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1 /*
2  * Copyright (C) 2011 Richard Weinberger <richrd@nod.at>
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License version 2 as
6  * published by the Free Software Foundation.
7  *
8  * This vDSO turns all calls into a syscall so that UML can trap them.
9  */
10 
11 
12 /* Disable profiling for userspace code */
13 #define DISABLE_BRANCH_PROFILING
14 
15 #include <linux/time.h>
16 #include <linux/getcpu.h>
17 #include <asm/unistd.h>
18 
__vdso_clock_gettime(clockid_t clock,struct timespec * ts)19 int __vdso_clock_gettime(clockid_t clock, struct timespec *ts)
20 {
21 	long ret;
22 
23 	asm("syscall" : "=a" (ret) :
24 		"0" (__NR_clock_gettime), "D" (clock), "S" (ts) : "memory");
25 
26 	return ret;
27 }
28 int clock_gettime(clockid_t, struct timespec *)
29 	__attribute__((weak, alias("__vdso_clock_gettime")));
30 
__vdso_gettimeofday(struct timeval * tv,struct timezone * tz)31 int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz)
32 {
33 	long ret;
34 
35 	asm("syscall" : "=a" (ret) :
36 		"0" (__NR_gettimeofday), "D" (tv), "S" (tz) : "memory");
37 
38 	return ret;
39 }
40 int gettimeofday(struct timeval *, struct timezone *)
41 	__attribute__((weak, alias("__vdso_gettimeofday")));
42 
__vdso_time(time_t * t)43 time_t __vdso_time(time_t *t)
44 {
45 	long secs;
46 
47 	asm volatile("syscall"
48 		: "=a" (secs)
49 		: "0" (__NR_time), "D" (t) : "cc", "r11", "cx", "memory");
50 
51 	return secs;
52 }
53 int time(time_t *t) __attribute__((weak, alias("__vdso_time")));
54 
55 long
__vdso_getcpu(unsigned * cpu,unsigned * node,struct getcpu_cache * unused)56 __vdso_getcpu(unsigned *cpu, unsigned *node, struct getcpu_cache *unused)
57 {
58 	/*
59 	 * UML does not support SMP, we can cheat here. :)
60 	 */
61 
62 	if (cpu)
63 		*cpu = 0;
64 	if (node)
65 		*node = 0;
66 
67 	return 0;
68 }
69 
70 long getcpu(unsigned *cpu, unsigned *node, struct getcpu_cache *tcache)
71 	__attribute__((weak, alias("__vdso_getcpu")));
72