a408699ce0
Removed stop sequence when MINIX is shut down. Disabled send mask checks --- to be replaced by proper mechanism. Fixed bug relating to 'shutdown -x'. Simplified clock accounting of realtime. Updated Makefiles for mkdept script.
506 lines
19 KiB
C
Executable file
506 lines
19 KiB
C
Executable file
/* This task handles the interface between the kernel and user-level servers.
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* System services can be accessed by doing a system call. System calls are
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* transformed into request messages, which are handled by this task. By
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* convention, a sys_call() is transformed in a SYS_CALL request message that
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* is handled in a function named do_call().
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*
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* A private call vector is used to map all system calls to the functions that
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* handle them. The actual handler functions are contained in separate files
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* to keep this file clean. The call vector is used in the system task's main
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* loop to handle all incoming requests.
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*
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* In addition to the main sys_task() entry point, which starts the main loop,
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* there are several other minor entry points:
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* cause_sig: take action to cause a signal to occur
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* clear_proc: clean up a process in the process table, e.g. on exit
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* umap_local: map virtual address in LOCAL_SEG to physical
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* umap_remote: map virtual address in REMOTE_SEG to physical
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* umap_bios: map virtual address in BIOS_SEG to physical
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* numap_local: umap_local D segment from proc nr instead of pointer
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* virtual_copy: copy bytes from one virtual address to another
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* get_randomness: accumulate randomness in a buffer
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* generic_handler: interrupt handler for user-level device drivers
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*
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* Changes:
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* Apr 25, 2005 made mapping of call vector explicit (Jorrit N. Herder)
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* Oct 29, 2004 new clear_proc() function (Jorrit N. Herder)
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* Oct 17, 2004 generic handler and IRQ policies (Jorrit N. Herder)
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* Oct 10, 2004 dispatch system calls from call vector (Jorrit N. Herder)
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* Sep 30, 2004 source code documentation updated (Jorrit N. Herder)
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* Sep 10, 2004 system call functions in library (Jorrit N. Herder)
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* 2004 to 2005 various new syscalls (see syslib.h) (Jorrit N. Herder)
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*/
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#include "kernel.h"
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#include "system.h"
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#include <stdlib.h>
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#include <signal.h>
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#include <unistd.h>
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#include <sys/sigcontext.h>
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#include <sys/svrctl.h>
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#include <minix/callnr.h>
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#include "sendmask.h"
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#if (CHIP == INTEL)
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#include <ibm/memory.h>
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#include "protect.h"
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#endif
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/* Declaration of the call vector that defines the mapping of system calls
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* to handler functions. The vector is initialized in sys_init() with map(),
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* which makes sure the system call numbers are ok. No space is allocated,
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* because the dummy is declared extern. If an illegal call is given, the
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* array size will be negative and this won't compile.
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*/
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PUBLIC int (*call_vec[NR_SYS_CALLS])(message *m_ptr);
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#define map(call_nr, handler) \
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{extern int dummy[NR_SYS_CALLS > (unsigned) (call_nr) ? 1 : -1];} \
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call_vec[(call_nr)] = (handler)
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FORWARD _PROTOTYPE( void initialize, (void));
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/*===========================================================================*
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* sys_task *
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*===========================================================================*/
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PUBLIC void sys_task()
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{
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/* Main entry point of sys_task. Get the message and dispatch on type. */
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static message m;
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register int result;
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/* Initialize the system task. */
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initialize();
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while (TRUE) {
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/* Get work. */
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receive(ANY, &m);
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/* Handle the request. */
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if ((unsigned) m.m_type < NR_SYS_CALLS) {
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result = (*call_vec[m.m_type])(&m); /* do system call */
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} else {
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kprintf("Warning, illegal SYSTASK request from %d.\n", m.m_source);
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result = EBADREQUEST; /* illegal message type */
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}
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/* Send a reply, unless inhibited by a handler function. Use the kernel
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* function lock_send() to prevent a system call trap. The destination
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* is known to be blocked waiting for a message.
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*/
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if (result != EDONTREPLY) {
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m.m_type = result; /* report status of call */
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if (OK != lock_send(m.m_source, &m)) {
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kprintf("Warning, SYSTASK couldn't reply to request from %d\n",
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m.m_source);
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}
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}
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}
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}
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/*===========================================================================*
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* initialize *
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*===========================================================================*/
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PRIVATE void initialize(void)
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{
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register struct proc *rp;
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int i;
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/* Initialize IRQ handler hooks. Mark all hooks available. */
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for (i=0; i<NR_IRQ_HOOKS; i++) {
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irq_hooks[i].proc_nr = NONE;
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}
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/* Initialize all alarm timers for all processes. */
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for (rp=BEG_PROC_ADDR; rp < END_PROC_ADDR; rp++) {
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tmr_inittimer(&(rp->p_alarm_timer));
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}
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/* Initialize the call vector to a safe default handler. Some system calls
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* may be disabled or nonexistant. Then explicitely map known calls to their
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* handler functions. This is done with a macro that gives a compile error
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* if an illegal call number is used. The ordering is not important here.
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*/
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for (i=0; i<NR_SYS_CALLS; i++) {
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call_vec[i] = do_unused;
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}
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/* Process management. */
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map(SYS_FORK, do_fork); /* informs kernel that a process has forked */
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map(SYS_XIT, do_xit); /* informs kernel that a process has exited */
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map(SYS_NEWMAP, do_newmap); /* allows PM to set up a process memory map */
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map(SYS_EXEC, do_exec); /* sets program counter and stack pointer after EXEC */
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map(SYS_TRACE, do_trace); /* request a trace operation */
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/* Signal handling. */
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map(SYS_KILL, do_kill); /* cause a process to be signaled */
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map(SYS_GETSIG, do_getsig); /* PM checks for pending signals */
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map(SYS_ENDSIG, do_endsig); /* PM finished processing signal */
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map(SYS_SIGSEND, do_sigsend); /* start POSIX-style signal */
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map(SYS_SIGRETURN, do_sigreturn); /* return from POSIX-style signal */
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/* Clock functionality. */
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map(SYS_TIMES, do_times); /* get uptime and process times */
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map(SYS_SIGNALRM, do_signalrm); /* causes an alarm signal */
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map(SYS_SYNCALRM, do_syncalrm); /* send a notification message */
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/* Device I/O. */
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map(SYS_IRQCTL, do_irqctl); /* interrupt control operations */
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map(SYS_DEVIO, do_devio); /* inb, inw, inl, outb, outw, outl */
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map(SYS_SDEVIO, do_sdevio); /* phys_insb, _insw, _outsb, _outsw */
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map(SYS_VDEVIO, do_vdevio); /* vector with devio requests */
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/* Server and driver control. */
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map(SYS_SEGCTL, do_segctl); /* add segment and get selector */
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map(SYS_IOPENABLE, do_iopenable); /* enable CPU I/O protection bits */
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map(SYS_SVRCTL, do_svrctl); /* kernel control functions */
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/* Copying. */
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map(SYS_UMAP, do_umap); /* map virtual to physical address */
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map(SYS_VIRCOPY, do_vircopy); /* use pure virtual addressing */
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map(SYS_PHYSCOPY, do_physcopy); /* use physical addressing */
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map(SYS_PHYSZERO, do_physzero); /* zero physical memory region */
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map(SYS_VIRVCOPY, do_virvcopy); /* vector with copy requests */
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map(SYS_PHYSVCOPY, do_physvcopy); /* vector with copy requests */
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/* Miscellaneous. */
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map(SYS_ABORT, do_abort); /* abort MINIX */
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map(SYS_GETINFO, do_getinfo); /* request system information */
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}
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/*===========================================================================*
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* clear_proc *
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*===========================================================================*/
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PUBLIC void clear_proc(proc_nr)
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int proc_nr; /* slot of process to clean up */
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{
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register struct proc *rp, *rc;
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register struct proc **xpp; /* iterate over caller queue */
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int i;
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/* Get a pointer to the process that exited. */
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rc = proc_addr(proc_nr);
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/* Turn off any alarm timers at the clock. */
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reset_timer(&rc->p_alarm_timer);
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/* Make sure the exiting process is no longer scheduled. */
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if (rc->p_flags == 0) lock_unready(rc);
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/* If the process being terminated happens to be queued trying to send a
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* message (e.g., the process was killed by a signal, rather than it doing
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* an exit or it is forcibly shutdown in the stop sequence), then it must
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* be removed from the message queues.
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*/
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if (rc->p_flags & SENDING) {
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/* Check all proc slots to see if the exiting process is queued. */
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for (rp = BEG_PROC_ADDR; rp < END_PROC_ADDR; rp++) {
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if (rp->p_caller_q == NIL_PROC) continue;
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/* Make sure that the exiting process is not on the queue. */
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xpp = &rp->p_caller_q;
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while (*xpp != NIL_PROC) { /* check entire queue */
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if (*xpp == rc) { /* process is on the queue */
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*xpp = (*xpp)->p_q_link; /* replace by next process */
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break;
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}
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xpp = &(*xpp)->p_q_link; /* proceed to next queued */
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}
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}
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}
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/* Check the table with IRQ hooks to see if hooks should be released. */
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for (i=0; i < NR_IRQ_HOOKS; i++) {
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if (irq_hooks[i].proc_nr == proc_nr)
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irq_hooks[i].proc_nr = NONE;
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}
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/* Check if there are pending notifications. Release the buffers. */
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while (rc->p_ntf_q != NULL) {
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i = (int) (rc->p_ntf_q - ¬ify_buffer[0]);
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free_bit(i, notify_bitmap, NR_NOTIFY_BUFS);
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rc->p_ntf_q = rc->p_ntf_q->n_next;
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}
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/* Now clean up the process table entry. Reset to defaults. */
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kstrncpy(rc->p_name, "<none>", P_NAME_LEN); /* unset name */
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sigemptyset(&rc->p_pending); /* remove pending signals */
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rc->p_flags = SLOT_FREE; /* announce slot empty */
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rc->p_sendmask = DENY_ALL_MASK; /* set most restrictive mask */
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#if (CHIP == M68000)
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pmmu_delete(rc); /* we're done, remove tables */
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#endif
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}
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/*===========================================================================*
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* get_randomness *
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*===========================================================================*/
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PUBLIC void get_randomness()
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{
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/* Gather random information with help of the CPU's cycle counter. Only use
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* the lowest bytes because the highest bytes won't differ that much.
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*/
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unsigned long tsc_high;
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read_tsc(&tsc_high, &krandom.r_buf[krandom.r_next]);
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if (krandom.r_size < RANDOM_ELEMENTS) krandom.r_size ++;
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krandom.r_next = (krandom.r_next + 1 ) % RANDOM_ELEMENTS;
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}
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/*===========================================================================*
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* generic_handler *
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*===========================================================================*/
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PUBLIC int generic_handler(hook)
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irq_hook_t *hook;
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{
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/* This function handles hardware interrupt in a simple and generic way. All
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* interrupts are transformed into messages to a driver. The IRQ line will be
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* reenabled if the policy says so.
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* In addition, the interrupt handler gathers random information in a buffer
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* by timestamping the interrupts.
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*/
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message m;
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/* Gather random information. */
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get_randomness();
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/* Build notification message and return. */
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m.NOTIFY_TYPE = HARD_INT;
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m.NOTIFY_ARG = hook->irq;
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lock_notify(hook->proc_nr, &m);
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return(hook->policy & IRQ_REENABLE);
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}
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/*===========================================================================*
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* cause_sig *
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*===========================================================================*/
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PUBLIC void cause_sig(proc_nr, sig_nr)
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int proc_nr; /* process to be signalled */
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int sig_nr; /* signal to be sent, 1 to _NSIG */
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{
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/* A system process wants to send a signal to a process. Examples are:
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* TTY wanting to cause SIGINT upon getting a DEL
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* CLOCK wanting to cause SIGALRM when timer expires
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* FS wanting to cause SIGPIPE for a broken pipe
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* Signals are handled by sending a message to PM. This function handles the
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* signals and makes sure the PM gets them by sending a notification. The
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* process being signaled is blocked while PM has not finished all signals
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* for it.
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* It is not sufficient to ready the process when PM is informed, because
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* PM can block waiting for FS to do a core dump.
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*/
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register struct proc *rp;
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message m;
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/* Check if the signal is already pending. Process it otherwise. */
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rp = proc_addr(proc_nr);
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if (! sigismember(&rp->p_pending, sig_nr)) {
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sigaddset(&rp->p_pending, sig_nr);
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if (rp->p_flags & SIGNALED) return; /* other signal pending */
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if (rp->p_flags == 0) lock_unready(rp); /* unready if not yet done */
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rp->p_flags |= SIGNALED | SIG_PENDING; /* update signal flags */
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m.NOTIFY_TYPE = KSIG_PENDING;
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m.NOTIFY_ARG = 0;
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m.NOTIFY_FLAGS = 0;
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lock_notify(PM_PROC_NR, &m);
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}
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}
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/*===========================================================================*
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* umap_bios *
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*===========================================================================*/
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PUBLIC phys_bytes umap_bios(rp, vir_addr, bytes)
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register struct proc *rp; /* pointer to proc table entry for process */
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vir_bytes vir_addr; /* virtual address in BIOS segment */
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vir_bytes bytes; /* # of bytes to be copied */
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{
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/* Calculate the physical memory address at the BIOS. Note: currently, BIOS
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* address zero (the first BIOS interrupt vector) is not considered, as an
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* error here, but since the physical address will be zero as well, the
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* calling function will think an error occurred. This is not a problem,
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* since no one uses the first BIOS interrupt vector.
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*/
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/* Check all acceptable ranges. */
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#if DEAD_CODE /* to be replaced by proper ranges, e.g. 640 - 1 KB */
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if (vir_addr >= BIOS_MEM_BEGIN && vir_addr + bytes <= BIOS_MEM_END)
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return (phys_bytes) vir_addr;
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else if (vir_addr >= UPPER_MEM_BEGIN && vir_addr + bytes <= UPPER_MEM_END)
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return (phys_bytes) vir_addr;
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#else
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if (vir_addr >= BIOS_MEM_BEGIN && vir_addr + bytes <= UPPER_MEM_END)
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return (phys_bytes) vir_addr;
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#endif
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kprintf("Warning, error in umap_bios, virtual address 0x%x\n", vir_addr);
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return 0;
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}
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/*===========================================================================*
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* umap_local *
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*===========================================================================*/
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PUBLIC phys_bytes umap_local(rp, seg, vir_addr, bytes)
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register struct proc *rp; /* pointer to proc table entry for process */
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int seg; /* T, D, or S segment */
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vir_bytes vir_addr; /* virtual address in bytes within the seg */
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vir_bytes bytes; /* # of bytes to be copied */
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{
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/* Calculate the physical memory address for a given virtual address. */
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vir_clicks vc; /* the virtual address in clicks */
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phys_bytes pa; /* intermediate variables as phys_bytes */
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#if (CHIP == INTEL)
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phys_bytes seg_base;
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#endif
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/* If 'seg' is D it could really be S and vice versa. T really means T.
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* If the virtual address falls in the gap, it causes a problem. On the
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* 8088 it is probably a legal stack reference, since "stackfaults" are
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* not detected by the hardware. On 8088s, the gap is called S and
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* accepted, but on other machines it is called D and rejected.
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* The Atari ST behaves like the 8088 in this respect.
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*/
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if (bytes <= 0) return( (phys_bytes) 0);
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if (vir_addr + bytes <= vir_addr) return 0; /* overflow */
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vc = (vir_addr + bytes - 1) >> CLICK_SHIFT; /* last click of data */
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#if (CHIP == INTEL) || (CHIP == M68000)
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if (seg != T)
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seg = (vc < rp->p_memmap[D].mem_vir + rp->p_memmap[D].mem_len ? D : S);
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#else
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if (seg != T)
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seg = (vc < rp->p_memmap[S].mem_vir ? D : S);
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#endif
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if((vir_addr>>CLICK_SHIFT) >= rp->p_memmap[seg].mem_vir +
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rp->p_memmap[seg].mem_len) return( (phys_bytes) 0 );
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if(vc >= rp->p_memmap[seg].mem_vir +
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rp->p_memmap[seg].mem_len) return( (phys_bytes) 0 );
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#if (CHIP == INTEL)
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seg_base = (phys_bytes) rp->p_memmap[seg].mem_phys;
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seg_base = seg_base << CLICK_SHIFT; /* segment origin in bytes */
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#endif
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pa = (phys_bytes) vir_addr;
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#if (CHIP != M68000)
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pa -= rp->p_memmap[seg].mem_vir << CLICK_SHIFT;
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return(seg_base + pa);
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#endif
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#if (CHIP == M68000)
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pa -= (phys_bytes)rp->p_memmap[seg].mem_vir << CLICK_SHIFT;
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pa += (phys_bytes)rp->p_memmap[seg].mem_phys << CLICK_SHIFT;
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return(pa);
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#endif
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}
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/*==========================================================================*
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* numap_local *
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*==========================================================================*/
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PUBLIC phys_bytes numap_local(proc_nr, vir_addr, bytes)
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int proc_nr; /* process number to be mapped */
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vir_bytes vir_addr; /* virtual address in bytes within D seg */
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vir_bytes bytes; /* # of bytes required in segment */
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{
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/* Do umap_local() starting from a process number instead of a pointer.
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* This function is used by device drivers, so they need not know about the
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* process table. To save time, there is no 'seg' parameter. The segment
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* is always D.
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*/
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return(umap_local(proc_addr(proc_nr), D, vir_addr, bytes));
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}
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/*===========================================================================*
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* umap_remote *
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*===========================================================================*/
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PUBLIC phys_bytes umap_remote(rp, seg, vir_addr, bytes)
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register struct proc *rp; /* pointer to proc table entry for process */
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int seg; /* index of remote segment */
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vir_bytes vir_addr; /* virtual address in bytes within the seg */
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vir_bytes bytes; /* # of bytes to be copied */
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{
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/* Calculate the physical memory address for a given virtual address. */
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struct far_mem *fm;
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if (bytes <= 0) return( (phys_bytes) 0);
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if (seg < 0 || seg >= NR_REMOTE_SEGS) return( (phys_bytes) 0);
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fm = &rp->p_farmem[seg];
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if (! fm->in_use) return( (phys_bytes) 0);
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if (vir_addr + bytes > fm->mem_len) return( (phys_bytes) 0);
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return(fm->mem_phys + (phys_bytes) vir_addr);
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}
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/*==========================================================================*
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* virtual_copy *
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*==========================================================================*/
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PUBLIC int virtual_copy(src_addr, dst_addr, bytes)
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struct vir_addr *src_addr; /* source virtual address */
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struct vir_addr *dst_addr; /* destination virtual address */
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vir_bytes bytes; /* # of bytes to copy */
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{
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/* Copy bytes from virtual address src_addr to virtual address dst_addr.
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* Virtual addresses can be in ABS, LOCAL_SEG, REMOTE_SEG, or BIOS_SEG.
|
|
*/
|
|
struct vir_addr *vir_addr[2]; /* virtual source and destination address */
|
|
phys_bytes phys_addr[2]; /* absolute source and destination */
|
|
int seg_index;
|
|
int i;
|
|
|
|
/* Check copy count. */
|
|
if (bytes <= 0) {
|
|
kprintf("v_cp: copy count problem <= 0\n", NO_NUM);
|
|
return(EDOM);
|
|
}
|
|
|
|
/* Do some more checks and map virtual addresses to physical addresses. */
|
|
vir_addr[_SRC_] = src_addr;
|
|
vir_addr[_DST_] = dst_addr;
|
|
for (i=_SRC_; i<=_DST_; i++) {
|
|
|
|
/* Get physical address. */
|
|
switch((vir_addr[i]->segment & SEGMENT_TYPE)) {
|
|
case LOCAL_SEG:
|
|
seg_index = vir_addr[i]->segment & SEGMENT_INDEX;
|
|
phys_addr[i] = umap_local( proc_addr(vir_addr[i]->proc_nr),
|
|
seg_index, vir_addr[i]->offset, bytes );
|
|
break;
|
|
case REMOTE_SEG:
|
|
seg_index = vir_addr[i]->segment & SEGMENT_INDEX;
|
|
phys_addr[i] = umap_remote( proc_addr(vir_addr[i]->proc_nr),
|
|
seg_index, vir_addr[i]->offset, bytes );
|
|
break;
|
|
case BIOS_SEG:
|
|
phys_addr[i] = umap_bios( proc_addr(vir_addr[i]->proc_nr),
|
|
vir_addr[i]->offset, bytes );
|
|
break;
|
|
case PHYS_SEG:
|
|
phys_addr[i] = vir_addr[i]->offset;
|
|
break;
|
|
default:
|
|
kprintf("v_cp: Unknown segment type: %d\n",
|
|
vir_addr[i]->segment & SEGMENT_TYPE);
|
|
return(EINVAL);
|
|
}
|
|
|
|
/* Check if mapping succeeded. */
|
|
if (phys_addr[i] <= 0 && vir_addr[i]->segment != PHYS_SEG) {
|
|
kprintf("v_cp: Mapping failed ... phys <= 0\n", NO_NUM);
|
|
return(EFAULT);
|
|
}
|
|
}
|
|
|
|
/* Now copy bytes between physical addresseses. */
|
|
phys_copy(phys_addr[_SRC_], phys_addr[_DST_], (phys_bytes) bytes);
|
|
return(OK);
|
|
}
|
|
|
|
|