xref: /openbmc/linux/arch/x86/um/vdso/um_vdso.c (revision 2cf1c348)
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" : "=a" (ret) :
21 		"0" (__NR_clock_gettime), "D" (clock), "S" (ts) : "memory");
22 
23 	return ret;
24 }
25 int clock_gettime(clockid_t, struct __kernel_old_timespec *)
26 	__attribute__((weak, alias("__vdso_clock_gettime")));
27 
28 int __vdso_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz)
29 {
30 	long ret;
31 
32 	asm("syscall" : "=a" (ret) :
33 		"0" (__NR_gettimeofday), "D" (tv), "S" (tz) : "memory");
34 
35 	return ret;
36 }
37 int gettimeofday(struct __kernel_old_timeval *, struct timezone *)
38 	__attribute__((weak, alias("__vdso_gettimeofday")));
39 
40 __kernel_old_time_t __vdso_time(__kernel_old_time_t *t)
41 {
42 	long secs;
43 
44 	asm volatile("syscall"
45 		: "=a" (secs)
46 		: "0" (__NR_time), "D" (t) : "cc", "r11", "cx", "memory");
47 
48 	return secs;
49 }
50 __kernel_old_time_t time(__kernel_old_time_t *t) __attribute__((weak, alias("__vdso_time")));
51 
52 long
53 __vdso_getcpu(unsigned *cpu, unsigned *node, struct getcpu_cache *unused)
54 {
55 	/*
56 	 * UML does not support SMP, we can cheat here. :)
57 	 */
58 
59 	if (cpu)
60 		*cpu = 0;
61 	if (node)
62 		*node = 0;
63 
64 	return 0;
65 }
66 
67 long getcpu(unsigned *cpu, unsigned *node, struct getcpu_cache *tcache)
68 	__attribute__((weak, alias("__vdso_getcpu")));
69