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. Neither the name of the University nor the names of its contributors 52 * may be used to endorse or promote products derived from this software 53 * without specific prior written permission. 54 * 55 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 56 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 57 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 58 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 59 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 60 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 61 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 62 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 63 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 64 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 65 * SUCH DAMAGE. 66 * 67 * @(#)ipl.s 68 * 69 * $FreeBSD: src/sys/i386/isa/ipl.s,v 1.32.2.3 2002/05/16 16:03:56 bde Exp $ 70 */ 71 72#include <machine/asmacros.h> 73#include <machine/segments.h> 74#include <machine/ipl.h> 75#include <machine/lock.h> 76#include <machine/psl.h> 77#include <machine/trap.h> 78 79#include "assym.s" 80 81/* 82 * AT/386 83 * Vector interrupt control section 84 * 85 * ipending - Pending interrupts (set when a masked interrupt occurs) 86 * spending - Pending software interrupts 87 */ 88 .data 89 ALIGN_DATA 90 91 .globl fastunpend_count 92fastunpend_count: .long 0 93 94 .text 95 SUPERALIGN_TEXT 96 97 /* 98 * GENERAL NOTES 99 * 100 * - interrupts are always called with a critical section held 101 * 102 * - we release our critical section when scheduling interrupt 103 * or softinterrupt threads in order so they can preempt 104 * (unless we are called manually from a critical section, in 105 * which case there will still be a critical section and 106 * they won't preempt anyway). 107 * 108 * - TD_NEST_COUNT prevents splz from nesting too deeply within 109 * itself. It is *not* actually an interrupt nesting count. 110 * PCPU(intr_nesting_level) is an interrupt nesting count. 111 * 112 * - We have to be careful in regards to local interrupts 113 * occuring simultaniously with our doreti and splz 114 * processing. 115 * 116 * - Interrupts must be enabled when calling higher level 117 * functions in order to avoid deadlocking against things 118 * like smp_invltlb. 119 */ 120 121 /* 122 * DORETI 123 * 124 * Handle return from interrupts, traps and syscalls. This function 125 * checks the cpl for unmasked pending interrupts (hardware or soft) 126 * and schedules them if appropriate, then irets. 127 * 128 * If we are in a critical section we cannot run any pending ints. 129 * 130 * The stack contains a trapframe at the start of doreti. 131 */ 132 SUPERALIGN_TEXT 133 .globl doreti 134 .type doreti,@function 135doreti: 136 FAKE_MCOUNT(bintr) /* init "from" bintr -> doreti */ 137 movq $0,%rax /* irq mask unavailable due to BGL */ 138 movq PCPU(curthread),%rbx 139 cli /* interlock with critical section */ 140 cmpl $0,PCPU(reqflags) /* short cut if nothing to do */ 141 je 5f 142 testl $-1,TD_CRITCOUNT(%rbx) /* can't unpend if in critical sec */ 143 jne 5f 144 incl TD_CRITCOUNT(%rbx) /* force all ints to pending */ 145doreti_next: 146 cli /* re-assert cli on loop */ 147 movq %rax,%rcx /* irq mask unavailable due to BGL */ 148 notq %rcx 149 testl $RQF_IPIQ,PCPU(reqflags) 150 jnz doreti_ipiq 151 testl $RQF_TIMER,PCPU(reqflags) 152 jnz doreti_timer 153 /* 154 * check for an unmasked int (3 groups) 155 */ 156 movq $0,%rdx 157 testq PCPU_E8(ipending,%rdx),%rcx 158 jnz doreti_fast 159 160 movq $1,%rdx 161 testq PCPU_E8(ipending,%rdx),%rcx 162 jnz doreti_fast 163 164 movq $2,%rdx 165 testq PCPU_E8(ipending,%rdx),%rcx 166 jnz doreti_fast 167 168 movl PCPU(spending),%ecx /* check for a pending software int */ 169 cmpl $0,%ecx 170 jnz doreti_soft 171 172 testl $RQF_AST_MASK,PCPU(reqflags) /* any pending ASTs? */ 173 jz 2f 174 175 /* ASTs are only applicable when returning to userland */ 176 testb $SEL_RPL_MASK,TF_CS(%rsp) 177 jnz doreti_ast 1782: 179 /* 180 * Nothing left to do, finish up. Interrupts are still disabled. 181 * %eax contains the mask of IRQ's that are not available due to 182 * BGL requirements. We can only clear RQF_INTPEND if *ALL* pending 183 * interrupts have been processed. 184 */ 185 decl TD_CRITCOUNT(%rbx) /* interlocked with cli */ 186 testl %eax,%eax 187 jnz 5f 188 andl $~RQF_INTPEND,PCPU(reqflags) 1895: 190 MEXITCOUNT 191 192 /* 193 * (interrupts are disabled here) 194 * 195 * Restore register and iret. iret can fault on %rip (which is 196 * really stupid). If this occurs we re-fault and vector to 197 * doreti_iret_fault(). 198 * 199 * ... 200 * can be set from user mode, this can result in a kernel mode 201 * exception. The trap code will revector to the *_fault code 202 * which then sets up a T_PROTFLT signal. If the signal is 203 * sent to userland, sendsig() will automatically clean up all 204 * the segment registers to avoid a loop. 205 */ 206 .globl doreti_iret 207 .globl doreti_syscall_ret 208doreti_syscall_ret: 209 POP_FRAME() /* registers and %gs (+cli) */ 210 /* WARNING: special global doreti_iret is also used by exception.S */ 211doreti_iret: 212 iretq 213 214 /* 215 * doreti_iret_fault. Alternative return code for the case where 216 * we get a fault from iretq above. 217 * 218 * iretq -> IDT(prot) -> trap -> iretq -> doreti_iret_fault. 219 * 220 * The iretq above was trying to return to usermode and issued 221 * a KMMUEXIT, so it might be on the trampoline stack. We must 222 * issue a KMMUENTER to ensure that we are on the correct stack 223 * and have the correct mmu context. 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 KMMUENTER_TFRIP 233 subq $TF_RIP,%rsp 234 PUSH_FRAME_REGS 235 sti 236 movq $T_PROTFLT,TF_TRAPNO(%rsp) 237 movq $0,TF_ERR(%rsp) /* XXX should be the error code */ 238 movq $0,TF_ADDR(%rsp) 239 FAKE_MCOUNT(TF_RIP(%rsp)) 240 jmp calltrap 241 242 /* 243 * Interrupt pending. NOTE: stack context holds frame structure 244 * for interrupt procedure, do not do random pushes or pops! 245 */ 246 ALIGN_TEXT 247doreti_fast: 248 andq PCPU_E8(ipending,%rdx),%rcx 249 sti 250 bsfq %rcx, %rcx /* locate the next dispatchable int */ 251 btrq %rcx, PCPU_E8(ipending,%rdx) 252 /* is it really still pending? */ 253 jnc doreti_next 254 255 shlq $6, %rdx 256 orq %rdx, %rcx /* form intr number */ 257 258 pushq %rax /* save IRQ mask unavailable for BGL */ 259 /* NOTE: is also CPL in frame */ 260 call dofastunpend /* unpend intr %rcx */ 261 popq %rax 262 jmp doreti_next 263 264 /* 265 * SOFT interrupt pending 266 * 267 * Temporarily back-out our critical section to allow an interrupt 268 * preempt us when we schedule it. Bump intr_nesting_level to 269 * prevent the switch code from recursing via splz too deeply. 270 */ 271 ALIGN_TEXT 272doreti_soft: 273 sti 274 bsfl %ecx,%ecx /* locate the next pending softint */ 275 btrl %ecx,PCPU(spending) /* make sure its still pending */ 276 jnc doreti_next 277 addl $FIRST_SOFTINT,%ecx /* actual intr number */ 278 pushq %rax 279 movl %ecx,%edi /* argument to C call */ 280 incl TD_NEST_COUNT(%rbx) /* prevent doreti/splz nesting */ 281 decl TD_CRITCOUNT(%rbx) /* so we can preempt */ 282 call sched_ithd_soft /* YYY must pull in imasks */ 283 incl TD_CRITCOUNT(%rbx) 284 decl TD_NEST_COUNT(%rbx) 285 popq %rax 286 jmp doreti_next 287 288 /* 289 * AST pending. We clear RQF_AST_SIGNAL automatically, the others 290 * are cleared by the trap as they are processed. 291 * 292 * Temporarily back-out our critical section because trap() can be 293 * a long-winded call, and we want to be more syscall-like. 294 * 295 * YYY theoretically we can call lwkt_switch directly if all we need 296 * to do is a reschedule. 297 */ 298doreti_ast: 299 andl $~RQF_AST_SIGNAL,PCPU(reqflags) 300 sti 301 movl %eax,%r12d /* save cpl (can't use stack) */ 302 movl $T_ASTFLT,TF_TRAPNO(%rsp) 303 movq %rsp,%rdi /* pass frame by ref (%edi = C arg) */ 304 decl TD_CRITCOUNT(%rbx) 305 call trap 306 incl TD_CRITCOUNT(%rbx) 307 movl %r12d,%eax /* restore cpl for loop */ 308 jmp doreti_next 309 310 /* 311 * IPIQ message pending. We clear RQF_IPIQ automatically. 312 */ 313doreti_ipiq: 314 movl %eax,%r12d /* save cpl (can't use stack) */ 315 incl PCPU(intr_nesting_level) 316 andl $~RQF_IPIQ,PCPU(reqflags) 317 subq %rax,%rax 318 sti 319 xchgl %eax,PCPU(npoll) /* (atomic op) allow another Xipi */ 320 subq $8,%rsp /* trapframe->intrframe */ 321 movq %rsp,%rdi /* pass frame by ref (C arg) */ 322 call lwkt_process_ipiq_frame 323 addq $8,%rsp /* intrframe->trapframe */ 324 decl PCPU(intr_nesting_level) 325 movl %r12d,%eax /* restore cpl for loop */ 326 jmp doreti_next 327 328doreti_timer: 329 movl %eax,%r12d /* save cpl (can't use stack) */ 330 incl PCPU(intr_nesting_level) 331 andl $~RQF_TIMER,PCPU(reqflags) 332 sti 333 subq $8,%rsp /* trapframe->intrframe */ 334 movq %rsp,%rdi /* pass frame by ref (C arg) */ 335 call pcpu_timer_process_frame 336 addq $8,%rsp /* intrframe->trapframe */ 337 decl PCPU(intr_nesting_level) 338 movl %r12d,%eax /* restore cpl for loop */ 339 jmp doreti_next 340 341 /* 342 * SPLZ() a C callable procedure to dispatch any unmasked pending 343 * interrupts regardless of critical section nesting. ASTs 344 * are not dispatched. 345 * 346 * Use %eax to track those IRQs that could not be processed 347 * due to BGL requirements. 348 */ 349 SUPERALIGN_TEXT 350 351ENTRY(splz) 352 pushfq 353 pushq %rbx 354 movq PCPU(curthread),%rbx 355 incl TD_CRITCOUNT(%rbx) 356 movq $0,%rax 357 358splz_next: 359 cli 360 movq %rax,%rcx /* rcx = ~CPL */ 361 notq %rcx 362 testl $RQF_IPIQ,PCPU(reqflags) 363 jnz splz_ipiq 364 testl $RQF_TIMER,PCPU(reqflags) 365 jnz splz_timer 366 /* 367 * check for an unmasked int (3 groups) 368 */ 369 movq $0,%rdx 370 testq PCPU_E8(ipending,%rdx),%rcx 371 jnz splz_fast 372 373 movq $1,%rdx 374 testq PCPU_E8(ipending,%rdx),%rcx 375 jnz splz_fast 376 377 movq $2,%rdx 378 testq PCPU_E8(ipending,%rdx),%rcx 379 jnz splz_fast 380 381 movl PCPU(spending),%ecx 382 cmpl $0,%ecx 383 jnz splz_soft 384 385 decl TD_CRITCOUNT(%rbx) 386 387 /* 388 * Nothing left to do, finish up. Interrupts are still disabled. 389 * If our mask of IRQs we couldn't process due to BGL requirements 390 * is 0 then there are no pending interrupt sources left and we 391 * can clear RQF_INTPEND. 392 */ 393 testl %eax,%eax 394 jnz 5f 395 andl $~RQF_INTPEND,PCPU(reqflags) 3965: 397 popq %rbx 398 popfq 399 ret 400 401 /* 402 * Interrupt pending 403 */ 404 ALIGN_TEXT 405splz_fast: 406 andq PCPU_E8(ipending,%rdx),%rcx 407 sti 408 bsfq %rcx, %rcx /* locate the next dispatchable int */ 409 btrq %rcx, PCPU_E8(ipending,%rdx) 410 /* is it really still pending? */ 411 jnc splz_next 412 413 shlq $6, %rdx 414 orq %rdx, %rcx /* form intr number */ 415 416 pushq %rax 417 call dofastunpend /* unpend intr %rcx */ 418 popq %rax 419 jmp splz_next 420 421 /* 422 * SOFT interrupt pending 423 * 424 * Temporarily back-out our critical section to allow the interrupt 425 * preempt us. 426 */ 427 ALIGN_TEXT 428splz_soft: 429 sti 430 bsfl %ecx,%ecx /* locate the next pending softint */ 431 btrl %ecx,PCPU(spending) /* make sure its still pending */ 432 jnc splz_next 433 addl $FIRST_SOFTINT,%ecx /* actual intr number */ 434 sti 435 pushq %rax 436 movl %ecx,%edi /* C argument */ 437 incl TD_NEST_COUNT(%rbx) /* prevent doreti/splz nesting */ 438 decl TD_CRITCOUNT(%rbx) 439 call sched_ithd_soft /* YYY must pull in imasks */ 440 incl TD_CRITCOUNT(%rbx) 441 decl TD_NEST_COUNT(%rbx) /* prevent doreti/splz nesting */ 442 popq %rax 443 jmp splz_next 444 445splz_ipiq: 446 andl $~RQF_IPIQ,PCPU(reqflags) 447 sti 448 pushq %rax 449 subq %rax,%rax 450 xchgl %eax,PCPU(npoll) /* (atomic op) allow another Xipi */ 451 call lwkt_process_ipiq 452 popq %rax 453 jmp splz_next 454 455splz_timer: 456 andl $~RQF_TIMER,PCPU(reqflags) 457 sti 458 pushq %rax 459 call pcpu_timer_process 460 popq %rax 461 jmp splz_next 462 463 /* 464 * dofastunpend(%rcx:intr) 465 * 466 * A interrupt previously made pending can now be run, 467 * execute it by pushing a dummy interrupt frame and 468 * calling ithread_fast_handler to execute or schedule it. 469 * 470 * ithread_fast_handler() returns 0 if it wants us to unmask 471 * further interrupts. 472 */ 473#define PUSH_DUMMY \ 474 pushfq ; /* phys int frame / flags */ \ 475 xorq %rax,%rax ; /* something not SEL_UPL */ \ 476 pushq %rax ; /* phys int frame / cs */ \ 477 pushq 3*8(%rsp) ; /* original caller eip */ \ 478 subq $TF_RIP,%rsp ; /* trap frame */ \ 479 movq $0,TF_XFLAGS(%rsp) ; /* extras */ \ 480 movq $0,TF_TRAPNO(%rsp) ; /* extras */ \ 481 movq $0,TF_ADDR(%rsp) ; /* extras */ \ 482 movq $0,TF_FLAGS(%rsp) ; /* extras */ \ 483 movq $0,TF_ERR(%rsp) ; /* extras */ \ 484 485#define POP_DUMMY \ 486 addq $TF_RIP+(3*8),%rsp ; \ 487 488dofastunpend: 489 pushq %rbp /* frame for backtrace */ 490 movq %rsp,%rbp 491 PUSH_DUMMY 492 pushq %rcx /* last part of intrframe = intr */ 493 incl fastunpend_count 494 movq %rsp,%rdi /* pass frame by reference C arg */ 495 call ithread_fast_handler /* returns 0 to unmask */ 496 popq %rdi /* intrframe->trapframe */ 497 /* + also rdi C arg to next call */ 498 cmpl $0,%eax 499 jnz 1f 500 movq MachIntrABI + MACHINTR_INTREN, %rax 501 callq *%rax /* MachIntrABI.intren(intr) */ 5021: 503 POP_DUMMY 504 popq %rbp 505 ret 506 507