src/runtime/x86-darwin-os.c

   1 #ifdef LISP_FEATURE_SB_THREAD
   2 #include <architecture/i386/table.h>
   3 #include <i386/user_ldt.h>
   4 #include <mach/mach_init.h>
   5 #endif
   6
   7 #include "thread.h"
   8 #include "validate.h"
   9 #include "runtime.h"
  10 #include "interrupt.h"
  11 #include "x86-darwin-os.h"
  12 #include "genesis/fdefn.h"
  13
  14 #include <mach/mach.h>
  15 #include <mach/mach_error.h>
  16 #include <mach/mach_types.h>
  17 #include <mach/sync_policy.h>
  18 #include <mach/vm_region.h>
  19 #include <mach/machine/thread_state.h>
  20 #include <mach/machine/thread_status.h>
  21 #include <sys/_types.h>
  22 #include <sys/ucontext.h>
  23 #include <pthread.h>
  24 #include <assert.h>
  25 #include <stdlib.h>
  26 #include <stdio.h>
  27
  28 #ifdef LISP_FEATURE_SB_THREAD
  29
  30 pthread_mutex_t modify_ldt_lock = PTHREAD_MUTEX_INITIALIZER;
  31
  32 void set_data_desc_size(data_desc_t* desc, unsigned long size)
  33 {
  34     desc->limit00 = (size - 1) & 0xffff;
  35     desc->limit16 = ((size - 1) >> 16) &0xf;
  36 }
  37
  38 void set_data_desc_addr(data_desc_t* desc, void* addr)
  39 {
  40     desc->base00 = (unsigned int)addr & 0xffff;
  41     desc->base16 = ((unsigned int)addr & 0xff0000) >> 16;
  42     desc->base24 = ((unsigned int)addr & 0xff000000) >> 24;
  43 }
  44
  45 #endif
  46
  47 int arch_os_thread_init(struct thread *thread) {
  48 #ifdef LISP_FEATURE_SB_THREAD
  49     int n;
  50     sel_t sel;
  51
  52     data_desc_t ldt_entry = { 0, 0, 0, DESC_DATA_WRITE,
  53                               3, 1, 0, DESC_DATA_32B, DESC_GRAN_BYTE, 0 };
  54
  55     set_data_desc_addr(&ldt_entry, thread);
  56     set_data_desc_size(&ldt_entry, dynamic_values_bytes);
  57
  58     thread_mutex_lock(&modify_ldt_lock);
  59     n = i386_set_ldt(LDT_AUTO_ALLOC, (union ldt_entry*) &ldt_entry, 1);
  60
  61     if (n < 0) {
  62         perror("i386_set_ldt");
  63         lose("unexpected i386_set_ldt(..) failure\n");
  64     }
  65     thread_mutex_unlock(&modify_ldt_lock);
  66
  67     FSHOW_SIGNAL((stderr, "/ TLS: Allocated LDT %x\n", n));
  68     sel.index = n;
  69     sel.rpl = USER_PRIV;
  70     sel.ti = SEL_LDT;
  71
  72     __asm__ __volatile__ ("mov %0, %%fs" : : "r"(sel));
  73
  74     thread->tls_cookie=n;
  75     pthread_setspecific(specials,thread);
  76 #endif
  77 #ifdef LISP_FEATURE_MACH_EXCEPTION_HANDLER
  78     mach_lisp_thread_init(thread);
  79 #endif
  80
  81 #ifdef LISP_FEATURE_C_STACK_IS_CONTROL_STACK
  82     stack_t sigstack;
  83
  84     /* Signal handlers are run on the control stack, so if it is exhausted
  85      * we had better use an alternate stack for whatever signal tells us
  86      * we've exhausted it */
  87     sigstack.ss_sp=((void *) thread)+dynamic_values_bytes;
  88     sigstack.ss_flags=0;
  89     sigstack.ss_size = 32*SIGSTKSZ;
  90     sigaltstack(&sigstack,0);
  91 #endif
  92     return 1;                  /* success */
  93 }
  94
  95 int arch_os_thread_cleanup(struct thread *thread) {
  96 #if defined(LISP_FEATURE_SB_THREAD)
  97     int n = thread->tls_cookie;
  98
  99     /* Set the %%fs register back to 0 and free the ldt by setting it
 100      * to NULL.
 101      */
 102     FSHOW_SIGNAL((stderr, "/ TLS: Freeing LDT %x\n", n));
 103
 104     __asm__ __volatile__ ("mov %0, %%fs" : : "r"(0));
 105     thread_mutex_lock(&modify_ldt_lock);
 106     i386_set_ldt(n, NULL, 1);
 107     thread_mutex_unlock(&modify_ldt_lock);
 108 #endif
 109     return 1;                  /* success */
 110 }
 111
 112 #ifdef LISP_FEATURE_MACH_EXCEPTION_HANDLER
 113
 114 void sigill_handler(int signal, siginfo_t *siginfo, os_context_t *context);
 115 void sigtrap_handler(int signal, siginfo_t *siginfo, os_context_t *context);
 116 void memory_fault_handler(int signal, siginfo_t *siginfo,
 117                           os_context_t *context);
 118
 119 /* This executes in the faulting thread as part of the signal
 120  * emulation.  It is passed a context with the uc_mcontext field
 121  * pointing to a valid block of memory. */
 122 void build_fake_signal_context(os_context_t *context,
 123                                x86_thread_state32_t *thread_state,
 124                                x86_float_state32_t *float_state) {
 125     pthread_sigmask(0, NULL, &context->uc_sigmask);
 126     context->uc_mcontext->SS = *thread_state;
 127     context->uc_mcontext->FS = *float_state;
 128 }
 129
 130 /* This executes in the faulting thread as part of the signal
 131  * emulation.  It is effectively the inverse operation from above. */
 132 void update_thread_state_from_context(x86_thread_state32_t *thread_state,
 133                                       x86_float_state32_t *float_state,
 134                                       os_context_t *context) {
 135     *thread_state = context->uc_mcontext->SS;
 136     *float_state = context->uc_mcontext->FS;
 137     pthread_sigmask(SIG_SETMASK, &context->uc_sigmask, NULL);
 138 }
 139
 140 /* Modify a context to push new data on its stack. */
 141 void push_context(u32 data, x86_thread_state32_t *thread_state)
 142 {
 143     u32 *stack_pointer;
 144
 145     stack_pointer = (u32*) thread_state->ESP;
 146     *(--stack_pointer) = data;
 147     thread_state->ESP = (unsigned int) stack_pointer;
 148 }
 149
 150 void align_context_stack(x86_thread_state32_t *thread_state)
 151 {
 152     /* 16byte align the stack (provided that the stack is, as it
 153      * should be, 4byte aligned. */
 154     while (thread_state->ESP & 15) push_context(0, thread_state);
 155 }
 156
 157 /* Stack allocation starts with a context that has a mod-4 ESP value
 158  * and needs to leave a context with a mod-16 ESP that will restore
 159  * the old ESP value and other register state when activated.  The
 160  * first part of this is the recovery trampoline, which loads ESP from
 161  * EBP, pops EBP, and returns. */
 162 asm("_stack_allocation_recover: movl %ebp, %esp; popl %ebp; ret;");
 163
 164 void open_stack_allocation(x86_thread_state32_t *thread_state)
 165 {
 166     void stack_allocation_recover(void);
 167
 168     push_context(thread_state->EIP, thread_state);
 169     push_context(thread_state->EBP, thread_state);
 170     thread_state->EBP = thread_state->ESP;
 171     thread_state->EIP = (unsigned int) stack_allocation_recover;
 172
 173     align_context_stack(thread_state);
 174 }
 175
 176 /* Stack allocation of data starts with a context with a mod-16 ESP
 177  * value and reserves some space on it by manipulating the ESP
 178  * register. */
 179 void *stack_allocate(x86_thread_state32_t *thread_state, size_t size)
 180 {
 181     /* round up size to 16byte multiple */
 182     size = (size + 15) & -16;
 183
 184     thread_state->ESP = ((u32)thread_state->ESP) - size;
 185
 186     return (void *)thread_state->ESP;
 187 }
 188
 189 /* Arranging to invoke a C function is tricky, as we have to assume
 190  * cdecl calling conventions (caller removes args) and x86/darwin
 191  * alignment requirements.  The simplest way to arrange this,
 192  * actually, is to open a new stack allocation.
 193  * WARNING!!! THIS DOES NOT PRESERVE REGISTERS! */
 194 void call_c_function_in_context(x86_thread_state32_t *thread_state,
 195                                 void *function,
 196                                 int nargs,
 197                                 ...)
 198 {
 199     va_list ap;
 200     int i;
 201     u32 *stack_pointer;
 202
 203     /* Set up to restore stack on exit. */
 204     open_stack_allocation(thread_state);
 205
 206     /* Have to keep stack 16byte aligned on x86/darwin. */
 207     for (i = (3 & -nargs); i; i--) {
 208         push_context(0, thread_state);
 209     }
 210
 211     thread_state->ESP = ((u32)thread_state->ESP) - nargs * 4;
 212     stack_pointer = (u32 *)thread_state->ESP;
 213
 214     va_start(ap, nargs);
 215     for (i = 0; i < nargs; i++) {
 216         //push_context(va_arg(ap, u32), thread_state);
 217         stack_pointer[i] = va_arg(ap, u32);
 218     }
 219     va_end(ap);
 220
 221     push_context(thread_state->EIP, thread_state);
 222     thread_state->EIP = (unsigned int) function;
 223 }
 224
 225 void signal_emulation_wrapper(x86_thread_state32_t *thread_state,
 226                               x86_float_state32_t *float_state,
 227                               int signal,
 228                               siginfo_t *siginfo,
 229                               void (*handler)(int, siginfo_t *, void *))
 230 {
 231
 232     /* CLH: FIXME **NOTE: HACK ALERT!** Ideally, we would allocate
 233      * context and regs on the stack as local variables, but this
 234      * causes problems for the lisp debugger. When it walks the stack
 235      * for a back trace, it sees the 1) address of the local variable
 236      * on the stack and thinks that is a frame pointer to a lisp
 237      * frame, and, 2) the address of the sap that we alloc'ed in
 238      * dynamic space and thinks that is a return address, so it,
 239      * heuristicly (and wrongly), chooses that this should be
 240      * interpreted as a lisp frame instead of as a C frame.
 241      * We can work around this in this case by os_validating the
 242      * context (and regs just for symmetry).
 243      */
 244
 245     os_context_t *context;
 246     mcontext_t *regs;
 247
 248     context = (os_context_t*) os_validate(0, sizeof(os_context_t));
 249     regs = (mcontext_t*) os_validate(0, sizeof(mcontext_t));
 250     context->uc_mcontext = regs;
 251
 252     /* when BSD signals are fired, they mask they signals in sa_mask
 253        which always seem to be the blockable_sigset, for us, so we
 254        need to:
 255        1) save the current sigmask
 256        2) block blockable signals
 257        3) call the signal handler
 258        4) restore the sigmask */
 259
 260     build_fake_signal_context(context, thread_state, float_state);
 261
 262     block_blockable_signals(0, 0);
 263
 264     handler(signal, siginfo, context);
 265
 266     update_thread_state_from_context(thread_state, float_state, context);
 267
 268     os_invalidate((os_vm_address_t)context, sizeof(os_context_t));
 269     os_invalidate((os_vm_address_t)regs, sizeof(mcontext_t));
 270
 271     /* Trap to restore the signal context. */
 272     asm volatile (".long 0xffff0b0f"
 273                   : : "a" (thread_state), "c" (float_state));
 274 }
 275
 276 /* Convenience wrapper for the above */
 277 void call_handler_on_thread(mach_port_t thread,
 278                             x86_thread_state32_t *thread_state,
 279                             int signal,
 280                             siginfo_t *siginfo,
 281                             void (*handler)(int, siginfo_t *, void *))
 282 {
 283     x86_thread_state32_t new_state;
 284     x86_thread_state32_t *save_thread_state;
 285     x86_float_state32_t *save_float_state;
 286     mach_msg_type_number_t state_count;
 287     siginfo_t *save_siginfo;
 288     kern_return_t ret;
 289     /* Initialize the new state */
 290     new_state = *thread_state;
 291     open_stack_allocation(&new_state);
 292     stack_allocate(&new_state, 256);
 293     /* Save old state */
 294     save_thread_state = (x86_thread_state32_t *)stack_allocate(&new_state, sizeof(*save_thread_state));
 295     *save_thread_state = *thread_state;
 296     /* Save float state */
 297     save_float_state = (x86_float_state32_t *)stack_allocate(&new_state, sizeof(*save_float_state));
 298     state_count = x86_FLOAT_STATE32_COUNT;
 299     if ((ret = thread_get_state(thread,
 300                                 x86_FLOAT_STATE32,
 301                                 (thread_state_t)save_float_state,
 302                                 &state_count)) != KERN_SUCCESS)
 303         lose("thread_get_state (x86_THREAD_STATE32) failed %d\n", ret);
 304     /* Set up siginfo */
 305     save_siginfo = stack_allocate(&new_state, sizeof(*siginfo));
 306     if (siginfo == NULL)
 307         save_siginfo = siginfo;
 308     else
 309         *save_siginfo = *siginfo;
 310     /* Prepare to call */
 311     call_c_function_in_context(&new_state,
 312                                signal_emulation_wrapper,
 313                                5,
 314                                save_thread_state,
 315                                save_float_state,
 316                                signal,
 317                                save_siginfo,
 318                                handler);
 319     /* Update the thread state */
 320     state_count = x86_THREAD_STATE32_COUNT;
 321     if ((ret = thread_set_state(thread,
 322                                 x86_THREAD_STATE32,
 323                                 (thread_state_t)&new_state,
 324                                 state_count)) != KERN_SUCCESS)
 325         lose("thread_set_state (x86_FLOAT_STATE32) failed %d\n", ret);
 326
 327 }
 328
 329 #if defined DUMP_CONTEXT
 330 void dump_context(x86_thread_state32_t *thread_state)
 331 {
 332     int i;
 333     u32 *stack_pointer;
 334
 335     printf("eax: %08lx  ecx: %08lx  edx: %08lx  ebx: %08lx\n",
 336            thread_state->EAX, thread_state->ECX, thread_state->EDX, thread_state->EAX);
 337     printf("esp: %08lx  ebp: %08lx  esi: %08lx  edi: %08lx\n",
 338            thread_state->ESP, thread_state->EBP, thread_state->ESI, thread_state->EDI);
 339     printf("eip: %08lx  eflags: %08lx\n",
 340            thread_state->EIP, thread_state->EFLAGS);
 341     printf("cs: %04hx  ds: %04hx  es: %04hx  "
 342            "ss: %04hx  fs: %04hx  gs: %04hx\n",
 343            thread_state->CS,
 344            thread_state->DS,
 345            thread_state->ES,
 346            thread_state->SS,
 347            thread_state->FS,
 348            thread_state->GS);
 349
 350     stack_pointer = (u32 *)thread_state->ESP;
 351     for (i = 0; i < 48; i+=4) {
 352         printf("%08x:  %08x %08x %08x %08x\n",
 353                thread_state->ESP + (i * 4),
 354                stack_pointer[i],
 355                stack_pointer[i+1],
 356                stack_pointer[i+2],
 357                stack_pointer[i+3]);
 358     }
 359 }
 360 #endif
 361
 362 void
 363 control_stack_exhausted_handler(int signal, siginfo_t *siginfo,
 364                                 os_context_t *context) {
 365
 366     unblock_signals_in_context_and_maybe_warn(context);
 367     arrange_return_to_lisp_function
 368         (context, StaticSymbolFunction(CONTROL_STACK_EXHAUSTED_ERROR));
 369 }
 370
 371 void
 372 undefined_alien_handler(int signal, siginfo_t *siginfo, os_context_t *context) {
 373     arrange_return_to_lisp_function
 374         (context, StaticSymbolFunction(UNDEFINED_ALIEN_VARIABLE_ERROR));
 375 }
 376
 377 kern_return_t
 378 catch_exception_raise(mach_port_t exception_port,
 379                       mach_port_t thread,
 380                       mach_port_t task,
 381                       exception_type_t exception,
 382                       exception_data_t code_vector,
 383                       mach_msg_type_number_t code_count)
 384 {
 385     x86_thread_state32_t thread_state;
 386     mach_msg_type_number_t state_count;
 387     vm_address_t region_addr;
 388     vm_size_t region_size;
 389     vm_region_basic_info_data_t region_info;
 390     mach_msg_type_number_t info_count;
 391     mach_port_t region_name;
 392     void *addr = NULL;
 393     int signal = 0;
 394     void (*handler)(int, siginfo_t *, void *) = NULL;
 395     siginfo_t siginfo;
 396     kern_return_t ret, dealloc_ret;
 397
 398     struct thread *th;
 399
 400     FSHOW((stderr,"/entering catch_exception_raise with exception: %d\n", exception));
 401     th = *(struct thread**)exception_port;
 402     /* Get state and info */
 403     state_count = x86_THREAD_STATE32_COUNT;
 404     if ((ret = thread_get_state(thread,
 405                                 x86_THREAD_STATE32,
 406                                 (thread_state_t)&thread_state,
 407                                 &state_count)) != KERN_SUCCESS)
 408         lose("thread_get_state (x86_THREAD_STATE32) failed %d\n", ret);
 409     switch (exception) {
 410     case EXC_BAD_ACCESS:
 411         signal = SIGBUS;
 412         /* Check if write protection fault */
 413         if ((code_vector[0] & OS_VM_PROT_ALL) == 0) {
 414             ret = KERN_INVALID_RIGHT;
 415             break;
 416         }
 417         addr = (void*)code_vector[1];
 418         /* Undefined alien */
 419         if (os_trunc_to_page(addr) == undefined_alien_address) {
 420             handler = undefined_alien_handler;
 421             break;
 422         }
 423         /* At stack guard */
 424         if (os_trunc_to_page(addr) == CONTROL_STACK_GUARD_PAGE(th)) {
 425             lower_thread_control_stack_guard_page(th);
 426             handler = control_stack_exhausted_handler;
 427             break;
 428         }
 429         /* Return from stack guard */
 430         if (os_trunc_to_page(addr) == CONTROL_STACK_RETURN_GUARD_PAGE(th)) {
 431             reset_thread_control_stack_guard_page(th);
 432             break;
 433         }
 434         /* Regular memory fault */
 435         handler = memory_fault_handler;
 436         break;
 437     case EXC_BAD_INSTRUCTION:
 438         signal = SIGTRAP;
 439         /* Check if illegal instruction trap */
 440         if (code_vector[0] != EXC_I386_INVOP) {
 441             ret = KERN_INVALID_RIGHT;
 442             break;
 443         }
 444         /* Check if UD2 instruction */
 445         if (*(unsigned short *)thread_state.EIP != 0x0b0f) {
 446             /* KLUDGE: There are two ways we could get here:
 447              * 1) We're executing data and we've hit some truly
 448              *    illegal opcode, of which there are a few, see
 449              *    Intel 64 and IA-32 Architectures
 450              *    Sofware Developer's Manual
 451              *    Volume 3A page 5-34)
 452              * 2) The kernel started an unrelated signal handler
 453              *    before we got a chance to run. The context that
 454              *    caused the exception is saved in a stack frame
 455              *    somewhere down below.
 456              * In either case we rely on the exception to retrigger,
 457              * eventually bailing out if we're spinning on case 2).
 458              */
 459             static mach_port_t last_thread;
 460             static unsigned int last_eip;
 461             if (last_thread == thread && last_eip == thread_state.EIP)
 462                 ret = KERN_INVALID_RIGHT;
 463             else
 464                 ret = KERN_SUCCESS;
 465             last_thread = thread;
 466             last_eip = thread_state.EIP;
 467             break;
 468         }
 469         /* Skip the trap code */
 470         thread_state.EIP += 2;
 471         /* Return from handler? */
 472         if (*(unsigned short *)thread_state.EIP == 0xffff) {
 473             if ((ret = thread_set_state(thread,
 474                                         x86_THREAD_STATE32,
 475                                         (thread_state_t)thread_state.EAX,
 476                                         x86_THREAD_STATE32_COUNT)) != KERN_SUCCESS)
 477                 lose("thread_set_state (x86_THREAD_STATE32) failed %d\n", ret);
 478             if ((ret = thread_set_state(thread,
 479                                         x86_FLOAT_STATE32,
 480                                         (thread_state_t)thread_state.ECX,
 481                                         x86_FLOAT_STATE32_COUNT)) != KERN_SUCCESS)
 482                 lose("thread_set_state (x86_FLOAT_STATE32) failed %d\n", ret);
 483             break;
 484         }
 485         /* Trap call */
 486         handler = sigtrap_handler;
 487         break;
 488     default:
 489         ret = KERN_INVALID_RIGHT;
 490     }
 491     /* Call handler */
 492     if (handler != 0) {
 493       siginfo.si_signo = signal;
 494       siginfo.si_addr = addr;
 495       call_handler_on_thread(thread, &thread_state, signal, &siginfo, handler);
 496     }
 497
 498     dealloc_ret = mach_port_deallocate (current_mach_task, thread);
 499     if (dealloc_ret) {
 500       lose("mach_port_deallocate (thread) failed with return_code %d\n", dealloc_ret);
 501     }
 502
 503     dealloc_ret = mach_port_deallocate (current_mach_task, task);
 504     if (dealloc_ret) {
 505       lose("mach_port_deallocate (task) failed with return_code %d\n", dealloc_ret);
 506     }
 507
 508     return ret;
 509 }
 510
 511 void
 512 os_restore_fp_control(os_context_t *context)
 513 {
 514     /* KLUDGE: The x87 FPU control word is some nasty bitfield struct
 515      * thing.  Rather than deal with that, just grab it as a 16-bit
 516      * integer. */
 517     unsigned short fpu_control_word =
 518         *((unsigned short *)&context->uc_mcontext->FS.FPU_FCW);
 519     /* reset exception flags and restore control flags on x87 FPU */
 520     asm ("fldcw %0" : : "m" (fpu_control_word));
 521 }
 522
 523 #endif