osfmk/i386/pcb_native.c

   1 /*
   2  * Copyright (c) 2000-2012 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 /*
  29  * @OSF_COPYRIGHT@
  30  */
  31 /*
  32  * Mach Operating System
  33  * Copyright (c) 1991,1990 Carnegie Mellon University
  34  * All Rights Reserved.
  35  *
  36  * Permission to use, copy, modify and distribute this software and its
  37  * documentation is hereby granted, provided that both the copyright
  38  * notice and this permission notice appear in all copies of the
  39  * software, derivative works or modified versions, and any portions
  40  * thereof, and that both notices appear in supporting documentation.
  41  *
  42  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  43  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  44  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  45  *
  46  * Carnegie Mellon requests users of this software to return to
  47  *
  48  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  49  *  School of Computer Science
  50  *  Carnegie Mellon University
  51  *  Pittsburgh PA 15213-3890
  52  *
  53  * any improvements or extensions that they make and grant Carnegie Mellon
  54  * the rights to redistribute these changes.
  55  */
  56
  57 #include <mach_debug.h>
  58 #include <mach_ldebug.h>
  59
  60 #include <sys/kdebug.h>
  61
  62 #include <mach/kern_return.h>
  63 #include <mach/thread_status.h>
  64 #include <mach/vm_param.h>
  65
  66 #include <kern/counters.h>
  67 #include <kern/kalloc.h>
  68 #include <kern/mach_param.h>
  69 #include <kern/processor.h>
  70 #include <kern/cpu_data.h>
  71 #include <kern/cpu_number.h>
  72 #include <kern/task.h>
  73 #include <kern/thread.h>
  74 #include <kern/sched_prim.h>
  75 #include <kern/misc_protos.h>
  76 #include <kern/assert.h>
  77 #include <kern/spl.h>
  78 #include <kern/machine.h>
  79 #include <ipc/ipc_port.h>
  80 #include <vm/vm_kern.h>
  81 #include <vm/vm_map.h>
  82 #include <vm/pmap.h>
  83 #include <vm/vm_protos.h>
  84
  85 #include <i386/commpage/commpage.h>
  86 #include <i386/cpu_data.h>
  87 #include <i386/cpu_number.h>
  88 #include <i386/eflags.h>
  89 #include <i386/proc_reg.h>
  90 #include <i386/tss.h>
  91 #include <i386/user_ldt.h>
  92 #include <i386/fpu.h>
  93 #include <i386/mp_desc.h>
  94 #include <i386/misc_protos.h>
  95 #include <i386/thread.h>
  96 #include <i386/seg.h>
  97 #include <i386/machine_routines.h>
  98
  99 #if HYPERVISOR
 100 #include <kern/hv_support.h>
 101 #endif
 102
 103 #define ASSERT_IS_16BYTE_MULTIPLE_SIZEOF(_type_)        \
 104 extern char assert_is_16byte_multiple_sizeof_ ## _type_ \
 105                 [(sizeof(_type_) % 16) == 0 ? 1 : -1]
 106
 107 /* Compile-time checks for vital save area sizing: */
 108 ASSERT_IS_16BYTE_MULTIPLE_SIZEOF(x86_64_intr_stack_frame_t);
 109 ASSERT_IS_16BYTE_MULTIPLE_SIZEOF(x86_saved_state_t);
 110
 111 #define DIRECTION_FLAG_DEBUG (DEBUG | DEVELOPMENT)
 112
 113 extern zone_t           iss_zone;               /* zone for saved_state area */
 114 extern zone_t           ids_zone;               /* zone for debug_state area */
 115
 116 void
 117 act_machine_switch_pcb(__unused thread_t old, thread_t new)
 118 {
 119         pcb_t                   pcb = THREAD_TO_PCB(new);
 120         cpu_data_t              *cdp = current_cpu_datap();
 121         struct real_descriptor  *ldtp;
 122         mach_vm_offset_t        pcb_stack_top;
 123
 124         assert(new->kernel_stack != 0);
 125         assert(ml_get_interrupts_enabled() == FALSE);
 126 #ifdef  DIRECTION_FLAG_DEBUG
 127         if (x86_get_flags() & EFL_DF) {
 128                 panic("Direction flag detected: 0x%lx", x86_get_flags());
 129         }
 130 #endif
 131
 132         /*
 133          * Clear segment state
 134          * unconditionally for DS/ES/FS but more carefully for GS whose
 135          * cached state we track.
 136          */
 137         set_ds(NULL_SEG);
 138         set_es(NULL_SEG);
 139         set_fs(NULL_SEG);
 140
 141         if (get_gs() != NULL_SEG) {
 142                 swapgs();               /* switch to user's GS context */
 143                 set_gs(NULL_SEG);
 144                 swapgs();               /* and back to kernel */
 145
 146                 /* record the active machine state lost */
 147                 cdp->cpu_uber.cu_user_gs_base = 0;
 148         }
 149
 150         vm_offset_t                     isf;
 151
 152         /*
 153          * Set pointer to PCB's interrupt stack frame in cpu data.
 154          * Used by syscall and double-fault trap handlers.
 155          */
 156         isf = (vm_offset_t) &pcb->iss->ss_64.isf;
 157         cdp->cpu_uber.cu_isf = isf;
 158         pcb_stack_top = (vm_offset_t) (pcb->iss + 1);
 159         /* require 16-byte alignment */
 160         assert((pcb_stack_top & 0xF) == 0);
 161
 162         current_ktss64()->rsp0 = cdp->cpu_desc_index.cdi_sstku;
 163         /*
 164          * Top of temporary sysenter stack points to pcb stack.
 165          * Although this is not normally used by 64-bit users,
 166          * it needs to be set in case a sysenter is attempted.
 167          */
 168         *current_sstk64() = pcb_stack_top;
 169
 170         cdp->cd_estack = cpu_shadowp(cdp->cpu_number)->cd_estack = cdp->cpu_desc_index.cdi_sstku;
 171
 172         if (is_saved_state64(pcb->iss)) {
 173
 174                 cdp->cpu_task_map = new->map->pmap->pm_task_map;
 175
 176                 /*
 177                  * Enable the 64-bit user code segment, USER64_CS.
 178                  * Disable the 32-bit user code segment, USER_CS.
 179                  */
 180                 gdt_desc_p(USER64_CS)->access |= ACC_PL_U;
 181                 gdt_desc_p(USER_CS)->access &= ~ACC_PL_U;
 182
 183                 /*
 184                  * Switch user's GS base if necessary
 185                  * by setting the Kernel's GS base MSR
 186                  * - this will become the user's on the swapgs when
 187                  * returning to user-space.  Avoid this for
 188                  * kernel threads (no user TLS support required)
 189                  * and verify the memory shadow of the segment base
 190                  * in the event it was altered in user space.
 191                  */
 192                 if ((pcb->cthread_self != 0) || (new->task != kernel_task)) {
 193                         if ((cdp->cpu_uber.cu_user_gs_base != pcb->cthread_self) ||
 194                             (pcb->cthread_self != rdmsr64(MSR_IA32_KERNEL_GS_BASE))) {
 195                                 cdp->cpu_uber.cu_user_gs_base = pcb->cthread_self;
 196                                 wrmsr64(MSR_IA32_KERNEL_GS_BASE, pcb->cthread_self);
 197                         }
 198                 }
 199         } else {
 200
 201                 cdp->cpu_task_map = TASK_MAP_32BIT;
 202
 203                 /*
 204                  * Disable USER64_CS
 205                  * Enable USER_CS
 206                  */
 207
 208                 /* It's possible that writing to the GDT areas
 209                  * is expensive, if the processor intercepts those
 210                  * writes to invalidate its internal segment caches
 211                  * TODO: perhaps only do this if switching bitness
 212                  */
 213                 gdt_desc_p(USER64_CS)->access &= ~ACC_PL_U;
 214                 gdt_desc_p(USER_CS)->access |= ACC_PL_U;
 215
 216                 /*
 217                  * Set the thread`s cthread (a.k.a pthread)
 218                  * For 32-bit user this involves setting the USER_CTHREAD
 219                  * descriptor in the LDT to point to the cthread data.
 220                  * The involves copying in the pre-initialized descriptor.
 221                  */
 222                 ldtp = (struct real_descriptor *)current_ldt();
 223                 ldtp[sel_idx(USER_CTHREAD)] = pcb->cthread_desc;
 224                 if (pcb->uldt_selector != 0)
 225                         ldtp[sel_idx(pcb->uldt_selector)] = pcb->uldt_desc;
 226                 cdp->cpu_uber.cu_user_gs_base = pcb->cthread_self;
 227
 228                 /*
 229                  * Set the thread`s LDT or LDT entry.
 230                  */
 231                 if (new->task == TASK_NULL || new->task->i386_ldt == 0) {
 232                         /*
 233                          * Use system LDT.
 234                          */
 235                         ml_cpu_set_ldt(KERNEL_LDT);
 236                 } else {
 237                         /*
 238                          * Task has its own LDT.
 239                          */
 240                         user_ldt_set(new);
 241                 }
 242         }
 243
 244         /*
 245          * Bump the scheduler generation count in the commpage.
 246          * This can be read by user code to detect its preemption.
 247          */
 248         commpage_sched_gen_inc();
 249 }
 250
 251 kern_return_t
 252 thread_set_wq_state32(thread_t thread, thread_state_t tstate)
 253 {
 254         x86_thread_state32_t    *state;
 255         x86_saved_state32_t     *saved_state;
 256         thread_t curth = current_thread();
 257         spl_t                   s=0;
 258
 259         pal_register_cache_state(thread, DIRTY);
 260
 261         saved_state = USER_REGS32(thread);
 262
 263         state = (x86_thread_state32_t *)tstate;
 264
 265         if (curth != thread) {
 266                 s = splsched();
 267                 thread_lock(thread);
 268         }
 269
 270         saved_state->ebp = 0;
 271         saved_state->eip = state->eip;
 272         saved_state->eax = state->eax;
 273         saved_state->ebx = state->ebx;
 274         saved_state->ecx = state->ecx;
 275         saved_state->edx = state->edx;
 276         saved_state->edi = state->edi;
 277         saved_state->esi = state->esi;
 278         saved_state->uesp = state->esp;
 279         saved_state->efl = EFL_USER_SET;
 280
 281         saved_state->cs = USER_CS;
 282         saved_state->ss = USER_DS;
 283         saved_state->ds = USER_DS;
 284         saved_state->es = USER_DS;
 285
 286         if (curth != thread) {
 287                 thread_unlock(thread);
 288                 splx(s);
 289         }
 290
 291         return KERN_SUCCESS;
 292 }
 293
 294
 295 kern_return_t
 296 thread_set_wq_state64(thread_t thread, thread_state_t tstate)
 297 {
 298         x86_thread_state64_t    *state;
 299         x86_saved_state64_t     *saved_state;
 300         thread_t curth = current_thread();
 301         spl_t                   s=0;
 302
 303         saved_state = USER_REGS64(thread);
 304         state = (x86_thread_state64_t *)tstate;
 305
 306         /* Disallow setting non-canonical PC or stack */
 307         if (!IS_USERADDR64_CANONICAL(state->rsp) ||
 308             !IS_USERADDR64_CANONICAL(state->rip)) {
 309                 return KERN_FAILURE;
 310         }
 311
 312         pal_register_cache_state(thread, DIRTY);
 313
 314         if (curth != thread) {
 315                 s = splsched();
 316                 thread_lock(thread);
 317         }
 318
 319         saved_state->rbp = 0;
 320         saved_state->rdi = state->rdi;
 321         saved_state->rsi = state->rsi;
 322         saved_state->rdx = state->rdx;
 323         saved_state->rcx = state->rcx;
 324         saved_state->r8  = state->r8;
 325         saved_state->r9  = state->r9;
 326
 327         saved_state->isf.rip = state->rip;
 328         saved_state->isf.rsp = state->rsp;
 329         saved_state->isf.cs = USER64_CS;
 330         saved_state->isf.rflags = EFL_USER_SET;
 331
 332         if (curth != thread) {
 333                 thread_unlock(thread);
 334                 splx(s);
 335         }
 336
 337         return KERN_SUCCESS;
 338 }
 339
 340 /*
 341  * Initialize the machine-dependent state for a new thread.
 342  */
 343 kern_return_t
 344 machine_thread_create(
 345         thread_t                thread,
 346         task_t                  task)
 347 {
 348         pcb_t                   pcb = THREAD_TO_PCB(thread);
 349
 350 #if NCOPY_WINDOWS > 0
 351         inval_copy_windows(thread);
 352
 353         thread->machine.physwindow_pte = 0;
 354         thread->machine.physwindow_busy = 0;
 355 #endif
 356
 357         /*
 358          * Allocate save frame only if required.
 359          */
 360         if (pcb->iss == NULL) {
 361                 assert((get_preemption_level() == 0));
 362                 pcb->iss = (x86_saved_state_t *) zalloc(iss_zone);
 363                 if (pcb->iss == NULL)
 364                         panic("iss_zone");
 365         }
 366
 367         /*
 368          * Ensure that the synthesized 32-bit state including
 369          * the 64-bit interrupt state can be acommodated in the
 370          * 64-bit state we allocate for both 32-bit and 64-bit threads.
 371          */
 372         assert(sizeof(pcb->iss->ss_32) + sizeof(pcb->iss->ss_64.isf) <=
 373                sizeof(pcb->iss->ss_64));
 374
 375         bzero((char *)pcb->iss, sizeof(x86_saved_state_t));
 376
 377         if (task_has_64Bit_addr(task)) {
 378                 pcb->iss->flavor = x86_SAVED_STATE64;
 379
 380                 pcb->iss->ss_64.isf.cs = USER64_CS;
 381                 pcb->iss->ss_64.isf.ss = USER_DS;
 382                 pcb->iss->ss_64.fs = USER_DS;
 383                 pcb->iss->ss_64.gs = USER_DS;
 384                 pcb->iss->ss_64.isf.rflags = EFL_USER_SET;
 385         } else {
 386                 pcb->iss->flavor = x86_SAVED_STATE32;
 387
 388                 pcb->iss->ss_32.cs = USER_CS;
 389                 pcb->iss->ss_32.ss = USER_DS;
 390                 pcb->iss->ss_32.ds = USER_DS;
 391                 pcb->iss->ss_32.es = USER_DS;
 392                 pcb->iss->ss_32.fs = USER_DS;
 393                 pcb->iss->ss_32.gs = USER_DS;
 394                 pcb->iss->ss_32.efl = EFL_USER_SET;
 395         }
 396
 397         simple_lock_init(&pcb->lock, 0);
 398
 399         pcb->cthread_self = 0;
 400         pcb->uldt_selector = 0;
 401         pcb->thread_gpu_ns = 0;
 402         /* Ensure that the "cthread" descriptor describes a valid
 403          * segment.
 404          */
 405         if ((pcb->cthread_desc.access & ACC_P) == 0) {
 406                 pcb->cthread_desc = *gdt_desc_p(USER_DS);
 407         }
 408
 409         return(KERN_SUCCESS);
 410 }
 411
 412 /*
 413  * Machine-dependent cleanup prior to destroying a thread
 414  */
 415 void
 416 machine_thread_destroy(
 417         thread_t                thread)
 418 {
 419         pcb_t   pcb = THREAD_TO_PCB(thread);
 420
 421 #if HYPERVISOR
 422         if (thread->hv_thread_target) {
 423                 hv_callbacks.thread_destroy(thread->hv_thread_target);
 424                 thread->hv_thread_target = NULL;
 425         }
 426 #endif
 427
 428         if (pcb->ifps != 0)
 429                 fpu_free(thread, pcb->ifps);
 430         if (pcb->iss != 0) {
 431                 zfree(iss_zone, pcb->iss);
 432                 pcb->iss = 0;
 433         }
 434         if (pcb->ids) {
 435                 zfree(ids_zone, pcb->ids);
 436                 pcb->ids = NULL;
 437         }
 438 }
 439
 440 kern_return_t
 441 machine_thread_set_tsd_base(
 442         thread_t                        thread,
 443         mach_vm_offset_t        tsd_base)
 444 {
 445
 446         if (thread->task == kernel_task) {
 447                 return KERN_INVALID_ARGUMENT;
 448         }
 449
 450         if (thread_is_64bit_addr(thread)) {
 451                 /* check for canonical address, set 0 otherwise  */
 452                 if (!IS_USERADDR64_CANONICAL(tsd_base))
 453                         tsd_base = 0ULL;
 454         } else {
 455                 if (tsd_base > UINT32_MAX)
 456                         tsd_base = 0ULL;
 457         }
 458
 459         pcb_t pcb = THREAD_TO_PCB(thread);
 460         pcb->cthread_self = tsd_base;
 461
 462         if (!thread_is_64bit_addr(thread)) {
 463                 /* Set up descriptor for later use */
 464                 struct real_descriptor desc = {
 465                         .limit_low = 1,
 466                         .limit_high = 0,
 467                         .base_low = tsd_base & 0xffff,
 468                         .base_med = (tsd_base >> 16) & 0xff,
 469                         .base_high = (tsd_base >> 24) & 0xff,
 470                         .access = ACC_P|ACC_PL_U|ACC_DATA_W,
 471                         .granularity = SZ_32|SZ_G,
 472                 };
 473
 474                 pcb->cthread_desc = desc;
 475                 saved_state32(pcb->iss)->gs = USER_CTHREAD;
 476         }
 477
 478         /* For current thread, make the TSD base active immediately */
 479         if (thread == current_thread()) {
 480
 481                 if (thread_is_64bit_addr(thread)) {
 482                         cpu_data_t              *cdp;
 483
 484                         mp_disable_preemption();
 485                         cdp = current_cpu_datap();
 486                         if ((cdp->cpu_uber.cu_user_gs_base != pcb->cthread_self) ||
 487                                 (pcb->cthread_self != rdmsr64(MSR_IA32_KERNEL_GS_BASE)))
 488                                 wrmsr64(MSR_IA32_KERNEL_GS_BASE, tsd_base);
 489                         cdp->cpu_uber.cu_user_gs_base = tsd_base;
 490                         mp_enable_preemption();
 491                 } else {
 492
 493                         /* assign descriptor */
 494                         mp_disable_preemption();
 495                         *ldt_desc_p(USER_CTHREAD) = pcb->cthread_desc;
 496                         mp_enable_preemption();
 497                 }
 498         }
 499
 500         return KERN_SUCCESS;
 501 }