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minix/kernel/main.c
Tomas Hruby dcc81d73e8 boot image - no need for entry point 
- removes the initial_pc from struct boot_image. It is always set
  to 0 and RS uses a.out headers.
2010-05-18 13:51:46 +00:00

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/* 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 <string.h>
#include <unistd.h>
#include <assert.h>
#include <a.out.h>
#include <minix/com.h>
#include <minix/endpoint.h>
#include "proc.h"
#include "debug.h"
#include "clock.h"
/* Prototype declarations for PRIVATE functions. */
FORWARD _PROTOTYPE( void announce, (void));
/*===========================================================================*
* main *
*===========================================================================*/
PUBLIC void main(void)
{
/* 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;
DEBUGEXTRA(("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 */
rp->p_magic = PMAGIC;
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 = (sys_id_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 */
DEBUGEXTRA(("initializing %s... ", ip->proc_name));
rp = proc_addr(ip->proc_nr); /* get process pointer */
ip->endpoint = rp->p_endpoint; /* ipc endpoint */
rp->p_scheduler = NULL; /* no user space scheduler */
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 */
priv(rp)->s_sig_mgr = RSYS_SM; /* signal manager */
}
/* 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 = 0; /* we cannot start anything else */
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);
DEBUGEXTRA(("done\n"));
}
/* Architecture-dependent initialization. */
DEBUGEXTRA(("arch_init()... "));
arch_init();
DEBUGEXTRA(("done\n"));
/* System and processes initialization */
DEBUGEXTRA(("system_init()... "));
system_init();
DEBUGEXTRA(("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_PROC_CHECK
FIXME("PROC check enabled");
#endif
DEBUGEXTRA(("cycles_accounting_init()... "));
cycles_accounting_init();
DEBUGEXTRA(("done\n"));
assert(runqueues_ok());
switch_to_user();
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(const 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(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);
}
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