198c976f7e
that passes signal map along. This mechanisms is also used for nonuser signals like SIGKMESS, SIGKSTOP, SIGKSIG. Revised comments of many system call handlers. Renamed setpriority to nice.
259 lines
9.7 KiB
C
Executable file
259 lines
9.7 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 <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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register struct proc *rp;
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register struct priv *sp;
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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;
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vir_clicks data_clicks;
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reg_t ktsb; /* kernel task stack base */
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struct system_image *ip; /* boot image pointer */
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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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* system properties structures.
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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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(void) init_proc(ip->proc_nr, NONE); /* initialize new process */
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rp = proc_addr(ip->proc_nr); /* get process pointer */
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kstrncpy(rp->p_name, ip->proc_name, P_NAME_LEN); /* set name */
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rp->p_name[P_NAME_LEN-1] = '\0'; /* just for safety */
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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_sched_ticks = ip->quantum; /* current credit */
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rp->p_full_quantums = QUANTUMS(ip->priority); /* quantums left */
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rp->p_priv->s_flags = ip->flags; /* process flags */
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rp->p_priv->s_call_mask = ip->call_mask;/* allowed system calls */
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if (i-NR_TASKS < 0) { /* 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; /* drivers, servers, INIT follow */
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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 (i-NR_TASKS >= 0) {
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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) lock_ready(rp);
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rp->p_rts_flags = 0;
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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. Copyright 2001 Prentice-Hall, Inc.\n",
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karg(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 ? karg("32-bit protected") : karg("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; /* reason to shut down */
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{
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/* This function prepares to shutdown MINIX. It uses a global flag to make
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* sure it is only executed once. Unless a CPU exception occurred, the
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*/
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static timer_t shutdown_timer; /* timer for watchdog function */
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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, &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 signal to TTY so that it can switch to the primary console. */
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send_sig(TTY, SIGKSTOP);
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/* Allow processes to be scheduled to clean up, unless a CPU exception
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* occurred. This is done by setting a timer. The timer argument passes
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* the shutdown status.
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*/
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tmr_arg(&shutdown_timer)->ta_int = how; /* pass how in timer */
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if (kernel_exception) { /* set in exception() */
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kprintf("\nAn exception occured; skipping stop sequence.\n", NO_NUM);
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shutdown(&shutdown_timer); /* TTY isn't scheduled */
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} else {
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kprintf("\nNotifying system services about MINIX shutdown.\n", NO_NUM);
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set_timer(&shutdown_timer, get_uptime(), shutdown);
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}
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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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