int
__vdso_clock_getres_fallback(clockid_t clock_id,struct l_timespec * ts)101 __vdso_clock_getres_fallback(clockid_t clock_id, struct l_timespec *ts)
102 {
103 int res;
104
105 __asm__ __volatile__
106 (
107 "syscall"
108 : "=a"(res)
109 : "a"(LINUX_SYS_linux_clock_getres), "D"(clock_id), "S"(ts)
110 : "cc", "rcx", "r11", "memory"
111 );
112 return (res);
113 }
114
115 static int
__vdso_getcpu_fallback(uint32_t * cpu,uint32_t * node,void * cache)116 __vdso_getcpu_fallback(uint32_t *cpu, uint32_t *node, void *cache)
117 {
118 int res;
119
120 __asm__ __volatile__
121 (
122 "syscall"
123 : "=a"(res)
124 : "a"(LINUX_SYS_linux_getcpu), "D"(cpu), "S"(node), "d"(cache)
125 : "cc", "rcx", "r11", "memory"
126 );
127 return (res);
128 }
129
130 static int
__vdso_time_fallback(long * tm)131 __vdso_time_fallback(long *tm)
132 {
133 int res;
134
135 __asm__ __volatile__
136 (
137 "syscall"
138 : "=a"(res)
139 : "a"(LINUX_SYS_linux_time), "D"(tm)
140 : "cc", "rcx", "r11", "memory"
141 );
142 return (res);
143 }
144
145 #include <compat/linux/linux_vdso_gtod.inc>
146