mono/mini/exceptions-mips.c

   1 /*
   2  * exceptions-mips.c: exception support for MIPS
   3  *
   4  * Authors:
   5  *   Mark Mason (mason@broadcom.com)
   6  *
   7  * Based on exceptions-ppc.c by:
   8  *   Dietmar Maurer (dietmar@ximian.com)
   9  *   Paolo Molaro (lupus@ximian.com)
  10  *
  11  * (C) 2006 Broadcom
  12  * (C) 2001 Ximian, Inc.
  13  */
  14
  15 #include <config.h>
  16 #include <glib.h>
  17 #include <signal.h>
  18 #include <string.h>
  19
  20 #include <mono/arch/mips/mips-codegen.h>
  21 #include <mono/metadata/appdomain.h>
  22 #include <mono/metadata/tabledefs.h>
  23 #include <mono/metadata/threads.h>
  24 #include <mono/metadata/debug-helpers.h>
  25 #include <mono/metadata/exception.h>
  26 #include <mono/metadata/mono-debug.h>
  27
  28 #include "mini.h"
  29 #include "mini-mips.h"
  30
  31 #define GENERIC_EXCEPTION_SIZE 256
  32
  33 /*
  34  * mono_arch_get_restore_context:
  35  *
  36  * Returns a pointer to a method which restores a previously saved MonoContext.
  37  * The first argument in a0 is the pointer to the MonoContext.
  38  */
  39 gpointer
  40 mono_arch_get_restore_context (MonoTrampInfo **info, gboolean aot)
  41 {
  42         int i;
  43         guint8 *code;
  44         static guint8 start [512];
  45         static int inited = 0;
  46         guint32 iregs_to_restore;
  47
  48         g_assert (!aot);
  49         if (info)
  50                 *info = NULL;
  51
  52         if (inited)
  53                 return start;
  54         inited = 1;
  55         code = start;
  56
  57         mips_move (code, mips_at, mips_a0);
  58
  59         iregs_to_restore = (MONO_ARCH_CALLEE_SAVED_REGS \
  60                             | (1 << mips_sp) | (1 << mips_ra));
  61         for (i = 0; i < MONO_SAVED_GREGS; ++i) {
  62                 //if (iregs_to_restore & (1 << i)) {
  63                 if (i != mips_zero && i != mips_at) {
  64                         MIPS_LW (code, i, mips_at, G_STRUCT_OFFSET (MonoContext, sc_regs[i]));
  65                 }
  66         }
  67
  68         /* Get the address to return to */
  69         mips_lw (code, mips_t9, mips_at, G_STRUCT_OFFSET (MonoContext, sc_pc));
  70
  71         /* jump to the saved IP */
  72         mips_jr (code, mips_t9);
  73         mips_nop (code);
  74
  75         /* never reached */
  76         mips_break (code, 0xff);
  77
  78         g_assert ((code - start) < sizeof(start));
  79         mono_arch_flush_icache (start, code - start);
  80         mono_profiler_code_buffer_new (start, code - start, MONO_PROFILER_CODE_BUFFER_EXCEPTION_HANDLING, NULL);
  81         return start;
  82 }
  83
  84 /*
  85  * mono_arch_get_call_filter:
  86  *
  87  * Returns a pointer to a method which calls an exception filter. We
  88  * also use this function to call finally handlers (we pass NULL as
  89  * @exc object in this case).
  90  *
  91  * This function is invoked as
  92  *      call_handler (MonoContext *ctx, handler)
  93  *
  94  * Where 'handler' is a function to be invoked as:
  95  *      handler (void)
  96  */
  97 gpointer
  98 mono_arch_get_call_filter (MonoTrampInfo **info, gboolean aot)
  99 {
 100         static guint8 start [320];
 101         static int inited = 0;
 102         guint8 *code;
 103         int alloc_size;
 104         int offset;
 105
 106         g_assert (!aot);
 107         if (info)
 108                 *info = NULL;
 109
 110         if (inited)
 111                 return start;
 112
 113         inited = 1;
 114         code = start;
 115
 116         alloc_size = 64;
 117         g_assert ((alloc_size & (MIPS_STACK_ALIGNMENT-1)) == 0);
 118
 119         mips_addiu (code, mips_sp, mips_sp, -alloc_size);
 120         mips_sw (code, mips_ra, mips_sp, alloc_size + MIPS_RET_ADDR_OFFSET);
 121
 122         /* Save global registers on stack (s0 - s7) */
 123         offset = 16;
 124         MIPS_SW (code, mips_s0, mips_sp, offset); offset += IREG_SIZE;
 125         MIPS_SW (code, mips_s1, mips_sp, offset); offset += IREG_SIZE;
 126         MIPS_SW (code, mips_s2, mips_sp, offset); offset += IREG_SIZE;
 127         MIPS_SW (code, mips_s3, mips_sp, offset); offset += IREG_SIZE;
 128         MIPS_SW (code, mips_s4, mips_sp, offset); offset += IREG_SIZE;
 129         MIPS_SW (code, mips_s5, mips_sp, offset); offset += IREG_SIZE;
 130         MIPS_SW (code, mips_s6, mips_sp, offset); offset += IREG_SIZE;
 131         MIPS_SW (code, mips_s7, mips_sp, offset); offset += IREG_SIZE;
 132         MIPS_SW (code, mips_fp, mips_sp, offset); offset += IREG_SIZE;
 133
 134         /* Restore global registers from MonoContext, including the frame pointer */
 135         MIPS_LW (code, mips_s0, mips_a0, G_STRUCT_OFFSET (MonoContext, sc_regs[mips_s0]));
 136         MIPS_LW (code, mips_s1, mips_a0, G_STRUCT_OFFSET (MonoContext, sc_regs[mips_s1]));
 137         MIPS_LW (code, mips_s2, mips_a0, G_STRUCT_OFFSET (MonoContext, sc_regs[mips_s2]));
 138         MIPS_LW (code, mips_s3, mips_a0, G_STRUCT_OFFSET (MonoContext, sc_regs[mips_s3]));
 139         MIPS_LW (code, mips_s4, mips_a0, G_STRUCT_OFFSET (MonoContext, sc_regs[mips_s4]));
 140         MIPS_LW (code, mips_s5, mips_a0, G_STRUCT_OFFSET (MonoContext, sc_regs[mips_s5]));
 141         MIPS_LW (code, mips_s6, mips_a0, G_STRUCT_OFFSET (MonoContext, sc_regs[mips_s6]));
 142         MIPS_LW (code, mips_s7, mips_a0, G_STRUCT_OFFSET (MonoContext, sc_regs[mips_s7]));
 143         MIPS_LW (code, mips_fp, mips_a0, G_STRUCT_OFFSET (MonoContext, sc_regs[mips_fp]));
 144
 145         /* a1 is the handler to call */
 146         mips_move (code, mips_t9, mips_a1);
 147
 148         /* jump to the saved IP */
 149         mips_jalr (code, mips_t9, mips_ra);
 150         mips_nop (code);
 151
 152         /* restore all regs from the stack */
 153         offset = 16;
 154         MIPS_LW (code, mips_s0, mips_sp, offset); offset += IREG_SIZE;
 155         MIPS_LW (code, mips_s1, mips_sp, offset); offset += IREG_SIZE;
 156         MIPS_LW (code, mips_s2, mips_sp, offset); offset += IREG_SIZE;
 157         MIPS_LW (code, mips_s3, mips_sp, offset); offset += IREG_SIZE;
 158         MIPS_LW (code, mips_s4, mips_sp, offset); offset += IREG_SIZE;
 159         MIPS_LW (code, mips_s5, mips_sp, offset); offset += IREG_SIZE;
 160         MIPS_LW (code, mips_s6, mips_sp, offset); offset += IREG_SIZE;
 161         MIPS_LW (code, mips_s7, mips_sp, offset); offset += IREG_SIZE;
 162         MIPS_LW (code, mips_fp, mips_sp, offset); offset += IREG_SIZE;
 163
 164         /* epilog */
 165         mips_lw (code, mips_ra, mips_sp, alloc_size + MIPS_RET_ADDR_OFFSET);
 166         mips_addiu (code, mips_sp, mips_sp, alloc_size);
 167         mips_jr (code, mips_ra);
 168         mips_nop (code);
 169
 170         g_assert ((code - start) < sizeof(start));
 171         mono_arch_flush_icache (start, code - start);
 172         mono_profiler_code_buffer_new (start, code - start, MONO_PROFILER_CODE_BUFFER_EXCEPTION_HANDLING, NULL);
 173         return start;
 174 }
 175
 176 static void
 177 throw_exception (MonoObject *exc, unsigned long eip, unsigned long esp, gboolean rethrow)
 178 {
 179         MonoError error;
 180         MonoContext ctx;
 181
 182 #ifdef DEBUG_EXCEPTIONS
 183         g_print ("throw_exception: exc=%p eip=%p esp=%p rethrow=%d\n",
 184                  exc, (void *)eip, (void *) esp, rethrow);
 185 #endif
 186
 187         /* adjust eip so that it point into the call instruction */
 188         eip -= 8;
 189
 190         memset (&ctx, 0, sizeof (MonoContext));
 191
 192         /*g_print  ("stack in throw: %p\n", esp);*/
 193         memcpy (&ctx.sc_regs, (void *)(esp + MIPS_STACK_PARAM_OFFSET),
 194                 sizeof (gulong) * MONO_SAVED_GREGS);
 195         memset (&ctx.sc_fpregs, 0, sizeof (mips_freg) * MONO_SAVED_FREGS);
 196         MONO_CONTEXT_SET_IP (&ctx, eip);
 197
 198         if (mono_object_isinst_checked (exc, mono_defaults.exception_class, &error)) {
 199                 MonoException *mono_ex = (MonoException*)exc;
 200                 if (!rethrow) {
 201                         mono_ex->stack_trace = NULL;
 202                         mono_ex->trace_ips = NULL;
 203                 }
 204         }
 205         mono_error_assert_ok (&error);
 206         mono_handle_exception (&ctx, exc);
 207 #ifdef DEBUG_EXCEPTIONS
 208         g_print ("throw_exception: restore to pc=%p sp=%p fp=%p ctx=%p\n",
 209                  (void *) ctx.sc_pc, (void *) ctx.sc_regs[mips_sp],
 210                  (void *) ctx.sc_regs[mips_fp], &ctx);
 211 #endif
 212         mono_restore_context (&ctx);
 213
 214         g_assert_not_reached ();
 215 }
 216
 217 /**
 218  * arch_get_throw_exception_generic:
 219  *
 220  * Returns a function pointer which can be used to raise
 221  * exceptions. The returned function has the following
 222  * signature: void (*func) (MonoException *exc); or
 223  * void (*func) (char *exc_name);
 224  *
 225  */
 226 static gpointer
 227 mono_arch_get_throw_exception_generic (guint8 *start, int size, int corlib, gboolean rethrow)
 228 {
 229         guint8 *code;
 230         int alloc_size, pos, i;
 231
 232         code = start;
 233
 234         //g_print ("mono_arch_get_throw_exception_generic: code=%p\n", code);
 235
 236         pos = 0;
 237         /* XXX - save all the FP regs on the stack ? */
 238
 239         pos += MONO_MAX_IREGS * sizeof(guint32);
 240
 241         alloc_size = MIPS_MINIMAL_STACK_SIZE + pos + 64;
 242         // align to MIPS_STACK_ALIGNMENT bytes
 243         alloc_size += MIPS_STACK_ALIGNMENT - 1;
 244         alloc_size &= ~(MIPS_STACK_ALIGNMENT - 1);
 245
 246         g_assert ((alloc_size & (MIPS_STACK_ALIGNMENT-1)) == 0);
 247         mips_addiu (code, mips_sp, mips_sp, -alloc_size);
 248         mips_sw (code, mips_ra, mips_sp, alloc_size + MIPS_RET_ADDR_OFFSET);
 249
 250         /* Save all the regs on the stack */
 251         for (i = 0; i < MONO_MAX_IREGS; i++) {
 252                 if (i != mips_sp)
 253                         MIPS_SW (code, i, mips_sp, i*IREG_SIZE + MIPS_STACK_PARAM_OFFSET);
 254                 else {
 255                         mips_addiu (code, mips_at, mips_sp, alloc_size);
 256                         MIPS_SW (code, mips_at, mips_sp, i*IREG_SIZE + MIPS_STACK_PARAM_OFFSET);
 257                 }
 258         }
 259
 260         if (corlib) {
 261                 mips_move (code, mips_a1, mips_a0);
 262                 mips_load (code, mips_a0, mono_defaults.corlib);
 263                 mips_load (code, mips_t9, mono_exception_from_token);
 264                 mips_jalr (code, mips_t9, mips_ra);
 265                 mips_nop (code);
 266                 mips_move (code, mips_a0, mips_v0);
 267         }
 268         /* call throw_exception (exc, ip, sp, rethrow) */
 269
 270         /* exc is already in place in a0 */
 271
 272         /* pointer to ip */
 273         if (corlib)
 274                 mips_lw (code, mips_a1, mips_sp, alloc_size + MIPS_RET_ADDR_OFFSET);
 275         else
 276                 mips_move (code, mips_a1, mips_ra);
 277
 278         /* current sp & rethrow */
 279         mips_move (code, mips_a2, mips_sp);
 280         mips_addiu (code, mips_a3, mips_zero, rethrow);
 281
 282         mips_load (code, mips_t9, throw_exception);
 283         mips_jr (code, mips_t9);
 284         mips_nop (code);
 285         /* we should never reach this breakpoint */
 286         mips_break (code, 0xfe);
 287
 288         g_assert ((code - start) < size);
 289         mono_arch_flush_icache (start, code - start);
 290         mono_profiler_code_buffer_new (start, code - start, MONO_PROFILER_CODE_BUFFER_EXCEPTION_HANDLING, NULL);
 291         return start;
 292 }
 293
 294 /**
 295  * mono_arch_get_rethrow_exception:
 296  *
 297  * Returns a function pointer which can be used to rethrow
 298  * exceptions. The returned function has the following
 299  * signature: void (*func) (MonoException *exc);
 300  *
 301  */
 302 gpointer
 303 mono_arch_get_rethrow_exception (MonoTrampInfo **info, gboolean aot)
 304 {
 305         static guint8 start [GENERIC_EXCEPTION_SIZE];
 306         static int inited = 0;
 307
 308         g_assert (!aot);
 309         if (info)
 310                 *info = NULL;
 311
 312         if (inited)
 313                 return start;
 314         mono_arch_get_throw_exception_generic (start, sizeof (start), FALSE, TRUE);
 315         inited = 1;
 316         return start;
 317 }
 318
 319 /**
 320  * arch_get_throw_exception:
 321  *
 322  * Returns a function pointer which can be used to raise
 323  * exceptions. The returned function has the following
 324  * signature: void (*func) (MonoException *exc);
 325  * For example to raise an arithmetic exception you can use:
 326  *
 327  * x86_push_imm (code, mono_get_exception_arithmetic ());
 328  * x86_call_code (code, arch_get_throw_exception ());
 329  *
 330  */
 331 gpointer
 332 mono_arch_get_throw_exception (MonoTrampInfo **info, gboolean aot)
 333 {
 334         static guint8 start [GENERIC_EXCEPTION_SIZE];
 335         static int inited = 0;
 336
 337         g_assert (!aot);
 338         if (info)
 339                 *info = NULL;
 340
 341         if (inited)
 342                 return start;
 343         mono_arch_get_throw_exception_generic (start, sizeof (start), FALSE, FALSE);
 344         inited = 1;
 345         return start;
 346 }
 347
 348 gpointer
 349 mono_arch_get_throw_exception_by_name (void)
 350 {
 351         guint8 *start, *code;
 352         int size = 64;
 353
 354         /* Not used on MIPS */
 355         start = code = mono_global_codeman_reserve (size);
 356         mips_break (code, 0xfd);
 357         mono_arch_flush_icache (start, code - start);
 358         mono_profiler_code_buffer_new (start, code - start, MONO_PROFILER_CODE_BUFFER_EXCEPTION_HANDLING, NULL);
 359         return start;
 360 }
 361
 362 /**
 363  * mono_arch_get_throw_corlib_exception:
 364  *
 365  * Returns a function pointer which can be used to raise
 366  * corlib exceptions. The returned function has the following
 367  * signature: void (*func) (guint32 ex_token, guint32 offset);
 368  * On MIPS, the offset argument is missing.
 369  */
 370 gpointer
 371 mono_arch_get_throw_corlib_exception (MonoTrampInfo **info, gboolean aot)
 372 {
 373         static guint8 start [GENERIC_EXCEPTION_SIZE];
 374         static int inited = 0;
 375
 376         g_assert (!aot);
 377         if (info)
 378                 *info = NULL;
 379
 380         if (inited)
 381                 return start;
 382         mono_arch_get_throw_exception_generic (start, sizeof (start), TRUE, FALSE);
 383         inited = 1;
 384         return start;
 385 }
 386
 387 /*
 388  * mono_arch_unwind_frame:
 389  *
 390  * This function is used to gather information from @ctx, and store it in @frame_info.
 391  * It unwinds one stack frame, and stores the resulting context into @new_ctx. @lmf
 392  * is modified if needed.
 393  * Returns TRUE on success, FALSE otherwise.
 394  */
 395 gboolean
 396 mono_arch_unwind_frame (MonoDomain *domain, MonoJitTlsData *jit_tls,
 397                                                          MonoJitInfo *ji, MonoContext *ctx,
 398                                                          MonoContext *new_ctx, MonoLMF **lmf,
 399                                                          mgreg_t **save_locations,
 400                                                          StackFrameInfo *frame)
 401 {
 402         memset (frame, 0, sizeof (StackFrameInfo));
 403         frame->ji = ji;
 404
 405         *new_ctx = *ctx;
 406
 407         if (ji != NULL) {
 408                 int i;
 409                 gpointer ip = MONO_CONTEXT_GET_IP (ctx);
 410                 mgreg_t regs [MONO_MAX_IREGS + 1];
 411                 guint8 *cfa;
 412                 guint32 unwind_info_len;
 413                 guint8 *unwind_info;
 414
 415                 if (ji->is_trampoline)
 416                         frame->type = FRAME_TYPE_TRAMPOLINE;
 417                 else
 418                         frame->type = FRAME_TYPE_MANAGED;
 419
 420                 unwind_info = mono_jinfo_get_unwind_info (ji, &unwind_info_len);
 421
 422                 for (i = 0; i < MONO_MAX_IREGS; ++i)
 423                         regs [i] = new_ctx->sc_regs [i];
 424
 425                 mono_unwind_frame (unwind_info, unwind_info_len, ji->code_start,
 426                                                    (guint8*)ji->code_start + ji->code_size,
 427                                                    ip, NULL, regs, MONO_MAX_IREGS,
 428                                                    save_locations, MONO_MAX_IREGS, &cfa);
 429
 430                 for (i = 0; i < MONO_MAX_IREGS; ++i)
 431                         new_ctx->sc_regs [i] = regs [i];
 432                 new_ctx->sc_pc = regs [mips_ra];
 433                 new_ctx->sc_regs [mips_sp] = (mgreg_t)cfa;
 434
 435                 /* we substract 8, so that the IP points into the call instruction */
 436                 MONO_CONTEXT_SET_IP (new_ctx, new_ctx->sc_pc - 8);
 437
 438                 /* Sanity check -- we should have made progress here */
 439                 g_assert (MONO_CONTEXT_GET_SP (new_ctx) != MONO_CONTEXT_GET_SP (ctx));
 440                 return TRUE;
 441         } else if (*lmf) {
 442
 443                 if (((mgreg_t)(*lmf)->previous_lmf) & 2) {
 444                         /*
 445                          * This LMF entry is created by the soft debug code to mark transitions to
 446                          * managed code done during invokes.
 447                          */
 448                         MonoLMFExt *ext = (MonoLMFExt*)(*lmf);
 449
 450                         g_assert (ext->debugger_invoke);
 451
 452                         memcpy (new_ctx, &ext->ctx, sizeof (MonoContext));
 453
 454                         *lmf = (gpointer)(((gsize)(*lmf)->previous_lmf) & ~3);
 455
 456                         frame->type = FRAME_TYPE_DEBUGGER_INVOKE;
 457
 458                         return TRUE;
 459                 }
 460
 461                 if (!(*lmf)->method) {
 462 #ifdef DEBUG_EXCEPTIONS
 463                         g_print ("mono_arch_unwind_frame: bad lmf @ %p\n", (void *) *lmf);
 464 #endif
 465                         return FALSE;
 466                 }
 467                 g_assert (((*lmf)->magic == MIPS_LMF_MAGIC1) || ((*lmf)->magic == MIPS_LMF_MAGIC2));
 468
 469                 ji = mini_jit_info_table_find (domain, (gpointer)(*lmf)->eip, NULL);
 470                 if (!ji) {
 471                         // FIXME: This can happen with multiple appdomains (bug #444383)
 472                         return FALSE;
 473                 }
 474
 475                 frame->ji = ji;
 476                 frame->type = FRAME_TYPE_MANAGED_TO_NATIVE;
 477
 478                 memcpy (&new_ctx->sc_regs, (*lmf)->iregs, sizeof (gulong) * MONO_SAVED_GREGS);
 479                 memcpy (&new_ctx->sc_fpregs, (*lmf)->fregs, sizeof (float) * MONO_SAVED_FREGS);
 480                 MONO_CONTEXT_SET_IP (new_ctx, (*lmf)->eip);
 481                 /* ensure that we've made progress */
 482                 g_assert (new_ctx->sc_pc != ctx->sc_pc);
 483
 484                 *lmf = (gpointer)(((gsize)(*lmf)->previous_lmf) & ~3);
 485
 486                 return TRUE;
 487         }
 488
 489         return FALSE;
 490 }
 491
 492 gpointer
 493 mono_arch_ip_from_context (void *sigctx)
 494 {
 495         return (gpointer)(gsize)UCONTEXT_REG_PC (sigctx);
 496 }
 497
 498 /*
 499  * handle_exception:
 500  *
 501  *   Called by resuming from a signal handler.
 502  */
 503 static void
 504 handle_signal_exception (gpointer obj)
 505 {
 506         MonoJitTlsData *jit_tls = mono_native_tls_get_value (mono_jit_tls_id);
 507         MonoContext ctx;
 508
 509         memcpy (&ctx, &jit_tls->ex_ctx, sizeof (MonoContext));
 510
 511         mono_handle_exception (&ctx, obj);
 512
 513         mono_restore_context (&ctx);
 514 }
 515
 516 /*
 517  * This is the function called from the signal handler
 518  */
 519 gboolean
 520 mono_arch_handle_exception (void *ctx, gpointer obj)
 521 {
 522 #if defined(MONO_CROSS_COMPILE)
 523         g_assert_not_reached ();
 524 #elif defined(MONO_ARCH_USE_SIGACTION)
 525         void *sigctx = ctx;
 526
 527         /*
 528          * Handling the exception in the signal handler is problematic, since the original
 529          * signal is disabled, and we could run arbitrary code though the debugger. So
 530          * resume into the normal stack and do most work there if possible.
 531          */
 532         MonoJitTlsData *jit_tls = mono_native_tls_get_value (mono_jit_tls_id);
 533         guint64 sp = UCONTEXT_GREGS (sigctx) [mips_sp];
 534
 535         /* Pass the ctx parameter in TLS */
 536         mono_sigctx_to_monoctx (sigctx, &jit_tls->ex_ctx);
 537         /* The others in registers */
 538         UCONTEXT_GREGS (sigctx)[mips_a0] = (gsize)obj;
 539
 540         /* Allocate a stack frame */
 541         sp -= 256;
 542         UCONTEXT_GREGS (sigctx)[mips_sp] = sp;
 543
 544         UCONTEXT_REG_PC (sigctx) = (gsize)handle_signal_exception;
 545
 546         return TRUE;
 547 #else
 548         MonoContext mctx;
 549         gboolean result;
 550
 551         mono_sigctx_to_monoctx (ctx, &mctx);
 552
 553         result = mono_handle_exception (&mctx, obj);
 554         /* restore the context so that returning from the signal handler will invoke
 555          * the catch clause
 556          */
 557         mono_monoctx_to_sigctx (&mctx, ctx);
 558         return result;
 559 #endif
 560 }
 561
 562 /*
 563  * mono_arch_setup_resume_sighandler_ctx:
 564  *
 565  *   Setup CTX so execution continues at FUNC.
 566  */
 567 void
 568 mono_arch_setup_resume_sighandler_ctx (MonoContext *ctx, gpointer func)
 569 {
 570         MONO_CONTEXT_SET_IP (ctx,func);
 571 }