xref: /openbmc/linux/arch/x86/um/vdso/um_vdso.c (revision 234489ac)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2011 Richard Weinberger <richrd@nod.at>
4  *
5  * This vDSO turns all calls into a syscall so that UML can trap them.
6  */
7 
8 
9 /* Disable profiling for userspace code */
10 #define DISABLE_BRANCH_PROFILING
11 
12 #include <linux/time.h>
13 #include <linux/getcpu.h>
14 #include <asm/unistd.h>
15 
16 int __vdso_clock_gettime(clockid_t clock, struct __kernel_old_timespec *ts)
17 {
18 	long ret;
19 
20 	asm("syscall"
21 		: "=a" (ret)
22 		: "0" (__NR_clock_gettime), "D" (clock), "S" (ts)
23 		: "rcx", "r11", "memory");
24 
25 	return ret;
26 }
27 int clock_gettime(clockid_t, struct __kernel_old_timespec *)
28 	__attribute__((weak, alias("__vdso_clock_gettime")));
29 
30 int __vdso_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz)
31 {
32 	long ret;
33 
34 	asm("syscall"
35 		: "=a" (ret)
36 		: "0" (__NR_gettimeofday), "D" (tv), "S" (tz)
37 		: "rcx", "r11", "memory");
38 
39 	return ret;
40 }
41 int gettimeofday(struct __kernel_old_timeval *, struct timezone *)
42 	__attribute__((weak, alias("__vdso_gettimeofday")));
43 
44 __kernel_old_time_t __vdso_time(__kernel_old_time_t *t)
45 {
46 	long secs;
47 
48 	asm volatile("syscall"
49 		: "=a" (secs)
50 		: "0" (__NR_time), "D" (t) : "cc", "r11", "cx", "memory");
51 
52 	return secs;
53 }
54 __kernel_old_time_t time(__kernel_old_time_t *t) __attribute__((weak, alias("__vdso_time")));
55 
56 long
57 __vdso_getcpu(unsigned *cpu, unsigned *node, struct getcpu_cache *unused)
58 {
59 	/*
60 	 * UML does not support SMP, we can cheat here. :)
61 	 */
62 
63 	if (cpu)
64 		*cpu = 0;
65 	if (node)
66 		*node = 0;
67 
68 	return 0;
69 }
70 
71 long getcpu(unsigned *cpu, unsigned *node, struct getcpu_cache *tcache)
72 	__attribute__((weak, alias("__vdso_getcpu")));
73