1/* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21/* 22 * Copyright (c) 1993, 2010, Oracle and/or its affiliates. All rights reserved. 23 */ 24 25/* 26 * Process switching routines. 27 */ 28 29#if !defined(lint) 30#include "assym.h" 31#else /* lint */ 32#include <sys/thread.h> 33#endif /* lint */ 34 35#include <sys/param.h> 36#include <sys/asm_linkage.h> 37#include <sys/mmu.h> 38#include <sys/pcb.h> 39#include <sys/machthread.h> 40#include <sys/machclock.h> 41#include <sys/privregs.h> 42#include <sys/vtrace.h> 43#include <vm/hat_sfmmu.h> 44 45/* 46 * resume(kthread_id_t) 47 * 48 * a thread can only run on one processor at a time. there 49 * exists a window on MPs where the current thread on one 50 * processor is capable of being dispatched by another processor. 51 * some overlap between outgoing and incoming threads can happen 52 * when they are the same thread. in this case where the threads 53 * are the same, resume() on one processor will spin on the incoming 54 * thread until resume() on the other processor has finished with 55 * the outgoing thread. 56 * 57 * The MMU context changes when the resuming thread resides in a different 58 * process. Kernel threads are known by resume to reside in process 0. 59 * The MMU context, therefore, only changes when resuming a thread in 60 * a process different from curproc. 61 * 62 * resume_from_intr() is called when the thread being resumed was not 63 * passivated by resume (e.g. was interrupted). This means that the 64 * resume lock is already held and that a restore context is not needed. 65 * Also, the MMU context is not changed on the resume in this case. 66 * 67 * resume_from_zombie() is the same as resume except the calling thread 68 * is a zombie and must be put on the deathrow list after the CPU is 69 * off the stack. 70 */ 71 72#if defined(lint) 73 74/* ARGSUSED */ 75void 76resume(kthread_id_t t) 77{} 78 79#else /* lint */ 80 81 ENTRY(resume) 82 save %sp, -SA(MINFRAME), %sp ! save ins and locals 83 84 call __dtrace_probe___sched_off__cpu ! DTrace probe 85 mov %i0, %o0 ! arg for DTrace probe 86 87 membar #Sync ! flush writebuffers 88 flushw ! flushes all but this window 89 90 stn %i7, [THREAD_REG + T_PC] ! save return address 91 stn %fp, [THREAD_REG + T_SP] ! save sp 92 93 ! 94 ! Save GSR (Graphics Status Register). 95 ! 96 ! Read fprs, call fp_save if FPRS_FEF set. 97 ! This handles floating-point state saving. 98 ! The fprs could be turned on by hw bcopy software, 99 ! *or* by fp_disabled. Handle it either way. 100 ! 101 ldn [THREAD_REG + T_LWP], %o4 ! get lwp pointer 102 rd %fprs, %g4 ! read fprs 103 brnz,pt %o4, 0f ! if user thread skip 104 ldn [THREAD_REG + T_CPU], %i1 ! get CPU pointer 105 106 ! 107 ! kernel thread 108 ! 109 ! we save fprs at the beginning the stack so we know 110 ! where to check at resume time 111 ldn [THREAD_REG + T_STACK], %i2 112 ldn [THREAD_REG + T_CTX], %g3 ! get ctx pointer 113 andcc %g4, FPRS_FEF, %g0 ! is FPRS_FEF set 114 bz,pt %icc, 1f ! nope, skip 115 st %g4, [%i2 + SA(MINFRAME) + FPU_FPRS] ! save fprs 116 117 ! save kernel fp state in stack 118 add %i2, SA(MINFRAME), %o0 ! o0 = kfpu_t ptr 119 rd %gsr, %g5 120 call fp_save 121 stx %g5, [%o0 + FPU_GSR] ! store GSR 122 ba,a,pt %icc, 1f 123 nop 124 1250: 126 ! user thread 127 ! o4 = lwp ptr 128 ! g4 = fprs 129 ! i1 = CPU ptr 130 ldn [%o4 + LWP_FPU], %o0 ! fp pointer 131 stn %fp, [THREAD_REG + T_SP] ! save sp 132 andcc %g4, FPRS_FEF, %g0 ! is FPRS_FEF set 133 st %g4, [%o0 + FPU_FPRS] ! store FPRS 134#if defined(DEBUG) || defined(NEED_FPU_EXISTS) 135 sethi %hi(fpu_exists), %g5 136 ld [%g5 + %lo(fpu_exists)], %g5 137 brz,pn %g5, 1f 138 ldn [THREAD_REG + T_CTX], %g3 ! get ctx pointer 139#endif 140 bz,pt %icc, 1f ! most apps don't use fp 141 ldn [THREAD_REG + T_CTX], %g3 ! get ctx pointer 142 ldn [%o4 + LWP_FPU], %o0 ! fp pointer 143 rd %gsr, %g5 144 call fp_save ! doesn't touch globals 145 stx %g5, [%o0 + FPU_GSR] ! store GSR 1461: 147 ! 148 ! Perform context switch callback if set. 149 ! This handles coprocessor state saving. 150 ! i1 = cpu ptr 151 ! g3 = ctx pointer 152 ! 153 wr %g0, %g0, %fprs ! disable fpu and clear fprs 154 brz,pt %g3, 2f ! skip call when zero 155 ldn [%i0 + T_PROCP], %i3 ! delay slot - get proc pointer 156 call savectx 157 mov THREAD_REG, %o0 ! delay - arg = thread pointer 1582: 159 ldn [THREAD_REG + T_PROCP], %i2 ! load old curproc - for mmu 160 161 ! 162 ! Temporarily switch to idle thread's stack 163 ! 164 ldn [%i1 + CPU_IDLE_THREAD], %o0 ! idle thread pointer 165 ldn [%o0 + T_SP], %o1 ! get onto idle thread stack 166 sub %o1, SA(MINFRAME), %sp ! save room for ins and locals 167 clr %fp 168 169 ! 170 ! Set the idle thread as the current thread 171 ! 172 mov THREAD_REG, %l3 ! save %g7 (current thread) 173 mov %o0, THREAD_REG ! set %g7 to idle 174 stn %o0, [%i1 + CPU_THREAD] ! set CPU's thread to idle 175 176 ! 177 ! Clear and unlock previous thread's t_lock 178 ! to allow it to be dispatched by another processor. 179 ! 180 clrb [%l3 + T_LOCK] ! clear tp->t_lock 181 182 ! 183 ! IMPORTANT: Registers at this point must be: 184 ! %i0 = new thread 185 ! %i1 = cpu pointer 186 ! %i2 = old proc pointer 187 ! %i3 = new proc pointer 188 ! 189 ! Here we are in the idle thread, have dropped the old thread. 190 ! 191 ALTENTRY(_resume_from_idle) 192 193 ! SET_KCONTEXTREG(reg0, reg1, reg2, reg3, reg4, label1, label2, label3) 194 SET_KCONTEXTREG(%o0, %g1, %g2, %g3, %o3, l1, l2, l3) 195 196 cmp %i2, %i3 ! resuming the same process? 197 be,pt %xcc, 5f ! yes. 198 nop 199 200 ldx [%i3 + P_AS], %o0 ! load p->p_as 201 ldx [%o0 + A_HAT], %i5 ! %i5 = new proc hat 202 203 ! 204 ! update cpusran field 205 ! 206 ld [%i1 + CPU_ID], %o4 207 add %i5, SFMMU_CPUSRAN, %o5 208 CPU_INDEXTOSET(%o5, %o4, %g1) 209 ldx [%o5], %o2 ! %o2 = cpusran field 210 mov 1, %g2 211 sllx %g2, %o4, %o4 ! %o4 = bit for this cpu 212 andcc %o4, %o2, %g0 213 bnz,pn %xcc, 0f ! bit already set, go to 0 214 nop 2153: 216 or %o2, %o4, %o1 ! or in this cpu's bit mask 217 casx [%o5], %o2, %o1 218 cmp %o2, %o1 219 bne,a,pn %xcc, 3b 220 ldx [%o5], %o2 ! o2 = cpusran field 221 membar #LoadLoad|#StoreLoad 222 2230: 224 ! 225 ! disable interrupts 226 ! 227 ! if resume from user to kernel thread 228 ! call sfmmu_setctx_sec 229 ! if resume from kernel (or a different user) thread to user thread 230 ! call sfmmu_alloc_ctx 231 ! sfmmu_load_mmustate 232 ! 233 ! enable interrupts 234 ! 235 ! %i5 = new proc hat 236 ! 237 238 sethi %hi(ksfmmup), %o2 239 ldx [%o2 + %lo(ksfmmup)], %o2 240 241 rdpr %pstate, %i4 242 cmp %i5, %o2 ! new proc hat == ksfmmup ? 243 bne,pt %xcc, 3f ! new proc is not kernel as, go to 3 244 wrpr %i4, PSTATE_IE, %pstate 245 246 SET_KAS_CTXSEC_ARGS(%i5, %o0, %o1) 247 248 ! new proc is kernel as 249 250 call sfmmu_setctx_sec ! switch to kernel context 251 or %o0, %o1, %o0 252 253 ba,a,pt %icc, 4f 254 255 ! 256 ! Switch to user address space. 257 ! 2583: 259 mov %i5, %o0 ! %o0 = sfmmup 260 mov %i1, %o2 ! %o2 = CPU 261 set SFMMU_PRIVATE, %o3 ! %o3 = sfmmu private flag 262 call sfmmu_alloc_ctx 263 mov %g0, %o1 ! %o1 = allocate flag = 0 264 265 brz,a,pt %o0, 4f ! %o0 == 0, no private alloc'ed 266 nop 267 268 ldn [%i5 + SFMMU_SCDP], %o0 ! using shared contexts? 269 brz,a,pt %o0, 4f 270 nop 271 272 ldn [%o0 + SCD_SFMMUP], %o0 ! %o0 = scdp->scd_sfmmup 273 mov %i1, %o2 ! %o2 = CPU 274 set SFMMU_SHARED, %o3 ! %o3 = sfmmu shared flag 275 call sfmmu_alloc_ctx 276 mov 1, %o1 ! %o1 = allocate flag = 1 277 2784: 279 call sfmmu_load_mmustate ! program MMU registers 280 mov %i5, %o0 281 282 wrpr %g0, %i4, %pstate ! enable interrupts 283 2845: 285 ! 286 ! spin until dispatched thread's mutex has 287 ! been unlocked. this mutex is unlocked when 288 ! it becomes safe for the thread to run. 289 ! 290 ldstub [%i0 + T_LOCK], %o0 ! lock curthread's t_lock 2916: 292 brnz,pn %o0, 7f ! lock failed 293 ldx [%i0 + T_PC], %i7 ! delay - restore resuming thread's pc 294 295 ! 296 ! Fix CPU structure to indicate new running thread. 297 ! Set pointer in new thread to the CPU structure. 298 ! XXX - Move migration statistic out of here 299 ! 300 ldx [%i0 + T_CPU], %g2 ! last CPU to run the new thread 301 cmp %g2, %i1 ! test for migration 302 be,pt %xcc, 4f ! no migration 303 ldn [%i0 + T_LWP], %o1 ! delay - get associated lwp (if any) 304 ldx [%i1 + CPU_STATS_SYS_CPUMIGRATE], %g2 305 inc %g2 306 stx %g2, [%i1 + CPU_STATS_SYS_CPUMIGRATE] 307 stx %i1, [%i0 + T_CPU] ! set new thread's CPU pointer 3084: 309 stx %i0, [%i1 + CPU_THREAD] ! set CPU's thread pointer 310 membar #StoreLoad ! synchronize with mutex_exit() 311 mov %i0, THREAD_REG ! update global thread register 312 stx %o1, [%i1 + CPU_LWP] ! set CPU's lwp ptr 313 brz,a,pn %o1, 1f ! if no lwp, branch and clr mpcb 314 stx %g0, [%i1 + CPU_MPCB] 315 ! 316 ! user thread 317 ! o1 = lwp 318 ! i0 = new thread 319 ! 320 ldx [%i0 + T_STACK], %o0 321 stx %o0, [%i1 + CPU_MPCB] ! set CPU's mpcb pointer 322#ifdef CPU_MPCB_PA 323 ldx [%o0 + MPCB_PA], %o0 324 stx %o0, [%i1 + CPU_MPCB_PA] 325#endif 326 ! Switch to new thread's stack 327 ldx [%i0 + T_SP], %o0 ! restore resuming thread's sp 328 sub %o0, SA(MINFRAME), %sp ! in case of intr or trap before restore 329 mov %o0, %fp 330 ! 331 ! Restore resuming thread's GSR reg and floating-point regs 332 ! Note that the ld to the gsr register ensures that the loading of 333 ! the floating point saved state has completed without necessity 334 ! of a membar #Sync. 335 ! 336#if defined(DEBUG) || defined(NEED_FPU_EXISTS) 337 sethi %hi(fpu_exists), %g3 338 ld [%g3 + %lo(fpu_exists)], %g3 339 brz,pn %g3, 2f 340 ldx [%i0 + T_CTX], %i5 ! should resumed thread restorectx? 341#endif 342 ldx [%o1 + LWP_FPU], %o0 ! fp pointer 343 ld [%o0 + FPU_FPRS], %g5 ! get fpu_fprs 344 andcc %g5, FPRS_FEF, %g0 ! is FPRS_FEF set? 345 bz,a,pt %icc, 9f ! no, skip fp_restore 346 wr %g0, FPRS_FEF, %fprs ! enable fprs so fp_zero works 347 348 ldx [THREAD_REG + T_CPU], %o4 ! cpu pointer 349 call fp_restore 350 wr %g5, %g0, %fprs ! enable fpu and restore fprs 351 352 ldx [%o0 + FPU_GSR], %g5 ! load saved GSR data 353 wr %g5, %g0, %gsr ! restore %gsr data 354 ba,pt %icc,2f 355 ldx [%i0 + T_CTX], %i5 ! should resumed thread restorectx? 356 3579: 358 ! 359 ! Zero resuming thread's fp registers, for *all* non-fp program 360 ! Remove all possibility of using the fp regs as a "covert channel". 361 ! 362 call fp_zero 363 wr %g0, %g0, %gsr 364 ldx [%i0 + T_CTX], %i5 ! should resumed thread restorectx? 365 ba,pt %icc, 2f 366 wr %g0, %g0, %fprs ! disable fprs 367 3681: 369#ifdef CPU_MPCB_PA 370 mov -1, %o1 371 stx %o1, [%i1 + CPU_MPCB_PA] 372#endif 373 ! 374 ! kernel thread 375 ! i0 = new thread 376 ! 377 ! Switch to new thread's stack 378 ! 379 ldx [%i0 + T_SP], %o0 ! restore resuming thread's sp 380 sub %o0, SA(MINFRAME), %sp ! in case of intr or trap before restore 381 mov %o0, %fp 382 ! 383 ! Restore resuming thread's GSR reg and floating-point regs 384 ! Note that the ld to the gsr register ensures that the loading of 385 ! the floating point saved state has completed without necessity 386 ! of a membar #Sync. 387 ! 388 ldx [%i0 + T_STACK], %o0 389 ld [%o0 + SA(MINFRAME) + FPU_FPRS], %g5 ! load fprs 390 ldx [%i0 + T_CTX], %i5 ! should thread restorectx? 391 andcc %g5, FPRS_FEF, %g0 ! did we save fp in stack? 392 bz,a,pt %icc, 2f 393 wr %g0, %g0, %fprs ! clr fprs 394 395 wr %g5, %g0, %fprs ! enable fpu and restore fprs 396 call fp_restore 397 add %o0, SA(MINFRAME), %o0 ! o0 = kpu_t ptr 398 ldx [%o0 + FPU_GSR], %g5 ! load saved GSR data 399 wr %g5, %g0, %gsr ! restore %gsr data 400 4012: 402 ! 403 ! Restore resuming thread's context 404 ! i5 = ctx ptr 405 ! 406 brz,a,pt %i5, 8f ! skip restorectx() when zero 407 ld [%i1 + CPU_BASE_SPL], %o0 408 call restorectx ! thread can not sleep on temp stack 409 mov THREAD_REG, %o0 ! delay slot - arg = thread pointer 410 ! 411 ! Set priority as low as possible, blocking all interrupt threads 412 ! that may be active. 413 ! 414 ld [%i1 + CPU_BASE_SPL], %o0 4158: 416 wrpr %o0, 0, %pil 417 wrpr %g0, WSTATE_KERN, %wstate 418 ! 419 ! If we are resuming an interrupt thread, store a starting timestamp 420 ! in the thread structure. 421 ! 422 lduh [THREAD_REG + T_FLAGS], %o0 423 andcc %o0, T_INTR_THREAD, %g0 424 bnz,pn %xcc, 0f 425 nop 4265: 427 call __dtrace_probe___sched_on__cpu ! DTrace probe 428 nop 429 430 ret ! resume curthread 431 restore 4320: 433 add THREAD_REG, T_INTR_START, %o2 4341: 435 ldx [%o2], %o1 436 RD_CLOCK_TICK(%o0,%o3,%g5,__LINE__) 437 casx [%o2], %o1, %o0 438 cmp %o0, %o1 439 be,pt %xcc, 5b 440 nop 441 ! If an interrupt occurred while we were attempting to store 442 ! the timestamp, try again. 443 ba,pt %xcc, 1b 444 nop 445 446 ! 447 ! lock failed - spin with regular load to avoid cache-thrashing. 448 ! 4497: 450 brnz,a,pt %o0, 7b ! spin while locked 451 ldub [%i0 + T_LOCK], %o0 452 ba %xcc, 6b 453 ldstub [%i0 + T_LOCK], %o0 ! delay - lock curthread's mutex 454 SET_SIZE(_resume_from_idle) 455 SET_SIZE(resume) 456 457#endif /* lint */ 458 459#if defined(lint) 460 461/* ARGSUSED */ 462void 463resume_from_zombie(kthread_id_t t) 464{} 465 466#else /* lint */ 467 468 ENTRY(resume_from_zombie) 469 save %sp, -SA(MINFRAME), %sp ! save ins and locals 470 471 call __dtrace_probe___sched_off__cpu ! DTrace probe 472 mov %i0, %o0 ! arg for DTrace probe 473 474 ldn [THREAD_REG + T_CPU], %i1 ! cpu pointer 475 476 flushw ! flushes all but this window 477 ldn [THREAD_REG + T_PROCP], %i2 ! old procp for mmu ctx 478 479 ! 480 ! Temporarily switch to the idle thread's stack so that 481 ! the zombie thread's stack can be reclaimed by the reaper. 482 ! 483 ldn [%i1 + CPU_IDLE_THREAD], %o2 ! idle thread pointer 484 ldn [%o2 + T_SP], %o1 ! get onto idle thread stack 485 sub %o1, SA(MINFRAME), %sp ! save room for ins and locals 486 clr %fp 487 ! 488 ! Set the idle thread as the current thread. 489 ! Put the zombie on death-row. 490 ! 491 mov THREAD_REG, %o0 ! save %g7 = curthread for arg 492 mov %o2, THREAD_REG ! set %g7 to idle 493 stn %g0, [%i1 + CPU_MPCB] ! clear mpcb 494#ifdef CPU_MPCB_PA 495 mov -1, %o1 496 stx %o1, [%i1 + CPU_MPCB_PA] 497#endif 498 call reapq_add ! reapq_add(old_thread); 499 stn %o2, [%i1 + CPU_THREAD] ! delay - CPU's thread = idle 500 501 ! 502 ! resume_from_idle args: 503 ! %i0 = new thread 504 ! %i1 = cpu 505 ! %i2 = old proc 506 ! %i3 = new proc 507 ! 508 b _resume_from_idle ! finish job of resume 509 ldn [%i0 + T_PROCP], %i3 ! new process 510 SET_SIZE(resume_from_zombie) 511 512#endif /* lint */ 513 514#if defined(lint) 515 516/* ARGSUSED */ 517void 518resume_from_intr(kthread_id_t t) 519{} 520 521#else /* lint */ 522 523 ENTRY(resume_from_intr) 524 save %sp, -SA(MINFRAME), %sp ! save ins and locals 525 526 ! 527 ! We read in the fprs and call fp_save if FPRS_FEF is set 528 ! to save the floating-point state if fprs has been 529 ! modified by operations such as hw bcopy or fp_disabled. 530 ! This is to resolve an issue where an interrupting thread 531 ! doesn't retain their floating-point registers when 532 ! switching out of the interrupt context. 533 ! 534 rd %fprs, %g4 535 ldn [THREAD_REG + T_STACK], %i2 536 andcc %g4, FPRS_FEF, %g0 ! is FPRS_FEF set 537 bz,pt %icc, 4f 538 st %g4, [%i2 + SA(MINFRAME) + FPU_FPRS] ! save fprs 539 540 ! save kernel fp state in stack 541 add %i2, SA(MINFRAME), %o0 ! %o0 = kfpu_t ptr 542 rd %gsr, %g5 543 call fp_save 544 stx %g5, [%o0 + FPU_GSR] ! store GSR 545 5464: 547 548 flushw ! flushes all but this window 549 stn %fp, [THREAD_REG + T_SP] ! delay - save sp 550 stn %i7, [THREAD_REG + T_PC] ! save return address 551 552 ldn [%i0 + T_PC], %i7 ! restore resuming thread's pc 553 ldn [THREAD_REG + T_CPU], %i1 ! cpu pointer 554 555 ! 556 ! Fix CPU structure to indicate new running thread. 557 ! The pinned thread we're resuming already has the CPU pointer set. 558 ! 559 mov THREAD_REG, %l3 ! save old thread 560 stn %i0, [%i1 + CPU_THREAD] ! set CPU's thread pointer 561 membar #StoreLoad ! synchronize with mutex_exit() 562 mov %i0, THREAD_REG ! update global thread register 563 564 ! 565 ! Switch to new thread's stack 566 ! 567 ldn [THREAD_REG + T_SP], %o0 ! restore resuming thread's sp 568 sub %o0, SA(MINFRAME), %sp ! in case of intr or trap before restore 569 mov %o0, %fp 570 clrb [%l3 + T_LOCK] ! clear intr thread's tp->t_lock 571 572 ! 573 ! If we are resuming an interrupt thread, store a timestamp in the 574 ! thread structure. 575 ! 576 lduh [THREAD_REG + T_FLAGS], %o0 577 andcc %o0, T_INTR_THREAD, %g0 578 bnz,pn %xcc, 0f 579 ! 580 ! We're resuming a non-interrupt thread. 581 ! Clear CPU_INTRCNT and check if cpu_kprunrun set? 582 ! 583 ldub [%i1 + CPU_KPRUNRUN], %o5 ! delay 584 brnz,pn %o5, 3f ! call kpreempt(KPREEMPT_SYNC); 585 stub %g0, [%i1 + CPU_INTRCNT] 5861: 587 ret ! resume curthread 588 restore 5890: 590 ! 591 ! We're an interrupt thread. Update t_intr_start and cpu_intrcnt 592 ! 593 add THREAD_REG, T_INTR_START, %o2 5942: 595 ldx [%o2], %o1 596 RD_CLOCK_TICK(%o0,%o3,%l1,__LINE__) 597 casx [%o2], %o1, %o0 598 cmp %o0, %o1 599 bne,pn %xcc, 2b 600 ldn [THREAD_REG + T_INTR], %l1 ! delay 601 ! Reset cpu_intrcnt if we aren't pinning anyone 602 brz,a,pt %l1, 2f 603 stub %g0, [%i1 + CPU_INTRCNT] 6042: 605 ba,pt %xcc, 1b 606 nop 6073: 608 ! 609 ! We're a non-interrupt thread and cpu_kprunrun is set. call kpreempt. 610 ! 611 call kpreempt 612 mov KPREEMPT_SYNC, %o0 613 ba,pt %xcc, 1b 614 nop 615 SET_SIZE(resume_from_intr) 616 617#endif /* lint */ 618 619 620/* 621 * thread_start() 622 * 623 * the current register window was crafted by thread_run() to contain 624 * an address of a procedure (in register %i7), and its args in registers 625 * %i0 through %i5. a stack trace of this thread will show the procedure 626 * that thread_start() invoked at the bottom of the stack. an exit routine 627 * is stored in %l0 and called when started thread returns from its called 628 * procedure. 629 */ 630 631#if defined(lint) 632 633void 634thread_start(void) 635{} 636 637#else /* lint */ 638 639 ENTRY(thread_start) 640 mov %i0, %o0 641 jmpl %i7, %o7 ! call thread_run()'s start() procedure. 642 mov %i1, %o1 643 644 call thread_exit ! destroy thread if it returns. 645 nop 646 unimp 0 647 SET_SIZE(thread_start) 648 649#endif /* lint */ 650