minix/servers/mm/main.c

/* This file contains the main program of the memory manager and some related
 * procedures.  When MINIX starts up, the kernel runs for a little while,
 * initializing itself and its tasks, and then it runs MM and FS.  Both MM
 * and FS initialize themselves as far as they can.  FS then makes a call to
 * MM, because MM has to wait for FS to acquire a RAM disk.  MM asks the
 * kernel for all free memory and starts serving requests.
 *
 * The entry points into this file are:
 *   main:	starts MM running
 *   setreply:	set the reply to be sent to process making an MM system call
 */

#include "mm.h"
#include <minix/utils.h>
#include <minix/callnr.h>
#include <minix/com.h>
#include <signal.h>
#include <fcntl.h>
#include <sys/ioc_memory.h>
#include "mproc.h"
#include "param.h"

FORWARD _PROTOTYPE( void get_work, (void)				);
FORWARD _PROTOTYPE( void mm_init, (void)				);

#define click_to_round_k(n) \
	((unsigned) ((((unsigned long) (n) << CLICK_SHIFT) + 512) / 1024))

/*===========================================================================*
 *				main					     *
 *===========================================================================*/
PUBLIC void main()
{
/* Main routine of the memory manager. */

  int result, proc_nr;
  struct mproc *rmp;

  mm_init();			/* initialize memory manager tables */

  /* This is MM's main loop-  get work and do it, forever and forever. */
  while (TRUE) {
	get_work();		/* wait for an MM system call */

	/* Check for system notifications first. Special cases. */
	if (call_nr == HARD_STOP) {		/* MINIX is shutting down */
		check_sig(-1, SIGKILL);		/* kill all processes */
		sys_exit(0);
		/* never reached */
	} else if (call_nr == KSIG_PENDING) {	/* signals pending */
		(void) ksig_pending();
		result = SUSPEND;		/* don't reply */
	}
	/* Else, if the system call number is valid, perform the call. */
	else if ((unsigned) call_nr >= NCALLS) {
		result = ENOSYS;
	} else {
		result = (*call_vec[call_nr])();
	}

	/* Send the results back to the user to indicate completion. */
	if (result != SUSPEND) setreply(who, result);

	swap_in();		/* maybe a process can be swapped in? */

	/* Send out all pending reply messages, including the answer to
	 * the call just made above.  The processes must not be swapped out.
	 */
	for (proc_nr=0, rmp=mproc; proc_nr < NR_PROCS; proc_nr++, rmp++) {
		if ((rmp->mp_flags & (REPLY | ONSWAP)) == REPLY) {
			if (send(proc_nr, &rmp->mp_reply) != OK)
				panic("MM can't reply to", proc_nr);
			rmp->mp_flags &= ~REPLY;
		}
	}
  }
}


/*===========================================================================*
 *				get_work				     *
 *===========================================================================*/
PRIVATE void get_work()
{
/* Wait for the next message and extract useful information from it. */

  if (receive(ANY, &m_in) != OK) panic("MM receive error", NO_NUM);
  who = m_in.m_source;		/* who sent the message */
  call_nr = m_in.m_type;	/* system call number */

  /* Process slot of caller. Misuse MM's own process slot if the kernel is
   * calling. The can happen in case of pending kernel signals.
   */
  mp = &mproc[who < 0 ? PM_PROC_NR : who];
}


/*===========================================================================*
 *				setreply				     *
 *===========================================================================*/
PUBLIC void setreply(proc_nr, result)
int proc_nr;			/* process to reply to */
int result;			/* result of the call (usually OK or error #)*/
{
/* Fill in a reply message to be sent later to a user process.  System calls
 * may occasionally fill in other fields, this is only for the main return
 * value, and for setting the "must send reply" flag.
 */

  register struct mproc *rmp = &mproc[proc_nr];

  rmp->mp_reply.reply_res = result;
  rmp->mp_flags |= REPLY;	/* reply pending */

  if (rmp->mp_flags & ONSWAP)
	swap_inqueue(rmp);	/* must swap this process back in */
}


/*===========================================================================*
 *				mm_init					     *
 *===========================================================================*/
PRIVATE void mm_init()
{
/* Initialize the memory manager. */
  int s;
  static char core_sigs[] = { SIGQUIT, SIGILL, SIGTRAP, SIGABRT,
			SIGEMT, SIGFPE, SIGUSR1, SIGSEGV, SIGUSR2 };
  static char ign_sigs[] = { SIGCHLD };
  register int proc_nr;
  register struct mproc *rmp;
  register char *sig_ptr;
  phys_clicks ram_clicks, total_clicks, minix_clicks, free_clicks;
  message mess;
  struct mem_map kernel_map[NR_LOCAL_SEGS];
  int mem;

  /* Build the set of signals which cause core dumps, and the set of signals
   * that are by default ignored.
   */
  sigemptyset(&core_sset);
  for (sig_ptr = core_sigs; sig_ptr < core_sigs+sizeof(core_sigs); sig_ptr++)
	sigaddset(&core_sset, *sig_ptr);
  sigemptyset(&ign_sset);
  for (sig_ptr = ign_sigs; sig_ptr < ign_sigs+sizeof(ign_sigs); sig_ptr++)
	sigaddset(&ign_sset, *sig_ptr);

  /* Get the memory map of the kernel to see how much memory it uses. */
  if ((s=p_getmap(SYSTASK, kernel_map)) != OK)
  	panic("MM couldn't get proc entry of SYSTASK",s);
  minix_clicks = (kernel_map[S].mem_phys + kernel_map[S].mem_len)
				- kernel_map[T].mem_phys;

  /* Initialize MM's tables. Request a copy of the system image table that
   * is defined at the kernel level to see which slots to fill in.
   */
  for (proc_nr = 0; proc_nr <= INIT_PROC_NR; proc_nr++) {
	rmp = &mproc[proc_nr];
	rmp->mp_flags |= IN_USE;
	if ((s=p_getmap(proc_nr, rmp->mp_seg)) != OK)
  		panic("MM couldn't get proc entry",s);
	if (rmp->mp_seg[T].mem_len != 0) rmp->mp_flags |= SEPARATE;
	minix_clicks += (rmp->mp_seg[S].mem_phys + rmp->mp_seg[S].mem_len)
				- rmp->mp_seg[T].mem_phys;
  }
  mproc[INIT_PROC_NR].mp_pid = INIT_PID;
  sigemptyset(&mproc[INIT_PROC_NR].mp_ignore);
  sigemptyset(&mproc[INIT_PROC_NR].mp_catch);
  procs_in_use = LOW_USER + 1;

  /* Wait for FS to send a message telling the RAM disk size then go "on-line".
   */
  if (receive(FS_PROC_NR, &mess) != OK)
	panic("MM can't obtain RAM disk size from FS", NO_NUM);

  ram_clicks = mess.MEM_CHUNK_SIZE;

  /* Initialize tables to all physical mem. */
  mem_init(&free_clicks);
  total_clicks = minix_clicks + ram_clicks + free_clicks;

  /* Print memory information. */
  printf("Memory size=%uK   ", click_to_round_k(total_clicks));
  printf("MINIX=%uK   ", click_to_round_k(minix_clicks));
  printf("RAM disk=%uK   ", click_to_round_k(ram_clicks));
  printf("Available=%uK\n\n", click_to_round_k(free_clicks));

  /* Tell FS to continue. */
  if (send(FS_PROC_NR, &mess) != OK)
	panic("MM can't sync up with FS", NO_NUM);

  /* Tell the memory task where my process table is for the sake of ps(1). */
  if ((mem = open("/dev/ram", O_RDWR)) != -1) {
	ioctl(mem, MIOCSPSINFO, (void *) mproc);
	close(mem);
  }
}