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 #ifdef LISP_FEATURE_SB_THREAD
  48 void
  49 arch_os_load_ldt(struct thread *thread)
  50 {
  51     sel_t sel;
  52
  53     sel.index = thread->tls_cookie;
  54     sel.rpl = USER_PRIV;
  55     sel.ti = SEL_LDT;
  56
  57     __asm__ __volatile__ ("mov %0, %%fs" : : "r"(sel));
  58 }
  59 #endif
  60
  61 int arch_os_thread_init(struct thread *thread) {
  62 #ifdef LISP_FEATURE_SB_THREAD
  63     int n;
  64
  65     data_desc_t ldt_entry = { 0, 0, 0, DESC_DATA_WRITE,
  66                               3, 1, 0, DESC_DATA_32B, DESC_GRAN_BYTE, 0 };
  67
  68     set_data_desc_addr(&ldt_entry, thread);
  69     set_data_desc_size(&ldt_entry, dynamic_values_bytes);
  70
  71     thread_mutex_lock(&modify_ldt_lock);
  72     n = i386_set_ldt(LDT_AUTO_ALLOC, (union ldt_entry*) &ldt_entry, 1);
  73
  74     if (n < 0) {
  75         perror("i386_set_ldt");
  76         lose("unexpected i386_set_ldt(..) failure\n");
  77     }
  78     thread_mutex_unlock(&modify_ldt_lock);
  79
  80     FSHOW_SIGNAL((stderr, "/ TLS: Allocated LDT %x\n", n));
  81     thread->tls_cookie=n;
  82     arch_os_load_ldt(thread);
  83
  84     pthread_setspecific(specials,thread);
  85 #endif
  86 #ifdef LISP_FEATURE_MACH_EXCEPTION_HANDLER
  87     mach_lisp_thread_init(thread);
  88 #endif
  89
  90 #ifdef LISP_FEATURE_C_STACK_IS_CONTROL_STACK
  91     stack_t sigstack;
  92
  93     /* Signal handlers are run on the control stack, so if it is exhausted
  94      * we had better use an alternate stack for whatever signal tells us
  95      * we've exhausted it */
  96     sigstack.ss_sp=((void *) thread)+dynamic_values_bytes;
  97     sigstack.ss_flags=0;
  98     sigstack.ss_size = 32*SIGSTKSZ;
  99     sigaltstack(&sigstack,0);
 100 #endif
 101     return 1;                  /* success */
 102 }
 103
 104 int arch_os_thread_cleanup(struct thread *thread) {
 105 #if defined(LISP_FEATURE_SB_THREAD)
 106     int n = thread->tls_cookie;
 107
 108     /* Set the %%fs register back to 0 and free the ldt by setting it
 109      * to NULL.
 110      */
 111     FSHOW_SIGNAL((stderr, "/ TLS: Freeing LDT %x\n", n));
 112
 113     __asm__ __volatile__ ("mov %0, %%fs" : : "r"(0));
 114     thread_mutex_lock(&modify_ldt_lock);
 115     i386_set_ldt(n, NULL, 1);
 116     thread_mutex_unlock(&modify_ldt_lock);
 117 #endif
 118     return 1;                  /* success */
 119 }
 120
 121 #ifdef LISP_FEATURE_MACH_EXCEPTION_HANDLER
 122
 123 void sigill_handler(int signal, siginfo_t *siginfo, os_context_t *context);
 124 void sigtrap_handler(int signal, siginfo_t *siginfo, os_context_t *context);
 125 void memory_fault_handler(int signal, siginfo_t *siginfo,
 126                           os_context_t *context);
 127
 128 /* This executes in the faulting thread as part of the signal
 129  * emulation.  It is passed a context with the uc_mcontext field
 130  * pointing to a valid block of memory. */
 131 void build_fake_signal_context(os_context_t *context,
 132                                x86_thread_state32_t *thread_state,
 133                                x86_float_state32_t *float_state) {
 134     pthread_sigmask(0, NULL, &context->uc_sigmask);
 135     context->uc_mcontext->SS = *thread_state;
 136     context->uc_mcontext->FS = *float_state;
 137 }
 138
 139 /* This executes in the faulting thread as part of the signal
 140  * emulation.  It is effectively the inverse operation from above. */
 141 void update_thread_state_from_context(x86_thread_state32_t *thread_state,
 142                                       x86_float_state32_t *float_state,
 143                                       os_context_t *context) {
 144     *thread_state = context->uc_mcontext->SS;
 145     *float_state = context->uc_mcontext->FS;
 146     pthread_sigmask(SIG_SETMASK, &context->uc_sigmask, NULL);
 147 }
 148
 149 /* Modify a context to push new data on its stack. */
 150 void push_context(u32 data, x86_thread_state32_t *thread_state)
 151 {
 152     u32 *stack_pointer;
 153
 154     stack_pointer = (u32*) thread_state->ESP;
 155     *(--stack_pointer) = data;
 156     thread_state->ESP = (unsigned int) stack_pointer;
 157 }
 158
 159 void align_context_stack(x86_thread_state32_t *thread_state)
 160 {
 161     /* 16byte align the stack (provided that the stack is, as it
 162      * should be, 4byte aligned. */
 163     while (thread_state->ESP & 15) push_context(0, thread_state);
 164 }
 165
 166 /* Stack allocation starts with a context that has a mod-4 ESP value
 167  * and needs to leave a context with a mod-16 ESP that will restore
 168  * the old ESP value and other register state when activated.  The
 169  * first part of this is the recovery trampoline, which loads ESP from
 170  * EBP, pops EBP, and returns. */
 171 asm("_stack_allocation_recover: movl %ebp, %esp; popl %ebp; ret;");
 172
 173 void open_stack_allocation(x86_thread_state32_t *thread_state)
 174 {
 175     void stack_allocation_recover(void);
 176
 177     push_context(thread_state->EIP, thread_state);
 178     push_context(thread_state->EBP, thread_state);
 179     thread_state->EBP = thread_state->ESP;
 180     thread_state->EIP = (unsigned int) stack_allocation_recover;
 181
 182     align_context_stack(thread_state);
 183 }
 184
 185 /* Stack allocation of data starts with a context with a mod-16 ESP
 186  * value and reserves some space on it by manipulating the ESP
 187  * register. */
 188 void *stack_allocate(x86_thread_state32_t *thread_state, size_t size)
 189 {
 190     /* round up size to 16byte multiple */
 191     size = (size + 15) & -16;
 192
 193     thread_state->ESP = ((u32)thread_state->ESP) - size;
 194
 195     return (void *)thread_state->ESP;
 196 }
 197
 198 /* Arranging to invoke a C function is tricky, as we have to assume
 199  * cdecl calling conventions (caller removes args) and x86/darwin
 200  * alignment requirements.  The simplest way to arrange this,
 201  * actually, is to open a new stack allocation.
 202  * WARNING!!! THIS DOES NOT PRESERVE REGISTERS! */
 203 void call_c_function_in_context(x86_thread_state32_t *thread_state,
 204                                 void *function,
 205                                 int nargs,
 206                                 ...)
 207 {
 208     va_list ap;
 209     int i;
 210     u32 *stack_pointer;
 211
 212     /* Set up to restore stack on exit. */
 213     open_stack_allocation(thread_state);
 214
 215     /* Have to keep stack 16byte aligned on x86/darwin. */
 216     for (i = (3 & -nargs); i; i--) {
 217         push_context(0, thread_state);
 218     }
 219
 220     thread_state->ESP = ((u32)thread_state->ESP) - nargs * 4;
 221     stack_pointer = (u32 *)thread_state->ESP;
 222
 223     va_start(ap, nargs);
 224     for (i = 0; i < nargs; i++) {
 225         //push_context(va_arg(ap, u32), thread_state);
 226         stack_pointer[i] = va_arg(ap, u32);
 227     }
 228     va_end(ap);
 229
 230     push_context(thread_state->EIP, thread_state);
 231     thread_state->EIP = (unsigned int) function;
 232 }
 233
 234 void signal_emulation_wrapper(x86_thread_state32_t *thread_state,
 235                               x86_float_state32_t *float_state,
 236                               int signal,
 237                               siginfo_t *siginfo,
 238                               void (*handler)(int, siginfo_t *, void *))
 239 {
 240
 241     /* CLH: FIXME **NOTE: HACK ALERT!** Ideally, we would allocate
 242      * context and regs on the stack as local variables, but this
 243      * causes problems for the lisp debugger. When it walks the stack
 244      * for a back trace, it sees the 1) address of the local variable
 245      * on the stack and thinks that is a frame pointer to a lisp
 246      * frame, and, 2) the address of the sap that we alloc'ed in
 247      * dynamic space and thinks that is a return address, so it,
 248      * heuristicly (and wrongly), chooses that this should be
 249      * interpreted as a lisp frame instead of as a C frame.
 250      * We can work around this in this case by os_validating the
 251      * context (and regs just for symmetry).
 252      */
 253
 254     os_context_t *context;
 255     mcontext_t *regs;
 256
 257     context = (os_context_t*) os_validate(0, sizeof(os_context_t));
 258     regs = (mcontext_t*) os_validate(0, sizeof(mcontext_t));
 259     context->uc_mcontext = regs;
 260
 261     /* when BSD signals are fired, they mask they signals in sa_mask
 262        which always seem to be the blockable_sigset, for us, so we
 263        need to:
 264        1) save the current sigmask
 265        2) block blockable signals
 266        3) call the signal handler
 267        4) restore the sigmask */
 268
 269     build_fake_signal_context(context, thread_state, float_state);
 270
 271     block_blockable_signals(0, 0);
 272
 273     handler(signal, siginfo, context);
 274
 275     update_thread_state_from_context(thread_state, float_state, context);
 276
 277     os_invalidate((os_vm_address_t)context, sizeof(os_context_t));
 278     os_invalidate((os_vm_address_t)regs, sizeof(mcontext_t));
 279
 280     /* Trap to restore the signal context. */
 281     asm volatile (".long 0xffff0b0f"
 282                   : : "a" (thread_state), "c" (float_state));
 283 }
 284
 285 /* Convenience wrapper for the above */
 286 void call_handler_on_thread(mach_port_t thread,
 287                             x86_thread_state32_t *thread_state,
 288                             int signal,
 289                             siginfo_t *siginfo,
 290                             void (*handler)(int, siginfo_t *, void *))
 291 {
 292     x86_thread_state32_t new_state;
 293     x86_thread_state32_t *save_thread_state;
 294     x86_float_state32_t *save_float_state;
 295     mach_msg_type_number_t state_count;
 296     siginfo_t *save_siginfo;
 297     kern_return_t ret;
 298     /* Initialize the new state */
 299     new_state = *thread_state;
 300     open_stack_allocation(&new_state);
 301     stack_allocate(&new_state, 256);
 302     /* Save old state */
 303     save_thread_state = (x86_thread_state32_t *)stack_allocate(&new_state, sizeof(*save_thread_state));
 304     *save_thread_state = *thread_state;
 305     /* Save float state */
 306     save_float_state = (x86_float_state32_t *)stack_allocate(&new_state, sizeof(*save_float_state));
 307     state_count = x86_FLOAT_STATE32_COUNT;
 308     if ((ret = thread_get_state(thread,
 309                                 x86_FLOAT_STATE32,
 310                                 (thread_state_t)save_float_state,
 311                                 &state_count)) != KERN_SUCCESS)
 312         lose("thread_get_state (x86_THREAD_STATE32) failed %d\n", ret);
 313     /* Set up siginfo */
 314     save_siginfo = stack_allocate(&new_state, sizeof(*siginfo));
 315     if (siginfo == NULL)
 316         save_siginfo = siginfo;
 317     else
 318         *save_siginfo = *siginfo;
 319     /* Prepare to call */
 320     call_c_function_in_context(&new_state,
 321                                signal_emulation_wrapper,
 322                                5,
 323                                save_thread_state,
 324                                save_float_state,
 325                                signal,
 326                                save_siginfo,
 327                                handler);
 328     /* Update the thread state */
 329     state_count = x86_THREAD_STATE32_COUNT;
 330     if ((ret = thread_set_state(thread,
 331                                 x86_THREAD_STATE32,
 332                                 (thread_state_t)&new_state,
 333                                 state_count)) != KERN_SUCCESS)
 334         lose("thread_set_state (x86_FLOAT_STATE32) failed %d\n", ret);
 335
 336 }
 337
 338 #if defined DUMP_CONTEXT
 339 void dump_context(x86_thread_state32_t *thread_state)
 340 {
 341     int i;
 342     u32 *stack_pointer;
 343
 344     printf("eax: %08lx  ecx: %08lx  edx: %08lx  ebx: %08lx\n",
 345            thread_state->EAX, thread_state->ECX, thread_state->EDX, thread_state->EAX);
 346     printf("esp: %08lx  ebp: %08lx  esi: %08lx  edi: %08lx\n",
 347            thread_state->ESP, thread_state->EBP, thread_state->ESI, thread_state->EDI);
 348     printf("eip: %08lx  eflags: %08lx\n",
 349            thread_state->EIP, thread_state->EFLAGS);
 350     printf("cs: %04hx  ds: %04hx  es: %04hx  "
 351            "ss: %04hx  fs: %04hx  gs: %04hx\n",
 352            thread_state->CS,
 353            thread_state->DS,
 354            thread_state->ES,
 355            thread_state->SS,
 356            thread_state->FS,
 357            thread_state->GS);
 358
 359     stack_pointer = (u32 *)thread_state->ESP;
 360     for (i = 0; i < 48; i+=4) {
 361         printf("%08x:  %08x %08x %08x %08x\n",
 362                thread_state->ESP + (i * 4),
 363                stack_pointer[i],
 364                stack_pointer[i+1],
 365                stack_pointer[i+2],
 366                stack_pointer[i+3]);
 367     }
 368 }
 369 #endif
 370
 371 void
 372 control_stack_exhausted_handler(int signal, siginfo_t *siginfo,
 373                                 os_context_t *context) {
 374
 375     unblock_signals_in_context_and_maybe_warn(context);
 376     arrange_return_to_lisp_function
 377         (context, StaticSymbolFunction(CONTROL_STACK_EXHAUSTED_ERROR));
 378 }
 379
 380 void
 381 undefined_alien_handler(int signal, siginfo_t *siginfo, os_context_t *context) {
 382     arrange_return_to_lisp_function
 383         (context, StaticSymbolFunction(UNDEFINED_ALIEN_VARIABLE_ERROR));
 384 }
 385
 386 kern_return_t
 387 catch_exception_raise(mach_port_t exception_port,
 388                       mach_port_t thread,
 389                       mach_port_t task,
 390                       exception_type_t exception,
 391                       exception_data_t code_vector,
 392                       mach_msg_type_number_t code_count)
 393 {
 394     x86_thread_state32_t thread_state;
 395     mach_msg_type_number_t state_count;
 396     vm_address_t region_addr;
 397     vm_size_t region_size;
 398     vm_region_basic_info_data_t region_info;
 399     mach_msg_type_number_t info_count;
 400     mach_port_t region_name;
 401     void *addr = NULL;
 402     int signal = 0;
 403     void (*handler)(int, siginfo_t *, void *) = NULL;
 404     siginfo_t siginfo;
 405     kern_return_t ret, dealloc_ret;
 406
 407     struct thread *th;
 408
 409     FSHOW((stderr,"/entering catch_exception_raise with exception: %d\n", exception));
 410     th = *(struct thread**)exception_port;
 411     /* Get state and info */
 412     state_count = x86_THREAD_STATE32_COUNT;
 413     if ((ret = thread_get_state(thread,
 414                                 x86_THREAD_STATE32,
 415                                 (thread_state_t)&thread_state,
 416                                 &state_count)) != KERN_SUCCESS)
 417         lose("thread_get_state (x86_THREAD_STATE32) failed %d\n", ret);
 418     switch (exception) {
 419     case EXC_BAD_ACCESS:
 420         signal = SIGBUS;
 421         /* Check if write protection fault */
 422         if ((code_vector[0] & OS_VM_PROT_ALL) == 0) {
 423             ret = KERN_INVALID_RIGHT;
 424             break;
 425         }
 426         addr = (void*)code_vector[1];
 427         /* Undefined alien */
 428         if (os_trunc_to_page(addr) == undefined_alien_address) {
 429             handler = undefined_alien_handler;
 430             break;
 431         }
 432         /* At stack guard */
 433         if (os_trunc_to_page(addr) == CONTROL_STACK_GUARD_PAGE(th)) {
 434             lower_thread_control_stack_guard_page(th);
 435             handler = control_stack_exhausted_handler;
 436             break;
 437         }
 438         /* Return from stack guard */
 439         if (os_trunc_to_page(addr) == CONTROL_STACK_RETURN_GUARD_PAGE(th)) {
 440             reset_thread_control_stack_guard_page(th);
 441             break;
 442         }
 443         /* Regular memory fault */
 444         handler = memory_fault_handler;
 445         break;
 446     case EXC_BAD_INSTRUCTION:
 447         signal = SIGTRAP;
 448         /* Check if illegal instruction trap */
 449         if (code_vector[0] != EXC_I386_INVOP) {
 450             ret = KERN_INVALID_RIGHT;
 451             break;
 452         }
 453         /* Check if UD2 instruction */
 454         if (*(unsigned short *)thread_state.EIP != 0x0b0f) {
 455             /* KLUDGE: There are two ways we could get here:
 456              * 1) We're executing data and we've hit some truly
 457              *    illegal opcode, of which there are a few, see
 458              *    Intel 64 and IA-32 Architectures
 459              *    Sofware Developer's Manual
 460              *    Volume 3A page 5-34)
 461              * 2) The kernel started an unrelated signal handler
 462              *    before we got a chance to run. The context that
 463              *    caused the exception is saved in a stack frame
 464              *    somewhere down below.
 465              * In either case we rely on the exception to retrigger,
 466              * eventually bailing out if we're spinning on case 2).
 467              */
 468             static mach_port_t last_thread;
 469             static unsigned int last_eip;
 470             if (last_thread == thread && last_eip == thread_state.EIP)
 471                 ret = KERN_INVALID_RIGHT;
 472             else
 473                 ret = KERN_SUCCESS;
 474             last_thread = thread;
 475             last_eip = thread_state.EIP;
 476             break;
 477         }
 478         /* Skip the trap code */
 479         thread_state.EIP += 2;
 480         /* Return from handler? */
 481         if (*(unsigned short *)thread_state.EIP == 0xffff) {
 482             if ((ret = thread_set_state(thread,
 483                                         x86_THREAD_STATE32,
 484                                         (thread_state_t)thread_state.EAX,
 485                                         x86_THREAD_STATE32_COUNT)) != KERN_SUCCESS)
 486                 lose("thread_set_state (x86_THREAD_STATE32) failed %d\n", ret);
 487             if ((ret = thread_set_state(thread,
 488                                         x86_FLOAT_STATE32,
 489                                         (thread_state_t)thread_state.ECX,
 490                                         x86_FLOAT_STATE32_COUNT)) != KERN_SUCCESS)
 491                 lose("thread_set_state (x86_FLOAT_STATE32) failed %d\n", ret);
 492             break;
 493         }
 494         /* Trap call */
 495         handler = sigtrap_handler;
 496         break;
 497     default:
 498         ret = KERN_INVALID_RIGHT;
 499     }
 500     /* Call handler */
 501     if (handler != 0) {
 502       siginfo.si_signo = signal;
 503       siginfo.si_addr = addr;
 504       call_handler_on_thread(thread, &thread_state, signal, &siginfo, handler);
 505     }
 506
 507     dealloc_ret = mach_port_deallocate (current_mach_task, thread);
 508     if (dealloc_ret) {
 509       lose("mach_port_deallocate (thread) failed with return_code %d\n", dealloc_ret);
 510     }
 511
 512     dealloc_ret = mach_port_deallocate (current_mach_task, task);
 513     if (dealloc_ret) {
 514       lose("mach_port_deallocate (task) failed with return_code %d\n", dealloc_ret);
 515     }
 516
 517     return ret;
 518 }
 519
 520 void
 521 os_restore_fp_control(os_context_t *context)
 522 {
 523     /* KLUDGE: The x87 FPU control word is some nasty bitfield struct
 524      * thing.  Rather than deal with that, just grab it as a 16-bit
 525      * integer. */
 526     unsigned short fpu_control_word =
 527         *((unsigned short *)&context->uc_mcontext->FS.FPU_FCW);
 528     /* reset exception flags and restore control flags on x87 FPU */
 529     asm ("fldcw %0" : : "m" (fpu_control_word));
 530 }
 531
 532 #endif