1/* 2 * Copyright (c) 2008 The DragonFly Project. All rights reserved. 3 * 4 * This code is derived from software contributed to The DragonFly Project 5 * by Matthew Dillon <dillon@backplane.com> 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in 15 * the documentation and/or other materials provided with the 16 * distribution. 17 * 3. Neither the name of The DragonFly Project nor the names of its 18 * contributors may be used to endorse or promote products derived 19 * from this software without specific, prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 25 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 26 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, 27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * --- 35 * 36 * Copyright (c) 1989, 1990 William F. Jolitz. 37 * Copyright (c) 1990 The Regents of the University of California. 38 * All rights reserved. 39 * 40 * This code is derived from software contributed to Berkeley by 41 * William Jolitz. 42 * 43 * Redistribution and use in source and binary forms, with or without 44 * modification, are permitted provided that the following conditions 45 * are met: 46 * 1. Redistributions of source code must retain the above copyright 47 * notice, this list of conditions and the following disclaimer. 48 * 2. Redistributions in binary form must reproduce the above copyright 49 * notice, this list of conditions and the following disclaimer in the 50 * documentation and/or other materials provided with the distribution. 51 * 3. All advertising materials mentioning features or use of this software 52 * must display the following acknowledgement: 53 * This product includes software developed by the University of 54 * California, Berkeley and its contributors. 55 * 4. Neither the name of the University nor the names of its contributors 56 * may be used to endorse or promote products derived from this software 57 * without specific prior written permission. 58 * 59 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 60 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 61 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 62 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 63 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 64 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 65 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 66 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 67 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 68 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 69 * SUCH DAMAGE. 70 * 71 * @(#)ipl.s 72 * 73 * $FreeBSD: src/sys/i386/isa/ipl.s,v 1.32.2.3 2002/05/16 16:03:56 bde Exp $ 74 */ 75 76#include <machine/asmacros.h> 77#include <machine/segments.h> 78#include <machine/ipl.h> 79#include <machine/lock.h> 80#include <machine/psl.h> 81#include <machine/trap.h> 82 83#include "assym.s" 84 85/* 86 * AT/386 87 * Vector interrupt control section 88 * 89 * ipending - Pending interrupts (set when a masked interrupt occurs) 90 * spending - Pending software interrupts 91 */ 92 .data 93 ALIGN_DATA 94 95 .globl fastunpend_count 96fastunpend_count: .long 0 97 98 .text 99 SUPERALIGN_TEXT 100 101 /* 102 * GENERAL NOTES 103 * 104 * - interrupts are always called with a critical section held 105 * 106 * - we release our critical section when scheduling interrupt 107 * or softinterrupt threads in order so they can preempt 108 * (unless we are called manually from a critical section, in 109 * which case there will still be a critical section and 110 * they won't preempt anyway). 111 * 112 * - TD_NEST_COUNT prevents splz from nesting too deeply within 113 * itself. It is *not* actually an interrupt nesting count. 114 * PCPU(intr_nesting_level) is an interrupt nesting count. 115 * 116 * - We have to be careful in regards to local interrupts 117 * occuring simultaniously with our doreti and splz 118 * processing. 119 * 120 * - Interrupts must be enabled when calling higher level 121 * functions in order to avoid deadlocking against things 122 * like smp_invltlb. 123 */ 124 125 /* 126 * DORETI 127 * 128 * Handle return from interrupts, traps and syscalls. This function 129 * checks the cpl for unmasked pending interrupts (hardware or soft) 130 * and schedules them if appropriate, then irets. 131 * 132 * If we are in a critical section we cannot run any pending ints. 133 * 134 * The stack contains a trapframe at the start of doreti. 135 */ 136 SUPERALIGN_TEXT 137 .globl doreti 138 .type doreti,@function 139doreti: 140 FAKE_MCOUNT(bintr) /* init "from" bintr -> doreti */ 141 movq $0,%rax /* irq mask unavailable due to BGL */ 142 movq PCPU(curthread),%rbx 143 cli /* interlock with critical section */ 144 cmpl $0,PCPU(reqflags) /* short cut if nothing to do */ 145 je 5f 146 testl $-1,TD_CRITCOUNT(%rbx) /* can't unpend if in critical sec */ 147 jne 5f 148 incl TD_CRITCOUNT(%rbx) /* force all ints to pending */ 149doreti_next: 150 cli /* re-assert cli on loop */ 151 movq %rax,%rcx /* irq mask unavailable due to BGL */ 152 notq %rcx 153 testl $RQF_IPIQ,PCPU(reqflags) 154 jnz doreti_ipiq 155 testl $RQF_TIMER,PCPU(reqflags) 156 jnz doreti_timer 157 /* 158 * check for an unmasked int (3 groups) 159 */ 160 movq $0,%rdx 161 testq PCPU_E8(ipending,%rdx),%rcx 162 jnz doreti_fast 163 164 movq $1,%rdx 165 testq PCPU_E8(ipending,%rdx),%rcx 166 jnz doreti_fast 167 168 movq $2,%rdx 169 testq PCPU_E8(ipending,%rdx),%rcx 170 jnz doreti_fast 171 172 movl PCPU(spending),%ecx /* check for a pending software int */ 173 cmpl $0,%ecx 174 jnz doreti_soft 175 176 testl $RQF_AST_MASK,PCPU(reqflags) /* any pending ASTs? */ 177 jz 2f 178 179 /* ASTs are only applicable when returning to userland */ 180 testb $SEL_RPL_MASK,TF_CS(%rsp) 181 jnz doreti_ast 1822: 183 /* 184 * Nothing left to do, finish up. Interrupts are still disabled. 185 * %eax contains the mask of IRQ's that are not available due to 186 * BGL requirements. We can only clear RQF_INTPEND if *ALL* pending 187 * interrupts have been processed. 188 */ 189 decl TD_CRITCOUNT(%rbx) /* interlocked with cli */ 190 testl %eax,%eax 191 jnz 5f 192 andl $~RQF_INTPEND,PCPU(reqflags) 1935: 194 MEXITCOUNT 195 196 /* 197 * (interrupts are disabled here) 198 * 199 * Restore register and iret. iret can fault on %rip (which is 200 * really stupid). If this occurs we re-fault and vector to 201 * doreti_iret_fault(). 202 * 203 * ... 204 * can be set from user mode, this can result in a kernel mode 205 * exception. The trap code will revector to the *_fault code 206 * which then sets up a T_PROTFLT signal. If the signal is 207 * sent to userland, sendsig() will automatically clean up all 208 * the segment registers to avoid a loop. 209 */ 210 .globl doreti_iret 211 .globl doreti_syscall_ret 212doreti_syscall_ret: 213 POP_FRAME /* registers and %gs (+cli) */ 214 /* WARNING: special global doreti_iret is also used by exception.S */ 215doreti_iret: 216 iretq 217 218 /* 219 * doreti_iret_fault. Alternative return code for the case where 220 * we get a fault in the doreti_exit code above. trap() 221 * (sys/platform/pc64/x86_64/trap.c) catches this specific * case, 222 * sends the process a signal and continues in the corresponding 223 * place in the code below. 224 * 225 * Interrupts are likely disabled due to the above interlock 226 * between cli/iretq. We must enable them before calling any 227 * high level function. 228 */ 229 ALIGN_TEXT 230 .globl doreti_iret_fault 231doreti_iret_fault: 232 PUSH_FRAME_NOSWAP 233 sti 234 movq $T_PROTFLT,TF_TRAPNO(%rsp) 235 movq $0,TF_ERR(%rsp) /* XXX should be the error code */ 236 movq $0,TF_ADDR(%rsp) 237 FAKE_MCOUNT(TF_RIP(%rsp)) 238 jmp calltrap 239 240 /* 241 * Interrupt pending. NOTE: stack context holds frame structure 242 * for interrupt procedure, do not do random pushes or pops! 243 */ 244 ALIGN_TEXT 245doreti_fast: 246 andq PCPU_E8(ipending,%rdx),%rcx 247 sti 248 bsfq %rcx, %rcx /* locate the next dispatchable int */ 249 btrq %rcx, PCPU_E8(ipending,%rdx) 250 /* is it really still pending? */ 251 jnc doreti_next 252 253 shlq $6, %rdx 254 orq %rdx, %rcx /* form intr number */ 255 256 pushq %rax /* save IRQ mask unavailable for BGL */ 257 /* NOTE: is also CPL in frame */ 258 call dofastunpend /* unpend intr %rcx */ 259 popq %rax 260 jmp doreti_next 261 262 /* 263 * SOFT interrupt pending 264 * 265 * Temporarily back-out our critical section to allow an interrupt 266 * preempt us when we schedule it. Bump intr_nesting_level to 267 * prevent the switch code from recursing via splz too deeply. 268 */ 269 ALIGN_TEXT 270doreti_soft: 271 sti 272 bsfl %ecx,%ecx /* locate the next pending softint */ 273 btrl %ecx,PCPU(spending) /* make sure its still pending */ 274 jnc doreti_next 275 addl $FIRST_SOFTINT,%ecx /* actual intr number */ 276 pushq %rax 277 movl %ecx,%edi /* argument to C call */ 278 incl TD_NEST_COUNT(%rbx) /* prevent doreti/splz nesting */ 279 decl TD_CRITCOUNT(%rbx) /* so we can preempt */ 280 call sched_ithd_soft /* YYY must pull in imasks */ 281 incl TD_CRITCOUNT(%rbx) 282 decl TD_NEST_COUNT(%rbx) 283 popq %rax 284 jmp doreti_next 285 286 /* 287 * AST pending. We clear RQF_AST_SIGNAL automatically, the others 288 * are cleared by the trap as they are processed. 289 * 290 * Temporarily back-out our critical section because trap() can be 291 * a long-winded call, and we want to be more syscall-like. 292 * 293 * YYY theoretically we can call lwkt_switch directly if all we need 294 * to do is a reschedule. 295 */ 296doreti_ast: 297 andl $~(RQF_AST_SIGNAL|RQF_AST_UPCALL),PCPU(reqflags) 298 sti 299 movl %eax,%r12d /* save cpl (can't use stack) */ 300 movl $T_ASTFLT,TF_TRAPNO(%rsp) 301 movq %rsp,%rdi /* pass frame by ref (%edi = C arg) */ 302 decl TD_CRITCOUNT(%rbx) 303 call trap 304 incl TD_CRITCOUNT(%rbx) 305 movl %r12d,%eax /* restore cpl for loop */ 306 jmp doreti_next 307 308 /* 309 * IPIQ message pending. We clear RQF_IPIQ automatically. 310 */ 311doreti_ipiq: 312 movl %eax,%r12d /* save cpl (can't use stack) */ 313 incl PCPU(intr_nesting_level) 314 andl $~RQF_IPIQ,PCPU(reqflags) 315 sti 316 subq $8,%rsp /* trapframe->intrframe */ 317 movq %rsp,%rdi /* pass frame by ref (C arg) */ 318 call lwkt_process_ipiq_frame 319 addq $8,%rsp /* intrframe->trapframe */ 320 decl PCPU(intr_nesting_level) 321 movl %r12d,%eax /* restore cpl for loop */ 322 jmp doreti_next 323 324doreti_timer: 325 movl %eax,%r12d /* save cpl (can't use stack) */ 326 incl PCPU(intr_nesting_level) 327 andl $~RQF_TIMER,PCPU(reqflags) 328 sti 329 subq $8,%rsp /* trapframe->intrframe */ 330 movq %rsp,%rdi /* pass frame by ref (C arg) */ 331 call lapic_timer_process_frame 332 addq $8,%rsp /* intrframe->trapframe */ 333 decl PCPU(intr_nesting_level) 334 movl %r12d,%eax /* restore cpl for loop */ 335 jmp doreti_next 336 337 /* 338 * SPLZ() a C callable procedure to dispatch any unmasked pending 339 * interrupts regardless of critical section nesting. ASTs 340 * are not dispatched. 341 * 342 * Use %eax to track those IRQs that could not be processed 343 * due to BGL requirements. 344 */ 345 SUPERALIGN_TEXT 346 347ENTRY(splz) 348 pushfq 349 pushq %rbx 350 movq PCPU(curthread),%rbx 351 incl TD_CRITCOUNT(%rbx) 352 movq $0,%rax 353 354splz_next: 355 cli 356 movq %rax,%rcx /* rcx = ~CPL */ 357 notq %rcx 358 testl $RQF_IPIQ,PCPU(reqflags) 359 jnz splz_ipiq 360 testl $RQF_TIMER,PCPU(reqflags) 361 jnz splz_timer 362 /* 363 * check for an unmasked int (3 groups) 364 */ 365 movq $0,%rdx 366 testq PCPU_E8(ipending,%rdx),%rcx 367 jnz splz_fast 368 369 movq $1,%rdx 370 testq PCPU_E8(ipending,%rdx),%rcx 371 jnz splz_fast 372 373 movq $2,%rdx 374 testq PCPU_E8(ipending,%rdx),%rcx 375 jnz splz_fast 376 377 movl PCPU(spending),%ecx 378 cmpl $0,%ecx 379 jnz splz_soft 380 381 decl TD_CRITCOUNT(%rbx) 382 383 /* 384 * Nothing left to do, finish up. Interrupts are still disabled. 385 * If our mask of IRQs we couldn't process due to BGL requirements 386 * is 0 then there are no pending interrupt sources left and we 387 * can clear RQF_INTPEND. 388 */ 389 testl %eax,%eax 390 jnz 5f 391 andl $~RQF_INTPEND,PCPU(reqflags) 3925: 393 popq %rbx 394 popfq 395 ret 396 397 /* 398 * Interrupt pending 399 */ 400 ALIGN_TEXT 401splz_fast: 402 andq PCPU_E8(ipending,%rdx),%rcx 403 sti 404 bsfq %rcx, %rcx /* locate the next dispatchable int */ 405 btrq %rcx, PCPU_E8(ipending,%rdx) 406 /* is it really still pending? */ 407 jnc splz_next 408 409 shlq $6, %rdx 410 orq %rdx, %rcx /* form intr number */ 411 412 pushq %rax 413 call dofastunpend /* unpend intr %rcx */ 414 popq %rax 415 jmp splz_next 416 417 /* 418 * SOFT interrupt pending 419 * 420 * Temporarily back-out our critical section to allow the interrupt 421 * preempt us. 422 */ 423 ALIGN_TEXT 424splz_soft: 425 sti 426 bsfl %ecx,%ecx /* locate the next pending softint */ 427 btrl %ecx,PCPU(spending) /* make sure its still pending */ 428 jnc splz_next 429 addl $FIRST_SOFTINT,%ecx /* actual intr number */ 430 sti 431 pushq %rax 432 movl %ecx,%edi /* C argument */ 433 incl TD_NEST_COUNT(%rbx) /* prevent doreti/splz nesting */ 434 decl TD_CRITCOUNT(%rbx) 435 call sched_ithd_soft /* YYY must pull in imasks */ 436 incl TD_CRITCOUNT(%rbx) 437 decl TD_NEST_COUNT(%rbx) /* prevent doreti/splz nesting */ 438 popq %rax 439 jmp splz_next 440 441splz_ipiq: 442 andl $~RQF_IPIQ,PCPU(reqflags) 443 sti 444 pushq %rax 445 call lwkt_process_ipiq 446 popq %rax 447 jmp splz_next 448 449splz_timer: 450 andl $~RQF_TIMER,PCPU(reqflags) 451 sti 452 pushq %rax 453 call lapic_timer_process 454 popq %rax 455 jmp splz_next 456 457 /* 458 * dofastunpend(%rcx:intr) 459 * 460 * A interrupt previously made pending can now be run, 461 * execute it by pushing a dummy interrupt frame and 462 * calling ithread_fast_handler to execute or schedule it. 463 * 464 * ithread_fast_handler() returns 0 if it wants us to unmask 465 * further interrupts. 466 */ 467#define PUSH_DUMMY \ 468 pushfq ; /* phys int frame / flags */ \ 469 xorq %rax,%rax ; /* something not SEL_UPL */ \ 470 pushq %rax ; /* phys int frame / cs */ \ 471 pushq 3*8(%rsp) ; /* original caller eip */ \ 472 subq $TF_RIP,%rsp ; /* trap frame */ \ 473 movq $0,TF_XFLAGS(%rsp) ; /* extras */ \ 474 movq $0,TF_TRAPNO(%rsp) ; /* extras */ \ 475 movq $0,TF_ADDR(%rsp) ; /* extras */ \ 476 movq $0,TF_FLAGS(%rsp) ; /* extras */ \ 477 movq $0,TF_ERR(%rsp) ; /* extras */ \ 478 479#define POP_DUMMY \ 480 addq $TF_RIP+(3*8),%rsp ; \ 481 482dofastunpend: 483 pushq %rbp /* frame for backtrace */ 484 movq %rsp,%rbp 485 PUSH_DUMMY 486 pushq %rcx /* last part of intrframe = intr */ 487 incl fastunpend_count 488 movq %rsp,%rdi /* pass frame by reference C arg */ 489 call ithread_fast_handler /* returns 0 to unmask */ 490 popq %rdi /* intrframe->trapframe */ 491 /* + also rdi C arg to next call */ 492 cmpl $0,%eax 493 jnz 1f 494 movq MachIntrABI + MACHINTR_INTREN, %rax 495 callq *%rax /* MachIntrABI.intren(intr) */ 4961: 497 POP_DUMMY 498 popq %rbp 499 ret 500 501