1 /* This task handles the interface between the kernel and user-level servers. 2 * System services can be accessed by doing a system call. System calls are 3 * transformed into request messages, which are handled by this task. By 4 * convention, a sys_call() is transformed in a SYS_CALL request message that 5 * is handled in a function named do_call(). 6 * 7 * A private call vector is used to map all system calls to the functions that 8 * handle them. The actual handler functions are contained in separate files 9 * to keep this file clean. The call vector is used in the system task's main 10 * loop to handle all incoming requests. 11 * 12 * In addition to the main sys_task() entry point, which starts the main loop, 13 * there are several other minor entry points: 14 * get_priv: assign privilege structure to user or system process 15 * set_sendto_bit: allow a process to send messages to a new target 16 * unset_sendto_bit: disallow a process from sending messages to a target 17 * fill_sendto_mask: fill the target mask of a given process 18 * send_sig: send a signal directly to a system process 19 * cause_sig: take action to cause a signal to occur via a signal mgr 20 * sig_delay_done: tell PM that a process is not sending 21 * send_diag_sig: send a diagnostics signal to interested processes 22 * get_randomness: accumulate randomness in a buffer 23 * clear_endpoint: remove a process' ability to send and receive messages 24 * sched_proc: schedule a process 25 * 26 * Changes: 27 * Nov 22, 2009 get_priv supports static priv ids (Cristiano Giuffrida) 28 * Aug 04, 2005 check if system call is allowed (Jorrit N. Herder) 29 * Jul 20, 2005 send signal to services with message (Jorrit N. Herder) 30 * Jan 15, 2005 new, generalized virtual copy function (Jorrit N. Herder) 31 * Oct 10, 2004 dispatch system calls from call vector (Jorrit N. Herder) 32 * Sep 30, 2004 source code documentation updated (Jorrit N. Herder) 33 */ 34 35 #include "kernel/kernel.h" 36 #include "kernel/system.h" 37 #include "kernel/vm.h" 38 #include "kernel/clock.h" 39 #include <stdlib.h> 40 #include <assert.h> 41 #include <signal.h> 42 #include <unistd.h> 43 #include <minix/endpoint.h> 44 #include <minix/safecopies.h> 45 46 /* Declaration of the call vector that defines the mapping of system calls 47 * to handler functions. The vector is initialized in sys_init() with map(), 48 * which makes sure the system call numbers are ok. No space is allocated, 49 * because the dummy is declared extern. If an illegal call is given, the 50 * array size will be negative and this won't compile. 51 */ 52 static int (*call_vec[NR_SYS_CALLS])(struct proc * caller, message *m_ptr); 53 54 #define map(call_nr, handler) \ 55 { int call_index = call_nr-KERNEL_CALL; \ 56 assert(call_index >= 0 && call_index < NR_SYS_CALLS); \ 57 call_vec[call_index] = (handler) ; } 58 59 static void kernel_call_finish(struct proc * caller, message *msg, int result) 60 { 61 if(result == VMSUSPEND) { 62 /* Special case: message has to be saved for handling 63 * until VM tells us it's allowed. VM has been notified 64 * and we must wait for its reply to restart the call. 65 */ 66 assert(RTS_ISSET(caller, RTS_VMREQUEST)); 67 assert(caller->p_vmrequest.type == VMSTYPE_KERNELCALL); 68 caller->p_vmrequest.saved.reqmsg = *msg; 69 caller->p_misc_flags |= MF_KCALL_RESUME; 70 } else { 71 /* 72 * call is finished, we could have been suspended because of VM, 73 * remove the request message 74 */ 75 caller->p_vmrequest.saved.reqmsg.m_source = NONE; 76 if (result != EDONTREPLY) { 77 /* copy the result as a message to the original user buffer */ 78 msg->m_source = SYSTEM; 79 msg->m_type = result; /* report status of call */ 80 #if DEBUG_IPC_HOOK 81 hook_ipc_msgkresult(msg, caller); 82 #endif 83 if (copy_msg_to_user(msg, (message *)caller->p_delivermsg_vir)) { 84 printf("WARNING wrong user pointer 0x%08x from " 85 "process %s / %d\n", 86 caller->p_delivermsg_vir, 87 caller->p_name, 88 caller->p_endpoint); 89 cause_sig(proc_nr(caller), SIGSEGV); 90 } 91 } 92 } 93 } 94 95 static int kernel_call_dispatch(struct proc * caller, message *msg) 96 { 97 int result = OK; 98 int call_nr; 99 100 #if DEBUG_IPC_HOOK 101 hook_ipc_msgkcall(msg, caller); 102 #endif 103 call_nr = msg->m_type - KERNEL_CALL; 104 105 /* See if the caller made a valid request and try to handle it. */ 106 if (call_nr < 0 || call_nr >= NR_SYS_CALLS) { /* check call number */ 107 printf("SYSTEM: illegal request %d from %d.\n", 108 call_nr,msg->m_source); 109 result = EBADREQUEST; /* illegal message type */ 110 } 111 else if (!GET_BIT(priv(caller)->s_k_call_mask, call_nr)) { 112 printf("SYSTEM: denied request %d from %d.\n", 113 call_nr,msg->m_source); 114 result = ECALLDENIED; /* illegal message type */ 115 } else { 116 /* handle the system call */ 117 if (call_vec[call_nr]) 118 result = (*call_vec[call_nr])(caller, msg); 119 else { 120 printf("Unused kernel call %d from %d\n", 121 call_nr, caller->p_endpoint); 122 result = EBADREQUEST; 123 } 124 } 125 126 return result; 127 } 128 129 /*===========================================================================* 130 * kernel_call * 131 *===========================================================================*/ 132 /* 133 * this function checks the basic syscall parameters and if accepted it 134 * dispatches its handling to the right handler 135 */ 136 void kernel_call(message *m_user, struct proc * caller) 137 { 138 int result = OK; 139 message msg; 140 141 caller->p_delivermsg_vir = (vir_bytes) m_user; 142 /* 143 * the ldt and cr3 of the caller process is loaded because it just've trapped 144 * into the kernel or was already set in switch_to_user() before we resume 145 * execution of an interrupted kernel call 146 */ 147 if (copy_msg_from_user(m_user, &msg) == 0) { 148 msg.m_source = caller->p_endpoint; 149 result = kernel_call_dispatch(caller, &msg); 150 } 151 else { 152 printf("WARNING wrong user pointer 0x%08x from process %s / %d\n", 153 m_user, caller->p_name, caller->p_endpoint); 154 cause_sig(proc_nr(caller), SIGSEGV); 155 return; 156 } 157 158 159 /* remember who invoked the kcall so we can bill it its time */ 160 kbill_kcall = caller; 161 162 kernel_call_finish(caller, &msg, result); 163 } 164 165 /*===========================================================================* 166 * initialize * 167 *===========================================================================*/ 168 void system_init(void) 169 { 170 register struct priv *sp; 171 int i; 172 173 /* Initialize IRQ handler hooks. Mark all hooks available. */ 174 for (i=0; i<NR_IRQ_HOOKS; i++) { 175 irq_hooks[i].proc_nr_e = NONE; 176 } 177 178 /* Initialize all alarm timers for all processes. */ 179 for (sp=BEG_PRIV_ADDR; sp < END_PRIV_ADDR; sp++) { 180 tmr_inittimer(&(sp->s_alarm_timer)); 181 } 182 183 /* Initialize the call vector to a safe default handler. Some system calls 184 * may be disabled or nonexistant. Then explicitly map known calls to their 185 * handler functions. This is done with a macro that gives a compile error 186 * if an illegal call number is used. The ordering is not important here. 187 */ 188 for (i=0; i<NR_SYS_CALLS; i++) { 189 call_vec[i] = NULL; 190 } 191 192 /* Process management. */ 193 map(SYS_FORK, do_fork); /* a process forked a new process */ 194 map(SYS_EXEC, do_exec); /* update process after execute */ 195 map(SYS_CLEAR, do_clear); /* clean up after process exit */ 196 map(SYS_EXIT, do_exit); /* a system process wants to exit */ 197 map(SYS_PRIVCTL, do_privctl); /* system privileges control */ 198 map(SYS_TRACE, do_trace); /* request a trace operation */ 199 map(SYS_SETGRANT, do_setgrant); /* get/set own parameters */ 200 map(SYS_RUNCTL, do_runctl); /* set/clear stop flag of a process */ 201 map(SYS_UPDATE, do_update); /* update a process into another */ 202 map(SYS_STATECTL, do_statectl); /* let a process control its state */ 203 204 /* Signal handling. */ 205 map(SYS_KILL, do_kill); /* cause a process to be signaled */ 206 map(SYS_GETKSIG, do_getksig); /* signal manager checks for signals */ 207 map(SYS_ENDKSIG, do_endksig); /* signal manager finished signal */ 208 map(SYS_SIGSEND, do_sigsend); /* start POSIX-style signal */ 209 map(SYS_SIGRETURN, do_sigreturn); /* return from POSIX-style signal */ 210 211 /* Device I/O. */ 212 map(SYS_IRQCTL, do_irqctl); /* interrupt control operations */ 213 #if defined(__i386__) 214 map(SYS_DEVIO, do_devio); /* inb, inw, inl, outb, outw, outl */ 215 map(SYS_VDEVIO, do_vdevio); /* vector with devio requests */ 216 #endif 217 218 /* Memory management. */ 219 map(SYS_MEMSET, do_memset); /* write char to memory area */ 220 map(SYS_VMCTL, do_vmctl); /* various VM process settings */ 221 222 /* Copying. */ 223 map(SYS_UMAP, do_umap); /* map virtual to physical address */ 224 map(SYS_UMAP_REMOTE, do_umap_remote); /* do_umap for non-caller process */ 225 map(SYS_VUMAP, do_vumap); /* vectored virtual to physical map */ 226 map(SYS_VIRCOPY, do_vircopy); /* use pure virtual addressing */ 227 map(SYS_PHYSCOPY, do_copy); /* use physical addressing */ 228 map(SYS_SAFECOPYFROM, do_safecopy_from);/* copy with pre-granted permission */ 229 map(SYS_SAFECOPYTO, do_safecopy_to); /* copy with pre-granted permission */ 230 map(SYS_VSAFECOPY, do_vsafecopy); /* vectored safecopy */ 231 232 /* safe memset */ 233 map(SYS_SAFEMEMSET, do_safememset); /* safememset */ 234 235 /* Clock functionality. */ 236 map(SYS_TIMES, do_times); /* get uptime and process times */ 237 map(SYS_SETALARM, do_setalarm); /* schedule a synchronous alarm */ 238 map(SYS_STIME, do_stime); /* set the boottime */ 239 map(SYS_SETTIME, do_settime); /* set the system time (realtime) */ 240 map(SYS_VTIMER, do_vtimer); /* set or retrieve a virtual timer */ 241 242 /* System control. */ 243 map(SYS_ABORT, do_abort); /* abort MINIX */ 244 map(SYS_GETINFO, do_getinfo); /* request system information */ 245 map(SYS_DIAGCTL, do_diagctl); /* diagnostics-related functionality */ 246 247 /* Profiling. */ 248 map(SYS_SPROF, do_sprofile); /* start/stop statistical profiling */ 249 250 /* arm-specific. */ 251 #if defined(__arm__) 252 map(SYS_PADCONF, do_padconf); /* configure pinmux */ 253 #endif 254 255 /* i386-specific. */ 256 #if defined(__i386__) 257 map(SYS_READBIOS, do_readbios); /* read from BIOS locations */ 258 map(SYS_IOPENABLE, do_iopenable); /* Enable I/O */ 259 map(SYS_SDEVIO, do_sdevio); /* phys_insb, _insw, _outsb, _outsw */ 260 #endif 261 262 /* Machine state switching. */ 263 map(SYS_SETMCONTEXT, do_setmcontext); /* set machine context */ 264 map(SYS_GETMCONTEXT, do_getmcontext); /* get machine context */ 265 266 /* Scheduling */ 267 map(SYS_SCHEDULE, do_schedule); /* reschedule a process */ 268 map(SYS_SCHEDCTL, do_schedctl); /* change process scheduler */ 269 270 } 271 /*===========================================================================* 272 * get_priv * 273 *===========================================================================*/ 274 int get_priv(rc, priv_id) 275 register struct proc *rc; /* new (child) process pointer */ 276 int priv_id; /* privilege id */ 277 { 278 /* Allocate a new privilege structure for a system process. Privilege ids 279 * can be assigned either statically or dynamically. 280 */ 281 register struct priv *sp; /* privilege structure */ 282 283 if(priv_id == NULL_PRIV_ID) { /* allocate slot dynamically */ 284 for (sp = BEG_DYN_PRIV_ADDR; sp < END_DYN_PRIV_ADDR; ++sp) 285 if (sp->s_proc_nr == NONE) break; 286 if (sp >= END_DYN_PRIV_ADDR) return(ENOSPC); 287 } 288 else { /* allocate slot from id */ 289 if(!is_static_priv_id(priv_id)) { 290 return EINVAL; /* invalid static priv id */ 291 } 292 if(priv[priv_id].s_proc_nr != NONE) { 293 return EBUSY; /* slot already in use */ 294 } 295 sp = &priv[priv_id]; 296 } 297 rc->p_priv = sp; /* assign new slot */ 298 rc->p_priv->s_proc_nr = proc_nr(rc); /* set association */ 299 300 return(OK); 301 } 302 303 /*===========================================================================* 304 * set_sendto_bit * 305 *===========================================================================*/ 306 void set_sendto_bit(const struct proc *rp, int id) 307 { 308 /* Allow a process to send messages to the process(es) associated with the 309 * system privilege structure with the given ID. 310 */ 311 312 /* Disallow the process from sending to a process privilege structure with no 313 * associated process, and disallow the process from sending to itself. 314 */ 315 if (id_to_nr(id) == NONE || priv_id(rp) == id) { 316 unset_sys_bit(priv(rp)->s_ipc_to, id); 317 return; 318 } 319 320 set_sys_bit(priv(rp)->s_ipc_to, id); 321 322 /* The process that this process can now send to, must be able to reply (or 323 * vice versa). Therefore, its send mask should be updated as well. Ignore 324 * receivers that don't support traps other than RECEIVE, they can't reply 325 * or send messages anyway. 326 */ 327 if (priv_addr(id)->s_trap_mask & ~((1 << RECEIVE))) 328 set_sys_bit(priv_addr(id)->s_ipc_to, priv_id(rp)); 329 } 330 331 /*===========================================================================* 332 * unset_sendto_bit * 333 *===========================================================================*/ 334 void unset_sendto_bit(const struct proc *rp, int id) 335 { 336 /* Prevent a process from sending to another process. Retain the send mask 337 * symmetry by also unsetting the bit for the other direction. 338 */ 339 340 unset_sys_bit(priv(rp)->s_ipc_to, id); 341 342 unset_sys_bit(priv_addr(id)->s_ipc_to, priv_id(rp)); 343 } 344 345 /*===========================================================================* 346 * fill_sendto_mask * 347 *===========================================================================*/ 348 void fill_sendto_mask(const struct proc *rp, sys_map_t *map) 349 { 350 int i; 351 352 for (i=0; i < NR_SYS_PROCS; i++) { 353 if (get_sys_bit(*map, i)) 354 set_sendto_bit(rp, i); 355 else 356 unset_sendto_bit(rp, i); 357 } 358 } 359 360 /*===========================================================================* 361 * send_sig * 362 *===========================================================================*/ 363 int send_sig(endpoint_t ep, int sig_nr) 364 { 365 /* Notify a system process about a signal. This is straightforward. Simply 366 * set the signal that is to be delivered in the pending signals map and 367 * send a notification with source SYSTEM. 368 */ 369 register struct proc *rp; 370 struct priv *priv; 371 int proc_nr; 372 373 if(!isokendpt(ep, &proc_nr) || isemptyn(proc_nr)) 374 return EINVAL; 375 376 rp = proc_addr(proc_nr); 377 priv = priv(rp); 378 if(!priv) return ENOENT; 379 sigaddset(&priv->s_sig_pending, sig_nr); 380 increase_proc_signals(rp); 381 mini_notify(proc_addr(SYSTEM), rp->p_endpoint); 382 383 return OK; 384 } 385 386 /*===========================================================================* 387 * cause_sig * 388 *===========================================================================*/ 389 void cause_sig(proc_nr, sig_nr) 390 proc_nr_t proc_nr; /* process to be signalled */ 391 int sig_nr; /* signal to be sent */ 392 { 393 /* A system process wants to send a signal to a process. Examples are: 394 * - HARDWARE wanting to cause a SIGSEGV after a CPU exception 395 * - TTY wanting to cause SIGINT upon getting a DEL 396 * - FS wanting to cause SIGPIPE for a broken pipe 397 * Signals are handled by sending a message to the signal manager assigned to 398 * the process. This function handles the signals and makes sure the signal 399 * manager gets them by sending a notification. The process being signaled 400 * is blocked while the signal manager has not finished all signals for it. 401 * Race conditions between calls to this function and the system calls that 402 * process pending kernel signals cannot exist. Signal related functions are 403 * only called when a user process causes a CPU exception and from the kernel 404 * process level, which runs to completion. 405 */ 406 register struct proc *rp, *sig_mgr_rp; 407 endpoint_t sig_mgr; 408 int sig_mgr_proc_nr; 409 int s; 410 411 /* Lookup signal manager. */ 412 rp = proc_addr(proc_nr); 413 sig_mgr = priv(rp)->s_sig_mgr; 414 if(sig_mgr == SELF) sig_mgr = rp->p_endpoint; 415 416 /* If the target is the signal manager of itself, send the signal directly. */ 417 if(rp->p_endpoint == sig_mgr) { 418 if(SIGS_IS_LETHAL(sig_nr)) { 419 /* If the signal is lethal, see if a backup signal manager exists. */ 420 sig_mgr = priv(rp)->s_bak_sig_mgr; 421 if(sig_mgr != NONE && isokendpt(sig_mgr, &sig_mgr_proc_nr)) { 422 priv(rp)->s_sig_mgr = sig_mgr; 423 priv(rp)->s_bak_sig_mgr = NONE; 424 sig_mgr_rp = proc_addr(sig_mgr_proc_nr); 425 RTS_UNSET(sig_mgr_rp, RTS_NO_PRIV); 426 cause_sig(proc_nr, sig_nr); /* try again with the new sig mgr. */ 427 return; 428 } 429 /* We are out of luck. Time to panic. */ 430 proc_stacktrace(rp); 431 panic("cause_sig: sig manager %d gets lethal signal %d for itself", 432 rp->p_endpoint, sig_nr); 433 } 434 sigaddset(&priv(rp)->s_sig_pending, sig_nr); 435 if(OK != send_sig(rp->p_endpoint, SIGKSIGSM)) 436 panic("send_sig failed"); 437 return; 438 } 439 440 if((s = sigismember(&rp->p_pending, sig_nr)) < 0) 441 panic("sigismember failed"); 442 /* Check if the signal is already pending. Process it otherwise. */ 443 if (!s) { 444 sigaddset(&rp->p_pending, sig_nr); 445 increase_proc_signals(rp); 446 if (! (RTS_ISSET(rp, RTS_SIGNALED))) { /* other pending */ 447 RTS_SET(rp, RTS_SIGNALED | RTS_SIG_PENDING); 448 if(OK != send_sig(sig_mgr, SIGKSIG)) 449 panic("send_sig failed"); 450 } 451 } 452 } 453 454 /*===========================================================================* 455 * sig_delay_done * 456 *===========================================================================*/ 457 void sig_delay_done(struct proc *rp) 458 { 459 /* A process is now known not to send any direct messages. 460 * Tell PM that the stop delay has ended, by sending a signal to the process. 461 * Used for actual signal delivery. 462 */ 463 464 rp->p_misc_flags &= ~MF_SIG_DELAY; 465 466 cause_sig(proc_nr(rp), SIGSNDELAY); 467 } 468 469 /*===========================================================================* 470 * send_diag_sig * 471 *===========================================================================*/ 472 void send_diag_sig(void) 473 { 474 /* Send a SIGKMESS signal to all processes in receiving updates about new 475 * diagnostics messages. 476 */ 477 struct priv *privp; 478 endpoint_t ep; 479 480 for (privp = BEG_PRIV_ADDR; privp < END_PRIV_ADDR; privp++) { 481 if (privp->s_proc_nr != NONE && privp->s_diag_sig == TRUE) { 482 ep = proc_addr(privp->s_proc_nr)->p_endpoint; 483 send_sig(ep, SIGKMESS); 484 } 485 } 486 } 487 488 /*===========================================================================* 489 * clear_ipc * 490 *===========================================================================*/ 491 static void clear_ipc( 492 register struct proc *rc /* slot of process to clean up */ 493 ) 494 { 495 /* Clear IPC data for a given process slot. */ 496 struct proc **xpp; /* iterate over caller queue */ 497 498 if (RTS_ISSET(rc, RTS_SENDING)) { 499 int target_proc; 500 501 okendpt(rc->p_sendto_e, &target_proc); 502 xpp = &proc_addr(target_proc)->p_caller_q; /* destination's queue */ 503 while (*xpp) { /* check entire queue */ 504 if (*xpp == rc) { /* process is on the queue */ 505 *xpp = (*xpp)->p_q_link; /* replace by next process */ 506 #if DEBUG_ENABLE_IPC_WARNINGS 507 printf("endpoint %d / %s removed from queue at %d\n", 508 rc->p_endpoint, rc->p_name, rc->p_sendto_e); 509 #endif 510 break; /* can only be queued once */ 511 } 512 xpp = &(*xpp)->p_q_link; /* proceed to next queued */ 513 } 514 RTS_UNSET(rc, RTS_SENDING); 515 } 516 RTS_UNSET(rc, RTS_RECEIVING); 517 } 518 519 /*===========================================================================* 520 * clear_endpoint * 521 *===========================================================================*/ 522 void clear_endpoint(rc) 523 register struct proc *rc; /* slot of process to clean up */ 524 { 525 if(isemptyp(rc)) panic("clear_proc: empty process: %d", rc->p_endpoint); 526 527 528 #if DEBUG_IPC_HOOK 529 hook_ipc_clear(rc); 530 #endif 531 532 /* Make sure that the exiting process is no longer scheduled. */ 533 RTS_SET(rc, RTS_NO_ENDPOINT); 534 if (priv(rc)->s_flags & SYS_PROC) 535 { 536 priv(rc)->s_asynsize= 0; 537 } 538 539 /* If the process happens to be queued trying to send a 540 * message, then it must be removed from the message queues. 541 */ 542 clear_ipc(rc); 543 544 /* Likewise, if another process was sending or receive a message to or from 545 * the exiting process, it must be alerted that process no longer is alive. 546 * Check all processes. 547 */ 548 clear_ipc_refs(rc, EDEADSRCDST); 549 550 } 551 552 /*===========================================================================* 553 * clear_ipc_refs * 554 *===========================================================================*/ 555 void clear_ipc_refs(rc, caller_ret) 556 register struct proc *rc; /* slot of process to clean up */ 557 int caller_ret; /* code to return on callers */ 558 { 559 /* Clear IPC references for a given process slot. */ 560 struct proc *rp; /* iterate over process table */ 561 int src_id; 562 563 /* Tell processes that sent asynchronous messages to 'rc' they are not 564 * going to be delivered */ 565 while ((src_id = has_pending_asend(rc, ANY)) != NULL_PRIV_ID) 566 cancel_async(proc_addr(id_to_nr(src_id)), rc); 567 568 for (rp = BEG_PROC_ADDR; rp < END_PROC_ADDR; rp++) { 569 if(isemptyp(rp)) 570 continue; 571 572 /* Unset pending notification bits. */ 573 unset_sys_bit(priv(rp)->s_notify_pending, priv(rc)->s_id); 574 575 /* Unset pending asynchronous messages */ 576 unset_sys_bit(priv(rp)->s_asyn_pending, priv(rc)->s_id); 577 578 /* Check if process depends on given process. */ 579 if (P_BLOCKEDON(rp) == rc->p_endpoint) { 580 rp->p_reg.retreg = caller_ret; /* return requested code */ 581 clear_ipc(rp); 582 } 583 } 584 } 585 586 /*===========================================================================* 587 * kernel_call_resume * 588 *===========================================================================*/ 589 void kernel_call_resume(struct proc *caller) 590 { 591 int result; 592 593 assert(!RTS_ISSET(caller, RTS_SLOT_FREE)); 594 assert(!RTS_ISSET(caller, RTS_VMREQUEST)); 595 596 assert(caller->p_vmrequest.saved.reqmsg.m_source == caller->p_endpoint); 597 598 /* 599 printf("KERNEL_CALL restart from %s / %d rts 0x%08x misc 0x%08x\n", 600 caller->p_name, caller->p_endpoint, 601 caller->p_rts_flags, caller->p_misc_flags); 602 */ 603 604 /* re-execute the kernel call, with MF_KCALL_RESUME still set so 605 * the call knows this is a retry. 606 */ 607 result = kernel_call_dispatch(caller, &caller->p_vmrequest.saved.reqmsg); 608 /* 609 * we are resuming the kernel call so we have to remove this flag so it 610 * can be set again 611 */ 612 caller->p_misc_flags &= ~MF_KCALL_RESUME; 613 kernel_call_finish(caller, &caller->p_vmrequest.saved.reqmsg, result); 614 } 615 616 /*===========================================================================* 617 * sched_proc * 618 *===========================================================================*/ 619 int sched_proc(struct proc *p, 620 int priority, 621 int quantum, 622 int cpu) 623 { 624 /* Make sure the values given are within the allowed range.*/ 625 if ((priority < TASK_Q && priority != -1) || priority > NR_SCHED_QUEUES) 626 return(EINVAL); 627 628 if (quantum < 1 && quantum != -1) 629 return(EINVAL); 630 631 #ifdef CONFIG_SMP 632 if ((cpu < 0 && cpu != -1) || (cpu > 0 && (unsigned) cpu >= ncpus)) 633 return(EINVAL); 634 if (cpu != -1 && !(cpu_is_ready(cpu))) 635 return EBADCPU; 636 #endif 637 638 /* In some cases, we might be rescheduling a runnable process. In such 639 * a case (i.e. if we are updating the priority) we set the NO_QUANTUM 640 * flag before the generic unset to dequeue/enqueue the process 641 */ 642 643 /* FIXME this preempts the process, do we really want to do that ?*/ 644 645 /* FIXME this is a problem for SMP if the processes currently runs on a 646 * different CPU */ 647 if (proc_is_runnable(p)) { 648 #ifdef CONFIG_SMP 649 if (p->p_cpu != cpuid && cpu != -1 && cpu != p->p_cpu) { 650 smp_schedule_migrate_proc(p, cpu); 651 } 652 #endif 653 654 RTS_SET(p, RTS_NO_QUANTUM); 655 } 656 657 if (proc_is_runnable(p)) 658 RTS_SET(p, RTS_NO_QUANTUM); 659 660 if (priority != -1) 661 p->p_priority = priority; 662 if (quantum != -1) { 663 p->p_quantum_size_ms = quantum; 664 p->p_cpu_time_left = ms_2_cpu_time(quantum); 665 } 666 #ifdef CONFIG_SMP 667 if (cpu != -1) 668 p->p_cpu = cpu; 669 #endif 670 671 /* Clear the scheduling bit and enqueue the process */ 672 RTS_UNSET(p, RTS_NO_QUANTUM); 673 674 return OK; 675 } 676 677