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
16 asmlinkage 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 /* If the sum of all the available memory (i.e. ram + swap +
37 * highmem) is less then can be stored in a 32 bit unsigned long
38 * then we can be binary compatible with 2.2.x kernels. If not,
39 * well, who cares since in that case 2.2.x was broken anyways...
40 *
41 * -Erik Andersen <andersee@debian.org> */
42
43 unsigned long mem_total = val.totalram + val.totalswap;
44 if ( !(mem_total < val.totalram || mem_total < val.totalswap)) {
45 unsigned long mem_total2 = mem_total + val.totalhigh;
46 if (!(mem_total2 < mem_total || mem_total2 < val.totalhigh))
47 {
48 /* If mem_total did not overflow. Divide all memory values by
49 * mem_unit and set mem_unit=1. This leaves things compatible with
50 * 2.2.x, and also retains compatibility with earlier 2.4.x
51 * kernels... */
52
53 int bitcount = 0;
54 while (val.mem_unit > 1)
55 {
56 bitcount++;
57 val.mem_unit >>= 1;
58 }
59 val.totalram <<= bitcount;
60 val.freeram <<= bitcount;
61 val.sharedram <<= bitcount;
62 val.bufferram <<= bitcount;
63 val.totalswap <<= bitcount;
64 val.freeswap <<= bitcount;
65 val.totalhigh <<= bitcount;
66 val.freehigh <<= bitcount;
67 }
68 }
69 }
70
71 if (copy_to_user(info, &val, sizeof(struct sysinfo)))
72 return -EFAULT;
73 return 0;
74 }
75
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