1/*
2 * linux/kernel/info.c
3 *
4 * Copyright (C) 1992 Darren Senn
5 */
6
7/* This implements the sysinfo() system call */
8
9#include <linux/mm.h>
10#include <linux/unistd.h>
11#include <linux/swap.h>
12#include <linux/smp_lock.h>
13
14#include <asm/uaccess.h>
15
16asmlinkage long sys_sysinfo(struct sysinfo *info)
17{
18	struct sysinfo val;
19
20	memset((char *)&val, 0, sizeof(struct sysinfo));
21
22	cli();
23	val.uptime = jiffies / HZ;
24
25	val.loads[0] = avenrun[0] << (SI_LOAD_SHIFT - FSHIFT);
26	val.loads[1] = avenrun[1] << (SI_LOAD_SHIFT - FSHIFT);
27	val.loads[2] = avenrun[2] << (SI_LOAD_SHIFT - FSHIFT);
28
29	val.procs = nr_threads-1;
30	sti();
31
32	si_meminfo(&val);
33	si_swapinfo(&val);
34
35	{
36		unsigned long mem_total, sav_total;
37		unsigned int mem_unit, bitcount;
38
39		/* If the sum of all the available memory (i.e. ram + swap)
40		 * is less than can be stored in a 32 bit unsigned long then
41		 * we can be binary compatible with 2.2.x kernels.  If not,
42		 * well, in that case 2.2.x was broken anyways...
43		 *
44		 *  -Erik Andersen <andersee@debian.org> */
45
46		mem_total = val.totalram + val.totalswap;
47		if (mem_total < val.totalram || mem_total < val.totalswap)
48			goto out;
49		bitcount = 0;
50		mem_unit = val.mem_unit;
51		while (mem_unit > 1) {
52			bitcount++;
53			mem_unit >>= 1;
54			sav_total = mem_total;
55			mem_total <<= 1;
56			if (mem_total < sav_total)
57				goto out;
58		}
59
60		/* If mem_total did not overflow, multiply all memory values by
61		 * val.mem_unit and set it to 1.  This leaves things compatible
62		 * with 2.2.x, and also retains compatibility with earlier 2.4.x
63		 * kernels...  */
64
65		val.mem_unit = 1;
66		val.totalram <<= bitcount;
67		val.freeram <<= bitcount;
68		val.sharedram <<= bitcount;
69		val.bufferram <<= bitcount;
70		val.totalswap <<= bitcount;
71		val.freeswap <<= bitcount;
72		val.totalhigh <<= bitcount;
73		val.freehigh <<= bitcount;
74	}
75out:
76	if (copy_to_user(info, &val, sizeof(struct sysinfo)))
77		return -EFAULT;
78	return 0;
79}
80