265 lines
10 KiB
C
Executable file
265 lines
10 KiB
C
Executable file
/* This file contains the main program of MINIX as well as its shutdown code.
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* The routine main() initializes the system and starts the ball rolling by
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* setting up the process table, interrupt vectors, and scheduling each task
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* to run to initialize itself.
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* The routine shutdown() does the opposite and brings down MINIX.
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*
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* The entries into this file are:
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* main: MINIX main program
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* prepare_shutdown: prepare to take MINIX down
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*
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* Changes:
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* Nov 24, 2004 simplified main() with system image (Jorrit N. Herder)
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* Aug 20, 2004 new prepare_shutdown() and shutdown() (Jorrit N. Herder)
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*/
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#include "kernel.h"
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#include <signal.h>
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#include <string.h>
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#include <unistd.h>
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#include <a.out.h>
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#include <minix/callnr.h>
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#include <minix/com.h>
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#include "proc.h"
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/* Prototype declarations for PRIVATE functions. */
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FORWARD _PROTOTYPE( void announce, (void));
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FORWARD _PROTOTYPE( void shutdown, (timer_t *tp));
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/*===========================================================================*
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* main *
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*===========================================================================*/
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PUBLIC void main()
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{
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/* Start the ball rolling. */
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struct boot_image *ip; /* boot image pointer */
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register struct proc *rp; /* process pointer */
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register struct priv *sp; /* privilege structure pointer */
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register int i, s;
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int hdrindex; /* index to array of a.out headers */
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phys_clicks text_base;
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vir_clicks text_clicks, data_clicks;
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reg_t ktsb; /* kernel task stack base */
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struct exec e_hdr; /* for a copy of an a.out header */
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/* Initialize the interrupt controller. */
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intr_init(1);
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/* Clear the process table. Anounce each slot as empty and set up mappings
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* for proc_addr() and proc_nr() macros. Do the same for the table with
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* privilege structures for the system processes.
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*/
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for (rp = BEG_PROC_ADDR, i = -NR_TASKS; rp < END_PROC_ADDR; ++rp, ++i) {
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rp->p_rts_flags = SLOT_FREE; /* initialize free slot */
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rp->p_nr = i; /* proc number from ptr */
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(pproc_addr + NR_TASKS)[i] = rp; /* proc ptr from number */
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}
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for (sp = BEG_PRIV_ADDR, i = 0; sp < END_PRIV_ADDR; ++sp, ++i) {
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sp->s_proc_nr = NONE; /* initialize as free */
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sp->s_id = i; /* priv structure index */
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ppriv_addr[i] = sp; /* priv ptr from number */
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}
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/* Set up proc table entries for tasks and servers. The stacks of the
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* kernel tasks are initialized to an array in data space. The stacks
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* of the servers have been added to the data segment by the monitor, so
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* the stack pointer is set to the end of the data segment. All the
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* processes are in low memory on the 8086. On the 386 only the kernel
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* is in low memory, the rest is loaded in extended memory.
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*/
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/* Task stacks. */
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ktsb = (reg_t) t_stack;
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for (i=0; i < NR_BOOT_PROCS; ++i) {
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ip = &image[i]; /* process' attributes */
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rp = proc_addr(ip->proc_nr); /* get process pointer */
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rp->p_max_priority = ip->priority; /* max scheduling priority */
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rp->p_priority = ip->priority; /* current priority */
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rp->p_quantum_size = ip->quantum; /* quantum size in ticks */
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rp->p_ticks_left = ip->quantum; /* current credit */
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strncpy(rp->p_name, ip->proc_name, P_NAME_LEN); /* set process name */
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(void) get_priv(rp, (ip->flags & SYS_PROC)); /* assign structure */
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priv(rp)->s_flags = ip->flags; /* process flags */
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priv(rp)->s_trap_mask = ip->trap_mask; /* allowed traps */
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priv(rp)->s_call_mask = ip->call_mask; /* kernel call mask */
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priv(rp)->s_ipc_to.chunk[0] = ip->ipc_to; /* restrict targets */
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if (iskerneln(proc_nr(rp))) { /* part of the kernel? */
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if (ip->stksize > 0) { /* HARDWARE stack size is 0 */
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rp->p_priv->s_stack_guard = (reg_t *) ktsb;
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*rp->p_priv->s_stack_guard = STACK_GUARD;
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}
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ktsb += ip->stksize; /* point to high end of stack */
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rp->p_reg.sp = ktsb; /* this task's initial stack ptr */
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text_base = kinfo.code_base >> CLICK_SHIFT;
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/* processes that are in the kernel */
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hdrindex = 0; /* all use the first a.out header */
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} else {
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hdrindex = 1 + i-NR_TASKS; /* servers, drivers, INIT */
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}
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/* The bootstrap loader created an array of the a.out headers at
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* absolute address 'aout'. Get one element to e_hdr.
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*/
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phys_copy(aout + hdrindex * A_MINHDR, vir2phys(&e_hdr),
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(phys_bytes) A_MINHDR);
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/* Convert addresses to clicks and build process memory map */
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text_base = e_hdr.a_syms >> CLICK_SHIFT;
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text_clicks = (e_hdr.a_text + CLICK_SIZE-1) >> CLICK_SHIFT;
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if (!(e_hdr.a_flags & A_SEP)) text_clicks = 0; /* common I&D */
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data_clicks = (e_hdr.a_total + CLICK_SIZE-1) >> CLICK_SHIFT;
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rp->p_memmap[T].mem_phys = text_base;
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rp->p_memmap[T].mem_len = text_clicks;
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rp->p_memmap[D].mem_phys = text_base + text_clicks;
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rp->p_memmap[D].mem_len = data_clicks;
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rp->p_memmap[S].mem_phys = text_base + text_clicks + data_clicks;
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rp->p_memmap[S].mem_vir = data_clicks; /* empty - stack is in data */
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/* Set initial register values. The processor status word for tasks
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* is different from that of other processes because tasks can
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* access I/O; this is not allowed to less-privileged processes
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*/
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rp->p_reg.pc = (reg_t) ip->initial_pc;
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rp->p_reg.psw = (iskernelp(rp)) ? INIT_TASK_PSW : INIT_PSW;
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/* Initialize the server stack pointer. Take it down one word
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* to give crtso.s something to use as "argc".
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*/
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if (isusern(proc_nr(rp))) { /* user-space process? */
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rp->p_reg.sp = (rp->p_memmap[S].mem_vir +
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rp->p_memmap[S].mem_len) << CLICK_SHIFT;
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rp->p_reg.sp -= sizeof(reg_t);
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}
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/* Set ready. The HARDWARE task is never ready. */
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if (rp->p_nr != HARDWARE) {
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rp->p_rts_flags = 0; /* runnable if no flags */
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lock_enqueue(rp); /* add to scheduling queues */
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} else {
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rp->p_rts_flags = NO_MAP; /* prevent from running */
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}
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/* Code and data segments must be allocated in protected mode. */
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alloc_segments(rp);
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}
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#if ENABLE_BOOTDEV
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/* Expect an image of the boot device to be loaded into memory as well.
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* The boot device is the last module that is loaded into memory, and,
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* for example, can contain the root FS (useful for embedded systems).
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*/
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hdrindex ++;
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phys_copy(aout + hdrindex * A_MINHDR,vir2phys(&e_hdr),(phys_bytes) A_MINHDR);
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if (e_hdr.a_flags & A_IMG) {
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kinfo.bootdev_base = e_hdr.a_syms;
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kinfo.bootdev_size = e_hdr.a_data;
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}
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#endif
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/* MINIX is now ready. All boot image processes are on the ready queue.
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* Return to the assembly code to start running the current process.
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*/
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bill_ptr = proc_addr(IDLE); /* it has to point somewhere */
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announce(); /* print MINIX startup banner */
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restart();
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}
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/*==========================================================================*
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* announce *
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*==========================================================================*/
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PRIVATE void announce(void)
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{
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/* Display the MINIX startup banner. */
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kprintf("MINIX %s.%s. Copyright 1987-2001 Prentice-Hall, Inc.\n",
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OS_RELEASE, OS_VERSION);
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#if (CHIP == INTEL)
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/* Real mode, or 16/32-bit protected mode? */
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kprintf("Executing in %s mode.\n\n",
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machine.protected ? "32-bit protected" : "real");
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#endif
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}
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/*==========================================================================*
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* prepare_shutdown *
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*==========================================================================*/
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PUBLIC void prepare_shutdown(how)
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int how;
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{
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/* This function prepares to shutdown MINIX. */
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static timer_t shutdown_timer;
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register struct proc *rp;
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message m;
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/* Show debugging dumps on panics. Make sure that the TTY task is still
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* available to handle them. This is done with help of a non-blocking send.
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* We rely on TTY to call sys_abort() when it is done with the dumps.
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*/
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if (how == RBT_PANIC) {
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m.m_type = PANIC_DUMPS;
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if (nb_send(TTY_PROC_NR,&m)==OK) /* don't block if TTY isn't ready */
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return; /* await sys_abort() from TTY */
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}
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/* Send a signal to all system processes that are still alive to inform
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* them that the MINIX kernel is shutting down. A proper shutdown sequence
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* should be implemented by a user-space server. This mechanism is useful
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* as a backup in case of system panics, so that system processes can still
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* run their shutdown code, e.g, to synchronize the FS or to let the TTY
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* switch to the first console.
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*/
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kprintf("Sending SIGKSTOP to system processes ...\n");
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for (rp=BEG_PROC_ADDR; rp<END_PROC_ADDR; rp++) {
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if (!isemptyp(rp) && (priv(rp)->s_flags & SYS_PROC) && !iskernelp(rp))
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send_sig(proc_nr(rp), SIGKSTOP);
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}
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/* Notify system processes of the upcoming shutdown and allow them to be
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* scheduled by setting a watchog timer that calls shutdown(). The timer
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* argument passes the shutdown status.
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*/
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kprintf("MINIX will now be shut down ...\n");
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tmr_arg(&shutdown_timer)->ta_int = how;
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#if DEAD_CODE /* timer hangs the boot monitor ... to be fixed! */
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set_timer(&shutdown_timer, get_uptime() + HZ, shutdown);
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#else
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shutdown(&shutdown_timer);
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#endif
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}
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/*==========================================================================*
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* shutdown *
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*==========================================================================*/
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PRIVATE void shutdown(tp)
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timer_t *tp;
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{
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/* This function is called from prepare_shutdown or stop_sequence to bring
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* down MINIX. How to shutdown is in the argument: RBT_HALT (return to the
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* monitor), RBT_MONITOR (execute given code), RBT_RESET (hard reset).
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*/
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int how = tmr_arg(tp)->ta_int;
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u16_t magic;
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/* Now mask all interrupts, including the clock, and stop the clock. */
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outb(INT_CTLMASK, ~0);
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clock_stop();
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if (mon_return && how != RBT_RESET) {
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/* Reinitialize the interrupt controllers to the BIOS defaults. */
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intr_init(0);
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outb(INT_CTLMASK, 0);
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outb(INT2_CTLMASK, 0);
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/* Return to the boot monitor. Set the program if not already done. */
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if (how != RBT_MONITOR) phys_copy(vir2phys(""), kinfo.params_base, 1);
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level0(monitor);
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}
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/* Reset the system by jumping to the reset address (real mode), or by
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* forcing a processor shutdown (protected mode). First stop the BIOS
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* memory test by setting a soft reset flag.
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*/
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magic = STOP_MEM_CHECK;
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phys_copy(vir2phys(&magic), SOFT_RESET_FLAG_ADDR, SOFT_RESET_FLAG_SIZE);
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level0(reset);
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}
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