350 lines
13 KiB
C
Executable File
350 lines
13 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 prepare_shutdown() tries to cleanly shuts down MINIX by running
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* the stop_sequence() to notify all system services and allowing them some
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* time to finalize. In case of an exception(), the stop sequence is skipped.
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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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* stop_sequence: take down all system services
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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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* Oct 21, 2004 moved copyright to announce() (Jorrit N. Herder)
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* Sep 04, 2004 created stop_sequence() to cleanup (Jorrit N. Herder)
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* Aug 20, 2004 split wreboot() and shutdown() (Jorrit N. Herder)
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* Jun 15, 2004 moved wreboot() to this file (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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#include "sendmask.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, (int how));
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#define STOP_TICKS (5*HZ) /* time allowed to stop */
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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 int i;
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int hdrindex; /* index to array of a.out headers */
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phys_clicks text_base, bootdev_base;
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vir_clicks text_clicks, bootdev_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 memory *memp;
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struct system_image *ttp;
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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
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* set up mappings for proc_addr() and proc_number() macros.
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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_type = P_NONE; /* isemptyp() tests on this */
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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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/* 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 < IMAGE_SIZE; ++i) {
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ttp = &image[i]; /* t's task attributes */
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rp = proc_addr(ttp->proc_nr); /* t's process slot */
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kstrncpy(rp->p_name, ttp->proc_name, PROC_NAME_LEN); /* set name */
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rp->p_type = ttp->type; /* type of process */
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rp->p_priority = ttp->priority; /* scheduling priority */
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rp->p_sendmask = ttp->sendmask; /* sendmask protection */
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if (i-NR_TASKS < 0) { /* part of the kernel? */
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if (ttp->stksize > 0) { /* HARDWARE stack size is 0 */
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rp->p_stguard = (reg_t *) ktsb;
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*rp->p_stguard = STACK_GUARD;
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}
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ktsb += ttp->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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/* Remove server memory from the free memory list. The boot monitor
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* promises to put processes at the start of memory chunks. The
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* tasks all use same base address, so only the first task changes
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* the memory lists. The servers and init have their own memory
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* spaces and their memory will be removed from the list.
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*/
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for (memp = mem; memp < &mem[NR_MEMS]; memp++) {
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if (memp->base == text_base) {
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memp->base += text_clicks + data_clicks;
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memp->size -= text_clicks + data_clicks;
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}
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}
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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) ttp->initial_pc;
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rp->p_reg.psw = (isidlep(rp)||istaskp(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_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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/* Remove from free list, to prevent being overwritten. */
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bootdev_base = e_hdr.a_syms >> CLICK_SHIFT;
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bootdev_clicks = (e_hdr.a_total + CLICK_SIZE-1) >> CLICK_SHIFT;
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for (memp = mem; memp < &mem[NR_MEMS]; memp++) {
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if (memp->base == bootdev_base) {
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memp->base += bootdev_clicks;
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memp->size -= bootdev_clicks;
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}
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}
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}
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#endif
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/* This actually is not needed, because ready() already set 'proc_ptr.' */
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lock_pick_proc();
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bill_ptr = proc_addr(IDLE); /* it has to point somewhere */
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/* MINIX is now ready. Display the startup banner to the user and return
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* to the assembly code to start running the current process.
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*/
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announce();
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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(kinfo.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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/* Check if boot device was loaded with the kernel. */
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if (kinfo.bootdev_base > 0)
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kprintf("Image of /dev/boot loaded. Size: %u KB.\n", kinfo.bootdev_size);
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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; /* 0 = halt, 1 = reboot, 2 = panic!, ... */
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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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* stop_sequence() is started.
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*/
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if (shutting_down)
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return;
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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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message m;
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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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/* The TTY expects two HARD_STOP notifications. One to switch to the
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* primary console for stop sequence output, and one to actually exit.
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*/
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notify(TTY, HARD_STOP); /* let TTY switch to console 0 */
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/* Run the stop sequence. The timer argument passes the shutdown status.
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* The stop sequence is skipped for fatal CPU exceptions.
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*/
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shutting_down = TRUE; /* flag for sys_exit() */
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tmr_arg(&shutdown_timer)->ta_int = how; /* pass how in timer */
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if (skip_stop_sequence) { /* set in exception() */
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kprintf("\nAn exception occured; skipping stop sequence.\n", NO_ARG);
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shutdown(how); /* TTY isn't scheduled */
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} else {
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kprintf("\nNotifying system services about MINIX shutdown.\n", NO_ARG);
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kprintf("Known bug: hitting a key before done will hang the monitor.\n", NO_ARG);
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stop_sequence(&shutdown_timer);
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}
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}
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/*==========================================================================*
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* stop_sequence *
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*==========================================================================*/
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PUBLIC void stop_sequence(tp)
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timer_t *tp;
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{
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/* Try to cleanly stop all system services before shutting down. For each
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* process type, all processes are notified and given STOP_TICKS to cleanly
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* shutdown. The notification order is servers, drivers, tasks. The variable
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* 'shutdown_process' is set globally to indicate the process next to stop
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* so that the stop sequence can directly continue if it has exited. Only if
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* stop sequence has finished, MINIX is brought down.
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*/
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static int level = P_SERVER; /* start at the highest level */
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static struct proc *p = NIL_PROC; /* next process to stop */
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static char *types[] = {"task","system","driver","server","user"};
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/* See if the last process' shutdown was successful. Else, force exit. */
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if (p != NIL_PROC) {
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kprintf("[%s]\n", isalivep(p) ? karg("FAILED") : karg("OK"));
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if (isalivep(p))
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clear_proc(p->p_nr); /* now force process to exit */
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}
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/* Find the next process that must be stopped. Continue where last search
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* ended or start at begin. Possibly go to next level while searching. If
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* the last level is completely searched, shutdown MINIX. Processes are
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* stopped in the order of dependencies, that is, from the highest level to
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* the lowest level so that, for example, the file system can still rely on
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* device drivers to cleanly shutdown.
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*/
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if (p == NIL_PROC) p = BEG_PROC_ADDR;
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while (TRUE) {
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if (isalivep(p) && p->p_type == level) { /* found a process */
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int w;
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kprintf("- Stopping %s ", karg(p->p_name));
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kprintf("%s ... ", karg(types[p->p_type]));
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shutdown_process = p; /* directly continue if exited */
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notify(proc_number(p), HARD_STOP);
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set_timer(tp, get_uptime()+STOP_TICKS, stop_sequence);
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return; /* allow the process to shut down */
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}
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p++; /* proceed to next process */
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if (p >= END_PROC_ADDR) { /* proceed to next level */
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p = BEG_PROC_ADDR;
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level = level - 1;
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if (level == P_TASK) { /* done; tasks must remain alive */
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shutdown(tmr_arg(tp)->ta_int);
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/* no return */
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return;
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}
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}
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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(int how)
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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_REBOOT, RBT_HALT,
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* RBT_RESET.
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*/
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static u16_t magic = STOP_MEM_CHECK;
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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 for the boot monitor.
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* For RBT_MONITOR, the MM has provided the program.
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*/
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if (how == RBT_HALT) {
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phys_copy(vir2phys("delay;"), kinfo.params_base, 7);
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} else if (how == RBT_REBOOT) {
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phys_copy(vir2phys("delay;boot"), kinfo.params_base, 11);
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}
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level0(monitor);
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}
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/* Stop BIOS memory test. */
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phys_copy(vir2phys(&magic), SOFT_RESET_FLAG_ADDR, SOFT_RESET_FLAG_SIZE);
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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).
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*/
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level0(reset);
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}
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