mono/mini/exceptions-hppa.c

   1 /*
   2  * exceptions-hppa.c: exception support for HPPA
   3  *
   4  * Copyright (c) 2007 Randolph Chung
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a copy
   7  * of this software and associated documentation files (the "Software"), to deal
   8  * in the Software without restriction, including without limitation the rights
   9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  10  * copies of the Software, and to permit persons to whom the Software is
  11  * furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included in
  14  * all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  19  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  22  * THE SOFTWARE.
  23  *
  24  */
  25
  26 #include <config.h>
  27 #include <glib.h>
  28 #include <signal.h>
  29 #include <string.h>
  30 #include <ucontext.h>
  31
  32 #include <mono/arch/hppa/hppa-codegen.h>
  33 #include <mono/metadata/appdomain.h>
  34 #include <mono/metadata/tabledefs.h>
  35 #include <mono/metadata/threads.h>
  36 #include <mono/metadata/debug-helpers.h>
  37 #include <mono/metadata/exception.h>
  38 #include <mono/metadata/mono-debug.h>
  39
  40 #include "mini.h"
  41 #include "mini-hppa.h"
  42
  43 #define ALIGN_TO(val,align) (((val) + ((align) - 1)) & ~((align) - 1))
  44
  45 #define restore_regs_from_context(ctx_reg,ip_reg) do {                  \
  46                 int reg, ofs;                                           \
  47                 hppa_ldw (code, G_STRUCT_OFFSET (MonoContext, pc), \
  48                         ctx_reg, ip_reg);                               \
  49                 ofs = G_STRUCT_OFFSET (MonoContext, regs);              \
  50                 for (reg = 0; reg < 32; ++reg) {                        \
  51                         if (HPPA_IS_SAVED_GREG (reg)) {                 \
  52                                 hppa_ldw (code, ofs, ctx_reg, reg);     \
  53                                 ofs += 4;                               \
  54                         }                                               \
  55                 }                                                       \
  56                 hppa_set (code, G_STRUCT_OFFSET (MonoContext, fregs), hppa_r1); \
  57                 for (reg = 4; reg < 32; ++reg) {                        \
  58                         if (HPPA_IS_SAVED_FREG (reg)) {                 \
  59                                 hppa_flddx (code, hppa_r1, ctx_reg, reg); \
  60                                 hppa_ldo (code, sizeof(double), hppa_r1, hppa_r1); \
  61                         }                                               \
  62                 }                                                       \
  63         } while (0)
  64
  65
  66 /* HPPA bit ops */
  67 static inline int
  68 hppa_low_sign_extend (unsigned val, unsigned bits)
  69 {
  70         return (int) ((val & 0x1 ? (-1 << (bits - 1)) : 0) | val >> 1);
  71 }
  72
  73 static inline int
  74 hppa_sign_extend (unsigned val, unsigned bits)
  75 {
  76         return (int) (val >> (bits - 1) ? (-1 << bits) | val : val);
  77 }
  78
  79 static inline int
  80 hppa_get_field (unsigned word, int from, int to)
  81 {
  82         return ((word) >> (31 - (to)) & ((1 << ((to) - (from) + 1)) - 1));
  83 }
  84
  85 static inline int
  86 hppa_extract_14 (unsigned word)
  87 {
  88         return hppa_low_sign_extend (word & 0x3fff, 14);
  89 }
  90
  91 static inline int
  92 hppa_extract_21 (unsigned word)
  93 {
  94         int val;
  95
  96         word &= 0x1fffff;
  97         word <<= 11;
  98         val = hppa_get_field (word, 20, 20);
  99         val <<= 11;
 100         val |= hppa_get_field (word, 9, 19);
 101         val <<= 2;
 102         val |= hppa_get_field (word, 5, 6);
 103         val <<= 5;
 104         val |= hppa_get_field (word, 0, 4);
 105         val <<= 2;
 106         val |= hppa_get_field (word, 7, 8);
 107         return hppa_sign_extend (val, 21) << 11;
 108 }
 109
 110 static inline int
 111 hppa_is_branch(unsigned int insn)
 112 {
 113         switch (insn >> 26)
 114         {
 115                 case 0x20:
 116                 case 0x21:
 117                 case 0x22:
 118                 case 0x23:
 119                 case 0x27:
 120                 case 0x28:
 121                 case 0x29:
 122                 case 0x2a:
 123                 case 0x2b:
 124                 case 0x2f:
 125                 case 0x30:
 126                 case 0x31:
 127                 case 0x32:
 128                 case 0x33:
 129                 case 0x38:
 130                 case 0x39:
 131                 case 0x3a:
 132                 case 0x3b:
 133                         return 1;
 134
 135                 default:
 136                         return 0;
 137         }
 138 }
 139
 140 /*
 141  * arch_get_restore_context:
 142  *
 143  * Returns a pointer to a method which restores a previously saved sigcontext.
 144  * called as restore_context(MonoContext *ctx)
 145  */
 146 gpointer
 147 mono_arch_get_restore_context (void)
 148 {
 149         guint8 *code;
 150         static guint8 start [384];
 151         static int inited = 0;
 152
 153         if (inited)
 154                 return start;
 155         inited = 1;
 156
 157         code = start;
 158         restore_regs_from_context (hppa_r26, hppa_r20);
 159         /* restore also the stack pointer */
 160         hppa_ldw (code, G_STRUCT_OFFSET (MonoContext, sp), hppa_r26, hppa_r30);
 161         /* jump to the saved IP */
 162         hppa_bv (code, hppa_r0, hppa_r20);
 163         hppa_nop (code);
 164
 165         /* not reached */
 166         *(guint32 *)code = 0xdeadbeef;
 167
 168         g_assert ((code - start) < sizeof(start));
 169         mono_arch_flush_icache (start, code - start);
 170         return start;
 171 }
 172
 173 /*
 174  * arch_get_call_filter:
 175  *
 176  * Returns a pointer to a method which calls an exception filter. We
 177  * also use this function to call finally handlers (we pass NULL as
 178  * @exc object in this case).
 179  */
 180 gpointer
 181 mono_arch_get_call_filter (void)
 182 {
 183         static guint8 start [1024];
 184         static int inited = 0;
 185         guint8 *code;
 186         int pos, i;
 187
 188         if (inited)
 189                 return start;
 190
 191         inited = 1;
 192         /* call_filter (MonoContext *ctx, unsigned long eip, gpointer exc) */
 193         code = start;
 194
 195         /* Save the return pointer in its regular location */
 196         hppa_stw (code, hppa_r2, -20, hppa_r30);
 197
 198         /* Save all the registers on the stack */
 199         pos = 0;
 200         for (i = 0; i < 32; i++) {
 201                 if (HPPA_IS_SAVED_GREG (i)) {
 202                         hppa_stw (code, i, pos, hppa_sp);
 203                         pos += sizeof(gulong);
 204                 }
 205         }
 206         pos = ALIGN_TO (pos, sizeof(double));
 207         hppa_set (code, pos, hppa_r1);
 208         for (i = 0; i < 32; i++) {
 209                 if (HPPA_IS_SAVED_FREG (i)) {
 210                         hppa_fstdx (code, i, hppa_r1, hppa_sp);
 211                         hppa_ldo (code, sizeof(double), hppa_r1, hppa_r1);
 212                         pos += sizeof(double);
 213                 }
 214         }
 215
 216         pos += 64; /* Leave space for the linkage area */
 217         pos = ALIGN_TO (pos, MONO_ARCH_FRAME_ALIGNMENT);
 218
 219         hppa_ldo (code, pos, hppa_sp, hppa_sp);
 220
 221         /* restore all the regs from ctx (in r26), but not the stack pointer */
 222         restore_regs_from_context (hppa_r26, hppa_r20);
 223
 224         /* call handler at the saved IP (r25) */
 225         hppa_ble (code, 0, hppa_r25);
 226         hppa_copy (code, hppa_r31, hppa_r2);
 227
 228         /* epilog */
 229         hppa_ldo (code, -pos, hppa_sp, hppa_sp);
 230
 231         /* Restore registers */
 232         pos = 0;
 233         for (i = 0; i < 32; i++) {
 234                 if (HPPA_IS_SAVED_GREG (i)) {
 235                         hppa_ldw (code, pos, hppa_sp, i);
 236                         pos += sizeof(gulong);
 237                 }
 238         }
 239         pos = ALIGN_TO (pos, sizeof(double));
 240         hppa_set (code, pos, hppa_r1);
 241         for (i = 0; i < 32; i++) {
 242                 if (HPPA_IS_SAVED_FREG (i)) {
 243                         hppa_flddx (code, hppa_r1, hppa_sp, i);
 244                         hppa_ldo (code, sizeof(double), hppa_r1, hppa_r1);
 245                         pos += sizeof(double);
 246                 }
 247         }
 248
 249         hppa_ldw (code, -20, hppa_sp, hppa_r2);
 250         hppa_bv (code, hppa_r0, hppa_r2);
 251         hppa_nop (code);
 252
 253         g_assert ((code - start) < sizeof(start));
 254         mono_arch_flush_icache (start, code - start);
 255         return start;
 256 }
 257
 258 static void
 259 throw_exception (MonoObject *exc, unsigned long eip, unsigned long esp, gulong *int_regs, gdouble *fp_regs, gboolean rethrow)
 260 {
 261         static void (*restore_context) (MonoContext *);
 262         MonoContext ctx;
 263
 264         if (!restore_context)
 265                 restore_context = mono_arch_get_restore_context ();
 266
 267         /* adjust eip so that it point into the call instruction */
 268         eip &= ~3;
 269         eip -= 8;
 270
 271         MONO_CONTEXT_SET_BP (&ctx, esp);
 272         MONO_CONTEXT_SET_IP (&ctx, eip);
 273         memcpy (&ctx.regs, int_regs, sizeof (gulong) * MONO_SAVED_GREGS);
 274         memcpy (&ctx.fregs, fp_regs, sizeof (double) * MONO_SAVED_FREGS);
 275
 276         if (mono_object_isinst (exc, mono_defaults.exception_class)) {
 277                 MonoException *mono_ex = (MonoException*)exc;
 278                 if (!rethrow)
 279                         mono_ex->stack_trace = NULL;
 280         }
 281         mono_handle_exception (&ctx, exc);
 282
 283         restore_context (&ctx);
 284
 285         g_assert_not_reached ();
 286 }
 287
 288 /**
 289  * arch_get_throw_exception_generic:
 290  *
 291  * Returns a function pointer which can be used to raise
 292  * exceptions. The returned function has the following
 293  * signature: void (*func) (MonoException *exc); or
 294  * void (*func) (char *exc_name);
 295  *
 296  */
 297 static gpointer
 298 mono_arch_get_throw_exception_generic (guint8 *start, int size, int by_name, gboolean rethrow)
 299 {
 300         guint8 *code;
 301         int pos, frpos, i;
 302
 303         code = start;
 304
 305         /* We are called with r26 = exception */
 306         /* Stash the call site IP in the "return pointer" slot */
 307         hppa_stw (code, hppa_r2, -20, hppa_sp);
 308
 309         /* Non-standard prologue - we don't want to clobber r3 */
 310         hppa_copy (code, hppa_sp, hppa_r1);
 311         hppa_ldo (code, 512, hppa_sp, hppa_sp);
 312
 313         /* Save all the registers on the stack */
 314         pos = 0;
 315         for (i = 0; i < 32; i++) {
 316                 if (HPPA_IS_SAVED_GREG (i)) {
 317                         hppa_stw (code, i, pos, hppa_r1);
 318                         pos += sizeof(gulong);
 319                 }
 320         }
 321         pos = ALIGN_TO (pos, sizeof(double));
 322         frpos = pos;
 323         hppa_set (code, pos, hppa_r20);
 324         for (i = 0; i < 32; i++) {
 325                 if (HPPA_IS_SAVED_FREG (i)) {
 326                         hppa_fstdx (code, i, hppa_r20, hppa_r1);
 327                         hppa_ldo (code, sizeof(double), hppa_r20, hppa_r20);
 328                         pos += sizeof(double);
 329                 }
 330         }
 331
 332         /* Now that we have saved r4, we copy the stack pointer to it for
 333          * use below - we want a callee save register in case we do the
 334          * function call below
 335          */
 336         hppa_copy (code, hppa_r1, hppa_r4);
 337
 338         if (by_name) {
 339                 /* mono_exception_from_name (MonoImage *image,
 340                  *                           const char *name_space,
 341                  *                           const char *name)
 342                  */
 343                 void *func = __canonicalize_funcptr_for_compare (mono_exception_from_name);
 344                 hppa_copy (code, hppa_r26, hppa_r24);
 345                 hppa_set (code, mono_defaults.corlib, hppa_r26);
 346                 hppa_set (code, "System", hppa_r25);
 347                 hppa_ldil (code, hppa_lsel (func), hppa_r1);
 348                 hppa_ble (code, hppa_rsel (func), hppa_r1);
 349                 hppa_copy (code, hppa_r31, hppa_r2);
 350                 hppa_copy (code, hppa_r28, hppa_r26);
 351         }
 352
 353         /* call throw_exception (exc, ip, sp, int_regs, fp_regs, rethrow) */
 354         /* exc is already in place in r26 */
 355
 356         hppa_ldw (code, -20, hppa_r4, hppa_r25); /* ip */
 357         hppa_copy (code, hppa_r4, hppa_r24); /* sp */
 358         hppa_ldo (code, 0, hppa_r4, hppa_r23);
 359         hppa_ldo (code, frpos, hppa_r4, hppa_r22);
 360         hppa_stw (code, hppa_r22, -52, hppa_sp);
 361         hppa_ldo (code, rethrow, hppa_r0, hppa_r22);
 362         hppa_stw (code, hppa_r22, -56, hppa_sp);
 363
 364         hppa_set (code, throw_exception, hppa_r1);
 365         hppa_depi (code, 0, 31, 2, hppa_r1);
 366         hppa_ldw (code, 0, hppa_r1, hppa_r1);
 367         hppa_bv (code, hppa_r0, hppa_r1);
 368         hppa_nop (code);
 369
 370         /* not reached */
 371         *(guint32 *)code = 0x88c0ffee;
 372
 373         g_assert ((code - start) < size);
 374         mono_arch_flush_icache (start, code - start);
 375         return start;
 376 }
 377
 378 /**
 379  * mono_arch_get_rethrow_exception:
 380  *
 381  * Returns a function pointer which can be used to rethrow
 382  * exceptions. The returned function has the following
 383  * signature: void (*func) (MonoException *exc);
 384  *
 385  */
 386 gpointer
 387 mono_arch_get_rethrow_exception (void)
 388 {
 389         static guint8 start [450];
 390         static int inited = 0;
 391
 392         if (inited)
 393                 return start;
 394         mono_arch_get_throw_exception_generic (start, sizeof (start), FALSE, TRUE);
 395         inited = 1;
 396         return start;
 397 }
 398 /**
 399  * arch_get_throw_exception:
 400  *
 401  * Returns a function pointer which can be used to raise
 402  * exceptions. The returned function has the following
 403  * signature: void (*func) (MonoException *exc);
 404  * For example to raise an arithmetic exception you can use:
 405  *
 406  * x86_push_imm (code, mono_get_exception_arithmetic ());
 407  * x86_call_code (code, arch_get_throw_exception ());
 408  *
 409  */
 410 gpointer
 411 mono_arch_get_throw_exception (void)
 412 {
 413         static guint8 start [450];
 414         static int inited = 0;
 415
 416         if (inited)
 417                 return start;
 418         mono_arch_get_throw_exception_generic (start, sizeof (start), FALSE, FALSE);
 419         inited = 1;
 420         return start;
 421 }
 422
 423 /**
 424  * arch_get_throw_exception_by_name:
 425  *
 426  * Returns a function pointer which can be used to raise
 427  * corlib exceptions. The returned function has the following
 428  * signature: void (*func) (char *exc_name);
 429  * For example to raise an arithmetic exception you can use:
 430  *
 431  * x86_push_imm (code, "ArithmeticException");
 432  * x86_call_code (code, arch_get_throw_exception_by_name ());
 433  *
 434  */
 435 gpointer
 436 mono_arch_get_throw_exception_by_name (void)
 437 {
 438         static guint8 start [450];
 439         static int inited = 0;
 440
 441         if (inited)
 442                 return start;
 443         mono_arch_get_throw_exception_generic (start, sizeof (start), TRUE, FALSE);
 444         inited = 1;
 445         return start;
 446 }
 447
 448 static int
 449 hppa_get_size_of_frame (MonoJitInfo *ji, int *stored_fp)
 450 {
 451         guint32 *insn = (guint32 *)((unsigned long)ji->code_start & ~3);
 452         guint32 *end = (guint32 *)((unsigned long)ji->code_start + ji->code_size);
 453         int saw_branch = 0;
 454         int stack_size = 0;
 455
 456         /* Look for the instruction that adjusts the stack pointer */
 457         while (insn < end) {
 458                 /* ldo X(sp), sp */
 459                 if ((insn[0] & 0xffffc000) == 0x37de0000) {
 460                         stack_size += hppa_extract_14 (insn [0]);
 461                 }
 462                 /* stwm X,D(sp) */
 463                 else if ((insn[0] & 0xffe00000) == 0x6fc00000) {
 464                         stack_size += hppa_extract_14 (insn [0]);
 465                         if (stored_fp)
 466                                 *stored_fp = 1;
 467                 }
 468                 /* addil/ldo */
 469                 else if (((insn[0] & 0xffe00000) == 0x28200000) &&
 470                          ((insn[1] & 0xffff0000) == 0x343e0000)) {
 471                          stack_size += hppa_extract_21 (insn [0]);
 472                          stack_size += hppa_extract_14 (insn [1]);
 473                          insn++;
 474                 }
 475
 476                 insn++;
 477                 if (saw_branch)
 478                         break;
 479                 saw_branch = hppa_is_branch (insn[0]);
 480         }
 481
 482         if (stack_size == 0) {
 483                 g_print ("No stack frame found for function at %p\n", ji->code_start);
 484         }
 485
 486         return stack_size;
 487 }
 488
 489 static void
 490 hppa_analyze_frame (MonoJitInfo *ji, MonoContext *ctx, MonoContext *new_ctx)
 491 {
 492         unsigned char *sp;
 493         int stack_size;
 494         int stored_fp = 0;
 495
 496         stack_size = hppa_get_size_of_frame (ji, &stored_fp);
 497
 498         sp = (unsigned char *)MONO_CONTEXT_GET_BP (ctx) - stack_size;
 499         MONO_CONTEXT_SET_BP (new_ctx, sp);
 500         MONO_CONTEXT_SET_IP (new_ctx, *(unsigned int *)(sp - 20));
 501
 502         if (ji->method->save_lmf) {
 503                 memcpy (&new_ctx->regs, (char *)sp + HPPA_STACK_LMF_OFFSET + G_STRUCT_OFFSET (MonoLMF, regs), sizeof (gulong) * MONO_SAVED_GREGS);
 504                 memcpy (&new_ctx->fregs, (char *)sp + HPPA_STACK_LMF_OFFSET + G_STRUCT_OFFSET (MonoLMF, fregs), sizeof (double) * MONO_SAVED_FREGS);
 505         }
 506         else if (ji->used_regs) {
 507                 char *pos = (char *)sp + HPPA_STACK_LMF_OFFSET;
 508                 gulong val;
 509                 int i, j = 0;
 510
 511                 for (i = 0; i <= 32; i++) {
 512                         if ((1 << i) & ji->used_regs) {
 513                                 val = *(gulong *)pos;
 514                                 pos += sizeof (gulong);
 515                                 new_ctx->regs [j] = val;
 516                         }
 517                         if (HPPA_IS_SAVED_GREG (i))
 518                                 j++;
 519                 }
 520         }
 521         if (stored_fp) {
 522                 gulong val;
 523                 val = *(gulong *)sp;
 524                 new_ctx->regs [0] = val;
 525         }
 526 }
 527
 528 /* mono_arch_find_jit_info:
 529  *
 530  * This function is used to gather information from @ctx. It return the
 531  * MonoJitInfo of the corresponding function, unwinds one stack frame and
 532  * stores the resulting context into @new_ctx. It also stores a string
 533  * describing the stack location into @trace (if not NULL), and modifies
 534  * the @lmf if necessary. @native_offset return the IP offset from the
 535  * start of the function or -1 if that info is not available.
 536  */
 537 MonoJitInfo *
 538 mono_arch_find_jit_info (MonoDomain *domain, MonoJitTlsData *jit_tls, MonoJitInfo *res, MonoJitInfo *prev_ji,
 539                          MonoContext *ctx, MonoContext *new_ctx, MonoLMF **lmf, gboolean *managed)
 540 {
 541         MonoJitInfo *ji;
 542         gpointer ip = MONO_CONTEXT_GET_IP (ctx);
 543
 544         /* Avoid costly table lookup during stack overflow */
 545         if (prev_ji && (ip > prev_ji->code_start && ((guint8*)ip < ((guint8*)prev_ji->code_start) + prev_ji->code_size)))
 546                 ji = prev_ji;
 547         else
 548                 ji = mini_jit_info_table_find (domain, ip, NULL);
 549
 550         if (managed)
 551                 *managed = FALSE;
 552
 553         if (ji != NULL) {
 554                 gint32 address;
 555
 556                 *new_ctx = *ctx;
 557
 558                 address = (char *)ip - (char *)ji->code_start;
 559
 560                 if (managed)
 561                         if (!ji->method->wrapper_type)
 562                                 *managed = TRUE;
 563
 564                 if (*lmf && (*lmf)->ebp != 0xffffffff && (MONO_CONTEXT_GET_BP (ctx) <= (gpointer)(*lmf)->ebp)) {
 565                         /* remove any unused lmf */
 566                         *lmf = (*lmf)->previous_lmf;
 567                 }
 568
 569                 hppa_analyze_frame (ji, ctx, new_ctx);
 570                 //printf("Managed frame: rewound (ip,sp)=(%x [%s],%x) to (%x,%x)\n", ctx->pc, mono_method_full_name (ji->method, FALSE), ctx->sp, new_ctx->pc, new_ctx->sp);
 571
 572                 return ji;
 573         } else if (*lmf) {
 574
 575                 *new_ctx = *ctx;
 576
 577                 if (!(*lmf)->method)
 578                         return (gpointer)-1;
 579
 580                 if ((ji = mini_jit_info_table_find (domain, (gpointer)(*lmf)->eip, NULL))) {
 581                 } else {
 582                         memset (res, 0, MONO_SIZEOF_JIT_INFO);
 583                         res->method = (*lmf)->method;
 584                 }
 585
 586                 MONO_CONTEXT_SET_BP (new_ctx, (*lmf)->ebp);
 587                 MONO_CONTEXT_SET_IP (new_ctx, (*lmf)->eip);
 588                 memcpy (&new_ctx->regs, (*lmf)->regs, sizeof (gulong) * MONO_SAVED_GREGS);
 589                 memcpy (&new_ctx->fregs, (*lmf)->regs, sizeof (double) * MONO_SAVED_FREGS);
 590                 *lmf = (*lmf)->previous_lmf;
 591                 //printf("Unmanaged frame: rewound to (ip,sp)=(%x [%s],%x)\n", new_ctx->pc, mono_method_full_name (ji ? ji->method : res->method, FALSE), new_ctx->sp);
 592
 593                 return ji ? ji : res;
 594         }
 595
 596         return NULL;
 597 }
 598
 599 /*
 600  * This is the function called from the signal handler
 601  */
 602 gboolean
 603 mono_arch_handle_exception (void *sigctx, gpointer obj)
 604 {
 605         struct ucontext *uc = sigctx;
 606         MonoContext mctx;
 607         gboolean result;
 608         int i, grs, frs;
 609
 610         mctx.pc = uc->uc_mcontext.sc_iaoq [0];
 611         mctx.sp = uc->uc_mcontext.sc_gr [30];
 612
 613         grs = 0; frs = 0;
 614         for (i = 0; i < 32; i++) {
 615                 if (HPPA_IS_SAVED_GREG (i))
 616                         mctx.regs[grs++] = uc->uc_mcontext.sc_gr [i];
 617                 if (HPPA_IS_SAVED_FREG (i))
 618                         mctx.fregs[frs++] = uc->uc_mcontext.sc_fr [i];
 619         }
 620         g_assert (grs == MONO_SAVED_GREGS && frs == MONO_SAVED_FREGS);
 621
 622         result = mono_handle_exception (&mctx, obj);
 623
 624         /* restore the context so that returning from the signal handler will invoke
 625          * the catch clause
 626          */
 627         uc->uc_mcontext.sc_iaoq [0] = mctx.pc;
 628         uc->uc_mcontext.sc_iaoq [1] = mctx.pc + 4;
 629         uc->uc_mcontext.sc_gr [30] = mctx.sp;
 630
 631         grs = 0; frs = 0;
 632         for (i = 0; i < 32; i++) {
 633                 if (HPPA_IS_SAVED_GREG (i))
 634                         uc->uc_mcontext.sc_gr [i] = mctx.regs [grs++];
 635                 if (HPPA_IS_SAVED_FREG (i))
 636                         uc->uc_mcontext.sc_fr [i] = mctx.fregs [frs++];
 637         }
 638
 639         return result;
 640 }
 641
 642 gpointer
 643 mono_arch_ip_from_context (void *sigctx)
 644 {
 645         struct ucontext *uc = sigctx;
 646         return (gpointer)uc->uc_mcontext.sc_iaoq [0];
 647 }