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 #include <ucontext.h>
  16
  17 #include <mono/arch/arm/arm-codegen.h>
  18 #include <mono/metadata/appdomain.h>
  19 #include <mono/metadata/tabledefs.h>
  20 #include <mono/metadata/threads.h>
  21 #include <mono/metadata/debug-helpers.h>
  22 #include <mono/metadata/exception.h>
  23 #include <mono/metadata/mono-debug.h>
  24
  25 #include "mini.h"
  26 #include "mini-arm.h"
  27
  28 /*
  29
  30 struct sigcontext {
  31         unsigned long trap_no;
  32         unsigned long error_code;
  33         unsigned long oldmask;
  34         unsigned long arm_r0;
  35         unsigned long arm_r1;
  36         unsigned long arm_r2;
  37         unsigned long arm_r3;
  38         unsigned long arm_r4;
  39         unsigned long arm_r5;
  40         unsigned long arm_r6;
  41         unsigned long arm_r7;
  42         unsigned long arm_r8;
  43         unsigned long arm_r9;
  44         unsigned long arm_r10;
  45         unsigned long arm_fp;
  46         unsigned long arm_ip;
  47         unsigned long arm_sp;
  48         unsigned long arm_lr;
  49         unsigned long arm_pc;
  50         unsigned long arm_cpsr;
  51         unsigned long fault_address;
  52 };
  53
  54 gregs below is this struct
  55 struct user_regs {
  56         unsigned long int uregs[18];
  57 };
  58
  59 the companion user_fpregs has just 8 double registers
  60 (it's valid for FPA mode, will need changes for VFP)
  61
  62 typedef struct {
  63         gregset_t gregs;
  64         fpregset_t fpregs;
  65 } mcontext_t;
  66
  67 typedef struct ucontext {
  68         unsigned long int uc_flags;
  69         struct ucontext *uc_link;
  70         __sigset_t uc_sigmask;
  71         stack_t uc_stack;
  72         mcontext_t uc_mcontext;
  73         long int uc_filler[5];
  74 } ucontext_t;
  75
  76 */
  77
  78 /*
  79  * So, it turns out that the ucontext struct defined by libc is incorrect.
  80  * We define our own version here and use it instead.
  81  */
  82
  83 #if __APPLE__
  84 #define my_ucontext ucontext_t
  85 #else
  86 typedef struct my_ucontext {
  87         unsigned long       uc_flags;
  88         struct my_ucontext *uc_link;
  89         struct {
  90                 void *p;
  91                 int flags;
  92                 size_t size;
  93         } sstack_data;
  94         struct sigcontext sig_ctx;
  95         /* some 2.6.x kernel has fp data here after a few other fields
  96          * we don't use them for now...
  97          */
  98 } my_ucontext;
  99 #endif
 100
 101 #define restore_regs_from_context(ctx_reg,ip_reg,tmp_reg) do {  \
 102                 ARM_LDR_IMM (code, ip_reg, ctx_reg, G_STRUCT_OFFSET (MonoContext, eip));        \
 103                 ARM_ADD_REG_IMM8 (code, tmp_reg, ctx_reg, G_STRUCT_OFFSET(MonoContext, regs));  \
 104                 ARM_LDMIA (code, tmp_reg, MONO_ARM_REGSAVE_MASK);       \
 105         } while (0)
 106
 107 /* nothing to do */
 108 #define setup_context(ctx)
 109
 110 /*
 111  * arch_get_restore_context:
 112  *
 113  * Returns a pointer to a method which restores a previously saved sigcontext.
 114  * The first argument in r0 is the pointer to the context.
 115  */
 116 gpointer
 117 mono_arch_get_restore_context_full (guint32 *code_size, MonoJumpInfo **ji, gboolean aot)
 118 {
 119         guint8 *code;
 120         guint8 *start;
 121
 122         *ji = NULL;
 123
 124         start = code = mono_global_codeman_reserve (128);
 125
 126         restore_regs_from_context (ARMREG_R0, ARMREG_R1, ARMREG_R2);
 127         /* restore also the stack pointer, FIXME: handle sp != fp */
 128         ARM_LDR_IMM (code, ARMREG_SP, ARMREG_R0, G_STRUCT_OFFSET (MonoContext, ebp));
 129         ARM_LDR_IMM (code, ARMREG_FP, ARMREG_R0, G_STRUCT_OFFSET (MonoContext, esp));
 130
 131         /* jump to the saved IP */
 132         ARM_MOV_REG_REG (code, ARMREG_PC, ARMREG_R1);
 133         /* never reached */
 134         ARM_DBRK (code);
 135
 136         g_assert ((code - start) < 128);
 137
 138         mono_arch_flush_icache (start, code - start);
 139
 140         *code_size = code - start;
 141
 142         return start;
 143 }
 144
 145 /*
 146  * arch_get_call_filter:
 147  *
 148  * Returns a pointer to a method which calls an exception filter. We
 149  * also use this function to call finally handlers (we pass NULL as
 150  * @exc object in this case).
 151  */
 152 gpointer
 153 mono_arch_get_call_filter_full (guint32 *code_size, MonoJumpInfo **ji, gboolean aot)
 154 {
 155         guint8 *code;
 156         guint8* start;
 157
 158         *ji = NULL;
 159
 160         /* call_filter (MonoContext *ctx, unsigned long eip, gpointer exc) */
 161         start = code = mono_global_codeman_reserve (320);
 162
 163         /* save all the regs on the stack */
 164         ARM_MOV_REG_REG (code, ARMREG_IP, ARMREG_SP);
 165         ARM_PUSH (code, MONO_ARM_REGSAVE_MASK);
 166
 167         /* restore all the regs from ctx (in r0), but not sp, the stack pointer */
 168         restore_regs_from_context (ARMREG_R0, ARMREG_IP, ARMREG_LR);
 169         /* call handler at eip (r1) and set the first arg with the exception (r2) */
 170         ARM_MOV_REG_REG (code, ARMREG_R0, ARMREG_R2);
 171         ARM_MOV_REG_REG (code, ARMREG_LR, ARMREG_PC);
 172         ARM_MOV_REG_REG (code, ARMREG_PC, ARMREG_R1);
 173
 174         /* epilog */
 175         ARM_POP_NWB (code, 0xff0 | ((1 << ARMREG_SP) | (1 << ARMREG_PC)));
 176
 177         g_assert ((code - start) < 320);
 178
 179         mono_arch_flush_icache (start, code - start);
 180
 181         *code_size = code - start;
 182
 183         return start;
 184 }
 185
 186 void
 187 mono_arm_throw_exception (MonoObject *exc, unsigned long eip, unsigned long esp, gulong *int_regs, gdouble *fp_regs)
 188 {
 189         static void (*restore_context) (MonoContext *);
 190         MonoContext ctx;
 191         gboolean rethrow = eip & 1;
 192
 193         if (!restore_context)
 194                 restore_context = mono_get_restore_context ();
 195
 196         eip &= ~1; /* clear the optional rethrow bit */
 197         /* adjust eip so that it point into the call instruction */
 198         eip -= 4;
 199
 200         setup_context (&ctx);
 201
 202         /*printf ("stack in throw: %p\n", esp);*/
 203         MONO_CONTEXT_SET_BP (&ctx, esp);
 204         MONO_CONTEXT_SET_SP (&ctx, esp);
 205         MONO_CONTEXT_SET_IP (&ctx, eip);
 206         memcpy (&ctx.regs, int_regs, sizeof (gulong) * 8);
 207         /* memcpy (&ctx.fregs, fp_regs, sizeof (double) * MONO_SAVED_FREGS); */
 208
 209         if (mono_object_isinst (exc, mono_defaults.exception_class)) {
 210                 MonoException *mono_ex = (MonoException*)exc;
 211                 if (!rethrow)
 212                         mono_ex->stack_trace = NULL;
 213         }
 214         mono_handle_exception (&ctx, exc, (gpointer)(eip + 4), FALSE);
 215         restore_context (&ctx);
 216         g_assert_not_reached ();
 217 }
 218
 219 void
 220 mono_arm_throw_exception_by_token (guint32 type_token, unsigned long eip, unsigned long esp, gulong *int_regs, gdouble *fp_regs)
 221 {
 222         mono_arm_throw_exception ((MonoObject*)mono_exception_from_token (mono_defaults.corlib, type_token), eip, esp, int_regs, fp_regs);
 223 }
 224
 225 /**
 226  * arch_get_throw_exception_generic:
 227  *
 228  * Returns a function pointer which can be used to raise
 229  * exceptions. The returned function has the following
 230  * signature: void (*func) (MonoException *exc); or
 231  * void (*func) (guint32 ex_token, guint8* ip);
 232  *
 233  */
 234 static gpointer
 235 mono_arch_get_throw_exception_generic (int size, int by_token, gboolean rethrow, guint32 *code_size, MonoJumpInfo **ji, gboolean aot)
 236 {
 237         guint8 *start;
 238         guint8 *code;
 239
 240         *ji = NULL;
 241
 242         code = start = mono_global_codeman_reserve (size);
 243
 244         /* save all the regs on the stack */
 245         ARM_MOV_REG_REG (code, ARMREG_IP, ARMREG_SP);
 246         ARM_PUSH (code, MONO_ARM_REGSAVE_MASK);
 247
 248         /* call throw_exception (exc, ip, sp, int_regs, fp_regs) */
 249         /* caller sp */
 250         ARM_ADD_REG_IMM8 (code, ARMREG_R2, ARMREG_SP, 10 * 4); /* 10 saved regs */
 251         /* exc is already in place in r0 */
 252         if (by_token) {
 253                 /* The caller ip is already in R1 */
 254         } else {
 255                 ARM_MOV_REG_REG (code, ARMREG_R1, ARMREG_LR); /* caller ip */
 256         }
 257         /* FIXME: pointer to the saved fp regs */
 258         /*pos = alloc_size - sizeof (double) * MONO_SAVED_FREGS;
 259         ppc_addi (code, ppc_r7, ppc_sp, pos);*/
 260         /* pointer to the saved int regs */
 261         ARM_MOV_REG_REG (code, ARMREG_R3, ARMREG_SP); /* the pushed regs */
 262         /* we encode rethrow in the ip, so we avoid args on the stack */
 263         ARM_ORR_REG_IMM8 (code, ARMREG_R1, ARMREG_R1, rethrow);
 264
 265         if (aot) {
 266                 *ji = mono_patch_info_list_prepend (*ji, code - start, MONO_PATCH_INFO_JIT_ICALL_ADDR, by_token ? "mono_arm_throw_exception_by_token" : "mono_arm_throw_exception");
 267                 ARM_LDR_IMM (code, ARMREG_IP, ARMREG_PC, 0);
 268                 ARM_B (code, 0);
 269                 *(gpointer*)(gpointer)code = NULL;
 270                 code += 4;
 271                 ARM_LDR_REG_REG (code, ARMREG_IP, ARMREG_PC, ARMREG_IP);
 272         } else {
 273                 code = mono_arm_emit_load_imm (code, ARMREG_IP, GPOINTER_TO_UINT (by_token ? (gpointer)mono_arm_throw_exception_by_token : (gpointer)mono_arm_throw_exception));
 274         }
 275         ARM_MOV_REG_REG (code, ARMREG_LR, ARMREG_PC);
 276         ARM_MOV_REG_REG (code, ARMREG_PC, ARMREG_IP);
 277         /* we should never reach this breakpoint */
 278         ARM_DBRK (code);
 279         g_assert ((code - start) < size);
 280         mono_arch_flush_icache (start, code - start);
 281
 282         *code_size = code - start;
 283
 284         return start;
 285 }
 286
 287 /**
 288  * mono_arch_get_rethrow_exception:
 289  *
 290  * Returns a function pointer which can be used to rethrow
 291  * exceptions. The returned function has the following
 292  * signature: void (*func) (MonoException *exc);
 293  *
 294  */
 295 gpointer
 296 mono_arch_get_rethrow_exception_full (guint32 *code_size, MonoJumpInfo **ji, gboolean aot)
 297 {
 298         return mono_arch_get_throw_exception_generic (132, FALSE, TRUE, code_size, ji, aot);
 299 }
 300
 301 /**
 302  * arch_get_throw_exception:
 303  *
 304  * Returns a function pointer which can be used to raise
 305  * exceptions. The returned function has the following
 306  * signature: void (*func) (MonoException *exc);
 307  * For example to raise an arithmetic exception you can use:
 308  *
 309  * x86_push_imm (code, mono_get_exception_arithmetic ());
 310  * x86_call_code (code, arch_get_throw_exception ());
 311  *
 312  */
 313 gpointer
 314 mono_arch_get_throw_exception_full (guint32 *code_size, MonoJumpInfo **ji, gboolean aot)
 315 {
 316         return mono_arch_get_throw_exception_generic (132, FALSE, FALSE, code_size, ji, aot);
 317 }
 318
 319 gpointer
 320 mono_arch_get_throw_exception_by_name_full (guint32 *code_size, MonoJumpInfo **ji, gboolean aot)
 321 {
 322         guint8* start;
 323         guint8 *code;
 324
 325         *ji = NULL;
 326
 327         start = code = mono_global_codeman_reserve (64);
 328
 329         /* Not used on ARM */
 330         ARM_DBRK (code);
 331
 332         *code_size = code - start;
 333
 334         return start;
 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_full (guint32 *code_size, MonoJumpInfo **ji, gboolean aot)
 350 {
 351         return mono_arch_get_throw_exception_generic (168, TRUE, FALSE, code_size, ji, aot);
 352 }
 353
 354 /* mono_arch_find_jit_info:
 355  *
 356  * This function is used to gather information from @ctx. It return the
 357  * MonoJitInfo of the corresponding function, unwinds one stack frame and
 358  * stores the resulting context into @new_ctx. It also stores a string
 359  * describing the stack location into @trace (if not NULL), and modifies
 360  * the @lmf if necessary. @native_offset return the IP offset from the
 361  * start of the function or -1 if that info is not available.
 362  */
 363 MonoJitInfo *
 364 mono_arch_find_jit_info (MonoDomain *domain, MonoJitTlsData *jit_tls, MonoJitInfo *res, MonoJitInfo *prev_ji,
 365                          MonoContext *ctx, MonoContext *new_ctx, MonoLMF **lmf, gboolean *managed)
 366 {
 367         MonoJitInfo *ji;
 368         gpointer ip = MONO_CONTEXT_GET_IP (ctx);
 369
 370         /* Avoid costly table lookup during stack overflow */
 371         if (prev_ji && (ip > prev_ji->code_start && ((guint8*)ip < ((guint8*)prev_ji->code_start) + prev_ji->code_size)))
 372                 ji = prev_ji;
 373         else
 374                 ji = mono_jit_info_table_find (domain, ip);
 375
 376         if (managed)
 377                 *managed = FALSE;
 378
 379         if (ji != NULL) {
 380                 int i;
 381                 gssize regs [MONO_MAX_IREGS + 1];
 382                 guint8 *cfa;
 383                 guint32 unwind_info_len;
 384                 guint8 *unwind_info;
 385
 386                 *new_ctx = *ctx;
 387
 388                 if (managed)
 389                         if (!ji->method->wrapper_type)
 390                                 *managed = TRUE;
 391
 392                 if (ji->from_aot)
 393                         unwind_info = mono_aot_get_unwind_info (ji, &unwind_info_len);
 394                 else
 395                         unwind_info = mono_get_cached_unwind_info (ji->used_regs, &unwind_info_len);
 396
 397                 /* Beautiful numbers */
 398                 for (i = 4; i < 12; ++i)
 399                         regs [i] = new_ctx->regs [i - 4];
 400                 regs [ARMREG_IP] = new_ctx->regs [8];
 401                 regs [ARMREG_LR] = new_ctx->regs [9];
 402                 regs [ARMREG_SP] = new_ctx->esp;
 403
 404                 mono_unwind_frame (unwind_info, unwind_info_len, ji->code_start,
 405                                                    (guint8*)ji->code_start + ji->code_size,
 406                                                    ip, regs, MONO_MAX_IREGS, &cfa);
 407
 408                 for (i = 4; i < 12; ++i)
 409                         new_ctx->regs [i - 4] = regs [i];
 410                 new_ctx->regs [8] = regs [ARMREG_IP];
 411                 new_ctx->regs [9] = regs [ARMREG_LR];
 412                 new_ctx->eip = regs [ARMREG_LR];
 413                 new_ctx->esp = (gsize)cfa;
 414                 new_ctx->ebp = new_ctx->esp;
 415
 416                 /* Needed by get_exception_catch_class () */
 417                 // FIXME: Is this neded ?
 418                 new_ctx->regs [ARMREG_R11] = new_ctx->esp;
 419
 420                 if (*lmf && (MONO_CONTEXT_GET_BP (ctx) >= (gpointer)(*lmf)->ebp)) {
 421                         /* remove any unused lmf */
 422                         *lmf = (*lmf)->previous_lmf;
 423                 }
 424
 425                 /* we substract 1, so that the IP points into the call instruction */
 426                 new_ctx->eip--;
 427
 428                 return ji;
 429         } else if (*lmf) {
 430
 431                 *new_ctx = *ctx;
 432
 433                 if ((ji = mono_jit_info_table_find (domain, (gpointer)(*lmf)->eip))) {
 434                 } else {
 435                         if (!(*lmf)->method)
 436                                 return (gpointer)-1;
 437                         memset (res, 0, sizeof (MonoJitInfo));
 438                         res->method = (*lmf)->method;
 439                 }
 440
 441                 memcpy (&new_ctx->regs [0], &(*lmf)->iregs [4], sizeof (gulong) * MONO_SAVED_GREGS);
 442                 /* This is the sp for the current frame */
 443                 new_ctx->esp = (*lmf)->iregs [ARMREG_FP];
 444                 new_ctx->eip = (*lmf)->iregs [13];
 445                 new_ctx->ebp = new_ctx->esp;
 446
 447                 *lmf = (*lmf)->previous_lmf;
 448
 449                 return ji ? ji : res;
 450         }
 451
 452         return NULL;
 453 }
 454
 455 void
 456 mono_arch_sigctx_to_monoctx (void *sigctx, MonoContext *mctx)
 457 {
 458 #if BROKEN_LINUX
 459         struct ucontext *uc = sigctx;
 460
 461         mctx->eip = uc->uc_mcontext.gregs [ARMREG_PC];
 462         mctx->ebp = uc->uc_mcontext.gregs [ARMREG_SP];
 463         memcpy (&mctx->regs, &uc->uc_mcontext.gregs [ARMREG_R4], sizeof (gulong) * 8);
 464         /* memcpy (&mctx->fregs, &uc->uc_mcontext.uc_regs->fpregs.fpregs [14], sizeof (double) * MONO_SAVED_FREGS);*/
 465 #else
 466         my_ucontext *my_uc = sigctx;
 467
 468         mctx->eip = UCONTEXT_REG_PC (my_uc);
 469         mctx->ebp = UCONTEXT_REG_SP (my_uc);
 470         memcpy (&mctx->regs, &UCONTEXT_REG_R4 (my_uc), sizeof (gulong) * 8);
 471 #endif
 472 }
 473
 474 void
 475 mono_arch_monoctx_to_sigctx (MonoContext *mctx, void *ctx)
 476 {
 477 #if BROKEN_LINUX
 478         struct ucontext *uc = ctx;
 479
 480         uc->uc_mcontext.gregs [ARMREG_PC] = mctx->eip;
 481         uc->uc_mcontext.gregs [ARMREG_SP] = mctx->ebp;
 482         memcpy (&uc->uc_mcontext.gregs [ARMREG_R4], &mctx->regs, sizeof (gulong) * 8);
 483         /* memcpy (&uc->uc_mcontext.uc_regs->fpregs.fpregs [14], &mctx->fregs, sizeof (double) * MONO_SAVED_FREGS);*/
 484 #else
 485         my_ucontext *my_uc = ctx;
 486
 487         UCONTEXT_REG_PC (my_uc) = mctx->eip;
 488         UCONTEXT_REG_SP (my_uc) = mctx->ebp;
 489         memcpy (&UCONTEXT_REG_R4 (my_uc), &mctx->regs, sizeof (gulong) * 8);
 490 #endif
 491 }
 492
 493 /*
 494  * This is the function called from the signal handler
 495  */
 496 gboolean
 497 mono_arch_handle_exception (void *ctx, gpointer obj, gboolean test_only)
 498 {
 499         MonoContext mctx;
 500         gboolean result;
 501
 502         mono_arch_sigctx_to_monoctx (ctx, &mctx);
 503
 504         result = mono_handle_exception (&mctx, obj, (gpointer)mctx.eip, test_only);
 505         /* restore the context so that returning from the signal handler will invoke
 506          * the catch clause
 507          */
 508         mono_arch_monoctx_to_sigctx (&mctx, ctx);
 509         return result;
 510 }
 511
 512 gpointer
 513 mono_arch_ip_from_context (void *sigctx)
 514 {
 515 #if BROKEN_LINUX
 516         struct ucontext *uc = sigctx;
 517         return (gpointer)uc->uc_mcontext.gregs [ARMREG_PC];
 518 #else
 519         my_ucontext *my_uc = sigctx;
 520         return (void*) UCONTEXT_REG_PC (my_uc);
 521 #endif
 522 }
 523
 524 gboolean
 525 mono_arch_has_unwind_info (gconstpointer addr)
 526 {
 527         return FALSE;
 528 }
 529