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) 2004, 2010, Oracle and/or its affiliates. All rights reserved. 23 * Copyright (c) 2012, Joyent, Inc. All rights reserved. 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 * 32 | callback pointer | 136 * | 24 | user (or interrupt) stack pointer | 137 * | 16 | lwp pointer | 138 * v 8 | userland return address | 139 * 0 | callback wrapper return addr | 140 * -------------------------------------- 141 * 142 * Since we're pushing the userland return address onto the kernel stack 143 * we need to get that address without accessing the user's stack (since we 144 * can't trust that data). There are different ways to get the userland 145 * return address depending on how the syscall trap was made: 146 * 147 * a) For sys_syscall and sys_syscall32 the return address is in %rcx. 148 * b) For sys_sysenter the return address is in %rdx. 149 * c) For sys_int80 and sys_syscall_int (int91), upon entry into the macro, 150 * the stack pointer points at the state saved when we took the interrupt: 151 * ------------------------ 152 * | | user's %ss | 153 * | | user's %esp | 154 * | | EFLAGS register | 155 * v | user's %cs | 156 * | user's %eip | 157 * ------------------------ 158 * 159 * The 2nd parameter to the BRAND_CALLBACK macro is either the 160 * BRAND_URET_FROM_REG or BRAND_URET_FROM_INTR_STACK macro. These macros are 161 * used to generate the proper code to get the userland return address for 162 * each syscall entry point. 163 * 164 * The interface to the brand callbacks on the 64-bit kernel assumes %r15 165 * is available as a scratch register within the callback. If the callback 166 * returns within the kernel then this macro will restore %r15. If the 167 * callback is going to return directly to userland then it should restore 168 * %r15 before returning to userland. 169 */ 170#define BRAND_URET_FROM_REG(rip_reg) \ 171 pushq rip_reg /* push the return address */ 172 173/* 174 * The interrupt stack pointer we saved on entry to the BRAND_CALLBACK macro 175 * is currently pointing at the user return address (%eip). 176 */ 177#define BRAND_URET_FROM_INTR_STACK() \ 178 movq %gs:CPU_RTMP_RSP, %r15 /* grab the intr. stack pointer */ ;\ 179 pushq (%r15) /* push the return address */ 180 181#define BRAND_CALLBACK(callback_id, push_userland_ret) \ 182 movq %rsp, %gs:CPU_RTMP_RSP /* save the stack pointer */ ;\ 183 movq %r15, %gs:CPU_RTMP_R15 /* save %r15 */ ;\ 184 movq %gs:CPU_THREAD, %r15 /* load the thread pointer */ ;\ 185 movq T_STACK(%r15), %rsp /* switch to the kernel stack */ ;\ 186 subq $16, %rsp /* save space for 2 pointers */ ;\ 187 pushq %r14 /* save %r14 */ ;\ 188 movq %gs:CPU_RTMP_RSP, %r14 ;\ 189 movq %r14, 8(%rsp) /* stash the user stack pointer */ ;\ 190 popq %r14 /* restore %r14 */ ;\ 191 movq T_LWP(%r15), %r15 /* load the lwp pointer */ ;\ 192 pushq %r15 /* push the lwp pointer */ ;\ 193 movq LWP_PROCP(%r15), %r15 /* load the proc pointer */ ;\ 194 movq P_BRAND(%r15), %r15 /* load the brand pointer */ ;\ 195 movq B_MACHOPS(%r15), %r15 /* load the machops pointer */ ;\ 196 movq _CONST(_MUL(callback_id, CPTRSIZE))(%r15), %r15 ;\ 197 cmpq $0, %r15 ;\ 198 je 1f ;\ 199 movq %r15, 16(%rsp) /* save the callback pointer */ ;\ 200 push_userland_ret /* push the return address */ ;\ 201 call *24(%rsp) /* call callback */ ;\ 2021: movq %gs:CPU_RTMP_R15, %r15 /* restore %r15 */ ;\ 203 movq %gs:CPU_RTMP_RSP, %rsp /* restore the stack pointer */ 204 205#define MSTATE_TRANSITION(from, to) \ 206 movl $from, %edi; \ 207 movl $to, %esi; \ 208 call syscall_mstate 209 210/* 211 * Check to see if a simple (direct) return is possible i.e. 212 * 213 * if (t->t_post_sys_ast | syscalltrace | 214 * lwp->lwp_pcb.pcb_rupdate == 1) 215 * do full version ; 216 * 217 * Preconditions: 218 * - t is curthread 219 * Postconditions: 220 * - condition code NE is set if post-sys is too complex 221 * - rtmp is zeroed if it isn't (we rely on this!) 222 * - ltmp is smashed 223 */ 224#define CHECK_POSTSYS_NE(t, ltmp, rtmp) \ 225 movq T_LWP(t), ltmp; \ 226 movzbl PCB_RUPDATE(ltmp), rtmp; \ 227 ORL_SYSCALLTRACE(rtmp); \ 228 orl T_POST_SYS_AST(t), rtmp; \ 229 cmpl $0, rtmp 230 231/* 232 * Fix up the lwp, thread, and eflags for a successful return 233 * 234 * Preconditions: 235 * - zwreg contains zero 236 */ 237#define SIMPLE_SYSCALL_POSTSYS(t, lwp, zwreg) \ 238 movb $LWP_USER, LWP_STATE(lwp); \ 239 movw zwreg, T_SYSNUM(t); \ 240 andb $_CONST(0xffff - PS_C), REGOFF_RFL(%rsp) 241 242/* 243 * ASSERT(lwptoregs(lwp) == rp); 244 * 245 * This may seem obvious, but very odd things happen if this 246 * assertion is false 247 * 248 * Preconditions: 249 * (%rsp is ready for normal call sequence) 250 * Postconditions (if assertion is true): 251 * %r11 is smashed 252 * 253 * ASSERT(rp->r_cs == descnum) 254 * 255 * The code selector is written into the regs structure when the 256 * lwp stack is created. We use this ASSERT to validate that 257 * the regs structure really matches how we came in. 258 * 259 * Preconditions: 260 * (%rsp is ready for normal call sequence) 261 * Postconditions (if assertion is true): 262 * -none- 263 * 264 * ASSERT(lwp->lwp_pcb.pcb_rupdate == 0); 265 * 266 * If this is false, it meant that we returned to userland without 267 * updating the segment registers as we were supposed to. 268 * 269 * Note that we must ensure no interrupts or other traps intervene 270 * between entering privileged mode and performing the assertion, 271 * otherwise we may perform a context switch on the thread, which 272 * will end up setting pcb_rupdate to 1 again. 273 */ 274#if defined(DEBUG) 275 276#if !defined(__lint) 277 278__lwptoregs_msg: 279 .string "syscall_asm_amd64.s:%d lwptoregs(%p) [%p] != rp [%p]" 280 281__codesel_msg: 282 .string "syscall_asm_amd64.s:%d rp->r_cs [%ld] != %ld" 283 284__no_rupdate_msg: 285 .string "syscall_asm_amd64.s:%d lwp %p, pcb_rupdate != 0" 286 287#endif /* !__lint */ 288 289#define ASSERT_LWPTOREGS(lwp, rp) \ 290 movq LWP_REGS(lwp), %r11; \ 291 cmpq rp, %r11; \ 292 je 7f; \ 293 leaq __lwptoregs_msg(%rip), %rdi; \ 294 movl $__LINE__, %esi; \ 295 movq lwp, %rdx; \ 296 movq %r11, %rcx; \ 297 movq rp, %r8; \ 298 xorl %eax, %eax; \ 299 call panic; \ 3007: 301 302#define ASSERT_NO_RUPDATE_PENDING(lwp) \ 303 testb $0x1, PCB_RUPDATE(lwp); \ 304 je 8f; \ 305 movq lwp, %rdx; \ 306 leaq __no_rupdate_msg(%rip), %rdi; \ 307 movl $__LINE__, %esi; \ 308 xorl %eax, %eax; \ 309 call panic; \ 3108: 311 312#else 313#define ASSERT_LWPTOREGS(lwp, rp) 314#define ASSERT_NO_RUPDATE_PENDING(lwp) 315#endif 316 317/* 318 * Do the traptrace thing and restore any registers we used 319 * in situ. Assumes that %rsp is pointing at the base of 320 * the struct regs, obviously .. 321 */ 322#ifdef TRAPTRACE 323#define SYSCALL_TRAPTRACE(ttype) \ 324 TRACE_PTR(%rdi, %rbx, %ebx, %rcx, ttype); \ 325 TRACE_REGS(%rdi, %rsp, %rbx, %rcx); \ 326 TRACE_STAMP(%rdi); /* rdtsc clobbers %eax, %edx */ \ 327 movq REGOFF_RAX(%rsp), %rax; \ 328 movq REGOFF_RBX(%rsp), %rbx; \ 329 movq REGOFF_RCX(%rsp), %rcx; \ 330 movq REGOFF_RDX(%rsp), %rdx; \ 331 movl %eax, TTR_SYSNUM(%rdi); \ 332 movq REGOFF_RDI(%rsp), %rdi 333 334#define SYSCALL_TRAPTRACE32(ttype) \ 335 SYSCALL_TRAPTRACE(ttype); \ 336 /* paranoia: clean the top 32-bits of the registers */ \ 337 orl %eax, %eax; \ 338 orl %ebx, %ebx; \ 339 orl %ecx, %ecx; \ 340 orl %edx, %edx; \ 341 orl %edi, %edi 342#else /* TRAPTRACE */ 343#define SYSCALL_TRAPTRACE(ttype) 344#define SYSCALL_TRAPTRACE32(ttype) 345#endif /* TRAPTRACE */ 346 347/* 348 * The 64-bit libc syscall wrapper does this: 349 * 350 * fn(<args>) 351 * { 352 * movq %rcx, %r10 -- because syscall smashes %rcx 353 * movl $CODE, %eax 354 * syscall 355 * <error processing> 356 * } 357 * 358 * Thus when we come into the kernel: 359 * 360 * %rdi, %rsi, %rdx, %r10, %r8, %r9 contain first six args 361 * %rax is the syscall number 362 * %r12-%r15 contain caller state 363 * 364 * The syscall instruction arranges that: 365 * 366 * %rcx contains the return %rip 367 * %r11d contains bottom 32-bits of %rflags 368 * %rflags is masked (as determined by the SFMASK msr) 369 * %cs is set to UCS_SEL (as determined by the STAR msr) 370 * %ss is set to UDS_SEL (as determined by the STAR msr) 371 * %rip is set to sys_syscall (as determined by the LSTAR msr) 372 * 373 * Or in other words, we have no registers available at all. 374 * Only swapgs can save us! 375 * 376 * Under the hypervisor, the swapgs has happened already. However, the 377 * state of the world is very different from that we're familiar with. 378 * 379 * In particular, we have a stack structure like that for interrupt 380 * gates, except that the %cs and %ss registers are modified for reasons 381 * that are not entirely clear. Critically, the %rcx/%r11 values do 382 * *not* reflect the usage of those registers under a 'real' syscall[1]; 383 * the stack, therefore, looks like this: 384 * 385 * 0x0(rsp) potentially junk %rcx 386 * 0x8(rsp) potentially junk %r11 387 * 0x10(rsp) user %rip 388 * 0x18(rsp) modified %cs 389 * 0x20(rsp) user %rflags 390 * 0x28(rsp) user %rsp 391 * 0x30(rsp) modified %ss 392 * 393 * 394 * and before continuing on, we must load the %rip into %rcx and the 395 * %rflags into %r11. 396 * 397 * [1] They used to, and we relied on it, but this was broken in 3.1.1. 398 * Sigh. 399 */ 400#if defined(__xpv) 401#define XPV_SYSCALL_PROD \ 402 movq 0x10(%rsp), %rcx; \ 403 movq 0x20(%rsp), %r11; \ 404 movq 0x28(%rsp), %rsp 405#else 406#define XPV_SYSCALL_PROD /* nothing */ 407#endif 408 409#if defined(__lint) 410 411/*ARGSUSED*/ 412void 413sys_syscall() 414{} 415 416void 417_allsyscalls() 418{} 419 420size_t _allsyscalls_size; 421 422#else /* __lint */ 423 424 ENTRY_NP2(brand_sys_syscall,_allsyscalls) 425 SWAPGS /* kernel gsbase */ 426 XPV_SYSCALL_PROD 427 BRAND_CALLBACK(BRAND_CB_SYSCALL, BRAND_URET_FROM_REG(%rcx)) 428 jmp noprod_sys_syscall 429 430 ALTENTRY(sys_syscall) 431 SWAPGS /* kernel gsbase */ 432 XPV_SYSCALL_PROD 433 434noprod_sys_syscall: 435 movq %r15, %gs:CPU_RTMP_R15 436 movq %rsp, %gs:CPU_RTMP_RSP 437 438 movq %gs:CPU_THREAD, %r15 439 movq T_STACK(%r15), %rsp /* switch from user to kernel stack */ 440 441 ASSERT_UPCALL_MASK_IS_SET 442 443 movl $UCS_SEL, REGOFF_CS(%rsp) 444 movq %rcx, REGOFF_RIP(%rsp) /* syscall: %rip -> %rcx */ 445 movq %r11, REGOFF_RFL(%rsp) /* syscall: %rfl -> %r11d */ 446 movl $UDS_SEL, REGOFF_SS(%rsp) 447 448 movl %eax, %eax /* wrapper: sysc# -> %eax */ 449 movq %rdi, REGOFF_RDI(%rsp) 450 movq %rsi, REGOFF_RSI(%rsp) 451 movq %rdx, REGOFF_RDX(%rsp) 452 movq %r10, REGOFF_RCX(%rsp) /* wrapper: %rcx -> %r10 */ 453 movq %r10, %rcx /* arg[3] for direct calls */ 454 455 movq %r8, REGOFF_R8(%rsp) 456 movq %r9, REGOFF_R9(%rsp) 457 movq %rax, REGOFF_RAX(%rsp) 458 movq %rbx, REGOFF_RBX(%rsp) 459 460 movq %rbp, REGOFF_RBP(%rsp) 461 movq %r10, REGOFF_R10(%rsp) 462 movq %gs:CPU_RTMP_RSP, %r11 463 movq %r11, REGOFF_RSP(%rsp) 464 movq %r12, REGOFF_R12(%rsp) 465 466 movq %r13, REGOFF_R13(%rsp) 467 movq %r14, REGOFF_R14(%rsp) 468 movq %gs:CPU_RTMP_R15, %r10 469 movq %r10, REGOFF_R15(%rsp) 470 movq $0, REGOFF_SAVFP(%rsp) 471 movq $0, REGOFF_SAVPC(%rsp) 472 473 /* 474 * Copy these registers here in case we end up stopped with 475 * someone (like, say, /proc) messing with our register state. 476 * We don't -restore- them unless we have to in update_sregs. 477 * 478 * Since userland -can't- change fsbase or gsbase directly, 479 * and capturing them involves two serializing instructions, 480 * we don't bother to capture them here. 481 */ 482 xorl %ebx, %ebx 483 movw %ds, %bx 484 movq %rbx, REGOFF_DS(%rsp) 485 movw %es, %bx 486 movq %rbx, REGOFF_ES(%rsp) 487 movw %fs, %bx 488 movq %rbx, REGOFF_FS(%rsp) 489 movw %gs, %bx 490 movq %rbx, REGOFF_GS(%rsp) 491 492 /* 493 * Machine state saved in the regs structure on the stack 494 * First six args in %rdi, %rsi, %rdx, %rcx, %r8, %r9 495 * %eax is the syscall number 496 * %rsp is the thread's stack, %r15 is curthread 497 * REG_RSP(%rsp) is the user's stack 498 */ 499 500 SYSCALL_TRAPTRACE($TT_SYSC64) 501 502 movq %rsp, %rbp 503 504 movq T_LWP(%r15), %r14 505 ASSERT_NO_RUPDATE_PENDING(%r14) 506 ENABLE_INTR_FLAGS 507 508 MSTATE_TRANSITION(LMS_USER, LMS_SYSTEM) 509 movl REGOFF_RAX(%rsp), %eax /* (%rax damaged by mstate call) */ 510 511 ASSERT_LWPTOREGS(%r14, %rsp) 512 513 movb $LWP_SYS, LWP_STATE(%r14) 514 incq LWP_RU_SYSC(%r14) 515 movb $NORMALRETURN, LWP_EOSYS(%r14) 516 517 incq %gs:CPU_STATS_SYS_SYSCALL 518 519 movw %ax, T_SYSNUM(%r15) 520 movzbl T_PRE_SYS(%r15), %ebx 521 ORL_SYSCALLTRACE(%ebx) 522 testl %ebx, %ebx 523 jne _syscall_pre 524 525_syscall_invoke: 526 movq REGOFF_RDI(%rbp), %rdi 527 movq REGOFF_RSI(%rbp), %rsi 528 movq REGOFF_RDX(%rbp), %rdx 529 movq REGOFF_RCX(%rbp), %rcx 530 movq REGOFF_R8(%rbp), %r8 531 movq REGOFF_R9(%rbp), %r9 532 533 cmpl $NSYSCALL, %eax 534 jae _syscall_ill 535 shll $SYSENT_SIZE_SHIFT, %eax 536 leaq sysent(%rax), %rbx 537 538 call *SY_CALLC(%rbx) 539 540 movq %rax, %r12 541 movq %rdx, %r13 542 543 /* 544 * If the handler returns two ints, then we need to split the 545 * 64-bit return value into two 32-bit values. 546 */ 547 testw $SE_32RVAL2, SY_FLAGS(%rbx) 548 je 5f 549 movq %r12, %r13 550 shrq $32, %r13 /* upper 32-bits into %edx */ 551 movl %r12d, %r12d /* lower 32-bits into %eax */ 5525: 553 /* 554 * Optimistically assume that there's no post-syscall 555 * work to do. (This is to avoid having to call syscall_mstate() 556 * with interrupts disabled) 557 */ 558 MSTATE_TRANSITION(LMS_SYSTEM, LMS_USER) 559 560 /* 561 * We must protect ourselves from being descheduled here; 562 * If we were, and we ended up on another cpu, or another 563 * lwp got in ahead of us, it could change the segment 564 * registers without us noticing before we return to userland. 565 */ 566 CLI(%r14) 567 CHECK_POSTSYS_NE(%r15, %r14, %ebx) 568 jne _syscall_post 569 570 /* 571 * We need to protect ourselves against non-canonical return values 572 * because Intel doesn't check for them on sysret (AMD does). Canonical 573 * addresses on current amd64 processors only use 48-bits for VAs; an 574 * address is canonical if all upper bits (47-63) are identical. If we 575 * find a non-canonical %rip, we opt to go through the full 576 * _syscall_post path which takes us into an iretq which is not 577 * susceptible to the same problems sysret is. 578 * 579 * We're checking for a canonical address by first doing an arithmetic 580 * shift. This will fill in the remaining bits with the value of bit 63. 581 * If the address were canonical, the register would now have either all 582 * zeroes or all ones in it. Therefore we add one (inducing overflow) 583 * and compare against 1. A canonical address will either be zero or one 584 * at this point, hence the use of ja. 585 * 586 * At this point, r12 and r13 have the return value so we can't use 587 * those registers. 588 */ 589 movq REGOFF_RIP(%rsp), %rcx 590 sarq $47, %rcx 591 incq %rcx 592 cmpq $1, %rcx 593 ja _syscall_post 594 595 596 SIMPLE_SYSCALL_POSTSYS(%r15, %r14, %bx) 597 598 movq %r12, REGOFF_RAX(%rsp) 599 movq %r13, REGOFF_RDX(%rsp) 600 601 /* 602 * To get back to userland, we need the return %rip in %rcx and 603 * the return %rfl in %r11d. The sysretq instruction also arranges 604 * to fix up %cs and %ss; everything else is our responsibility. 605 */ 606 movq REGOFF_RDI(%rsp), %rdi 607 movq REGOFF_RSI(%rsp), %rsi 608 movq REGOFF_RDX(%rsp), %rdx 609 /* %rcx used to restore %rip value */ 610 611 movq REGOFF_R8(%rsp), %r8 612 movq REGOFF_R9(%rsp), %r9 613 movq REGOFF_RAX(%rsp), %rax 614 movq REGOFF_RBX(%rsp), %rbx 615 616 movq REGOFF_RBP(%rsp), %rbp 617 movq REGOFF_R10(%rsp), %r10 618 /* %r11 used to restore %rfl value */ 619 movq REGOFF_R12(%rsp), %r12 620 621 movq REGOFF_R13(%rsp), %r13 622 movq REGOFF_R14(%rsp), %r14 623 movq REGOFF_R15(%rsp), %r15 624 625 movq REGOFF_RIP(%rsp), %rcx 626 movl REGOFF_RFL(%rsp), %r11d 627 628#if defined(__xpv) 629 addq $REGOFF_RIP, %rsp 630#else 631 movq REGOFF_RSP(%rsp), %rsp 632#endif 633 634 /* 635 * There can be no instructions between the ALTENTRY below and 636 * SYSRET or we could end up breaking brand support. See label usage 637 * in sn1_brand_syscall_callback for an example. 638 */ 639 ASSERT_UPCALL_MASK_IS_SET 640#if defined(__xpv) 641 SYSRETQ 642 ALTENTRY(nopop_sys_syscall_swapgs_sysretq) 643 644 /* 645 * We can only get here after executing a brand syscall 646 * interposition callback handler and simply need to 647 * "sysretq" back to userland. On the hypervisor this 648 * involves the iret hypercall which requires us to construct 649 * just enough of the stack needed for the hypercall. 650 * (rip, cs, rflags, rsp, ss). 651 */ 652 movq %rsp, %gs:CPU_RTMP_RSP /* save user's rsp */ 653 movq %gs:CPU_THREAD, %r11 654 movq T_STACK(%r11), %rsp 655 656 movq %rcx, REGOFF_RIP(%rsp) 657 movl $UCS_SEL, REGOFF_CS(%rsp) 658 movq %gs:CPU_RTMP_RSP, %r11 659 movq %r11, REGOFF_RSP(%rsp) 660 pushfq 661 popq %r11 /* hypercall enables ints */ 662 movq %r11, REGOFF_RFL(%rsp) 663 movl $UDS_SEL, REGOFF_SS(%rsp) 664 addq $REGOFF_RIP, %rsp 665 /* 666 * XXPV: see comment in SYSRETQ definition for future optimization 667 * we could take. 668 */ 669 ASSERT_UPCALL_MASK_IS_SET 670 SYSRETQ 671#else 672 ALTENTRY(nopop_sys_syscall_swapgs_sysretq) 673 SWAPGS /* user gsbase */ 674 SYSRETQ 675#endif 676 /*NOTREACHED*/ 677 SET_SIZE(nopop_sys_syscall_swapgs_sysretq) 678 679_syscall_pre: 680 call pre_syscall 681 movl %eax, %r12d 682 testl %eax, %eax 683 jne _syscall_post_call 684 /* 685 * Didn't abort, so reload the syscall args and invoke the handler. 686 */ 687 movzwl T_SYSNUM(%r15), %eax 688 jmp _syscall_invoke 689 690_syscall_ill: 691 call nosys 692 movq %rax, %r12 693 movq %rdx, %r13 694 jmp _syscall_post_call 695 696_syscall_post: 697 STI 698 /* 699 * Sigh, our optimism wasn't justified, put it back to LMS_SYSTEM 700 * so that we can account for the extra work it takes us to finish. 701 */ 702 MSTATE_TRANSITION(LMS_USER, LMS_SYSTEM) 703_syscall_post_call: 704 movq %r12, %rdi 705 movq %r13, %rsi 706 call post_syscall 707 MSTATE_TRANSITION(LMS_SYSTEM, LMS_USER) 708 jmp _sys_rtt 709 SET_SIZE(sys_syscall) 710 SET_SIZE(brand_sys_syscall) 711 712#endif /* __lint */ 713 714#if defined(__lint) 715 716/*ARGSUSED*/ 717void 718sys_syscall32() 719{} 720 721#else /* __lint */ 722 723 ENTRY_NP(brand_sys_syscall32) 724 SWAPGS /* kernel gsbase */ 725 XPV_TRAP_POP 726 BRAND_CALLBACK(BRAND_CB_SYSCALL32, BRAND_URET_FROM_REG(%rcx)) 727 jmp nopop_sys_syscall32 728 729 ALTENTRY(sys_syscall32) 730 SWAPGS /* kernel gsbase */ 731 XPV_TRAP_POP 732 733nopop_sys_syscall32: 734 movl %esp, %r10d 735 movq %gs:CPU_THREAD, %r15 736 movq T_STACK(%r15), %rsp 737 movl %eax, %eax 738 739 movl $U32CS_SEL, REGOFF_CS(%rsp) 740 movl %ecx, REGOFF_RIP(%rsp) /* syscall: %rip -> %rcx */ 741 movq %r11, REGOFF_RFL(%rsp) /* syscall: %rfl -> %r11d */ 742 movq %r10, REGOFF_RSP(%rsp) 743 movl $UDS_SEL, REGOFF_SS(%rsp) 744 745_syscall32_save: 746 movl %edi, REGOFF_RDI(%rsp) 747 movl %esi, REGOFF_RSI(%rsp) 748 movl %ebp, REGOFF_RBP(%rsp) 749 movl %ebx, REGOFF_RBX(%rsp) 750 movl %edx, REGOFF_RDX(%rsp) 751 movl %ecx, REGOFF_RCX(%rsp) 752 movl %eax, REGOFF_RAX(%rsp) /* wrapper: sysc# -> %eax */ 753 movq $0, REGOFF_SAVFP(%rsp) 754 movq $0, REGOFF_SAVPC(%rsp) 755 756 /* 757 * Copy these registers here in case we end up stopped with 758 * someone (like, say, /proc) messing with our register state. 759 * We don't -restore- them unless we have to in update_sregs. 760 * 761 * Since userland -can't- change fsbase or gsbase directly, 762 * we don't bother to capture them here. 763 */ 764 xorl %ebx, %ebx 765 movw %ds, %bx 766 movq %rbx, REGOFF_DS(%rsp) 767 movw %es, %bx 768 movq %rbx, REGOFF_ES(%rsp) 769 movw %fs, %bx 770 movq %rbx, REGOFF_FS(%rsp) 771 movw %gs, %bx 772 movq %rbx, REGOFF_GS(%rsp) 773 774 /* 775 * Application state saved in the regs structure on the stack 776 * %eax is the syscall number 777 * %rsp is the thread's stack, %r15 is curthread 778 * REG_RSP(%rsp) is the user's stack 779 */ 780 781 SYSCALL_TRAPTRACE32($TT_SYSC) 782 783 movq %rsp, %rbp 784 785 movq T_LWP(%r15), %r14 786 ASSERT_NO_RUPDATE_PENDING(%r14) 787 788 ENABLE_INTR_FLAGS 789 790 MSTATE_TRANSITION(LMS_USER, LMS_SYSTEM) 791 movl REGOFF_RAX(%rsp), %eax /* (%rax damaged by mstate call) */ 792 793 ASSERT_LWPTOREGS(%r14, %rsp) 794 795 incq %gs:CPU_STATS_SYS_SYSCALL 796 797 /* 798 * Make some space for MAXSYSARGS (currently 8) 32-bit args placed 799 * into 64-bit (long) arg slots, maintaining 16 byte alignment. Or 800 * more succinctly: 801 * 802 * SA(MAXSYSARGS * sizeof (long)) == 64 803 */ 804#define SYS_DROP 64 /* drop for args */ 805 subq $SYS_DROP, %rsp 806 movb $LWP_SYS, LWP_STATE(%r14) 807 movq %r15, %rdi 808 movq %rsp, %rsi 809 call syscall_entry 810 811 /* 812 * Fetch the arguments copied onto the kernel stack and put 813 * them in the right registers to invoke a C-style syscall handler. 814 * %rax contains the handler address. 815 * 816 * Ideas for making all this go faster of course include simply 817 * forcibly fetching 6 arguments from the user stack under lofault 818 * protection, reverting to copyin_args only when watchpoints 819 * are in effect. 820 * 821 * (If we do this, make sure that exec and libthread leave 822 * enough space at the top of the stack to ensure that we'll 823 * never do a fetch from an invalid page.) 824 * 825 * Lots of ideas here, but they won't really help with bringup B-) 826 * Correctness can't wait, performance can wait a little longer .. 827 */ 828 829 movq %rax, %rbx 830 movl 0(%rsp), %edi 831 movl 8(%rsp), %esi 832 movl 0x10(%rsp), %edx 833 movl 0x18(%rsp), %ecx 834 movl 0x20(%rsp), %r8d 835 movl 0x28(%rsp), %r9d 836 837 call *SY_CALLC(%rbx) 838 839 movq %rbp, %rsp /* pop the args */ 840 841 /* 842 * amd64 syscall handlers -always- return a 64-bit value in %rax. 843 * On the 32-bit kernel, they always return that value in %eax:%edx 844 * as required by the 32-bit ABI. 845 * 846 * Simulate the same behaviour by unconditionally splitting the 847 * return value in the same way. 848 */ 849 movq %rax, %r13 850 shrq $32, %r13 /* upper 32-bits into %edx */ 851 movl %eax, %r12d /* lower 32-bits into %eax */ 852 853 /* 854 * Optimistically assume that there's no post-syscall 855 * work to do. (This is to avoid having to call syscall_mstate() 856 * with interrupts disabled) 857 */ 858 MSTATE_TRANSITION(LMS_SYSTEM, LMS_USER) 859 860 /* 861 * We must protect ourselves from being descheduled here; 862 * If we were, and we ended up on another cpu, or another 863 * lwp got in ahead of us, it could change the segment 864 * registers without us noticing before we return to userland. 865 */ 866 CLI(%r14) 867 CHECK_POSTSYS_NE(%r15, %r14, %ebx) 868 jne _full_syscall_postsys32 869 SIMPLE_SYSCALL_POSTSYS(%r15, %r14, %bx) 870 871 /* 872 * To get back to userland, we need to put the return %rip in %rcx and 873 * the return %rfl in %r11d. The sysret instruction also arranges 874 * to fix up %cs and %ss; everything else is our responsibility. 875 */ 876 877 movl %r12d, %eax /* %eax: rval1 */ 878 movl REGOFF_RBX(%rsp), %ebx 879 /* %ecx used for return pointer */ 880 movl %r13d, %edx /* %edx: rval2 */ 881 movl REGOFF_RBP(%rsp), %ebp 882 movl REGOFF_RSI(%rsp), %esi 883 movl REGOFF_RDI(%rsp), %edi 884 885 movl REGOFF_RFL(%rsp), %r11d /* %r11 -> eflags */ 886 movl REGOFF_RIP(%rsp), %ecx /* %ecx -> %eip */ 887 movl REGOFF_RSP(%rsp), %esp 888 889 ASSERT_UPCALL_MASK_IS_SET 890 ALTENTRY(nopop_sys_syscall32_swapgs_sysretl) 891 SWAPGS /* user gsbase */ 892 SYSRETL 893 SET_SIZE(nopop_sys_syscall32_swapgs_sysretl) 894 /*NOTREACHED*/ 895 896_full_syscall_postsys32: 897 STI 898 /* 899 * Sigh, our optimism wasn't justified, put it back to LMS_SYSTEM 900 * so that we can account for the extra work it takes us to finish. 901 */ 902 MSTATE_TRANSITION(LMS_USER, LMS_SYSTEM) 903 movq %r15, %rdi 904 movq %r12, %rsi /* rval1 - %eax */ 905 movq %r13, %rdx /* rval2 - %edx */ 906 call syscall_exit 907 MSTATE_TRANSITION(LMS_SYSTEM, LMS_USER) 908 jmp _sys_rtt 909 SET_SIZE(sys_syscall32) 910 SET_SIZE(brand_sys_syscall32) 911 912#endif /* __lint */ 913 914/* 915 * System call handler via the sysenter instruction 916 * Used only for 32-bit system calls on the 64-bit kernel. 917 * 918 * The caller in userland has arranged that: 919 * 920 * - %eax contains the syscall number 921 * - %ecx contains the user %esp 922 * - %edx contains the return %eip 923 * - the user stack contains the args to the syscall 924 * 925 * Hardware and (privileged) initialization code have arranged that by 926 * the time the sysenter instructions completes: 927 * 928 * - %rip is pointing to sys_sysenter (below). 929 * - %cs and %ss are set to kernel text and stack (data) selectors. 930 * - %rsp is pointing at the lwp's stack 931 * - interrupts have been disabled. 932 * 933 * Note that we are unable to return both "rvals" to userland with 934 * this call, as %edx is used by the sysexit instruction. 935 * 936 * One final complication in this routine is its interaction with 937 * single-stepping in a debugger. For most of the system call mechanisms, 938 * the CPU automatically clears the single-step flag before we enter the 939 * kernel. The sysenter mechanism does not clear the flag, so a user 940 * single-stepping through a libc routine may suddenly find him/herself 941 * single-stepping through the kernel. To detect this, kmdb compares the 942 * trap %pc to the [brand_]sys_enter addresses on each single-step trap. 943 * If it finds that we have single-stepped to a sysenter entry point, it 944 * explicitly clears the flag and executes the sys_sysenter routine. 945 * 946 * One final complication in this final complication is the fact that we 947 * have two different entry points for sysenter: brand_sys_sysenter and 948 * sys_sysenter. If we enter at brand_sys_sysenter and start single-stepping 949 * through the kernel with kmdb, we will eventually hit the instruction at 950 * sys_sysenter. kmdb cannot distinguish between that valid single-step 951 * and the undesirable one mentioned above. To avoid this situation, we 952 * simply add a jump over the instruction at sys_sysenter to make it 953 * impossible to single-step to it. 954 */ 955#if defined(__lint) 956 957void 958sys_sysenter() 959{} 960 961#else /* __lint */ 962 963 ENTRY_NP(brand_sys_sysenter) 964 SWAPGS /* kernel gsbase */ 965 ALTENTRY(_brand_sys_sysenter_post_swapgs) 966 BRAND_CALLBACK(BRAND_CB_SYSENTER, BRAND_URET_FROM_REG(%rdx)) 967 /* 968 * Jump over sys_sysenter to allow single-stepping as described 969 * above. 970 */ 971 jmp _sys_sysenter_post_swapgs 972 973 ALTENTRY(sys_sysenter) 974 SWAPGS /* kernel gsbase */ 975 976 ALTENTRY(_sys_sysenter_post_swapgs) 977 movq %gs:CPU_THREAD, %r15 978 979 movl $U32CS_SEL, REGOFF_CS(%rsp) 980 movl %ecx, REGOFF_RSP(%rsp) /* wrapper: %esp -> %ecx */ 981 movl %edx, REGOFF_RIP(%rsp) /* wrapper: %eip -> %edx */ 982 pushfq 983 popq %r10 984 movl $UDS_SEL, REGOFF_SS(%rsp) 985 986 /* 987 * Set the interrupt flag before storing the flags to the 988 * flags image on the stack so we can return to user with 989 * interrupts enabled if we return via sys_rtt_syscall32 990 */ 991 orq $PS_IE, %r10 992 movq %r10, REGOFF_RFL(%rsp) 993 994 movl %edi, REGOFF_RDI(%rsp) 995 movl %esi, REGOFF_RSI(%rsp) 996 movl %ebp, REGOFF_RBP(%rsp) 997 movl %ebx, REGOFF_RBX(%rsp) 998 movl %edx, REGOFF_RDX(%rsp) 999 movl %ecx, REGOFF_RCX(%rsp) 1000 movl %eax, REGOFF_RAX(%rsp) /* wrapper: sysc# -> %eax */ 1001 movq $0, REGOFF_SAVFP(%rsp) 1002 movq $0, REGOFF_SAVPC(%rsp) 1003 1004 /* 1005 * Copy these registers here in case we end up stopped with 1006 * someone (like, say, /proc) messing with our register state. 1007 * We don't -restore- them unless we have to in update_sregs. 1008 * 1009 * Since userland -can't- change fsbase or gsbase directly, 1010 * we don't bother to capture them here. 1011 */ 1012 xorl %ebx, %ebx 1013 movw %ds, %bx 1014 movq %rbx, REGOFF_DS(%rsp) 1015 movw %es, %bx 1016 movq %rbx, REGOFF_ES(%rsp) 1017 movw %fs, %bx 1018 movq %rbx, REGOFF_FS(%rsp) 1019 movw %gs, %bx 1020 movq %rbx, REGOFF_GS(%rsp) 1021 1022 /* 1023 * Application state saved in the regs structure on the stack 1024 * %eax is the syscall number 1025 * %rsp is the thread's stack, %r15 is curthread 1026 * REG_RSP(%rsp) is the user's stack 1027 */ 1028 1029 SYSCALL_TRAPTRACE($TT_SYSENTER) 1030 1031 movq %rsp, %rbp 1032 1033 movq T_LWP(%r15), %r14 1034 ASSERT_NO_RUPDATE_PENDING(%r14) 1035 1036 ENABLE_INTR_FLAGS 1037 1038 /* 1039 * Catch 64-bit process trying to issue sysenter instruction 1040 * on Nocona based systems. 1041 */ 1042 movq LWP_PROCP(%r14), %rax 1043 cmpq $DATAMODEL_ILP32, P_MODEL(%rax) 1044 je 7f 1045 1046 /* 1047 * For a non-32-bit process, simulate a #ud, since that's what 1048 * native hardware does. The traptrace entry (above) will 1049 * let you know what really happened. 1050 */ 1051 movq $T_ILLINST, REGOFF_TRAPNO(%rsp) 1052 movq REGOFF_CS(%rsp), %rdi 1053 movq %rdi, REGOFF_ERR(%rsp) 1054 movq %rsp, %rdi 1055 movq REGOFF_RIP(%rsp), %rsi 1056 movl %gs:CPU_ID, %edx 1057 call trap 1058 jmp _sys_rtt 10597: 1060 1061 MSTATE_TRANSITION(LMS_USER, LMS_SYSTEM) 1062 movl REGOFF_RAX(%rsp), %eax /* (%rax damaged by mstate calls) */ 1063 1064 ASSERT_LWPTOREGS(%r14, %rsp) 1065 1066 incq %gs:CPU_STATS_SYS_SYSCALL 1067 1068 /* 1069 * Make some space for MAXSYSARGS (currently 8) 32-bit args 1070 * placed into 64-bit (long) arg slots, plus one 64-bit 1071 * (long) arg count, maintaining 16 byte alignment. 1072 */ 1073 subq $SYS_DROP, %rsp 1074 movb $LWP_SYS, LWP_STATE(%r14) 1075 movq %r15, %rdi 1076 movq %rsp, %rsi 1077 call syscall_entry 1078 1079 /* 1080 * Fetch the arguments copied onto the kernel stack and put 1081 * them in the right registers to invoke a C-style syscall handler. 1082 * %rax contains the handler address. 1083 */ 1084 movq %rax, %rbx 1085 movl 0(%rsp), %edi 1086 movl 8(%rsp), %esi 1087 movl 0x10(%rsp), %edx 1088 movl 0x18(%rsp), %ecx 1089 movl 0x20(%rsp), %r8d 1090 movl 0x28(%rsp), %r9d 1091 1092 call *SY_CALLC(%rbx) 1093 1094 movq %rbp, %rsp /* pop the args */ 1095 1096 /* 1097 * amd64 syscall handlers -always- return a 64-bit value in %rax. 1098 * On the 32-bit kernel, the always return that value in %eax:%edx 1099 * as required by the 32-bit ABI. 1100 * 1101 * Simulate the same behaviour by unconditionally splitting the 1102 * return value in the same way. 1103 */ 1104 movq %rax, %r13 1105 shrq $32, %r13 /* upper 32-bits into %edx */ 1106 movl %eax, %r12d /* lower 32-bits into %eax */ 1107 1108 /* 1109 * Optimistically assume that there's no post-syscall 1110 * work to do. (This is to avoid having to call syscall_mstate() 1111 * with interrupts disabled) 1112 */ 1113 MSTATE_TRANSITION(LMS_SYSTEM, LMS_USER) 1114 1115 /* 1116 * We must protect ourselves from being descheduled here; 1117 * If we were, and we ended up on another cpu, or another 1118 * lwp got int ahead of us, it could change the segment 1119 * registers without us noticing before we return to userland. 1120 */ 1121 cli 1122 CHECK_POSTSYS_NE(%r15, %r14, %ebx) 1123 jne _full_syscall_postsys32 1124 SIMPLE_SYSCALL_POSTSYS(%r15, %r14, %bx) 1125 1126 /* 1127 * To get back to userland, load up the 32-bit registers and 1128 * sysexit back where we came from. 1129 */ 1130 1131 /* 1132 * Interrupts will be turned on by the 'sti' executed just before 1133 * sysexit. The following ensures that restoring the user's rflags 1134 * doesn't enable interrupts too soon. 1135 */ 1136 andq $_BITNOT(PS_IE), REGOFF_RFL(%rsp) 1137 1138 /* 1139 * (There's no point in loading up %edx because the sysexit 1140 * mechanism smashes it.) 1141 */ 1142 movl %r12d, %eax 1143 movl REGOFF_RBX(%rsp), %ebx 1144 movl REGOFF_RBP(%rsp), %ebp 1145 movl REGOFF_RSI(%rsp), %esi 1146 movl REGOFF_RDI(%rsp), %edi 1147 1148 movl REGOFF_RIP(%rsp), %edx /* sysexit: %edx -> %eip */ 1149 pushq REGOFF_RFL(%rsp) 1150 popfq 1151 movl REGOFF_RSP(%rsp), %ecx /* sysexit: %ecx -> %esp */ 1152 ALTENTRY(sys_sysenter_swapgs_sysexit) 1153 swapgs 1154 sti 1155 sysexitl 1156 SET_SIZE(sys_sysenter_swapgs_sysexit) 1157 SET_SIZE(sys_sysenter) 1158 SET_SIZE(_sys_sysenter_post_swapgs) 1159 SET_SIZE(brand_sys_sysenter) 1160 1161#endif /* __lint */ 1162 1163/* 1164 * This is the destination of the "int $T_SYSCALLINT" interrupt gate, used by 1165 * the generic i386 libc to do system calls. We do a small amount of setup 1166 * before jumping into the existing sys_syscall32 path. 1167 */ 1168#if defined(__lint) 1169 1170/*ARGSUSED*/ 1171void 1172sys_syscall_int() 1173{} 1174 1175#else /* __lint */ 1176 1177 ENTRY_NP(brand_sys_syscall_int) 1178 SWAPGS /* kernel gsbase */ 1179 XPV_TRAP_POP 1180 BRAND_CALLBACK(BRAND_CB_INT91, BRAND_URET_FROM_INTR_STACK()) 1181 jmp nopop_syscall_int 1182 1183 ALTENTRY(sys_syscall_int) 1184 SWAPGS /* kernel gsbase */ 1185 XPV_TRAP_POP 1186 1187nopop_syscall_int: 1188 movq %gs:CPU_THREAD, %r15 1189 movq T_STACK(%r15), %rsp 1190 movl %eax, %eax 1191 /* 1192 * Set t_post_sys on this thread to force ourselves out via the slow 1193 * path. It might be possible at some later date to optimize this out 1194 * and use a faster return mechanism. 1195 */ 1196 movb $1, T_POST_SYS(%r15) 1197 CLEAN_CS 1198 jmp _syscall32_save 1199 /* 1200 * There should be no instructions between this label and SWAPGS/IRET 1201 * or we could end up breaking branded zone support. See the usage of 1202 * this label in lx_brand_int80_callback and sn1_brand_int91_callback 1203 * for examples. 1204 */ 1205 ALTENTRY(sys_sysint_swapgs_iret) 1206 SWAPGS /* user gsbase */ 1207 IRET 1208 /*NOTREACHED*/ 1209 SET_SIZE(sys_sysint_swapgs_iret) 1210 SET_SIZE(sys_syscall_int) 1211 SET_SIZE(brand_sys_syscall_int) 1212 1213#endif /* __lint */ 1214 1215/* 1216 * Legacy 32-bit applications and old libc implementations do lcalls; 1217 * we should never get here because the LDT entry containing the syscall 1218 * segment descriptor has the "segment present" bit cleared, which means 1219 * we end up processing those system calls in trap() via a not-present trap. 1220 * 1221 * We do it this way because a call gate unhelpfully does -nothing- to the 1222 * interrupt flag bit, so an interrupt can run us just after the lcall 1223 * completes, but just before the swapgs takes effect. Thus the INTR_PUSH and 1224 * INTR_POP paths would have to be slightly more complex to dance around 1225 * this problem, and end up depending explicitly on the first 1226 * instruction of this handler being either swapgs or cli. 1227 */ 1228 1229#if defined(__lint) 1230 1231/*ARGSUSED*/ 1232void 1233sys_lcall32() 1234{} 1235 1236#else /* __lint */ 1237 1238 ENTRY_NP(sys_lcall32) 1239 SWAPGS /* kernel gsbase */ 1240 pushq $0 1241 pushq %rbp 1242 movq %rsp, %rbp 1243 leaq __lcall_panic_str(%rip), %rdi 1244 xorl %eax, %eax 1245 call panic 1246 SET_SIZE(sys_lcall32) 1247 1248__lcall_panic_str: 1249 .string "sys_lcall32: shouldn't be here!" 1250 1251/* 1252 * Declare a uintptr_t which covers the entire pc range of syscall 1253 * handlers for the stack walkers that need this. 1254 */ 1255 .align CPTRSIZE 1256 .globl _allsyscalls_size 1257 .type _allsyscalls_size, @object 1258_allsyscalls_size: 1259 .NWORD . - _allsyscalls 1260 SET_SIZE(_allsyscalls_size) 1261 1262#endif /* __lint */ 1263 1264/* 1265 * These are the thread context handlers for lwps using sysenter/sysexit. 1266 */ 1267 1268#if defined(__lint) 1269 1270/*ARGSUSED*/ 1271void 1272sep_save(void *ksp) 1273{} 1274 1275/*ARGSUSED*/ 1276void 1277sep_restore(void *ksp) 1278{} 1279 1280#else /* __lint */ 1281 1282 /* 1283 * setting this value to zero as we switch away causes the 1284 * stack-pointer-on-sysenter to be NULL, ensuring that we 1285 * don't silently corrupt another (preempted) thread stack 1286 * when running an lwp that (somehow) didn't get sep_restore'd 1287 */ 1288 ENTRY_NP(sep_save) 1289 xorl %edx, %edx 1290 xorl %eax, %eax 1291 movl $MSR_INTC_SEP_ESP, %ecx 1292 wrmsr 1293 ret 1294 SET_SIZE(sep_save) 1295 1296 /* 1297 * Update the kernel stack pointer as we resume onto this cpu. 1298 */ 1299 ENTRY_NP(sep_restore) 1300 movq %rdi, %rdx 1301 shrq $32, %rdx 1302 movl %edi, %eax 1303 movl $MSR_INTC_SEP_ESP, %ecx 1304 wrmsr 1305 ret 1306 SET_SIZE(sep_restore) 1307 1308#endif /* __lint */ 1309