mono/mini/exceptions-arm.c

   1 /*
   2  * exceptions-arm.c: exception support for ARM
   3  *
   4  * Authors:
   5  *   Dietmar Maurer (dietmar@ximian.com)
   6  *   Paolo Molaro (lupus@ximian.com)
   7  *
   8  * (C) 2001 Ximian, Inc.
   9  */
  10
  11 #include <config.h>
  12 #include <glib.h>
  13 #include <signal.h>
  14 #include <string.h>
  15
  16 #ifndef MONO_CROSS_COMPILE
  17 #ifdef PLATFORM_ANDROID
  18 #include <asm/sigcontext.h>
  19 #endif  /* def PLATFORM_ANDROID */
  20 #endif
  21
  22 #ifdef HAVE_UCONTEXT_H
  23 #include <ucontext.h>
  24 #endif  /* def HAVE_UCONTEXT_H */
  25
  26 #include <mono/arch/arm/arm-codegen.h>
  27 #include <mono/arch/arm/arm-vfp-codegen.h>
  28 #include <mono/metadata/abi-details.h>
  29 #include <mono/metadata/appdomain.h>
  30 #include <mono/metadata/tabledefs.h>
  31 #include <mono/metadata/threads.h>
  32 #include <mono/metadata/debug-helpers.h>
  33 #include <mono/metadata/exception.h>
  34 #include <mono/metadata/mono-debug.h>
  35
  36 #include "mini.h"
  37 #include "mini-arm.h"
  38 #include "mono/utils/mono-sigcontext.h"
  39 #include "mono/utils/mono-compiler.h"
  40
  41 /*
  42  * arch_get_restore_context:
  43  *
  44  * Returns a pointer to a method which restores a previously saved sigcontext.
  45  * The first argument in r0 is the pointer to the context.
  46  */
  47 gpointer
  48 mono_arch_get_restore_context (MonoTrampInfo **info, gboolean aot)
  49 {
  50         guint8 *code;
  51         guint8 *start;
  52         int ctx_reg;
  53         MonoJumpInfo *ji = NULL;
  54         GSList *unwind_ops = NULL;
  55
  56         start = code = mono_global_codeman_reserve (128);
  57
  58         /*
  59          * Move things to their proper place so we can restore all the registers with
  60          * one instruction.
  61          */
  62
  63         ctx_reg = ARMREG_R0;
  64
  65         if (!mono_arch_is_soft_float ()) {
  66                 ARM_ADD_REG_IMM8 (code, ARMREG_IP, ctx_reg, MONO_STRUCT_OFFSET (MonoContext, fregs));
  67                 ARM_FLDMD (code, ARM_VFP_D0, 16, ARMREG_IP);
  68         }
  69
  70         /* move pc to PC */
  71         ARM_LDR_IMM (code, ARMREG_IP, ctx_reg, MONO_STRUCT_OFFSET (MonoContext, pc));
  72         ARM_STR_IMM (code, ARMREG_IP, ctx_reg, MONO_STRUCT_OFFSET (MonoContext, regs) + (ARMREG_PC * sizeof (mgreg_t)));
  73
  74         /* restore everything */
  75         ARM_ADD_REG_IMM8 (code, ARMREG_IP, ctx_reg, MONO_STRUCT_OFFSET(MonoContext, regs));
  76         ARM_LDM (code, ARMREG_IP, 0xffff);
  77
  78         /* never reached */
  79         ARM_DBRK (code);
  80
  81         g_assert ((code - start) < 128);
  82
  83         mono_arch_flush_icache (start, code - start);
  84
  85         if (info)
  86                 *info = mono_tramp_info_create ("restore_context", start, code - start, ji, unwind_ops);
  87
  88         return start;
  89 }
  90
  91 /*
  92  * arch_get_call_filter:
  93  *
  94  * Returns a pointer to a method which calls an exception filter. We
  95  * also use this function to call finally handlers (we pass NULL as
  96  * @exc object in this case).
  97  */
  98 gpointer
  99 mono_arch_get_call_filter (MonoTrampInfo **info, gboolean aot)
 100 {
 101         guint8 *code;
 102         guint8* start;
 103         int ctx_reg;
 104         MonoJumpInfo *ji = NULL;
 105         GSList *unwind_ops = NULL;
 106
 107         /* call_filter (MonoContext *ctx, unsigned long eip, gpointer exc) */
 108         start = code = mono_global_codeman_reserve (320);
 109
 110         /* save all the regs on the stack */
 111         ARM_MOV_REG_REG (code, ARMREG_IP, ARMREG_SP);
 112         ARM_PUSH (code, MONO_ARM_REGSAVE_MASK);
 113
 114         ARM_SUB_REG_IMM8 (code, ARMREG_SP, ARMREG_SP, 8);
 115
 116         /* restore all the regs from ctx (in r0), but not sp, the stack pointer */
 117         ctx_reg = ARMREG_R0;
 118         ARM_LDR_IMM (code, ARMREG_IP, ctx_reg, MONO_STRUCT_OFFSET (MonoContext, pc));
 119         ARM_ADD_REG_IMM8 (code, ARMREG_LR, ctx_reg, MONO_STRUCT_OFFSET(MonoContext, regs) + (MONO_ARM_FIRST_SAVED_REG * sizeof (mgreg_t)));
 120         ARM_LDM (code, ARMREG_LR, MONO_ARM_REGSAVE_MASK);
 121         /* call handler at eip (r1) and set the first arg with the exception (r2) */
 122         ARM_MOV_REG_REG (code, ARMREG_R0, ARMREG_R2);
 123         ARM_MOV_REG_REG (code, ARMREG_LR, ARMREG_PC);
 124         ARM_MOV_REG_REG (code, ARMREG_PC, ARMREG_R1);
 125
 126         ARM_ADD_REG_IMM8 (code, ARMREG_SP, ARMREG_SP, 8);
 127
 128         /* epilog */
 129         ARM_POP_NWB (code, 0xff0 | ((1 << ARMREG_SP) | (1 << ARMREG_PC)));
 130
 131         g_assert ((code - start) < 320);
 132
 133         mono_arch_flush_icache (start, code - start);
 134
 135         if (info)
 136                 *info = mono_tramp_info_create ("call_filter", start, code - start, ji, unwind_ops);
 137
 138         return start;
 139 }
 140
 141 void
 142 mono_arm_throw_exception (MonoObject *exc, mgreg_t pc, mgreg_t sp, mgreg_t *int_regs, gdouble *fp_regs)
 143 {
 144         MonoError error;
 145         MonoContext ctx;
 146         gboolean rethrow = sp & 1;
 147
 148         sp &= ~1; /* clear the optional rethrow bit */
 149         pc &= ~1; /* clear the thumb bit */
 150         /* adjust eip so that it point into the call instruction */
 151         pc -= 4;
 152
 153         /*printf ("stack in throw: %p\n", esp);*/
 154         MONO_CONTEXT_SET_BP (&ctx, int_regs [ARMREG_FP - 4]);
 155         MONO_CONTEXT_SET_SP (&ctx, sp);
 156         MONO_CONTEXT_SET_IP (&ctx, pc);
 157         memcpy (((guint8*)&ctx.regs) + (ARMREG_R4 * sizeof (mgreg_t)), int_regs, 8 * sizeof (mgreg_t));
 158         memcpy (&ctx.fregs, fp_regs, sizeof (double) * 16);
 159
 160         if (mono_object_isinst_checked (exc, mono_defaults.exception_class, &error)) {
 161                 MonoException *mono_ex = (MonoException*)exc;
 162                 if (!rethrow) {
 163                         mono_ex->stack_trace = NULL;
 164                         mono_ex->trace_ips = NULL;
 165                 }
 166         }
 167         mono_error_assert_ok (&error);
 168         mono_handle_exception (&ctx, exc);
 169         mono_restore_context (&ctx);
 170         g_assert_not_reached ();
 171 }
 172
 173 void
 174 mono_arm_throw_exception_by_token (guint32 ex_token_index, mgreg_t pc, mgreg_t sp, mgreg_t *int_regs, gdouble *fp_regs)
 175 {
 176         guint32 ex_token = MONO_TOKEN_TYPE_DEF | ex_token_index;
 177         /* Clear thumb bit */
 178         pc &= ~1;
 179
 180         mono_arm_throw_exception ((MonoObject*)mono_exception_from_token (mono_defaults.corlib, ex_token), pc, sp, int_regs, fp_regs);
 181 }
 182
 183 void
 184 mono_arm_resume_unwind (guint32 dummy1, mgreg_t pc, mgreg_t sp, mgreg_t *int_regs, gdouble *fp_regs)
 185 {
 186         MonoContext ctx;
 187
 188         pc &= ~1; /* clear the optional rethrow bit */
 189         /* adjust eip so that it point into the call instruction */
 190         pc -= 4;
 191
 192         MONO_CONTEXT_SET_BP (&ctx, int_regs [ARMREG_FP - 4]);
 193         MONO_CONTEXT_SET_SP (&ctx, sp);
 194         MONO_CONTEXT_SET_IP (&ctx, pc);
 195         memcpy (((guint8*)&ctx.regs) + (ARMREG_R4 * sizeof (mgreg_t)), int_regs, 8 * sizeof (mgreg_t));
 196
 197         mono_resume_unwind (&ctx);
 198 }
 199
 200 /**
 201  * get_throw_trampoline:
 202  *
 203  * Returns a function pointer which can be used to raise
 204  * exceptions. The returned function has the following
 205  * signature: void (*func) (MonoException *exc); or
 206  * void (*func) (guint32 ex_token, guint8* ip);
 207  *
 208  */
 209 static gpointer
 210 get_throw_trampoline (int size, gboolean corlib, gboolean rethrow, gboolean llvm, gboolean resume_unwind, const char *tramp_name, MonoTrampInfo **info, gboolean aot)
 211 {
 212         guint8 *start;
 213         guint8 *code;
 214         MonoJumpInfo *ji = NULL;
 215         GSList *unwind_ops = NULL;
 216         int cfa_offset;
 217
 218         code = start = mono_global_codeman_reserve (size);
 219
 220         mono_add_unwind_op_def_cfa (unwind_ops, code, start, ARMREG_SP, 0);
 221
 222         /* save all the regs on the stack */
 223         ARM_MOV_REG_REG (code, ARMREG_IP, ARMREG_SP);
 224         ARM_PUSH (code, MONO_ARM_REGSAVE_MASK);
 225
 226         cfa_offset = MONO_ARM_NUM_SAVED_REGS * sizeof (mgreg_t);
 227         mono_add_unwind_op_def_cfa (unwind_ops, code, start, ARMREG_SP, cfa_offset);
 228         mono_add_unwind_op_offset (unwind_ops, code, start, ARMREG_LR, - sizeof (mgreg_t));
 229
 230         /* Save fp regs */
 231         if (!mono_arch_is_soft_float ()) {
 232                 ARM_SUB_REG_IMM8 (code, ARMREG_SP, ARMREG_SP, sizeof (double) * 16);
 233                 cfa_offset += sizeof (double) * 16;
 234                 mono_add_unwind_op_def_cfa_offset (unwind_ops, code, start, cfa_offset);
 235                 ARM_FSTMD (code, ARM_VFP_D0, 16, ARMREG_SP);
 236         }
 237
 238         /* Param area */
 239         ARM_SUB_REG_IMM8 (code, ARMREG_SP, ARMREG_SP, 8);
 240         cfa_offset += 8;
 241         mono_add_unwind_op_def_cfa_offset (unwind_ops, code, start, cfa_offset);
 242
 243         /* call throw_exception (exc, ip, sp, int_regs, fp_regs) */
 244         /* caller sp */
 245         ARM_ADD_REG_IMM8 (code, ARMREG_R2, ARMREG_SP, cfa_offset);
 246         /* we encode rethrow in sp */
 247         if (rethrow) {
 248                 g_assert (!resume_unwind);
 249                 g_assert (!corlib);
 250                 ARM_ORR_REG_IMM8 (code, ARMREG_R2, ARMREG_R2, rethrow);
 251         }
 252         /* exc is already in place in r0 */
 253         if (corlib) {
 254                 /* The caller ip is already in R1 */
 255                 if (llvm) {
 256                         /*
 257                          * The address passed by llvm might point to before the call,
 258                          * thus outside the eh range recorded by llvm. Use the return
 259                          * address instead.
 260                          * FIXME: Do this on more platforms.
 261                          */
 262                         ARM_MOV_REG_REG (code, ARMREG_R1, ARMREG_LR); /* caller ip */
 263                 }
 264         } else {
 265                 ARM_MOV_REG_REG (code, ARMREG_R1, ARMREG_LR); /* caller ip */
 266         }
 267         /* int regs */
 268         ARM_ADD_REG_IMM8 (code, ARMREG_R3, ARMREG_SP, (cfa_offset - (MONO_ARM_NUM_SAVED_REGS * sizeof (mgreg_t))));
 269         /* fp regs */
 270         ARM_ADD_REG_IMM8 (code, ARMREG_LR, ARMREG_SP, 8);
 271         ARM_STR_IMM (code, ARMREG_LR, ARMREG_SP, 0);
 272
 273         if (aot) {
 274                 const char *icall_name;
 275
 276                 if (resume_unwind)
 277                         icall_name = "mono_arm_resume_unwind";
 278                 else if (corlib)
 279                         icall_name = "mono_arm_throw_exception_by_token";
 280                 else
 281                         icall_name = "mono_arm_throw_exception";
 282
 283                 ji = mono_patch_info_list_prepend (ji, code - start, MONO_PATCH_INFO_JIT_ICALL_ADDR, icall_name);
 284                 ARM_LDR_IMM (code, ARMREG_IP, ARMREG_PC, 0);
 285                 ARM_B (code, 0);
 286                 *(gpointer*)(gpointer)code = NULL;
 287                 code += 4;
 288                 ARM_LDR_REG_REG (code, ARMREG_IP, ARMREG_PC, ARMREG_IP);
 289         } else {
 290                 code = mono_arm_emit_load_imm (code, ARMREG_IP, GPOINTER_TO_UINT (resume_unwind ? (gpointer)mono_arm_resume_unwind : (corlib ? (gpointer)mono_arm_throw_exception_by_token : (gpointer)mono_arm_throw_exception)));
 291         }
 292         ARM_MOV_REG_REG (code, ARMREG_LR, ARMREG_PC);
 293         ARM_MOV_REG_REG (code, ARMREG_PC, ARMREG_IP);
 294         /* we should never reach this breakpoint */
 295         ARM_DBRK (code);
 296         g_assert ((code - start) < size);
 297         mono_arch_flush_icache (start, code - start);
 298
 299         if (info)
 300                 *info = mono_tramp_info_create (tramp_name, start, code - start, ji, unwind_ops);
 301
 302         return start;
 303 }
 304
 305 /**
 306  * arch_get_throw_exception:
 307  *
 308  * Returns a function pointer which can be used to raise
 309  * exceptions. The returned function has the following
 310  * signature: void (*func) (MonoException *exc);
 311  * For example to raise an arithmetic exception you can use:
 312  *
 313  * x86_push_imm (code, mono_get_exception_arithmetic ());
 314  * x86_call_code (code, arch_get_throw_exception ());
 315  *
 316  */
 317 gpointer
 318 mono_arch_get_throw_exception (MonoTrampInfo **info, gboolean aot)
 319 {
 320         return get_throw_trampoline (132, FALSE, FALSE, FALSE, FALSE, "throw_exception", info, aot);
 321 }
 322
 323 /**
 324  * mono_arch_get_rethrow_exception:
 325  *
 326  * Returns a function pointer which can be used to rethrow
 327  * exceptions. The returned function has the following
 328  * signature: void (*func) (MonoException *exc);
 329  *
 330  */
 331 gpointer
 332 mono_arch_get_rethrow_exception (MonoTrampInfo **info, gboolean aot)
 333 {
 334         return get_throw_trampoline (132, FALSE, TRUE, FALSE, FALSE, "rethrow_exception", info, aot);
 335 }
 336
 337 /**
 338  * mono_arch_get_throw_corlib_exception:
 339  *
 340  * Returns a function pointer which can be used to raise
 341  * corlib exceptions. The returned function has the following
 342  * signature: void (*func) (guint32 ex_token, guint32 offset);
 343  * Here, offset is the offset which needs to be substracted from the caller IP
 344  * to get the IP of the throw. Passing the offset has the advantage that it
 345  * needs no relocations in the caller.
 346  * On ARM, the ip is passed instead of an offset.
 347  */
 348 gpointer
 349 mono_arch_get_throw_corlib_exception (MonoTrampInfo **info, gboolean aot)
 350 {
 351         return get_throw_trampoline (168, TRUE, FALSE, FALSE, FALSE, "throw_corlib_exception", info, aot);
 352 }
 353
 354 GSList*
 355 mono_arm_get_exception_trampolines (gboolean aot)
 356 {
 357         MonoTrampInfo *info;
 358         GSList *tramps = NULL;
 359
 360         /* LLVM uses the normal trampolines, but with a different name */
 361         get_throw_trampoline (168, TRUE, FALSE, FALSE, FALSE, "llvm_throw_corlib_exception_trampoline", &info, aot);
 362         tramps = g_slist_prepend (tramps, info);
 363
 364         get_throw_trampoline (168, TRUE, FALSE, TRUE, FALSE, "llvm_throw_corlib_exception_abs_trampoline", &info, aot);
 365         tramps = g_slist_prepend (tramps, info);
 366
 367         get_throw_trampoline (168, FALSE, FALSE, FALSE, TRUE, "llvm_resume_unwind_trampoline", &info, aot);
 368         tramps = g_slist_prepend (tramps, info);
 369
 370         return tramps;
 371 }
 372
 373 void
 374 mono_arch_exceptions_init (void)
 375 {
 376         guint8 *tramp;
 377         GSList *tramps, *l;
 378
 379         if (mono_aot_only) {
 380                 tramp = mono_aot_get_trampoline ("llvm_throw_corlib_exception_trampoline");
 381                 mono_register_jit_icall (tramp, "llvm_throw_corlib_exception_trampoline", NULL, TRUE);
 382                 tramp = mono_aot_get_trampoline ("llvm_throw_corlib_exception_abs_trampoline");
 383                 mono_register_jit_icall (tramp, "llvm_throw_corlib_exception_abs_trampoline", NULL, TRUE);
 384                 tramp = mono_aot_get_trampoline ("llvm_resume_unwind_trampoline");
 385                 mono_register_jit_icall (tramp, "llvm_resume_unwind_trampoline", NULL, TRUE);
 386         } else {
 387                 tramps = mono_arm_get_exception_trampolines (FALSE);
 388                 for (l = tramps; l; l = l->next) {
 389                         MonoTrampInfo *info = l->data;
 390
 391                         mono_register_jit_icall (info->code, g_strdup (info->name), NULL, TRUE);
 392                         mono_tramp_info_register (info, NULL);
 393                 }
 394                 g_slist_free (tramps);
 395         }
 396 }
 397
 398 /*
 399  * mono_arch_unwind_frame:
 400  *
 401  * See exceptions-amd64.c for docs;
 402  */
 403 gboolean
 404 mono_arch_unwind_frame (MonoDomain *domain, MonoJitTlsData *jit_tls,
 405                                                          MonoJitInfo *ji, MonoContext *ctx,
 406                                                          MonoContext *new_ctx, MonoLMF **lmf,
 407                                                          mgreg_t **save_locations,
 408                                                          StackFrameInfo *frame)
 409 {
 410         gpointer ip = MONO_CONTEXT_GET_IP (ctx);
 411
 412         memset (frame, 0, sizeof (StackFrameInfo));
 413         frame->ji = ji;
 414
 415         *new_ctx = *ctx;
 416
 417         if (ji != NULL) {
 418                 int i;
 419                 mono_unwind_reg_t regs [MONO_MAX_IREGS + 1 + 8];
 420                 guint8 *cfa;
 421                 guint32 unwind_info_len;
 422                 guint8 *unwind_info;
 423
 424                 if (ji->is_trampoline)
 425                         frame->type = FRAME_TYPE_TRAMPOLINE;
 426                 else
 427                         frame->type = FRAME_TYPE_MANAGED;
 428
 429                 unwind_info = mono_jinfo_get_unwind_info (ji, &unwind_info_len);
 430
 431                 /*
 432                 printf ("%s %p %p\n", ji->d.method->name, ji->code_start, ip);
 433                 mono_print_unwind_info (unwind_info, unwind_info_len);
 434                 */
 435
 436                 for (i = 0; i < 16; ++i)
 437                         regs [i] = new_ctx->regs [i];
 438 #ifdef TARGET_IOS
 439                 /* On IOS, d8..d15 are callee saved. They are mapped to 8..15 in unwind.c */
 440                 for (i = 0; i < 8; ++i)
 441                         regs [MONO_MAX_IREGS + i] = *(guint64*)&(new_ctx->fregs [8 + i]);
 442 #endif
 443
 444                 mono_unwind_frame (unwind_info, unwind_info_len, ji->code_start,
 445                                                    (guint8*)ji->code_start + ji->code_size,
 446                                                    ip, NULL, regs, MONO_MAX_IREGS + 8,
 447                                                    save_locations, MONO_MAX_IREGS, &cfa);
 448
 449                 for (i = 0; i < 16; ++i)
 450                         new_ctx->regs [i] = regs [i];
 451                 new_ctx->pc = regs [ARMREG_LR];
 452                 new_ctx->regs [ARMREG_SP] = (gsize)cfa;
 453 #ifdef TARGET_IOS
 454                 for (i = 0; i < 8; ++i)
 455                         new_ctx->fregs [8 + i] = *(double*)&(regs [MONO_MAX_IREGS + i]);
 456 #endif
 457
 458                 /* Clear thumb bit */
 459                 new_ctx->pc &= ~1;
 460
 461                 /* we substract 1, so that the IP points into the call instruction */
 462                 new_ctx->pc--;
 463
 464                 return TRUE;
 465         } else if (*lmf) {
 466
 467                 if (((gsize)(*lmf)->previous_lmf) & 2) {
 468                         /*
 469                          * This LMF entry is created by the soft debug code to mark transitions to
 470                          * managed code done during invokes.
 471                          */
 472                         MonoLMFExt *ext = (MonoLMFExt*)(*lmf);
 473
 474                         g_assert (ext->debugger_invoke);
 475
 476                         memcpy (new_ctx, &ext->ctx, sizeof (MonoContext));
 477
 478                         *lmf = (gpointer)(((gsize)(*lmf)->previous_lmf) & ~3);
 479
 480                         frame->type = FRAME_TYPE_DEBUGGER_INVOKE;
 481
 482                         return TRUE;
 483                 }
 484
 485                 frame->type = FRAME_TYPE_MANAGED_TO_NATIVE;
 486
 487                 if ((ji = mini_jit_info_table_find (domain, (gpointer)(*lmf)->ip, NULL))) {
 488                         frame->ji = ji;
 489                 } else {
 490                         if (!(*lmf)->method)
 491                                 return FALSE;
 492                         frame->method = (*lmf)->method;
 493                 }
 494
 495                 /*
 496                  * The LMF is saved at the start of the method using:
 497                  * ARM_MOV_REG_REG (code, ARMREG_IP, ARMREG_SP)
 498                  * ARM_PUSH (code, 0x5ff0);
 499                  * So it stores the register state as it existed at the caller. We need to
 500                  * produce the register state which existed at the time of the call which
 501                  * transitioned to native call, so we save the sp/fp/ip in the LMF.
 502                  */
 503                 memcpy (&new_ctx->regs [0], &(*lmf)->iregs [0], sizeof (mgreg_t) * 13);
 504                 new_ctx->pc = (*lmf)->ip;
 505                 new_ctx->regs [ARMREG_SP] = (*lmf)->sp;
 506                 new_ctx->regs [ARMREG_FP] = (*lmf)->fp;
 507
 508                 /* Clear thumb bit */
 509                 new_ctx->pc &= ~1;
 510
 511                 /* we substract 1, so that the IP points into the call instruction */
 512                 new_ctx->pc--;
 513
 514                 *lmf = (gpointer)(((gsize)(*lmf)->previous_lmf) & ~3);
 515
 516                 return TRUE;
 517         }
 518
 519         return FALSE;
 520 }
 521
 522 /*
 523  * handle_exception:
 524  *
 525  *   Called by resuming from a signal handler.
 526  */
 527 static void
 528 handle_signal_exception (gpointer obj)
 529 {
 530         MonoJitTlsData *jit_tls = mono_native_tls_get_value (mono_jit_tls_id);
 531         MonoContext ctx;
 532
 533         memcpy (&ctx, &jit_tls->ex_ctx, sizeof (MonoContext));
 534
 535         mono_handle_exception (&ctx, obj);
 536
 537         mono_restore_context (&ctx);
 538 }
 539
 540 /*
 541  * This works around a gcc 4.5 bug:
 542  * https://bugs.launchpad.net/ubuntu/+source/gcc-4.5/+bug/721531
 543  */
 544 static MONO_NEVER_INLINE gpointer
 545 get_handle_signal_exception_addr (void)
 546 {
 547         return handle_signal_exception;
 548 }
 549
 550 /*
 551  * This is the function called from the signal handler
 552  */
 553 gboolean
 554 mono_arch_handle_exception (void *ctx, gpointer obj)
 555 {
 556 #if defined(MONO_CROSS_COMPILE) || !defined(MONO_ARCH_HAVE_SIGCTX_TO_MONOCTX)
 557         g_assert_not_reached ();
 558 #elif defined(MONO_ARCH_USE_SIGACTION)
 559         arm_ucontext *sigctx = ctx;
 560         /*
 561          * Handling the exception in the signal handler is problematic, since the original
 562          * signal is disabled, and we could run arbitrary code though the debugger. So
 563          * resume into the normal stack and do most work there if possible.
 564          */
 565         MonoJitTlsData *jit_tls = mono_native_tls_get_value (mono_jit_tls_id);
 566         guint64 sp = UCONTEXT_REG_SP (sigctx);
 567
 568         /* Pass the ctx parameter in TLS */
 569         mono_sigctx_to_monoctx (sigctx, &jit_tls->ex_ctx);
 570         /* The others in registers */
 571         UCONTEXT_REG_R0 (sigctx) = (gsize)obj;
 572
 573         /* Allocate a stack frame */
 574         sp -= 16;
 575         UCONTEXT_REG_SP (sigctx) = sp;
 576
 577         UCONTEXT_REG_PC (sigctx) = (gsize)get_handle_signal_exception_addr ();
 578 #ifdef UCONTEXT_REG_CPSR
 579         if ((gsize)UCONTEXT_REG_PC (sigctx) & 1)
 580                 /* Transition to thumb */
 581                 UCONTEXT_REG_CPSR (sigctx) |= (1 << 5);
 582         else
 583                 /* Transition to ARM */
 584                 UCONTEXT_REG_CPSR (sigctx) &= ~(1 << 5);
 585 #endif
 586
 587         return TRUE;
 588 #else
 589         MonoContext mctx;
 590         gboolean result;
 591
 592         mono_sigctx_to_monoctx (ctx, &mctx);
 593
 594         result = mono_handle_exception (&mctx, obj);
 595         /* restore the context so that returning from the signal handler will invoke
 596          * the catch clause
 597          */
 598         mono_monoctx_to_sigctx (&mctx, ctx);
 599         return result;
 600 #endif
 601 }
 602
 603 gpointer
 604 mono_arch_ip_from_context (void *sigctx)
 605 {
 606 #ifdef MONO_CROSS_COMPILE
 607         g_assert_not_reached ();
 608 #else
 609         arm_ucontext *my_uc = sigctx;
 610         return (void*) UCONTEXT_REG_PC (my_uc);
 611 #endif
 612 }
 613
 614 void
 615 mono_arch_setup_async_callback (MonoContext *ctx, void (*async_cb)(void *fun), gpointer user_data)
 616 {
 617         mgreg_t sp = (mgreg_t)MONO_CONTEXT_GET_SP (ctx);
 618
 619         // FIXME:
 620         g_assert (!user_data);
 621
 622         /* Allocate a stack frame */
 623         sp -= 16;
 624         MONO_CONTEXT_SET_SP (ctx, sp);
 625
 626         mono_arch_setup_resume_sighandler_ctx (ctx, async_cb);
 627 }
 628
 629 /*
 630  * mono_arch_setup_resume_sighandler_ctx:
 631  *
 632  *   Setup CTX so execution continues at FUNC.
 633  */
 634 void
 635 mono_arch_setup_resume_sighandler_ctx (MonoContext *ctx, gpointer func)
 636 {
 637         MONO_CONTEXT_SET_IP (ctx,func);
 638         if ((mgreg_t)MONO_CONTEXT_GET_IP (ctx) & 1)
 639                 /* Transition to thumb */
 640                 ctx->cpsr |= (1 << 5);
 641         else
 642                 /* Transition to ARM */
 643                 ctx->cpsr &= ~(1 << 5);
 644 }