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