/* This file contains the main program of MINIX as well as its shutdown code. * The routine main() initializes the system and starts the ball rolling by * setting up the process table, interrupt vectors, and scheduling each task * to run to initialize itself. * The routine shutdown() does the opposite and brings down MINIX. * * The entries into this file are: * main: MINIX main program * prepare_shutdown: prepare to take MINIX down */ #include "kernel.h" #include #include #include #include #include #include "proc.h" #include "debug.h" #include "clock.h" /* Prototype declarations for PRIVATE functions. */ FORWARD _PROTOTYPE( void announce, (void)); /*===========================================================================* * main * *===========================================================================*/ PUBLIC void main() { /* Start the ball rolling. */ struct boot_image *ip; /* boot image pointer */ register struct proc *rp; /* process pointer */ register struct priv *sp; /* privilege structure pointer */ register int i, j; int hdrindex; /* index to array of a.out headers */ phys_clicks text_base; vir_clicks text_clicks, data_clicks, st_clicks; reg_t ktsb; /* kernel task stack base */ struct exec e_hdr; /* for a copy of an a.out header */ /* Global value to test segment sanity. */ magictest = MAGICTEST; DEBUGMAX(("main()\n")); /* Clear the process table. Anounce each slot as empty and set up mappings * for proc_addr() and proc_nr() macros. Do the same for the table with * privilege structures for the system processes. */ for (rp = BEG_PROC_ADDR, i = -NR_TASKS; rp < END_PROC_ADDR; ++rp, ++i) { rp->p_rts_flags = RTS_SLOT_FREE; /* initialize free slot */ #if DEBUG_SCHED_CHECK rp->p_magic = PMAGIC; #endif rp->p_nr = i; /* proc number from ptr */ rp->p_endpoint = _ENDPOINT(0, rp->p_nr); /* generation no. 0 */ } for (sp = BEG_PRIV_ADDR, i = 0; sp < END_PRIV_ADDR; ++sp, ++i) { sp->s_proc_nr = NONE; /* initialize as free */ sp->s_id = (proc_nr_t) i; /* priv structure index */ ppriv_addr[i] = sp; /* priv ptr from number */ } /* Set up proc table entries for processes in boot image. The stacks of the * kernel tasks are initialized to an array in data space. The stacks * of the servers have been added to the data segment by the monitor, so * the stack pointer is set to the end of the data segment. All the * processes are in low memory on the 8086. On the 386 only the kernel * is in low memory, the rest is loaded in extended memory. */ /* Task stacks. */ ktsb = (reg_t) t_stack; for (i=0; i < NR_BOOT_PROCS; ++i) { int schedulable_proc; proc_nr_t proc_nr; int ipc_to_m, kcalls; ip = &image[i]; /* process' attributes */ DEBUGMAX(("initializing %s... ", ip->proc_name)); rp = proc_addr(ip->proc_nr); /* get process pointer */ ip->endpoint = rp->p_endpoint; /* ipc endpoint */ rp->p_max_priority = ip->priority; /* max scheduling priority */ rp->p_priority = ip->priority; /* current priority */ rp->p_quantum_size = ip->quantum; /* quantum size in ticks */ rp->p_ticks_left = ip->quantum; /* current credit */ strncpy(rp->p_name, ip->proc_name, P_NAME_LEN); /* set process name */ /* See if this process is immediately schedulable. * In that case, set its privileges now and allow it to run. * Only kernel tasks and the root system process get to run immediately. * All the other system processes are inhibited from running by the * RTS_NO_PRIV flag. They can only be scheduled once the root system * process has set their privileges. */ proc_nr = proc_nr(rp); schedulable_proc = (iskerneln(proc_nr) || isrootsysn(proc_nr)); if(schedulable_proc) { /* Assign privilege structure. Force a static privilege id. */ (void) get_priv(rp, static_priv_id(proc_nr)); /* Priviliges for kernel tasks. */ if(iskerneln(proc_nr)) { /* Privilege flags. */ priv(rp)->s_flags = (proc_nr == IDLE ? IDL_F : TSK_F); /* Allowed traps. */ priv(rp)->s_trap_mask = (proc_nr == CLOCK || proc_nr == SYSTEM ? CSK_T : TSK_T); ipc_to_m = TSK_M; /* allowed targets */ kcalls = TSK_KC; /* allowed kernel calls */ } /* Priviliges for the root system process. */ else if(isrootsysn(proc_nr)) { priv(rp)->s_flags= RSYS_F; /* privilege flags */ priv(rp)->s_trap_mask= RSYS_T; /* allowed traps */ ipc_to_m = RSYS_M; /* allowed targets */ kcalls = RSYS_KC; /* allowed kernel calls */ } /* Priviliges for ordinary process. */ else { NOT_REACHABLE; } /* Fill in target mask. */ for (j=0; j < NR_SYS_PROCS; j++) { if (ipc_to_m & (1 << j)) set_sendto_bit(rp, j); else unset_sendto_bit(rp, j); } /* Fill in kernel call mask. */ for(j = 0; j < SYS_CALL_MASK_SIZE; j++) { priv(rp)->s_k_call_mask[j] = (kcalls == NO_C ? 0 : (~0)); } } else { /* Don't let the process run for now. */ RTS_SET(rp, RTS_NO_PRIV); } if (iskerneln(proc_nr)) { /* part of the kernel? */ if (ip->stksize > 0) { /* HARDWARE stack size is 0 */ rp->p_priv->s_stack_guard = (reg_t *) ktsb; *rp->p_priv->s_stack_guard = STACK_GUARD; } ktsb += ip->stksize; /* point to high end of stack */ rp->p_reg.sp = ktsb; /* this task's initial stack ptr */ hdrindex = 0; /* all use the first a.out header */ } else { hdrindex = 1 + i-NR_TASKS; /* system/user processes */ } /* Architecture-specific way to find out aout header of this * boot process. */ arch_get_aout_headers(hdrindex, &e_hdr); /* Convert addresses to clicks and build process memory map */ text_base = e_hdr.a_syms >> CLICK_SHIFT; text_clicks = (vir_clicks) (CLICK_CEIL(e_hdr.a_text) >> CLICK_SHIFT); data_clicks = (vir_clicks) (CLICK_CEIL(e_hdr.a_data + e_hdr.a_bss) >> CLICK_SHIFT); st_clicks = (vir_clicks) (CLICK_CEIL(e_hdr.a_total) >> CLICK_SHIFT); if (!(e_hdr.a_flags & A_SEP)) { data_clicks = (vir_clicks) (CLICK_CEIL(e_hdr.a_text + e_hdr.a_data + e_hdr.a_bss) >> CLICK_SHIFT); text_clicks = 0; /* common I&D */ } rp->p_memmap[T].mem_phys = text_base; rp->p_memmap[T].mem_len = text_clicks; rp->p_memmap[D].mem_phys = text_base + text_clicks; rp->p_memmap[D].mem_len = data_clicks; rp->p_memmap[S].mem_phys = text_base + text_clicks + st_clicks; rp->p_memmap[S].mem_vir = st_clicks; rp->p_memmap[S].mem_len = 0; /* Set initial register values. The processor status word for tasks * is different from that of other processes because tasks can * access I/O; this is not allowed to less-privileged processes */ rp->p_reg.pc = (reg_t) ip->initial_pc; rp->p_reg.psw = (iskerneln(proc_nr)) ? INIT_TASK_PSW : INIT_PSW; /* Initialize the server stack pointer. Take it down one word * to give crtso.s something to use as "argc". */ if (isusern(proc_nr)) { /* user-space process? */ rp->p_reg.sp = (rp->p_memmap[S].mem_vir + rp->p_memmap[S].mem_len) << CLICK_SHIFT; rp->p_reg.sp -= sizeof(reg_t); } /* scheduling functions depend on proc_ptr pointing somewhere. */ if(!proc_ptr) proc_ptr = rp; /* If this process has its own page table, VM will set the * PT up and manage it. VM will signal the kernel when it has * done this; until then, don't let it run. */ if(ip->flags & PROC_FULLVM) RTS_SET(rp, RTS_VMINHIBIT); /* None of the kernel tasks run */ if (rp->p_nr < 0) RTS_SET(rp, RTS_PROC_STOP); RTS_UNSET(rp, RTS_SLOT_FREE); /* remove RTS_SLOT_FREE and schedule */ alloc_segments(rp); DEBUGMAX(("done\n")); } /* Architecture-dependent initialization. */ DEBUGMAX(("arch_init()... ")); arch_init(); DEBUGMAX(("done\n")); /* System and processes initialization */ DEBUGMAX(("system_init()... ")); system_init(); DEBUGMAX(("done\n")); /* Initialize timers handling */ DEBUGMAX(("clock_init()... ")); clock_init(); DEBUGMAX(("done\n")); #if SPROFILE sprofiling = 0; /* we're not profiling until instructed to */ #endif /* SPROFILE */ cprof_procs_no = 0; /* init nr of hash table slots used */ vm_running = 0; krandom.random_sources = RANDOM_SOURCES; krandom.random_elements = RANDOM_ELEMENTS; /* MINIX is now ready. All boot image processes are on the ready queue. * Return to the assembly code to start running the current process. */ bill_ptr = proc_addr(IDLE); /* it has to point somewhere */ announce(); /* print MINIX startup banner */ /* * enable timer interrupts and clock task on the boot CPU */ if (boot_cpu_init_timer(system_hz)) { panic( "FATAL : failed to initialize timer interrupts; " "cannot continue without any clock source!"); } /* Warnings for sanity checks that take time. These warnings are printed * so it's a clear warning no full release should be done with them * enabled. */ #if DEBUG_SCHED_CHECK FIXME("DEBUG_SCHED_CHECK enabled"); #endif #if DEBUG_VMASSERT FIXME("DEBUG_VMASSERT enabled"); #endif #if DEBUG_PROC_CHECK FIXME("PROC check enabled"); #endif DEBUGMAX(("cycles_accounting_init()... ")); cycles_accounting_init(); DEBUGMAX(("done\n")); restart(); NOT_REACHABLE; } /*===========================================================================* * announce * *===========================================================================*/ PRIVATE void announce(void) { /* Display the MINIX startup banner. */ printf("\nMINIX %s.%s. " #ifdef _SVN_REVISION "(" _SVN_REVISION ")\n" #endif "Copyright 2010, Vrije Universiteit, Amsterdam, The Netherlands\n", OS_RELEASE, OS_VERSION); printf("MINIX is open source software, see http://www.minix3.org\n"); } /*===========================================================================* * prepare_shutdown * *===========================================================================*/ PUBLIC void prepare_shutdown(how) int how; { /* This function prepares to shutdown MINIX. */ static timer_t shutdown_timer; /* Continue after 1 second, to give processes a chance to get scheduled to * do shutdown work. Set a watchog timer to call shutdown(). The timer * argument passes the shutdown status. */ printf("MINIX will now be shut down ...\n"); tmr_arg(&shutdown_timer)->ta_int = how; set_timer(&shutdown_timer, get_uptime() + system_hz, minix_shutdown); } /*===========================================================================* * shutdown * *===========================================================================*/ PUBLIC void minix_shutdown(tp) timer_t *tp; { /* This function is called from prepare_shutdown or stop_sequence to bring * down MINIX. How to shutdown is in the argument: RBT_HALT (return to the * monitor), RBT_MONITOR (execute given code), RBT_RESET (hard reset). */ arch_stop_local_timer(); intr_init(INTS_ORIG, 0); arch_shutdown(tp ? tmr_arg(tp)->ta_int : RBT_PANIC); }