/*
       * linux/kernel/info.c
       *
       * Copyright (C) 1992 Darren Senn
       */
      
      /* This implements the sysinfo() system call */
      
      #include <linux/mm.h>
      #include <linux/unistd.h>
      #include <linux/swap.h>
      #include <linux/smp_lock.h>
      
      #include <asm/uaccess.h>
      
  16  asmlinkage long sys_sysinfo(struct sysinfo *info)
      {
      	struct sysinfo val;
      
      	memset((char *)&val, 0, sizeof(struct sysinfo));
      
      	cli();
      	val.uptime = jiffies / HZ;
      
      	val.loads[0] = avenrun[0] << (SI_LOAD_SHIFT - FSHIFT);
      	val.loads[1] = avenrun[1] << (SI_LOAD_SHIFT - FSHIFT);
      	val.loads[2] = avenrun[2] << (SI_LOAD_SHIFT - FSHIFT);
      
      	val.procs = nr_threads-1;
      	sti();
      
      	si_meminfo(&val);
      	si_swapinfo(&val);
      
      	{
      		/* If the sum of all the available memory (i.e. ram + swap +
      		 * highmem) is less then can be stored in a 32 bit unsigned long
      		 * then we can be binary compatible with 2.2.x kernels.  If not,
      		 * well, who cares since in that case 2.2.x was broken anyways...
      		 *
      		 *  -Erik Andersen <andersee@debian.org> */
      
      		unsigned long mem_total = val.totalram + val.totalswap;
  44  		if ( !(mem_total < val.totalram || mem_total < val.totalswap)) {
      			unsigned long mem_total2 = mem_total + val.totalhigh; 
  46  			if (!(mem_total2 < mem_total || mem_total2 < val.totalhigh))
      			{
      				/* If mem_total did not overflow.  Divide all memory values by
      				 * mem_unit and set mem_unit=1.  This leaves things compatible with
      				 * 2.2.x, and also retains compatibility with earlier 2.4.x
      				 * kernels...  */
      
      				int bitcount = 0;
  54  				while (val.mem_unit > 1) 
      				{
      					bitcount++;
      					val.mem_unit >>= 1;
      				}
      				val.totalram <<= bitcount;
      				val.freeram <<= bitcount;
      				val.sharedram <<= bitcount;
      				val.bufferram <<= bitcount;
      				val.totalswap <<= bitcount;
      				val.freeswap <<= bitcount;
      				val.totalhigh <<= bitcount;
      				val.freehigh <<= bitcount;
      			}
      		}
      	}
      
  71  	if (copy_to_user(info, &val, sizeof(struct sysinfo)))
  72  		return -EFAULT;
  73  	return 0;
      }