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) 1992, 2010, Oracle and/or its affiliates. All rights reserved. 23 * Copyright 2021 Joyent, Inc. 24 * Copyright 2021 Oxide Computer Company 25 */ 26 27 /* Copyright (c) 1990, 1991 UNIX System Laboratories, Inc. */ 28 /* Copyright (c) 1984, 1986, 1987, 1988, 1989, 1990 AT&T */ 29 /* All Rights Reserved */ 30 31 #include <sys/types.h> 32 #include <sys/stdbool.h> 33 #include <sys/param.h> 34 #include <sys/sysmacros.h> 35 #include <sys/signal.h> 36 #include <sys/systm.h> 37 #include <sys/user.h> 38 #include <sys/mman.h> 39 #include <sys/class.h> 40 #include <sys/proc.h> 41 #include <sys/procfs.h> 42 #include <sys/buf.h> 43 #include <sys/kmem.h> 44 #include <sys/cred.h> 45 #include <sys/archsystm.h> 46 #include <sys/vmparam.h> 47 #include <sys/prsystm.h> 48 #include <sys/reboot.h> 49 #include <sys/uadmin.h> 50 #include <sys/vfs.h> 51 #include <sys/vnode.h> 52 #include <sys/file.h> 53 #include <sys/session.h> 54 #include <sys/ucontext.h> 55 #include <sys/dnlc.h> 56 #include <sys/var.h> 57 #include <sys/cmn_err.h> 58 #include <sys/debugreg.h> 59 #include <sys/thread.h> 60 #include <sys/vtrace.h> 61 #include <sys/consdev.h> 62 #include <sys/psw.h> 63 #include <sys/regset.h> 64 #include <sys/privregs.h> 65 #include <sys/cpu.h> 66 #include <sys/stack.h> 67 #include <sys/swap.h> 68 #include <vm/hat.h> 69 #include <vm/anon.h> 70 #include <vm/as.h> 71 #include <vm/page.h> 72 #include <vm/seg.h> 73 #include <vm/seg_kmem.h> 74 #include <vm/seg_map.h> 75 #include <vm/seg_vn.h> 76 #include <sys/exec.h> 77 #include <sys/acct.h> 78 #include <sys/core.h> 79 #include <sys/corectl.h> 80 #include <sys/modctl.h> 81 #include <sys/tuneable.h> 82 #include <c2/audit.h> 83 #include <sys/bootconf.h> 84 #include <sys/brand.h> 85 #include <sys/dumphdr.h> 86 #include <sys/promif.h> 87 #include <sys/systeminfo.h> 88 #include <sys/kdi.h> 89 #include <sys/contract_impl.h> 90 #include <sys/x86_archext.h> 91 #include <sys/segments.h> 92 #include <sys/ontrap.h> 93 #include <sys/cpu.h> 94 #ifdef __xpv 95 #include <sys/hypervisor.h> 96 #endif 97 98 /* 99 * Compare the version of boot that boot says it is against 100 * the version of boot the kernel expects. 101 */ 102 int 103 check_boot_version(int boots_version) 104 { 105 if (boots_version == BO_VERSION) 106 return (0); 107 108 prom_printf("Wrong boot interface - kernel needs v%d found v%d\n", 109 BO_VERSION, boots_version); 110 prom_panic("halting"); 111 /*NOTREACHED*/ 112 } 113 114 /* 115 * Process the physical installed list for boot. 116 * Finds: 117 * 1) the pfn of the highest installed physical page, 118 * 2) the number of pages installed 119 * 3) the number of distinct contiguous regions these pages fall into. 120 * 4) the number of contiguous memory ranges 121 */ 122 void 123 installed_top_size_ex( 124 struct memlist *list, /* pointer to start of installed list */ 125 pfn_t *high_pfn, /* return ptr for top value */ 126 pgcnt_t *pgcnt, /* return ptr for sum of installed pages */ 127 int *ranges) /* return ptr for the count of contig. ranges */ 128 { 129 pfn_t top = 0; 130 pgcnt_t sumpages = 0; 131 pfn_t highp; /* high page in a chunk */ 132 int cnt = 0; 133 134 for (; list; list = list->ml_next) { 135 ++cnt; 136 highp = (list->ml_address + list->ml_size - 1) >> PAGESHIFT; 137 if (top < highp) 138 top = highp; 139 sumpages += btop(list->ml_size); 140 } 141 142 *high_pfn = top; 143 *pgcnt = sumpages; 144 *ranges = cnt; 145 } 146 147 void 148 installed_top_size( 149 struct memlist *list, /* pointer to start of installed list */ 150 pfn_t *high_pfn, /* return ptr for top value */ 151 pgcnt_t *pgcnt) /* return ptr for sum of installed pages */ 152 { 153 int ranges; 154 155 installed_top_size_ex(list, high_pfn, pgcnt, &ranges); 156 } 157 158 void 159 phys_install_has_changed(void) 160 {} 161 162 /* 163 * Copy in a memory list from boot to kernel, with a filter function 164 * to remove pages. The filter function can increase the address and/or 165 * decrease the size to filter out pages. It will also align addresses and 166 * sizes to PAGESIZE. 167 */ 168 void 169 copy_memlist_filter( 170 struct memlist *src, 171 struct memlist **dstp, 172 void (*filter)(uint64_t *, uint64_t *)) 173 { 174 struct memlist *dst, *prev; 175 uint64_t addr; 176 uint64_t size; 177 uint64_t eaddr; 178 179 dst = *dstp; 180 prev = dst; 181 182 /* 183 * Move through the memlist applying a filter against 184 * each range of memory. Note that we may apply the 185 * filter multiple times against each memlist entry. 186 */ 187 for (; src; src = src->ml_next) { 188 addr = P2ROUNDUP(src->ml_address, PAGESIZE); 189 eaddr = P2ALIGN(src->ml_address + src->ml_size, PAGESIZE); 190 while (addr < eaddr) { 191 size = eaddr - addr; 192 if (filter != NULL) 193 filter(&addr, &size); 194 if (size == 0) 195 break; 196 dst->ml_address = addr; 197 dst->ml_size = size; 198 dst->ml_next = 0; 199 if (prev == dst) { 200 dst->ml_prev = 0; 201 dst++; 202 } else { 203 dst->ml_prev = prev; 204 prev->ml_next = dst; 205 dst++; 206 prev++; 207 } 208 addr += size; 209 } 210 } 211 212 *dstp = dst; 213 } 214 215 /* 216 * Kernel setup code, called from startup(). 217 */ 218 void 219 kern_setup1(void) 220 { 221 proc_t *pp; 222 223 pp = &p0; 224 225 proc_sched = pp; 226 227 /* 228 * Initialize process 0 data structures 229 */ 230 pp->p_stat = SRUN; 231 pp->p_flag = SSYS; 232 233 pp->p_pidp = &pid0; 234 pp->p_pgidp = &pid0; 235 pp->p_sessp = &session0; 236 pp->p_tlist = &t0; 237 pid0.pid_pglink = pp; 238 pid0.pid_pgtail = pp; 239 240 /* 241 * XXX - we asssume that the u-area is zeroed out except for 242 * ttolwp(curthread)->lwp_regs. 243 */ 244 PTOU(curproc)->u_cmask = (mode_t)CMASK; 245 246 thread_init(); /* init thread_free list */ 247 pid_init(); /* initialize pid (proc) table */ 248 contract_init(); /* initialize contracts */ 249 250 init_pages_pp_maximum(); 251 } 252 253 /* 254 * Load a procedure into a thread. 255 */ 256 void 257 thread_load(kthread_t *t, void (*start)(), caddr_t arg, size_t len) 258 { 259 caddr_t sp; 260 size_t framesz; 261 caddr_t argp; 262 long *p; 263 extern void thread_start(); 264 265 /* 266 * Push a "c" call frame onto the stack to represent 267 * the caller of "start". 268 */ 269 sp = t->t_stk; 270 ASSERT(((uintptr_t)t->t_stk & (STACK_ENTRY_ALIGN - 1)) == 0); 271 if (len != 0) { 272 /* 273 * the object that arg points at is copied into the 274 * caller's frame. 275 */ 276 framesz = SA(len); 277 sp -= framesz; 278 ASSERT(sp > t->t_stkbase); 279 argp = sp + SA(MINFRAME); 280 bcopy(arg, argp, len); 281 arg = argp; 282 } 283 /* 284 * Set up arguments (arg and len) on the caller's stack frame. 285 */ 286 p = (long *)sp; 287 288 *--p = 0; /* fake call */ 289 *--p = 0; /* null frame pointer terminates stack trace */ 290 *--p = (long)len; 291 *--p = (intptr_t)arg; 292 *--p = (intptr_t)start; 293 294 /* 295 * initialize thread to resume at thread_start() which will 296 * turn around and invoke (*start)(arg, len). 297 */ 298 t->t_pc = (uintptr_t)thread_start; 299 t->t_sp = (uintptr_t)p; 300 301 ASSERT((t->t_sp & (STACK_ENTRY_ALIGN - 1)) == 0); 302 } 303 304 /* 305 * load user registers into lwp. 306 */ 307 /*ARGSUSED2*/ 308 void 309 lwp_load(klwp_t *lwp, gregset_t grp, uintptr_t thrptr) 310 { 311 struct regs *rp = lwptoregs(lwp); 312 313 setgregs(lwp, grp); 314 rp->r_ps = PSL_USER; 315 316 /* 317 * For 64-bit lwps, we allow one magic %fs selector value, and one 318 * magic %gs selector to point anywhere in the address space using 319 * %fsbase and %gsbase behind the scenes. libc uses %fs to point 320 * at the ulwp_t structure. 321 * 322 * For 32-bit lwps, libc wedges its lwp thread pointer into the 323 * ucontext ESP slot (which is otherwise irrelevant to setting a 324 * ucontext) and LWPGS_SEL value into gregs[REG_GS]. This is so 325 * syslwp_create() can atomically setup %gs. 326 * 327 * See setup_context() in libc. 328 */ 329 #ifdef _SYSCALL32_IMPL 330 if (lwp_getdatamodel(lwp) == DATAMODEL_ILP32) { 331 if (grp[REG_GS] == LWPGS_SEL) 332 (void) lwp_setprivate(lwp, _LWP_GSBASE, thrptr); 333 } else { 334 /* 335 * See lwp_setprivate in kernel and setup_context in libc. 336 * 337 * Currently libc constructs a ucontext from whole cloth for 338 * every new (not main) lwp created. For 64 bit processes 339 * %fsbase is directly set to point to current thread pointer. 340 * In the past (solaris 10) %fs was also set LWPFS_SEL to 341 * indicate %fsbase. Now we use the null GDT selector for 342 * this purpose. LWP[FS|GS]_SEL are only intended for 32 bit 343 * processes. To ease transition we support older libcs in 344 * the newer kernel by forcing %fs or %gs selector to null 345 * by calling lwp_setprivate if LWP[FS|GS]_SEL is passed in 346 * the ucontext. This is should be ripped out at some future 347 * date. Another fix would be for libc to do a getcontext 348 * and inherit the null %fs/%gs from the current context but 349 * that means an extra system call and could hurt performance. 350 */ 351 if (grp[REG_FS] == 0x1bb) /* hard code legacy LWPFS_SEL */ 352 (void) lwp_setprivate(lwp, _LWP_FSBASE, 353 (uintptr_t)grp[REG_FSBASE]); 354 355 if (grp[REG_GS] == 0x1c3) /* hard code legacy LWPGS_SEL */ 356 (void) lwp_setprivate(lwp, _LWP_GSBASE, 357 (uintptr_t)grp[REG_GSBASE]); 358 } 359 #else 360 if (grp[GS] == LWPGS_SEL) 361 (void) lwp_setprivate(lwp, _LWP_GSBASE, thrptr); 362 #endif 363 364 lwp->lwp_eosys = JUSTRETURN; 365 lwptot(lwp)->t_post_sys = 1; 366 } 367 368 /* 369 * set syscall()'s return values for a lwp. 370 */ 371 void 372 lwp_setrval(klwp_t *lwp, int v1, int v2) 373 { 374 lwptoregs(lwp)->r_ps &= ~PS_C; 375 lwptoregs(lwp)->r_r0 = v1; 376 lwptoregs(lwp)->r_r1 = v2; 377 } 378 379 /* 380 * set syscall()'s return values for a lwp. 381 */ 382 void 383 lwp_setsp(klwp_t *lwp, caddr_t sp) 384 { 385 lwptoregs(lwp)->r_sp = (intptr_t)sp; 386 } 387 388 /* 389 * Copy regs from parent to child. 390 */ 391 void 392 lwp_forkregs(klwp_t *lwp, klwp_t *clwp) 393 { 394 struct pcb *pcb = &clwp->lwp_pcb; 395 struct regs *rp = lwptoregs(lwp); 396 397 if (!PCB_NEED_UPDATE_SEGS(pcb)) { 398 pcb->pcb_ds = rp->r_ds; 399 pcb->pcb_es = rp->r_es; 400 pcb->pcb_fs = rp->r_fs; 401 pcb->pcb_gs = rp->r_gs; 402 PCB_SET_UPDATE_SEGS(pcb); 403 lwptot(clwp)->t_post_sys = 1; 404 } 405 ASSERT(lwptot(clwp)->t_post_sys); 406 407 fp_lwp_dup(clwp); 408 409 bcopy(lwp->lwp_regs, clwp->lwp_regs, sizeof (struct regs)); 410 } 411 412 /* 413 * This function is currently unused on x86. 414 */ 415 /*ARGSUSED*/ 416 void 417 lwp_freeregs(klwp_t *lwp, int isexec) 418 {} 419 420 /* 421 * This function is currently unused on x86. 422 */ 423 void 424 lwp_pcb_exit(void) 425 {} 426 427 /* 428 * Lwp context ops for segment registers. 429 */ 430 431 /* 432 * Every time we come into the kernel (syscall, interrupt or trap 433 * but not fast-traps) we capture the current values of the user's 434 * segment registers into the lwp's reg structure. This includes 435 * lcall for i386 generic system call support since it is handled 436 * as a segment-not-present trap. 437 * 438 * Here we save the current values from the lwp regs into the pcb 439 * and or PCB_UPDATE_SEGS (1) in pcb->pcb_rupdate to tell the rest 440 * of the kernel that the pcb copy of the segment registers is the 441 * current one. This ensures the lwp's next trip to user land via 442 * update_sregs. Finally we set t_post_sys to ensure that no 443 * system call fast-path's its way out of the kernel via sysret. 444 * 445 * (This means that we need to have interrupts disabled when we 446 * test t->t_post_sys in the syscall handlers; if the test fails, 447 * we need to keep interrupts disabled until we return to userland 448 * so we can't be switched away.) 449 * 450 * As a result of all this, we don't really have to do a whole lot 451 * if the thread is just mucking about in the kernel, switching on 452 * and off the cpu for whatever reason it feels like. And yet we 453 * still preserve fast syscalls, cause if we -don't- get 454 * descheduled, we never come here either. 455 */ 456 457 #define VALID_LWP_DESC(udp) ((udp)->usd_type == SDT_MEMRWA && \ 458 (udp)->usd_p == 1 && (udp)->usd_dpl == SEL_UPL) 459 460 /*ARGSUSED*/ 461 void 462 lwp_segregs_save(void *arg) 463 { 464 klwp_t *lwp = arg; 465 pcb_t *pcb = &lwp->lwp_pcb; 466 struct regs *rp; 467 468 ASSERT(VALID_LWP_DESC(&pcb->pcb_fsdesc)); 469 ASSERT(VALID_LWP_DESC(&pcb->pcb_gsdesc)); 470 471 if (!PCB_NEED_UPDATE_SEGS(pcb)) { 472 rp = lwptoregs(lwp); 473 474 /* 475 * If there's no update already pending, capture the current 476 * %ds/%es/%fs/%gs values from lwp's regs in case the user 477 * changed them; %fsbase and %gsbase are privileged so the 478 * kernel versions of these registers in pcb_fsbase and 479 * pcb_gsbase are always up-to-date. 480 */ 481 pcb->pcb_ds = rp->r_ds; 482 pcb->pcb_es = rp->r_es; 483 pcb->pcb_fs = rp->r_fs; 484 pcb->pcb_gs = rp->r_gs; 485 PCB_SET_UPDATE_SEGS(pcb); 486 lwp->lwp_thread->t_post_sys = 1; 487 } 488 489 #if !defined(__xpv) /* XXPV not sure if we can re-read gdt? */ 490 ASSERT(bcmp(&CPU->cpu_gdt[GDT_LWPFS], &lwp->lwp_pcb.pcb_fsdesc, 491 sizeof (lwp->lwp_pcb.pcb_fsdesc)) == 0); 492 ASSERT(bcmp(&CPU->cpu_gdt[GDT_LWPGS], &lwp->lwp_pcb.pcb_gsdesc, 493 sizeof (lwp->lwp_pcb.pcb_gsdesc)) == 0); 494 #endif 495 } 496 497 /* 498 * Update the segment registers with new values from the pcb. 499 * 500 * We have to do this carefully, and in the following order, 501 * in case any of the selectors points at a bogus descriptor. 502 * If they do, we'll catch trap with on_trap and return 1. 503 * returns 0 on success. 504 * 505 * This is particularly tricky for %gs. 506 * This routine must be executed under a cli. 507 */ 508 int 509 update_sregs(struct regs *rp, klwp_t *lwp) 510 { 511 pcb_t *pcb = &lwp->lwp_pcb; 512 ulong_t kgsbase; 513 on_trap_data_t otd; 514 int rc; 515 516 if (!on_trap(&otd, OT_SEGMENT_ACCESS)) { 517 rc = 0; 518 #if defined(__xpv) 519 /* 520 * On the hyervisor this is easy. The hypercall below will 521 * swapgs and load %gs with the user selector. If the user 522 * selector is bad the hypervisor will catch the fault and 523 * load %gs with the null selector instead. Either way the 524 * kernel's gsbase is not damaged. 525 */ 526 kgsbase = (ulong_t)CPU; 527 if (HYPERVISOR_set_segment_base(SEGBASE_GS_USER_SEL, 528 pcb->pcb_gs) != 0) { 529 no_trap(); 530 return (1); 531 } 532 533 rp->r_gs = pcb->pcb_gs; 534 ASSERT((cpu_t *)kgsbase == CPU); 535 536 #else /* __xpv */ 537 538 /* 539 * A little more complicated running native. 540 */ 541 kgsbase = (ulong_t)CPU; 542 __set_gs(pcb->pcb_gs); 543 544 /* 545 * If __set_gs fails it's because the new %gs is a bad %gs, 546 * we'll be taking a trap but with the original %gs and %gsbase 547 * undamaged (i.e. pointing at curcpu). 548 * 549 * We've just mucked up the kernel's gsbase. Oops. In 550 * particular we can't take any traps at all. Make the newly 551 * computed gsbase be the hidden gs via swapgs, and fix 552 * the kernel's gsbase back again. Later, when we return to 553 * userland we'll swapgs again restoring gsbase just loaded 554 * above. 555 */ 556 __asm__ __volatile__("mfence; swapgs"); 557 558 rp->r_gs = pcb->pcb_gs; 559 560 /* 561 * Restore kernel's gsbase. Note that this also serializes any 562 * attempted speculation from loading the user-controlled 563 * %gsbase. 564 */ 565 wrmsr(MSR_AMD_GSBASE, kgsbase); 566 567 #endif /* __xpv */ 568 569 /* 570 * Only override the descriptor base address if 571 * r_gs == LWPGS_SEL or if r_gs == NULL. A note on 572 * NULL descriptors -- 32-bit programs take faults 573 * if they deference NULL descriptors; however, 574 * when 64-bit programs load them into %fs or %gs, 575 * they DONT fault -- only the base address remains 576 * whatever it was from the last load. Urk. 577 * 578 * XXX - note that lwp_setprivate now sets %fs/%gs to the 579 * null selector for 64 bit processes. Whereas before 580 * %fs/%gs were set to LWP(FS|GS)_SEL regardless of 581 * the process's data model. For now we check for both 582 * values so that the kernel can also support the older 583 * libc. This should be ripped out at some point in the 584 * future. 585 */ 586 if (pcb->pcb_gs == LWPGS_SEL || pcb->pcb_gs == 0) { 587 #if defined(__xpv) 588 if (HYPERVISOR_set_segment_base(SEGBASE_GS_USER, 589 pcb->pcb_gsbase)) { 590 no_trap(); 591 return (1); 592 } 593 #else 594 wrmsr(MSR_AMD_KGSBASE, pcb->pcb_gsbase); 595 #endif 596 } 597 598 __set_ds(pcb->pcb_ds); 599 rp->r_ds = pcb->pcb_ds; 600 601 __set_es(pcb->pcb_es); 602 rp->r_es = pcb->pcb_es; 603 604 __set_fs(pcb->pcb_fs); 605 rp->r_fs = pcb->pcb_fs; 606 607 /* 608 * Same as for %gs 609 */ 610 if (pcb->pcb_fs == LWPFS_SEL || pcb->pcb_fs == 0) { 611 #if defined(__xpv) 612 if (HYPERVISOR_set_segment_base(SEGBASE_FS, 613 pcb->pcb_fsbase)) { 614 no_trap(); 615 return (1); 616 } 617 #else 618 wrmsr(MSR_AMD_FSBASE, pcb->pcb_fsbase); 619 #endif 620 } 621 622 } else { 623 cli(); 624 rc = 1; 625 } 626 no_trap(); 627 return (rc); 628 } 629 630 /* 631 * Make sure any stale selectors are cleared from the segment registers 632 * by putting KDS_SEL (the kernel's default %ds gdt selector) into them. 633 * This is necessary because the kernel itself does not use %es, %fs, nor 634 * %ds. (%cs and %ss are necessary, and are set up by the kernel - along with 635 * %gs - to point to the current cpu struct.) If we enter kmdb while in the 636 * kernel and resume with a stale ldt or brandz selector sitting there in a 637 * segment register, kmdb will #gp fault if the stale selector points to, 638 * for example, an ldt in the context of another process. 639 * 640 * WARNING: Intel and AMD chips behave differently when storing 641 * the null selector into %fs and %gs while in long mode. On AMD 642 * chips fsbase and gsbase are not cleared. But on Intel chips, storing 643 * a null selector into %fs or %gs has the side effect of clearing 644 * fsbase or gsbase. For that reason we use KDS_SEL, which has 645 * consistent behavor between AMD and Intel. 646 * 647 * Caller responsible for preventing cpu migration. 648 */ 649 void 650 reset_sregs(void) 651 { 652 ulong_t kgsbase = (ulong_t)CPU; 653 654 ASSERT(curthread->t_preempt != 0 || getpil() >= DISP_LEVEL); 655 656 cli(); 657 __set_gs(KGS_SEL); 658 659 /* 660 * restore kernel gsbase 661 */ 662 #if defined(__xpv) 663 xen_set_segment_base(SEGBASE_GS_KERNEL, kgsbase); 664 #else 665 wrmsr(MSR_AMD_GSBASE, kgsbase); 666 #endif 667 668 sti(); 669 670 __set_ds(KDS_SEL); 671 __set_es(0 | SEL_KPL); /* selector RPL not ring 0 on hypervisor */ 672 __set_fs(KFS_SEL); 673 } 674 675 676 #ifdef _SYSCALL32_IMPL 677 678 /* 679 * Make it impossible for a process to change its data model. 680 * We do this by toggling the present bits for the 32 and 681 * 64-bit user code descriptors. That way if a user lwp attempts 682 * to change its data model (by using the wrong code descriptor in 683 * %cs) it will fault immediately. This also allows us to simplify 684 * assertions and checks in the kernel. 685 */ 686 687 static void 688 gdt_ucode_model(model_t model) 689 { 690 kpreempt_disable(); 691 if (model == DATAMODEL_NATIVE) { 692 gdt_update_usegd(GDT_UCODE, &ucs_on); 693 gdt_update_usegd(GDT_U32CODE, &ucs32_off); 694 } else { 695 gdt_update_usegd(GDT_U32CODE, &ucs32_on); 696 gdt_update_usegd(GDT_UCODE, &ucs_off); 697 } 698 kpreempt_enable(); 699 } 700 701 #endif /* _SYSCALL32_IMPL */ 702 703 /* 704 * Restore lwp private fs and gs segment descriptors 705 * on current cpu's GDT. 706 */ 707 static void 708 lwp_segregs_restore(void *arg) 709 { 710 klwp_t *lwp = arg; 711 pcb_t *pcb = &lwp->lwp_pcb; 712 713 ASSERT(VALID_LWP_DESC(&pcb->pcb_fsdesc)); 714 ASSERT(VALID_LWP_DESC(&pcb->pcb_gsdesc)); 715 716 #ifdef _SYSCALL32_IMPL 717 gdt_ucode_model(DATAMODEL_NATIVE); 718 #endif 719 720 gdt_update_usegd(GDT_LWPFS, &pcb->pcb_fsdesc); 721 gdt_update_usegd(GDT_LWPGS, &pcb->pcb_gsdesc); 722 723 } 724 725 #ifdef _SYSCALL32_IMPL 726 727 static void 728 lwp_segregs_restore32(void *arg) 729 { 730 klwp_t *lwp = arg; 731 pcb_t *pcb = &lwp->lwp_pcb; 732 733 ASSERT(VALID_LWP_DESC(&lwp->lwp_pcb.pcb_fsdesc)); 734 ASSERT(VALID_LWP_DESC(&lwp->lwp_pcb.pcb_gsdesc)); 735 736 gdt_ucode_model(DATAMODEL_ILP32); 737 gdt_update_usegd(GDT_LWPFS, &pcb->pcb_fsdesc); 738 gdt_update_usegd(GDT_LWPGS, &pcb->pcb_gsdesc); 739 } 740 741 #endif /* _SYSCALL32_IMPL */ 742 743 static const struct ctxop_template brand_interpose_ctxop_tpl = { 744 .ct_rev = CTXOP_TPL_REV, 745 .ct_save = brand_interpositioning_disable, 746 .ct_restore = brand_interpositioning_enable, 747 .ct_exit = brand_interpositioning_disable, 748 }; 749 750 /* 751 * If this is a process in a branded zone, then we want it to use the brand 752 * syscall entry points instead of the standard Solaris entry points. This 753 * routine must be called when a new lwp is created within a branded zone 754 * or when an existing lwp moves into a branded zone via a zone_enter() 755 * operation. 756 */ 757 void 758 lwp_attach_brand_hdlrs(klwp_t *lwp) 759 { 760 kthread_t *t = lwptot(lwp); 761 762 ASSERT(PROC_IS_BRANDED(lwptoproc(lwp))); 763 764 /* Confirm that brand interposition ctxop is not already present */ 765 ASSERT0(ctxop_remove(t, &brand_interpose_ctxop_tpl, NULL)); 766 767 ctxop_install(t, &brand_interpose_ctxop_tpl, NULL); 768 769 if (t == curthread) { 770 kpreempt_disable(); 771 brand_interpositioning_enable(NULL); 772 kpreempt_enable(); 773 } 774 } 775 776 /* 777 * If this is a process in a branded zone, then we want it to disable the 778 * brand syscall entry points. This routine must be called when the last 779 * lwp in a process is exiting in proc_exit(). 780 */ 781 void 782 lwp_detach_brand_hdlrs(klwp_t *lwp) 783 { 784 kthread_t *t = lwptot(lwp); 785 786 ASSERT(PROC_IS_BRANDED(lwptoproc(lwp))); 787 if (t == curthread) 788 kpreempt_disable(); 789 790 /* Remove the original context handlers */ 791 ctxop_remove(t, &brand_interpose_ctxop_tpl, NULL); 792 793 if (t == curthread) { 794 /* Cleanup our MSR and IDT entries. */ 795 brand_interpositioning_disable(NULL); 796 kpreempt_enable(); 797 } 798 } 799 800 static const struct ctxop_template sep_tpl = { 801 .ct_rev = CTXOP_TPL_REV, 802 .ct_save = sep_save, 803 .ct_restore = sep_restore, 804 }; 805 806 /* 807 * Add any lwp-associated context handlers to the lwp at the beginning 808 * of the lwp's useful life. 809 * 810 * All paths which create lwp's invoke lwp_create(); lwp_create() 811 * invokes lwp_stk_init() which initializes the stack, sets up 812 * lwp_regs, and invokes this routine. 813 * 814 * All paths which destroy lwp's invoke lwp_exit() to rip the lwp 815 * apart and put it on 'lwp_deathrow'; if the lwp is destroyed it 816 * ends up in thread_free() which invokes freectx(t, 0) before 817 * invoking lwp_stk_fini(). When the lwp is recycled from death 818 * row, lwp_stk_fini() is invoked, then thread_free(), and thus 819 * freectx(t, 0) as before. 820 * 821 * In the case of exec, the surviving lwp is thoroughly scrubbed 822 * clean; exec invokes freectx(t, 1) to destroy associated contexts. 823 * On the way back to the new image, it invokes setregs() which 824 * in turn invokes this routine. 825 */ 826 void 827 lwp_installctx(klwp_t *lwp) 828 { 829 kthread_t *t = lwptot(lwp); 830 bool thisthread = (t == curthread); 831 struct ctxop *ctx; 832 833 const struct ctxop_template segreg_tpl = { 834 .ct_rev = CTXOP_TPL_REV, 835 .ct_save = lwp_segregs_save, 836 #ifdef _SYSCALL32_IMPL 837 .ct_restore = lwp_getdatamodel(lwp) == DATAMODEL_NATIVE ? 838 lwp_segregs_restore : lwp_segregs_restore32 839 #else 840 .ct_restore = lwp_segregs_restore; 841 #endif 842 }; 843 844 /* 845 * Install the basic lwp context handlers on each lwp. 846 * 847 * On the amd64 kernel, the context handlers are responsible for 848 * virtualizing %ds, %es, %fs, and %gs to the lwp. The register 849 * values are only ever changed via sys_rtt when the 850 * PCB_UPDATE_SEGS bit (1) is set in pcb->pcb_rupdate. Only 851 * sys_rtt gets to clear the bit. 852 * 853 * On the i386 kernel, the context handlers are responsible for 854 * virtualizing %gs/%fs to the lwp by updating the per-cpu GDTs 855 */ 856 ASSERT0(ctxop_remove(t, &segreg_tpl, lwp)); 857 858 ctx = ctxop_allocate(&segreg_tpl, lwp); 859 if (thisthread) { 860 kpreempt_disable(); 861 } 862 ctxop_attach(t, ctx); 863 if (thisthread) { 864 /* 865 * Since we're the right thread, set the values in the GDT 866 */ 867 segreg_tpl.ct_restore(lwp); 868 kpreempt_enable(); 869 } 870 871 /* 872 * If we have sysenter/sysexit instructions enabled, we need 873 * to ensure that the hardware mechanism is kept up-to-date with the 874 * lwp's kernel stack pointer across context switches. 875 * 876 * sep_save zeros the sysenter stack pointer msr; sep_restore sets 877 * it to the lwp's kernel stack pointer (kstktop). 878 */ 879 if (is_x86_feature(x86_featureset, X86FSET_SEP)) { 880 caddr_t kstktop = (caddr_t)lwp->lwp_regs; 881 882 ASSERT0(ctxop_remove(t, &sep_tpl, kstktop)); 883 884 ctx = ctxop_allocate(&sep_tpl, kstktop); 885 if (thisthread) { 886 kpreempt_disable(); 887 } 888 ctxop_attach(t, ctx); 889 if (thisthread) { 890 /* 891 * We're the right thread, so set the stack pointer 892 * for the first sysenter instruction to use 893 */ 894 sep_restore(kstktop); 895 kpreempt_enable(); 896 } 897 } 898 899 if (PROC_IS_BRANDED(ttoproc(t))) 900 lwp_attach_brand_hdlrs(lwp); 901 } 902 903 /* 904 * Clear registers on exec(2). 905 */ 906 void 907 setregs(uarg_t *args) 908 { 909 struct regs *rp; 910 kthread_t *t = curthread; 911 klwp_t *lwp = ttolwp(t); 912 pcb_t *pcb = &lwp->lwp_pcb; 913 greg_t sp; 914 915 /* 916 * Initialize user registers 917 */ 918 (void) save_syscall_args(); /* copy args from registers first */ 919 rp = lwptoregs(lwp); 920 sp = rp->r_sp; 921 bzero(rp, sizeof (*rp)); 922 923 rp->r_ss = UDS_SEL; 924 rp->r_sp = sp; 925 rp->r_pc = args->entry; 926 rp->r_ps = PSL_USER; 927 928 pcb->pcb_fs = pcb->pcb_gs = 0; 929 pcb->pcb_fsbase = pcb->pcb_gsbase = 0; 930 931 if (ttoproc(t)->p_model == DATAMODEL_NATIVE) { 932 933 rp->r_cs = UCS_SEL; 934 935 /* 936 * Only allow 64-bit user code descriptor to be present. 937 */ 938 gdt_ucode_model(DATAMODEL_NATIVE); 939 940 /* 941 * Arrange that the virtualized %fs and %gs GDT descriptors 942 * have a well-defined initial state (present, ring 3 943 * and of type data). 944 */ 945 pcb->pcb_fsdesc = pcb->pcb_gsdesc = zero_udesc; 946 947 /* 948 * thrptr is either NULL or a value used by DTrace. 949 * 64-bit processes use %fs as their "thread" register. 950 */ 951 if (args->thrptr) 952 (void) lwp_setprivate(lwp, _LWP_FSBASE, args->thrptr); 953 954 } else { 955 956 rp->r_cs = U32CS_SEL; 957 rp->r_ds = rp->r_es = UDS_SEL; 958 959 /* 960 * only allow 32-bit user code selector to be present. 961 */ 962 gdt_ucode_model(DATAMODEL_ILP32); 963 964 pcb->pcb_fsdesc = pcb->pcb_gsdesc = zero_u32desc; 965 966 /* 967 * thrptr is either NULL or a value used by DTrace. 968 * 32-bit processes use %gs as their "thread" register. 969 */ 970 if (args->thrptr) 971 (void) lwp_setprivate(lwp, _LWP_GSBASE, args->thrptr); 972 973 } 974 975 pcb->pcb_ds = rp->r_ds; 976 pcb->pcb_es = rp->r_es; 977 PCB_SET_UPDATE_SEGS(pcb); 978 979 lwp->lwp_eosys = JUSTRETURN; 980 t->t_post_sys = 1; 981 982 /* 983 * Add the lwp context handlers that virtualize segment registers, 984 * and/or system call stacks etc. 985 */ 986 lwp_installctx(lwp); 987 988 /* 989 * Reset the FPU flags and then initialize the FPU for this lwp. 990 */ 991 fp_exec(); 992 } 993 994 user_desc_t * 995 cpu_get_gdt(void) 996 { 997 return (CPU->cpu_gdt); 998 } 999 1000 1001 #if !defined(lwp_getdatamodel) 1002 1003 /* 1004 * Return the datamodel of the given lwp. 1005 */ 1006 /*ARGSUSED*/ 1007 model_t 1008 lwp_getdatamodel(klwp_t *lwp) 1009 { 1010 return (lwp->lwp_procp->p_model); 1011 } 1012 1013 #endif /* !lwp_getdatamodel */ 1014 1015 #if !defined(get_udatamodel) 1016 1017 model_t 1018 get_udatamodel(void) 1019 { 1020 return (curproc->p_model); 1021 } 1022 1023 #endif /* !get_udatamodel */ 1024