xref: /freebsd/sys/amd64/linux/linux_vdso_gtod.c (revision a50d73d5782a351ad83e8d1f84d11720a12e70d3)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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/cdefs.h>
29 __FBSDID("$FreeBSD$");
30 
31 #include <sys/elf.h>
32 #include <sys/errno.h>
33 #include <sys/proc.h>
34 #include <sys/stddef.h>
35 #define	_KERNEL
36 #include <sys/vdso.h>
37 #undef	_KERNEL
38 #include <stdbool.h>
39 
40 #include <machine/atomic.h>
41 #include <machine/cpufunc.h>
42 #include <machine/stdarg.h>
43 
44 #include <amd64/linux/linux.h>
45 #include <amd64/linux/linux_syscall.h>
46 #include <compat/linux/linux_errno.h>
47 #include <compat/linux/linux_time.h>
48 
49 /* The kernel fixup this at vDSO install */
50 uintptr_t *kern_timekeep_base = NULL;
51 uint32_t kern_tsc_selector = 0;
52 uint32_t kern_cpu_selector = 0;
53 
54 #include <x86/linux/linux_vdso_gettc_x86.inc>
55 #include <x86/linux/linux_vdso_getcpu_x86.inc>
56 
57 /* for debug purpose */
58 static int
59 write(int fd, const void *buf, size_t size)
60 {
61 	int res;
62 
63 	__asm__ __volatile__
64 	(
65 	    "syscall"
66 	    : "=a"(res)
67 	    : "a"(LINUX_SYS_write), "D"(fd), "S"(buf), "d"(size)
68 	    : "cc", "rcx", "r11", "memory"
69 	);
70 	return (res);
71 }
72 
73 static int
74 __vdso_clock_gettime_fallback(clockid_t clock_id, struct l_timespec *ts)
75 {
76 	int res;
77 
78 	__asm__ __volatile__
79 	(
80 	    "syscall"
81 	    : "=a"(res)
82 	    : "a"(LINUX_SYS_linux_clock_gettime), "D"(clock_id), "S"(ts)
83 	    : "cc", "rcx", "r11", "memory"
84 	);
85 	return (res);
86 }
87 
88 static int
89 __vdso_gettimeofday_fallback(l_timeval *tv, struct timezone *tz)
90 {
91 	int res;
92 
93 	__asm__ __volatile__
94 	(
95 	    "syscall"
96 	    : "=a"(res)
97 	    : "a"(LINUX_SYS_gettimeofday), "D"(tv), "S"(tz)
98 	    : "cc", "rcx", "r11", "memory"
99 	);
100 	return (res);
101 }
102 
103 static int
104 __vdso_clock_getres_fallback(clockid_t clock_id, struct l_timespec *ts)
105 {
106 	int res;
107 
108 	__asm__ __volatile__
109 	(
110 	    "syscall"
111 	    : "=a"(res)
112 	    : "a"(LINUX_SYS_linux_clock_getres), "D"(clock_id), "S"(ts)
113 	    : "cc", "rcx", "r11", "memory"
114 	);
115 	return (res);
116 }
117 
118 static int
119 __vdso_getcpu_fallback(uint32_t *cpu, uint32_t *node, void *cache)
120 {
121 	int res;
122 
123 	__asm__ __volatile__
124 	(
125 	    "syscall"
126 	    : "=a"(res)
127 	    : "a"(LINUX_SYS_linux_getcpu), "D"(cpu), "S"(node), "d"(cache)
128 	    : "cc", "rcx", "r11", "memory"
129 	);
130 	return (res);
131 }
132 
133 static int
134 __vdso_time_fallback(long *tm)
135 {
136 	int res;
137 
138 	__asm__ __volatile__
139 	(
140 	    "syscall"
141 	    : "=a"(res)
142 	    : "a"(LINUX_SYS_linux_time), "D"(tm)
143 	    : "cc", "rcx", "r11", "memory"
144 	);
145 	return (res);
146 }
147 
148 #include <compat/linux/linux_vdso_gtod.inc>
149