301 lines
11 KiB
C
301 lines
11 KiB
C
/* 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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#include "kernel.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/com.h>
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#include <minix/endpoint.h>
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#include "proc.h"
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#include "debug.h"
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#include "clock.h"
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/* Prototype declarations for PRIVATE functions. */
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FORWARD _PROTOTYPE( void announce, (void));
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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, j;
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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, st_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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/* Global value to test segment sanity. */
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magictest = MAGICTEST;
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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 = RTS_SLOT_FREE; /* initialize free slot */
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#if DEBUG_SCHED_CHECK
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rp->p_magic = PMAGIC;
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#endif
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rp->p_nr = i; /* proc number from ptr */
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rp->p_endpoint = _ENDPOINT(0, rp->p_nr); /* generation no. 0 */
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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 processes in boot image. 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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int schedulable_proc, proc_nr;
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int ipc_to_m, kcalls;
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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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ip->endpoint = rp->p_endpoint; /* ipc endpoint */
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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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/* See if this process is immediately schedulable.
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* In that case, set its privileges now and allow it to run.
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* Only kernel tasks and the root system process get to run immediately.
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* All the other system processes are inhibited from running by the
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* RTS_NO_PRIV flag. They can only be scheduled once the root system
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* process has set their privileges.
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*/
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proc_nr = proc_nr(rp);
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schedulable_proc = (iskerneln(proc_nr) || isrootsysn(proc_nr));
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if(schedulable_proc) {
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/* Assign privilege structure. Force a static privilege id. */
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(void) get_priv(rp, static_priv_id(proc_nr));
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/* Priviliges for kernel tasks. */
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if(iskerneln(proc_nr)) {
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/* Privilege flags. */
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priv(rp)->s_flags = (proc_nr == IDLE ? IDL_F : TSK_F);
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/* Allowed traps. */
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priv(rp)->s_trap_mask = (proc_nr == CLOCK
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|| proc_nr == SYSTEM ? CSK_T : TSK_T);
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ipc_to_m = TSK_M; /* allowed targets */
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kcalls = TSK_KC; /* allowed kernel calls */
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}
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/* Priviliges for the root system process. */
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else if(isrootsysn(proc_nr)) {
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priv(rp)->s_flags= RSYS_F; /* privilege flags */
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priv(rp)->s_trap_mask= RSYS_T; /* allowed traps */
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ipc_to_m = RSYS_M; /* allowed targets */
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kcalls = RSYS_KC; /* allowed kernel calls */
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}
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/* Fill in target mask. */
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for (j=0; j < NR_SYS_PROCS; j++) {
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if (ipc_to_m & (1 << j))
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set_sendto_bit(rp, j);
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else
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unset_sendto_bit(rp, j);
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}
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/* Fill in kernel call mask. */
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for(j = 0; j < SYS_CALL_MASK_SIZE; j++) {
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priv(rp)->s_k_call_mask[j] = (kcalls == NO_C ? 0 : (~0));
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}
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}
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else {
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/* Don't let the process run for now. */
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RTS_SET(rp, RTS_NO_PRIV);
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}
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if (iskerneln(proc_nr)) { /* 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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hdrindex = 0; /* all use the first a.out header */
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} else {
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hdrindex = 1 + i-NR_TASKS; /* system/user processes */
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}
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/* Architecture-specific way to find out aout header of this
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* boot process.
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*/
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arch_get_aout_headers(hdrindex, &e_hdr);
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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 = (vir_clicks) (CLICK_CEIL(e_hdr.a_text) >> CLICK_SHIFT);
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data_clicks = (vir_clicks) (CLICK_CEIL(e_hdr.a_data
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+ e_hdr.a_bss) >> CLICK_SHIFT);
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st_clicks = (vir_clicks) (CLICK_CEIL(e_hdr.a_total) >> CLICK_SHIFT);
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if (!(e_hdr.a_flags & A_SEP))
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{
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data_clicks = (vir_clicks) (CLICK_CEIL(e_hdr.a_text +
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e_hdr.a_data + e_hdr.a_bss) >> CLICK_SHIFT);
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text_clicks = 0; /* common I&D */
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}
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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 + st_clicks;
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rp->p_memmap[S].mem_vir = st_clicks;
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rp->p_memmap[S].mem_len = 0;
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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 = (iskerneln(proc_nr)) ? 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)) { /* 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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/* scheduling functions depend on proc_ptr pointing somewhere. */
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if(!proc_ptr) proc_ptr = rp;
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/* If this process has its own page table, VM will set the
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* PT up and manage it. VM will signal the kernel when it has
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* done this; until then, don't let it run.
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*/
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if(ip->flags & PROC_FULLVM)
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RTS_SET(rp, RTS_VMINHIBIT);
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/* Set ready. The HARDWARE task is never ready. */
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if (rp->p_nr == HARDWARE) RTS_SET(rp, RTS_PROC_STOP);
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/* IDLE task is never put on a run queue as it is never ready to run */
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if (rp->p_nr == IDLE) RTS_SET(rp, RTS_PROC_STOP);
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RTS_UNSET(rp, RTS_SLOT_FREE); /* remove RTS_SLOT_FREE and schedule */
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alloc_segments(rp);
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}
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/* Architecture-dependent initialization. */
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arch_init();
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#if SPROFILE
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sprofiling = 0; /* we're not profiling until instructed to */
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#endif /* SPROFILE */
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cprof_procs_no = 0; /* init nr of hash table slots used */
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#ifdef CONFIG_IDLE_TSC
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idle_tsc = cvu64(0);
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#endif
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vm_running = 0;
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krandom.random_sources = RANDOM_SOURCES;
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krandom.random_elements = RANDOM_ELEMENTS;
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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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/*
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* enable timer interrupts and clock task on the boot CPU
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*/
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if (boot_cpu_init_timer(system_hz)) {
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minix_panic("FATAL : failed to initialize timer interrupts, "
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"cannot continue without any clock source!",
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NO_NUM);
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}
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/* Warnings for sanity checks that take time. These warnings are printed
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* so it's a clear warning no full release should be done with them
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* enabled.
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*/
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#if DEBUG_SCHED_CHECK
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FIXME("DEBUG_SCHED_CHECK enabled");
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#endif
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#if DEBUG_VMASSERT
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FIXME("DEBUG_VMASSERT enabled");
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#endif
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#if DEBUG_PROC_CHECK
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FIXME("PROC check enabled");
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#endif
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restart();
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NOT_REACHABLE;
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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("\nMINIX %s.%s. "
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#ifdef _SVN_REVISION
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"(" _SVN_REVISION ")\n"
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#endif
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"Copyright 2009, Vrije Universiteit, Amsterdam, The Netherlands\n",
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OS_RELEASE, OS_VERSION);
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kprintf("MINIX is open source software, see http://www.minix3.org\n");
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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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/* Continue after 1 second, to give processes a chance to get scheduled to
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* do shutdown work. Set a watchog timer to call 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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set_timer(&shutdown_timer, get_uptime() + system_hz, minix_shutdown);
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}
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/*===========================================================================*
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* shutdown *
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*===========================================================================*/
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PUBLIC void minix_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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arch_stop_local_timer();
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intr_init(INTS_ORIG, 0);
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arch_shutdown(tp ? tmr_arg(tp)->ta_int : RBT_PANIC);
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}
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