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 2009 Sun Microsystems, Inc. All rights reserved. 23 * Use is subject to license terms. 24 */ 25 26#include <sys/asm_linkage.h> 27#include <sys/asm_misc.h> 28#include <sys/regset.h> 29#include <sys/privregs.h> 30#include <sys/psw.h> 31#include <sys/machbrand.h> 32 33#if defined(__lint) 34 35#include <sys/types.h> 36#include <sys/thread.h> 37#include <sys/systm.h> 38 39#else /* __lint */ 40 41#include <sys/segments.h> 42#include <sys/pcb.h> 43#include <sys/trap.h> 44#include <sys/ftrace.h> 45#include <sys/traptrace.h> 46#include <sys/clock.h> 47#include <sys/model.h> 48#include <sys/panic.h> 49 50#if defined(__xpv) 51#include <sys/hypervisor.h> 52#endif 53 54#include "assym.h" 55 56#endif /* __lint */ 57 58/* 59 * We implement five flavours of system call entry points 60 * 61 * - syscall/sysretq (amd64 generic) 62 * - syscall/sysretl (i386 plus SYSC bit) 63 * - sysenter/sysexit (i386 plus SEP bit) 64 * - int/iret (i386 generic) 65 * - lcall/iret (i386 generic) 66 * 67 * The current libc included in Solaris uses int/iret as the base unoptimized 68 * kernel entry method. Older libc implementations and legacy binaries may use 69 * the lcall call gate, so it must continue to be supported. 70 * 71 * System calls that use an lcall call gate are processed in trap() via a 72 * segment-not-present trap, i.e. lcalls are extremely slow(!). 73 * 74 * The basic pattern used in the 32-bit SYSC handler at this point in time is 75 * to have the bare minimum of assembler, and get to the C handlers as 76 * quickly as possible. 77 * 78 * The 64-bit handler is much closer to the sparcv9 handler; that's 79 * because of passing arguments in registers. The 32-bit world still 80 * passes arguments on the stack -- that makes that handler substantially 81 * more complex. 82 * 83 * The two handlers share a few code fragments which are broken 84 * out into preprocessor macros below. 85 * 86 * XX64 come back and speed all this up later. The 32-bit stuff looks 87 * especially easy to speed up the argument copying part .. 88 * 89 * 90 * Notes about segment register usage (c.f. the 32-bit kernel) 91 * 92 * In the 32-bit kernel, segment registers are dutifully saved and 93 * restored on all mode transitions because the kernel uses them directly. 94 * When the processor is running in 64-bit mode, segment registers are 95 * largely ignored. 96 * 97 * %cs and %ss 98 * controlled by the hardware mechanisms that make mode transitions 99 * 100 * The remaining segment registers have to either be pointing at a valid 101 * descriptor i.e. with the 'present' bit set, or they can NULL descriptors 102 * 103 * %ds and %es 104 * always ignored 105 * 106 * %fs and %gs 107 * fsbase and gsbase are used to control the place they really point at. 108 * The kernel only depends on %gs, and controls its own gsbase via swapgs 109 * 110 * Note that loading segment registers is still costly because the GDT 111 * lookup still happens (this is because the hardware can't know that we're 112 * not setting up these segment registers for a 32-bit program). Thus we 113 * avoid doing this in the syscall path, and defer them to lwp context switch 114 * handlers, so the register values remain virtualized to the lwp. 115 */ 116 117#if defined(SYSCALLTRACE) 118#define ORL_SYSCALLTRACE(r32) \ 119 orl syscalltrace(%rip), r32 120#else 121#define ORL_SYSCALLTRACE(r32) 122#endif 123 124/* 125 * In the 32-bit kernel, we do absolutely nothing before getting into the 126 * brand callback checks. In 64-bit land, we do swapgs and then come here. 127 * We assume that the %rsp- and %r15-stashing fields in the CPU structure 128 * are still unused. 129 * 130 * Check if a brand_mach_ops callback is defined for the specified callback_id 131 * type. If so invoke it with the kernel's %gs value loaded and the following 132 * data on the stack: 133 * 134 * stack: -------------------------------------- 135 * 40 | user %gs | 136 * 32 | callback pointer | 137 * | 24 | user stack pointer | 138 * | 16 | lwp pointer | 139 * v 8 | userland return address | 140 * 0 | callback wrapper return addr | 141 * -------------------------------------- 142 * 143 */ 144#define BRAND_CALLBACK(callback_id) \ 145 movq %rsp, %gs:CPU_RTMP_RSP /* save the stack pointer */ ;\ 146 movq %r15, %gs:CPU_RTMP_R15 /* save %r15 */ ;\ 147 movq %gs:CPU_THREAD, %r15 /* load the thread pointer */ ;\ 148 movq T_STACK(%r15), %rsp /* switch to the kernel stack */ ;\ 149 subq $24, %rsp /* save space for 3 pointers */ ;\ 150 pushq %r14 /* save %r14 */ ;\ 151 movq %gs:CPU_RTMP_RSP, %r14 ;\ 152 movq %r14, 8(%rsp) /* stash the user stack pointer */ ;\ 153 popq %r14 /* restore %r14 */ ;\ 154 movq T_LWP(%r15), %r15 /* load the lwp pointer */ ;\ 155 pushq %r15 /* push the lwp pointer */ ;\ 156 movq LWP_PROCP(%r15), %r15 /* load the proc pointer */ ;\ 157 movq P_BRAND(%r15), %r15 /* load the brand pointer */ ;\ 158 movq B_MACHOPS(%r15), %r15 /* load the machops pointer */ ;\ 159 movq _CONST(_MUL(callback_id, CPTRSIZE))(%r15), %r15 ;\ 160 cmpq $0, %r15 ;\ 161 je 1f ;\ 162 movq %r15, 16(%rsp) /* save the callback pointer */ ;\ 163 movq %gs:CPU_RTMP_RSP, %r15 /* grab the user stack pointer */ ;\ 164 pushq (%r15) /* push the return address */ ;\ 165 SWAPGS /* user gsbase */ ;\ 166 mov %gs, %r15 /* get %gs */ ;\ 167 movq %r15, 32(%rsp) /* save %gs on stack */ ;\ 168 SWAPGS /* kernel gsbase */ ;\ 169 movq %gs:CPU_RTMP_R15, %r15 /* restore %r15 */ ;\ 170 call *24(%rsp) /* call callback */ ;\ 1711: movq %gs:CPU_RTMP_R15, %r15 /* restore %r15 */ ;\ 172 movq %gs:CPU_RTMP_RSP, %rsp /* restore the stack pointer */ 173 174#define MSTATE_TRANSITION(from, to) \ 175 movl $from, %edi; \ 176 movl $to, %esi; \ 177 call syscall_mstate 178 179/* 180 * Check to see if a simple (direct) return is possible i.e. 181 * 182 * if (t->t_post_sys_ast | syscalltrace | 183 * lwp->lwp_pcb.pcb_rupdate == 1) 184 * do full version ; 185 * 186 * Preconditions: 187 * - t is curthread 188 * Postconditions: 189 * - condition code NE is set if post-sys is too complex 190 * - rtmp is zeroed if it isn't (we rely on this!) 191 * - ltmp is smashed 192 */ 193#define CHECK_POSTSYS_NE(t, ltmp, rtmp) \ 194 movq T_LWP(t), ltmp; \ 195 movzbl PCB_RUPDATE(ltmp), rtmp; \ 196 ORL_SYSCALLTRACE(rtmp); \ 197 orl T_POST_SYS_AST(t), rtmp; \ 198 cmpl $0, rtmp 199 200/* 201 * Fix up the lwp, thread, and eflags for a successful return 202 * 203 * Preconditions: 204 * - zwreg contains zero 205 */ 206#define SIMPLE_SYSCALL_POSTSYS(t, lwp, zwreg) \ 207 movb $LWP_USER, LWP_STATE(lwp); \ 208 movw zwreg, T_SYSNUM(t); \ 209 andb $_CONST(0xffff - PS_C), REGOFF_RFL(%rsp) 210 211/* 212 * ASSERT(lwptoregs(lwp) == rp); 213 * 214 * This may seem obvious, but very odd things happen if this 215 * assertion is false 216 * 217 * Preconditions: 218 * (%rsp is ready for normal call sequence) 219 * Postconditions (if assertion is true): 220 * %r11 is smashed 221 * 222 * ASSERT(rp->r_cs == descnum) 223 * 224 * The code selector is written into the regs structure when the 225 * lwp stack is created. We use this ASSERT to validate that 226 * the regs structure really matches how we came in. 227 * 228 * Preconditions: 229 * (%rsp is ready for normal call sequence) 230 * Postconditions (if assertion is true): 231 * -none- 232 * 233 * ASSERT(lwp->lwp_pcb.pcb_rupdate == 0); 234 * 235 * If this is false, it meant that we returned to userland without 236 * updating the segment registers as we were supposed to. 237 * 238 * Note that we must ensure no interrupts or other traps intervene 239 * between entering privileged mode and performing the assertion, 240 * otherwise we may perform a context switch on the thread, which 241 * will end up setting pcb_rupdate to 1 again. 242 */ 243#if defined(DEBUG) 244 245#if !defined(__lint) 246 247__lwptoregs_msg: 248 .string "syscall_asm_amd64.s:%d lwptoregs(%p) [%p] != rp [%p]" 249 250__codesel_msg: 251 .string "syscall_asm_amd64.s:%d rp->r_cs [%ld] != %ld" 252 253__no_rupdate_msg: 254 .string "syscall_asm_amd64.s:%d lwp %p, pcb_rupdate != 0" 255 256#endif /* !__lint */ 257 258#define ASSERT_LWPTOREGS(lwp, rp) \ 259 movq LWP_REGS(lwp), %r11; \ 260 cmpq rp, %r11; \ 261 je 7f; \ 262 leaq __lwptoregs_msg(%rip), %rdi; \ 263 movl $__LINE__, %esi; \ 264 movq lwp, %rdx; \ 265 movq %r11, %rcx; \ 266 movq rp, %r8; \ 267 xorl %eax, %eax; \ 268 call panic; \ 2697: 270 271#define ASSERT_NO_RUPDATE_PENDING(lwp) \ 272 testb $0x1, PCB_RUPDATE(lwp); \ 273 je 8f; \ 274 movq lwp, %rdx; \ 275 leaq __no_rupdate_msg(%rip), %rdi; \ 276 movl $__LINE__, %esi; \ 277 xorl %eax, %eax; \ 278 call panic; \ 2798: 280 281#else 282#define ASSERT_LWPTOREGS(lwp, rp) 283#define ASSERT_NO_RUPDATE_PENDING(lwp) 284#endif 285 286/* 287 * Do the traptrace thing and restore any registers we used 288 * in situ. Assumes that %rsp is pointing at the base of 289 * the struct regs, obviously .. 290 */ 291#ifdef TRAPTRACE 292#define SYSCALL_TRAPTRACE(ttype) \ 293 TRACE_PTR(%rdi, %rbx, %ebx, %rcx, ttype); \ 294 TRACE_REGS(%rdi, %rsp, %rbx, %rcx); \ 295 TRACE_STAMP(%rdi); /* rdtsc clobbers %eax, %edx */ \ 296 movq REGOFF_RAX(%rsp), %rax; \ 297 movq REGOFF_RBX(%rsp), %rbx; \ 298 movq REGOFF_RCX(%rsp), %rcx; \ 299 movq REGOFF_RDX(%rsp), %rdx; \ 300 movl %eax, TTR_SYSNUM(%rdi); \ 301 movq REGOFF_RDI(%rsp), %rdi 302 303#define SYSCALL_TRAPTRACE32(ttype) \ 304 SYSCALL_TRAPTRACE(ttype); \ 305 /* paranoia: clean the top 32-bits of the registers */ \ 306 orl %eax, %eax; \ 307 orl %ebx, %ebx; \ 308 orl %ecx, %ecx; \ 309 orl %edx, %edx; \ 310 orl %edi, %edi 311#else /* TRAPTRACE */ 312#define SYSCALL_TRAPTRACE(ttype) 313#define SYSCALL_TRAPTRACE32(ttype) 314#endif /* TRAPTRACE */ 315 316/* 317 * The 64-bit libc syscall wrapper does this: 318 * 319 * fn(<args>) 320 * { 321 * movq %rcx, %r10 -- because syscall smashes %rcx 322 * movl $CODE, %eax 323 * syscall 324 * <error processing> 325 * } 326 * 327 * Thus when we come into the kernel: 328 * 329 * %rdi, %rsi, %rdx, %r10, %r8, %r9 contain first six args 330 * %rax is the syscall number 331 * %r12-%r15 contain caller state 332 * 333 * The syscall instruction arranges that: 334 * 335 * %rcx contains the return %rip 336 * %r11d contains bottom 32-bits of %rflags 337 * %rflags is masked (as determined by the SFMASK msr) 338 * %cs is set to UCS_SEL (as determined by the STAR msr) 339 * %ss is set to UDS_SEL (as determined by the STAR msr) 340 * %rip is set to sys_syscall (as determined by the LSTAR msr) 341 * 342 * Or in other words, we have no registers available at all. 343 * Only swapgs can save us! 344 * 345 * Under the hypervisor, the swapgs has happened already. However, the 346 * state of the world is very different from that we're familiar with. 347 * 348 * In particular, we have a stack structure like that for interrupt 349 * gates, except that the %cs and %ss registers are modified for reasons 350 * that are not entirely clear. Critically, the %rcx/%r11 values do 351 * *not* reflect the usage of those registers under a 'real' syscall[1]; 352 * the stack, therefore, looks like this: 353 * 354 * 0x0(rsp) potentially junk %rcx 355 * 0x8(rsp) potentially junk %r11 356 * 0x10(rsp) user %rip 357 * 0x18(rsp) modified %cs 358 * 0x20(rsp) user %rflags 359 * 0x28(rsp) user %rsp 360 * 0x30(rsp) modified %ss 361 * 362 * 363 * and before continuing on, we must load the %rip into %rcx and the 364 * %rflags into %r11. 365 * 366 * [1] They used to, and we relied on it, but this was broken in 3.1.1. 367 * Sigh. 368 */ 369 370#if defined(__xpv) 371#define XPV_SYSCALL_PROD \ 372 XPV_TRAP_POP; \ 373 movq (%rsp), %rcx; \ 374 movq 0x10(%rsp), %r11 375#else 376#define XPV_SYSCALL_PROD /* nothing */ 377#endif 378 379#if defined(__lint) 380 381/*ARGSUSED*/ 382void 383sys_syscall() 384{} 385 386void 387_allsyscalls() 388{} 389 390size_t _allsyscalls_size; 391 392#else /* __lint */ 393 394 ENTRY_NP2(brand_sys_syscall,_allsyscalls) 395 SWAPGS /* kernel gsbase */ 396 XPV_SYSCALL_PROD 397 BRAND_CALLBACK(BRAND_CB_SYSCALL) 398 SWAPGS /* user gsbase */ 399 400#if defined(__xpv) 401 jmp noprod_sys_syscall 402#endif 403 404 ALTENTRY(sys_syscall) 405 SWAPGS /* kernel gsbase */ 406 XPV_SYSCALL_PROD 407 408noprod_sys_syscall: 409 ASSERT_UPCALL_MASK_IS_SET 410 411 movq %r15, %gs:CPU_RTMP_R15 412#if defined(__xpv) 413 movq 0x18(%rsp), %r15 /* save user stack */ 414 movq %r15, %gs:CPU_RTMP_RSP 415#else 416 movq %rsp, %gs:CPU_RTMP_RSP 417#endif /* __xpv */ 418 419 movq %gs:CPU_THREAD, %r15 420 movq T_STACK(%r15), %rsp 421 422 movl $UCS_SEL, REGOFF_CS(%rsp) 423 movq %rcx, REGOFF_RIP(%rsp) /* syscall: %rip -> %rcx */ 424 movq %r11, REGOFF_RFL(%rsp) /* syscall: %rfl -> %r11d */ 425 movl $UDS_SEL, REGOFF_SS(%rsp) 426 427 movl %eax, %eax /* wrapper: sysc# -> %eax */ 428 movq %rdi, REGOFF_RDI(%rsp) 429 movq %rsi, REGOFF_RSI(%rsp) 430 movq %rdx, REGOFF_RDX(%rsp) 431 movq %r10, REGOFF_RCX(%rsp) /* wrapper: %rcx -> %r10 */ 432 movq %r10, %rcx /* arg[3] for direct calls */ 433 434 movq %r8, REGOFF_R8(%rsp) 435 movq %r9, REGOFF_R9(%rsp) 436 movq %rax, REGOFF_RAX(%rsp) 437 movq %rbx, REGOFF_RBX(%rsp) 438 439 movq %rbp, REGOFF_RBP(%rsp) 440 movq %r10, REGOFF_R10(%rsp) 441 movq %gs:CPU_RTMP_RSP, %r11 442 movq %r11, REGOFF_RSP(%rsp) 443 movq %r12, REGOFF_R12(%rsp) 444 445 movq %r13, REGOFF_R13(%rsp) 446 movq %r14, REGOFF_R14(%rsp) 447 movq %gs:CPU_RTMP_R15, %r10 448 movq %r10, REGOFF_R15(%rsp) 449 movq $0, REGOFF_SAVFP(%rsp) 450 movq $0, REGOFF_SAVPC(%rsp) 451 452 /* 453 * Copy these registers here in case we end up stopped with 454 * someone (like, say, /proc) messing with our register state. 455 * We don't -restore- them unless we have to in update_sregs. 456 * 457 * Since userland -can't- change fsbase or gsbase directly, 458 * and capturing them involves two serializing instructions, 459 * we don't bother to capture them here. 460 */ 461 xorl %ebx, %ebx 462 movw %ds, %bx 463 movq %rbx, REGOFF_DS(%rsp) 464 movw %es, %bx 465 movq %rbx, REGOFF_ES(%rsp) 466 movw %fs, %bx 467 movq %rbx, REGOFF_FS(%rsp) 468 movw %gs, %bx 469 movq %rbx, REGOFF_GS(%rsp) 470 471 /* 472 * Machine state saved in the regs structure on the stack 473 * First six args in %rdi, %rsi, %rdx, %rcx, %r8, %r9 474 * %eax is the syscall number 475 * %rsp is the thread's stack, %r15 is curthread 476 * REG_RSP(%rsp) is the user's stack 477 */ 478 479 SYSCALL_TRAPTRACE($TT_SYSC64) 480 481 movq %rsp, %rbp 482 483 movq T_LWP(%r15), %r14 484 ASSERT_NO_RUPDATE_PENDING(%r14) 485 ENABLE_INTR_FLAGS 486 487 MSTATE_TRANSITION(LMS_USER, LMS_SYSTEM) 488 movl REGOFF_RAX(%rsp), %eax /* (%rax damaged by mstate call) */ 489 490 ASSERT_LWPTOREGS(%r14, %rsp) 491 492 movb $LWP_SYS, LWP_STATE(%r14) 493 incq LWP_RU_SYSC(%r14) 494 movb $NORMALRETURN, LWP_EOSYS(%r14) 495 496 incq %gs:CPU_STATS_SYS_SYSCALL 497 498 movw %ax, T_SYSNUM(%r15) 499 movzbl T_PRE_SYS(%r15), %ebx 500 ORL_SYSCALLTRACE(%ebx) 501 testl %ebx, %ebx 502 jne _syscall_pre 503 504_syscall_invoke: 505 movq REGOFF_RDI(%rbp), %rdi 506 movq REGOFF_RSI(%rbp), %rsi 507 movq REGOFF_RDX(%rbp), %rdx 508 movq REGOFF_RCX(%rbp), %rcx 509 movq REGOFF_R8(%rbp), %r8 510 movq REGOFF_R9(%rbp), %r9 511 512 cmpl $NSYSCALL, %eax 513 jae _syscall_ill 514 shll $SYSENT_SIZE_SHIFT, %eax 515 leaq sysent(%rax), %rbx 516 517 call *SY_CALLC(%rbx) 518 519 movq %rax, %r12 520 movq %rdx, %r13 521 522 /* 523 * If the handler returns two ints, then we need to split the 524 * 64-bit return value into two 32-bit values. 525 */ 526 testw $SE_32RVAL2, SY_FLAGS(%rbx) 527 je 5f 528 movq %r12, %r13 529 shrq $32, %r13 /* upper 32-bits into %edx */ 530 movl %r12d, %r12d /* lower 32-bits into %eax */ 5315: 532 /* 533 * Optimistically assume that there's no post-syscall 534 * work to do. (This is to avoid having to call syscall_mstate() 535 * with interrupts disabled) 536 */ 537 MSTATE_TRANSITION(LMS_SYSTEM, LMS_USER) 538 539 /* 540 * We must protect ourselves from being descheduled here; 541 * If we were, and we ended up on another cpu, or another 542 * lwp got in ahead of us, it could change the segment 543 * registers without us noticing before we return to userland. 544 */ 545 CLI(%r14) 546 CHECK_POSTSYS_NE(%r15, %r14, %ebx) 547 jne _syscall_post 548 SIMPLE_SYSCALL_POSTSYS(%r15, %r14, %bx) 549 550 movq %r12, REGOFF_RAX(%rsp) 551 movq %r13, REGOFF_RDX(%rsp) 552 553 /* 554 * To get back to userland, we need the return %rip in %rcx and 555 * the return %rfl in %r11d. The sysretq instruction also arranges 556 * to fix up %cs and %ss; everything else is our responsibility. 557 */ 558 movq REGOFF_RDI(%rsp), %rdi 559 movq REGOFF_RSI(%rsp), %rsi 560 movq REGOFF_RDX(%rsp), %rdx 561 /* %rcx used to restore %rip value */ 562 563 movq REGOFF_R8(%rsp), %r8 564 movq REGOFF_R9(%rsp), %r9 565 movq REGOFF_RAX(%rsp), %rax 566 movq REGOFF_RBX(%rsp), %rbx 567 568 movq REGOFF_RBP(%rsp), %rbp 569 movq REGOFF_R10(%rsp), %r10 570 /* %r11 used to restore %rfl value */ 571 movq REGOFF_R12(%rsp), %r12 572 573 movq REGOFF_R13(%rsp), %r13 574 movq REGOFF_R14(%rsp), %r14 575 movq REGOFF_R15(%rsp), %r15 576 577 movq REGOFF_RIP(%rsp), %rcx 578 movl REGOFF_RFL(%rsp), %r11d 579 580#if defined(__xpv) 581 addq $REGOFF_RIP, %rsp 582#else 583 movq REGOFF_RSP(%rsp), %rsp 584#endif 585 586 /* 587 * There can be no instructions between the ALTENTRY below and 588 * SYSRET or we could end up breaking brand support. See label usage 589 * in sn1_brand_syscall_callback for an example. 590 */ 591 ASSERT_UPCALL_MASK_IS_SET 592 ALTENTRY(nopop_sys_syscall_swapgs_sysretq) 593 SWAPGS /* user gsbase */ 594 SYSRETQ 595 /*NOTREACHED*/ 596 SET_SIZE(nopop_sys_syscall_swapgs_sysretq) 597 598_syscall_pre: 599 call pre_syscall 600 movl %eax, %r12d 601 testl %eax, %eax 602 jne _syscall_post_call 603 /* 604 * Didn't abort, so reload the syscall args and invoke the handler. 605 */ 606 movzwl T_SYSNUM(%r15), %eax 607 jmp _syscall_invoke 608 609_syscall_ill: 610 call nosys 611 movq %rax, %r12 612 movq %rdx, %r13 613 jmp _syscall_post_call 614 615_syscall_post: 616 STI 617 /* 618 * Sigh, our optimism wasn't justified, put it back to LMS_SYSTEM 619 * so that we can account for the extra work it takes us to finish. 620 */ 621 MSTATE_TRANSITION(LMS_USER, LMS_SYSTEM) 622_syscall_post_call: 623 movq %r12, %rdi 624 movq %r13, %rsi 625 call post_syscall 626 MSTATE_TRANSITION(LMS_SYSTEM, LMS_USER) 627 jmp _sys_rtt 628 SET_SIZE(sys_syscall) 629 SET_SIZE(brand_sys_syscall) 630 631#endif /* __lint */ 632 633#if defined(__lint) 634 635/*ARGSUSED*/ 636void 637sys_syscall32() 638{} 639 640#else /* __lint */ 641 642 ENTRY_NP(brand_sys_syscall32) 643 SWAPGS /* kernel gsbase */ 644 XPV_TRAP_POP 645 BRAND_CALLBACK(BRAND_CB_SYSCALL32) 646 SWAPGS /* user gsbase */ 647 648#if defined(__xpv) 649 jmp nopop_sys_syscall32 650#endif 651 652 ALTENTRY(sys_syscall32) 653 SWAPGS /* kernel gsbase */ 654 655#if defined(__xpv) 656 XPV_TRAP_POP 657nopop_sys_syscall32: 658#endif 659 660 movl %esp, %r10d 661 movq %gs:CPU_THREAD, %r15 662 movq T_STACK(%r15), %rsp 663 movl %eax, %eax 664 665 movl $U32CS_SEL, REGOFF_CS(%rsp) 666 movl %ecx, REGOFF_RIP(%rsp) /* syscall: %rip -> %rcx */ 667 movq %r11, REGOFF_RFL(%rsp) /* syscall: %rfl -> %r11d */ 668 movq %r10, REGOFF_RSP(%rsp) 669 movl $UDS_SEL, REGOFF_SS(%rsp) 670 671_syscall32_save: 672 movl %edi, REGOFF_RDI(%rsp) 673 movl %esi, REGOFF_RSI(%rsp) 674 movl %ebp, REGOFF_RBP(%rsp) 675 movl %ebx, REGOFF_RBX(%rsp) 676 movl %edx, REGOFF_RDX(%rsp) 677 movl %ecx, REGOFF_RCX(%rsp) 678 movl %eax, REGOFF_RAX(%rsp) /* wrapper: sysc# -> %eax */ 679 movq $0, REGOFF_SAVFP(%rsp) 680 movq $0, REGOFF_SAVPC(%rsp) 681 682 /* 683 * Copy these registers here in case we end up stopped with 684 * someone (like, say, /proc) messing with our register state. 685 * We don't -restore- them unless we have to in update_sregs. 686 * 687 * Since userland -can't- change fsbase or gsbase directly, 688 * we don't bother to capture them here. 689 */ 690 xorl %ebx, %ebx 691 movw %ds, %bx 692 movq %rbx, REGOFF_DS(%rsp) 693 movw %es, %bx 694 movq %rbx, REGOFF_ES(%rsp) 695 movw %fs, %bx 696 movq %rbx, REGOFF_FS(%rsp) 697 movw %gs, %bx 698 movq %rbx, REGOFF_GS(%rsp) 699 700 /* 701 * Application state saved in the regs structure on the stack 702 * %eax is the syscall number 703 * %rsp is the thread's stack, %r15 is curthread 704 * REG_RSP(%rsp) is the user's stack 705 */ 706 707 SYSCALL_TRAPTRACE32($TT_SYSC) 708 709 movq %rsp, %rbp 710 711 movq T_LWP(%r15), %r14 712 ASSERT_NO_RUPDATE_PENDING(%r14) 713 714 ENABLE_INTR_FLAGS 715 716 MSTATE_TRANSITION(LMS_USER, LMS_SYSTEM) 717 movl REGOFF_RAX(%rsp), %eax /* (%rax damaged by mstate call) */ 718 719 ASSERT_LWPTOREGS(%r14, %rsp) 720 721 incq %gs:CPU_STATS_SYS_SYSCALL 722 723 /* 724 * Make some space for MAXSYSARGS (currently 8) 32-bit args placed 725 * into 64-bit (long) arg slots, maintaining 16 byte alignment. Or 726 * more succinctly: 727 * 728 * SA(MAXSYSARGS * sizeof (long)) == 64 729 */ 730#define SYS_DROP 64 /* drop for args */ 731 subq $SYS_DROP, %rsp 732 movb $LWP_SYS, LWP_STATE(%r14) 733 movq %r15, %rdi 734 movq %rsp, %rsi 735 call syscall_entry 736 737 /* 738 * Fetch the arguments copied onto the kernel stack and put 739 * them in the right registers to invoke a C-style syscall handler. 740 * %rax contains the handler address. 741 * 742 * Ideas for making all this go faster of course include simply 743 * forcibly fetching 6 arguments from the user stack under lofault 744 * protection, reverting to copyin_args only when watchpoints 745 * are in effect. 746 * 747 * (If we do this, make sure that exec and libthread leave 748 * enough space at the top of the stack to ensure that we'll 749 * never do a fetch from an invalid page.) 750 * 751 * Lots of ideas here, but they won't really help with bringup B-) 752 * Correctness can't wait, performance can wait a little longer .. 753 */ 754 755 movq %rax, %rbx 756 movl 0(%rsp), %edi 757 movl 8(%rsp), %esi 758 movl 0x10(%rsp), %edx 759 movl 0x18(%rsp), %ecx 760 movl 0x20(%rsp), %r8d 761 movl 0x28(%rsp), %r9d 762 763 call *SY_CALLC(%rbx) 764 765 movq %rbp, %rsp /* pop the args */ 766 767 /* 768 * amd64 syscall handlers -always- return a 64-bit value in %rax. 769 * On the 32-bit kernel, they always return that value in %eax:%edx 770 * as required by the 32-bit ABI. 771 * 772 * Simulate the same behaviour by unconditionally splitting the 773 * return value in the same way. 774 */ 775 movq %rax, %r13 776 shrq $32, %r13 /* upper 32-bits into %edx */ 777 movl %eax, %r12d /* lower 32-bits into %eax */ 778 779 /* 780 * Optimistically assume that there's no post-syscall 781 * work to do. (This is to avoid having to call syscall_mstate() 782 * with interrupts disabled) 783 */ 784 MSTATE_TRANSITION(LMS_SYSTEM, LMS_USER) 785 786 /* 787 * We must protect ourselves from being descheduled here; 788 * If we were, and we ended up on another cpu, or another 789 * lwp got in ahead of us, it could change the segment 790 * registers without us noticing before we return to userland. 791 */ 792 CLI(%r14) 793 CHECK_POSTSYS_NE(%r15, %r14, %ebx) 794 jne _full_syscall_postsys32 795 SIMPLE_SYSCALL_POSTSYS(%r15, %r14, %bx) 796 797 /* 798 * To get back to userland, we need to put the return %rip in %rcx and 799 * the return %rfl in %r11d. The sysret instruction also arranges 800 * to fix up %cs and %ss; everything else is our responsibility. 801 */ 802 803 movl %r12d, %eax /* %eax: rval1 */ 804 movl REGOFF_RBX(%rsp), %ebx 805 /* %ecx used for return pointer */ 806 movl %r13d, %edx /* %edx: rval2 */ 807 movl REGOFF_RBP(%rsp), %ebp 808 movl REGOFF_RSI(%rsp), %esi 809 movl REGOFF_RDI(%rsp), %edi 810 811 movl REGOFF_RFL(%rsp), %r11d /* %r11 -> eflags */ 812 movl REGOFF_RIP(%rsp), %ecx /* %ecx -> %eip */ 813 movl REGOFF_RSP(%rsp), %esp 814 815 ASSERT_UPCALL_MASK_IS_SET 816 ALTENTRY(nopop_sys_syscall32_swapgs_sysretl) 817 SWAPGS /* user gsbase */ 818 SYSRETL 819 SET_SIZE(nopop_sys_syscall32_swapgs_sysretl) 820 /*NOTREACHED*/ 821 822_full_syscall_postsys32: 823 STI 824 /* 825 * Sigh, our optimism wasn't justified, put it back to LMS_SYSTEM 826 * so that we can account for the extra work it takes us to finish. 827 */ 828 MSTATE_TRANSITION(LMS_USER, LMS_SYSTEM) 829 movq %r15, %rdi 830 movq %r12, %rsi /* rval1 - %eax */ 831 movq %r13, %rdx /* rval2 - %edx */ 832 call syscall_exit 833 MSTATE_TRANSITION(LMS_SYSTEM, LMS_USER) 834 jmp _sys_rtt 835 SET_SIZE(sys_syscall32) 836 SET_SIZE(brand_sys_syscall32) 837 838#endif /* __lint */ 839 840/* 841 * System call handler via the sysenter instruction 842 * Used only for 32-bit system calls on the 64-bit kernel. 843 * 844 * The caller in userland has arranged that: 845 * 846 * - %eax contains the syscall number 847 * - %ecx contains the user %esp 848 * - %edx contains the return %eip 849 * - the user stack contains the args to the syscall 850 * 851 * Hardware and (privileged) initialization code have arranged that by 852 * the time the sysenter instructions completes: 853 * 854 * - %rip is pointing to sys_sysenter (below). 855 * - %cs and %ss are set to kernel text and stack (data) selectors. 856 * - %rsp is pointing at the lwp's stack 857 * - interrupts have been disabled. 858 * 859 * Note that we are unable to return both "rvals" to userland with 860 * this call, as %edx is used by the sysexit instruction. 861 * 862 * One final complication in this routine is its interaction with 863 * single-stepping in a debugger. For most of the system call mechanisms, 864 * the CPU automatically clears the single-step flag before we enter the 865 * kernel. The sysenter mechanism does not clear the flag, so a user 866 * single-stepping through a libc routine may suddenly find him/herself 867 * single-stepping through the kernel. To detect this, kmdb compares the 868 * trap %pc to the [brand_]sys_enter addresses on each single-step trap. 869 * If it finds that we have single-stepped to a sysenter entry point, it 870 * explicitly clears the flag and executes the sys_sysenter routine. 871 * 872 * One final complication in this final complication is the fact that we 873 * have two different entry points for sysenter: brand_sys_sysenter and 874 * sys_sysenter. If we enter at brand_sys_sysenter and start single-stepping 875 * through the kernel with kmdb, we will eventually hit the instruction at 876 * sys_sysenter. kmdb cannot distinguish between that valid single-step 877 * and the undesirable one mentioned above. To avoid this situation, we 878 * simply add a jump over the instruction at sys_sysenter to make it 879 * impossible to single-step to it. 880 */ 881#if defined(__lint) 882 883void 884sys_sysenter() 885{} 886 887#else /* __lint */ 888 889 ENTRY_NP(brand_sys_sysenter) 890 SWAPGS /* kernel gsbase */ 891 ALTENTRY(_brand_sys_sysenter_post_swapgs) 892 BRAND_CALLBACK(BRAND_CB_SYSENTER) 893 /* 894 * Jump over sys_sysenter to allow single-stepping as described 895 * above. 896 */ 897 jmp _sys_sysenter_post_swapgs 898 899 ALTENTRY(sys_sysenter) 900 SWAPGS /* kernel gsbase */ 901 902 ALTENTRY(_sys_sysenter_post_swapgs) 903 movq %gs:CPU_THREAD, %r15 904 905 movl $U32CS_SEL, REGOFF_CS(%rsp) 906 movl %ecx, REGOFF_RSP(%rsp) /* wrapper: %esp -> %ecx */ 907 movl %edx, REGOFF_RIP(%rsp) /* wrapper: %eip -> %edx */ 908 pushfq 909 popq %r10 910 movl $UDS_SEL, REGOFF_SS(%rsp) 911 912 /* 913 * Set the interrupt flag before storing the flags to the 914 * flags image on the stack so we can return to user with 915 * interrupts enabled if we return via sys_rtt_syscall32 916 */ 917 orq $PS_IE, %r10 918 movq %r10, REGOFF_RFL(%rsp) 919 920 movl %edi, REGOFF_RDI(%rsp) 921 movl %esi, REGOFF_RSI(%rsp) 922 movl %ebp, REGOFF_RBP(%rsp) 923 movl %ebx, REGOFF_RBX(%rsp) 924 movl %edx, REGOFF_RDX(%rsp) 925 movl %ecx, REGOFF_RCX(%rsp) 926 movl %eax, REGOFF_RAX(%rsp) /* wrapper: sysc# -> %eax */ 927 movq $0, REGOFF_SAVFP(%rsp) 928 movq $0, REGOFF_SAVPC(%rsp) 929 930 /* 931 * Copy these registers here in case we end up stopped with 932 * someone (like, say, /proc) messing with our register state. 933 * We don't -restore- them unless we have to in update_sregs. 934 * 935 * Since userland -can't- change fsbase or gsbase directly, 936 * we don't bother to capture them here. 937 */ 938 xorl %ebx, %ebx 939 movw %ds, %bx 940 movq %rbx, REGOFF_DS(%rsp) 941 movw %es, %bx 942 movq %rbx, REGOFF_ES(%rsp) 943 movw %fs, %bx 944 movq %rbx, REGOFF_FS(%rsp) 945 movw %gs, %bx 946 movq %rbx, REGOFF_GS(%rsp) 947 948 /* 949 * Application state saved in the regs structure on the stack 950 * %eax is the syscall number 951 * %rsp is the thread's stack, %r15 is curthread 952 * REG_RSP(%rsp) is the user's stack 953 */ 954 955 SYSCALL_TRAPTRACE($TT_SYSENTER) 956 957 movq %rsp, %rbp 958 959 movq T_LWP(%r15), %r14 960 ASSERT_NO_RUPDATE_PENDING(%r14) 961 962 ENABLE_INTR_FLAGS 963 964 /* 965 * Catch 64-bit process trying to issue sysenter instruction 966 * on Nocona based systems. 967 */ 968 movq LWP_PROCP(%r14), %rax 969 cmpq $DATAMODEL_ILP32, P_MODEL(%rax) 970 je 7f 971 972 /* 973 * For a non-32-bit process, simulate a #ud, since that's what 974 * native hardware does. The traptrace entry (above) will 975 * let you know what really happened. 976 */ 977 movq $T_ILLINST, REGOFF_TRAPNO(%rsp) 978 movq REGOFF_CS(%rsp), %rdi 979 movq %rdi, REGOFF_ERR(%rsp) 980 movq %rsp, %rdi 981 movq REGOFF_RIP(%rsp), %rsi 982 movl %gs:CPU_ID, %edx 983 call trap 984 jmp _sys_rtt 9857: 986 987 MSTATE_TRANSITION(LMS_USER, LMS_SYSTEM) 988 movl REGOFF_RAX(%rsp), %eax /* (%rax damaged by mstate calls) */ 989 990 ASSERT_LWPTOREGS(%r14, %rsp) 991 992 incq %gs:CPU_STATS_SYS_SYSCALL 993 994 /* 995 * Make some space for MAXSYSARGS (currently 8) 32-bit args 996 * placed into 64-bit (long) arg slots, plus one 64-bit 997 * (long) arg count, maintaining 16 byte alignment. 998 */ 999 subq $SYS_DROP, %rsp 1000 movb $LWP_SYS, LWP_STATE(%r14) 1001 movq %r15, %rdi 1002 movq %rsp, %rsi 1003 call syscall_entry 1004 1005 /* 1006 * Fetch the arguments copied onto the kernel stack and put 1007 * them in the right registers to invoke a C-style syscall handler. 1008 * %rax contains the handler address. 1009 */ 1010 movq %rax, %rbx 1011 movl 0(%rsp), %edi 1012 movl 8(%rsp), %esi 1013 movl 0x10(%rsp), %edx 1014 movl 0x18(%rsp), %ecx 1015 movl 0x20(%rsp), %r8d 1016 movl 0x28(%rsp), %r9d 1017 1018 call *SY_CALLC(%rbx) 1019 1020 movq %rbp, %rsp /* pop the args */ 1021 1022 /* 1023 * amd64 syscall handlers -always- return a 64-bit value in %rax. 1024 * On the 32-bit kernel, the always return that value in %eax:%edx 1025 * as required by the 32-bit ABI. 1026 * 1027 * Simulate the same behaviour by unconditionally splitting the 1028 * return value in the same way. 1029 */ 1030 movq %rax, %r13 1031 shrq $32, %r13 /* upper 32-bits into %edx */ 1032 movl %eax, %r12d /* lower 32-bits into %eax */ 1033 1034 /* 1035 * Optimistically assume that there's no post-syscall 1036 * work to do. (This is to avoid having to call syscall_mstate() 1037 * with interrupts disabled) 1038 */ 1039 MSTATE_TRANSITION(LMS_SYSTEM, LMS_USER) 1040 1041 /* 1042 * We must protect ourselves from being descheduled here; 1043 * If we were, and we ended up on another cpu, or another 1044 * lwp got int ahead of us, it could change the segment 1045 * registers without us noticing before we return to userland. 1046 */ 1047 cli 1048 CHECK_POSTSYS_NE(%r15, %r14, %ebx) 1049 jne _full_syscall_postsys32 1050 SIMPLE_SYSCALL_POSTSYS(%r15, %r14, %bx) 1051 1052 /* 1053 * To get back to userland, load up the 32-bit registers and 1054 * sysexit back where we came from. 1055 */ 1056 1057 /* 1058 * Interrupts will be turned on by the 'sti' executed just before 1059 * sysexit. The following ensures that restoring the user's rflags 1060 * doesn't enable interrupts too soon. 1061 */ 1062 andq $_BITNOT(PS_IE), REGOFF_RFL(%rsp) 1063 1064 /* 1065 * (There's no point in loading up %edx because the sysexit 1066 * mechanism smashes it.) 1067 */ 1068 movl %r12d, %eax 1069 movl REGOFF_RBX(%rsp), %ebx 1070 movl REGOFF_RBP(%rsp), %ebp 1071 movl REGOFF_RSI(%rsp), %esi 1072 movl REGOFF_RDI(%rsp), %edi 1073 1074 movl REGOFF_RIP(%rsp), %edx /* sysexit: %edx -> %eip */ 1075 pushq REGOFF_RFL(%rsp) 1076 popfq 1077 movl REGOFF_RSP(%rsp), %ecx /* sysexit: %ecx -> %esp */ 1078 ALTENTRY(sys_sysenter_swapgs_sysexit) 1079 swapgs 1080 sti 1081 sysexit 1082 SET_SIZE(sys_sysenter_swapgs_sysexit) 1083 SET_SIZE(sys_sysenter) 1084 SET_SIZE(_sys_sysenter_post_swapgs) 1085 SET_SIZE(brand_sys_sysenter) 1086 1087#endif /* __lint */ 1088 1089#if defined(__lint) 1090/* 1091 * System call via an int80. This entry point is only used by the Linux 1092 * application environment. Unlike the other entry points, there is no 1093 * default action to take if no callback is registered for this process. 1094 */ 1095void 1096sys_int80() 1097{} 1098 1099#else /* __lint */ 1100 1101 ENTRY_NP(brand_sys_int80) 1102 SWAPGS /* kernel gsbase */ 1103 XPV_TRAP_POP 1104 BRAND_CALLBACK(BRAND_CB_INT80) 1105 SWAPGS /* user gsbase */ 1106#if defined(__xpv) 1107 jmp nopop_int80 1108#endif 1109 1110 ENTRY_NP(sys_int80) 1111 /* 1112 * We hit an int80, but this process isn't of a brand with an int80 1113 * handler. Bad process! Make it look as if the INT failed. 1114 * Modify %rip to point before the INT, push the expected error 1115 * code and fake a GP fault. Note on 64-bit hypervisor we need 1116 * to undo the XPV_TRAP_POP and push rcx and r11 back on the stack 1117 * because gptrap will pop them again with its own XPV_TRAP_POP. 1118 */ 1119#if defined(__xpv) 1120 XPV_TRAP_POP 1121nopop_int80: 1122#endif 1123 subq $2, (%rsp) /* int insn 2-bytes */ 1124 pushq $_CONST(_MUL(T_INT80, GATE_DESC_SIZE) + 2) 1125#if defined(__xpv) 1126 push %r11 1127 push %rcx 1128#endif 1129 jmp gptrap / GP fault 1130 SET_SIZE(sys_int80) 1131 SET_SIZE(brand_sys_int80) 1132#endif /* __lint */ 1133 1134 1135/* 1136 * This is the destination of the "int $T_SYSCALLINT" interrupt gate, used by 1137 * the generic i386 libc to do system calls. We do a small amount of setup 1138 * before jumping into the existing sys_syscall32 path. 1139 */ 1140#if defined(__lint) 1141 1142/*ARGSUSED*/ 1143void 1144sys_syscall_int() 1145{} 1146 1147#else /* __lint */ 1148 1149 ENTRY_NP(brand_sys_syscall_int) 1150 SWAPGS /* kernel gsbase */ 1151 XPV_TRAP_POP 1152 BRAND_CALLBACK(BRAND_CB_INT91) 1153 SWAPGS /* user gsbase */ 1154 1155#if defined(__xpv) 1156 jmp nopop_syscall_int 1157#endif 1158 1159 ALTENTRY(sys_syscall_int) 1160 SWAPGS /* kernel gsbase */ 1161 1162#if defined(__xpv) 1163 XPV_TRAP_POP 1164nopop_syscall_int: 1165#endif 1166 1167 movq %gs:CPU_THREAD, %r15 1168 movq T_STACK(%r15), %rsp 1169 movl %eax, %eax 1170 /* 1171 * Set t_post_sys on this thread to force ourselves out via the slow 1172 * path. It might be possible at some later date to optimize this out 1173 * and use a faster return mechanism. 1174 */ 1175 movb $1, T_POST_SYS(%r15) 1176 CLEAN_CS 1177 jmp _syscall32_save 1178 /* 1179 * There should be no instructions between this label and SWAPGS/IRET 1180 * or we could end up breaking branded zone support. See the usage of 1181 * this label in lx_brand_int80_callback and sn1_brand_int91_callback 1182 * for examples. 1183 */ 1184 ALTENTRY(sys_sysint_swapgs_iret) 1185 SWAPGS /* user gsbase */ 1186 IRET 1187 /*NOTREACHED*/ 1188 SET_SIZE(sys_sysint_swapgs_iret) 1189 SET_SIZE(sys_syscall_int) 1190 SET_SIZE(brand_sys_syscall_int) 1191 1192#endif /* __lint */ 1193 1194/* 1195 * Legacy 32-bit applications and old libc implementations do lcalls; 1196 * we should never get here because the LDT entry containing the syscall 1197 * segment descriptor has the "segment present" bit cleared, which means 1198 * we end up processing those system calls in trap() via a not-present trap. 1199 * 1200 * We do it this way because a call gate unhelpfully does -nothing- to the 1201 * interrupt flag bit, so an interrupt can run us just after the lcall 1202 * completes, but just before the swapgs takes effect. Thus the INTR_PUSH and 1203 * INTR_POP paths would have to be slightly more complex to dance around 1204 * this problem, and end up depending explicitly on the first 1205 * instruction of this handler being either swapgs or cli. 1206 */ 1207 1208#if defined(__lint) 1209 1210/*ARGSUSED*/ 1211void 1212sys_lcall32() 1213{} 1214 1215#else /* __lint */ 1216 1217 ENTRY_NP(sys_lcall32) 1218 SWAPGS /* kernel gsbase */ 1219 pushq $0 1220 pushq %rbp 1221 movq %rsp, %rbp 1222 leaq __lcall_panic_str(%rip), %rdi 1223 xorl %eax, %eax 1224 call panic 1225 SET_SIZE(sys_lcall32) 1226 1227__lcall_panic_str: 1228 .string "sys_lcall32: shouldn't be here!" 1229 1230/* 1231 * Declare a uintptr_t which covers the entire pc range of syscall 1232 * handlers for the stack walkers that need this. 1233 */ 1234 .align CPTRSIZE 1235 .globl _allsyscalls_size 1236 .type _allsyscalls_size, @object 1237_allsyscalls_size: 1238 .NWORD . - _allsyscalls 1239 SET_SIZE(_allsyscalls_size) 1240 1241#endif /* __lint */ 1242 1243/* 1244 * These are the thread context handlers for lwps using sysenter/sysexit. 1245 */ 1246 1247#if defined(__lint) 1248 1249/*ARGSUSED*/ 1250void 1251sep_save(void *ksp) 1252{} 1253 1254/*ARGSUSED*/ 1255void 1256sep_restore(void *ksp) 1257{} 1258 1259#else /* __lint */ 1260 1261 /* 1262 * setting this value to zero as we switch away causes the 1263 * stack-pointer-on-sysenter to be NULL, ensuring that we 1264 * don't silently corrupt another (preempted) thread stack 1265 * when running an lwp that (somehow) didn't get sep_restore'd 1266 */ 1267 ENTRY_NP(sep_save) 1268 xorl %edx, %edx 1269 xorl %eax, %eax 1270 movl $MSR_INTC_SEP_ESP, %ecx 1271 wrmsr 1272 ret 1273 SET_SIZE(sep_save) 1274 1275 /* 1276 * Update the kernel stack pointer as we resume onto this cpu. 1277 */ 1278 ENTRY_NP(sep_restore) 1279 movq %rdi, %rdx 1280 shrq $32, %rdx 1281 movl %edi, %eax 1282 movl $MSR_INTC_SEP_ESP, %ecx 1283 wrmsr 1284 ret 1285 SET_SIZE(sep_restore) 1286 1287#endif /* __lint */ 1288