mono/mini/exceptions-ppc.c

   1 /*
   2  * exceptions-ppc.c: exception support for PowerPC
   3  *
   4  * Authors:
   5  *   Dietmar Maurer (dietmar@ximian.com)
   6  *   Paolo Molaro (lupus@ximian.com)
   7  *   Andreas Faerber <andreas.faerber@web.de>
   8  *
   9  * (C) 2001 Ximian, Inc.
  10  * (C) 2007-2008 Andreas Faerber
  11  */
  12
  13 #include <config.h>
  14 #include <glib.h>
  15 #include <signal.h>
  16 #include <string.h>
  17 #include <stddef.h>
  18 #if HAVE_UCONTEXT_H
  19 #include <ucontext.h>
  20 #endif
  21
  22 #include <mono/arch/ppc/ppc-codegen.h>
  23 #include <mono/metadata/appdomain.h>
  24 #include <mono/metadata/tabledefs.h>
  25 #include <mono/metadata/threads.h>
  26 #include <mono/metadata/debug-helpers.h>
  27 #include <mono/metadata/exception.h>
  28 #include <mono/metadata/mono-debug.h>
  29
  30 #include "mini.h"
  31 #include "mini-ppc.h"
  32
  33 /*
  34
  35 struct sigcontext {
  36     int      sc_onstack;     // sigstack state to restore
  37     int      sc_mask;        // signal mask to restore
  38     int      sc_ir;          // pc
  39     int      sc_psw;         // processor status word
  40     int      sc_sp;          // stack pointer if sc_regs == NULL
  41     void    *sc_regs;        // (kernel private) saved state
  42 };
  43
  44 struct ucontext {
  45         int             uc_onstack;
  46         sigset_t        uc_sigmask;     // signal mask used by this context
  47         stack_t         uc_stack;       // stack used by this context
  48         struct ucontext *uc_link;       // pointer to resuming context
  49         size_t          uc_mcsize;      // size of the machine context passed in
  50         mcontext_t      uc_mcontext;    // machine specific context
  51 };
  52
  53 typedef struct ppc_exception_state {
  54         unsigned long dar;      // Fault registers for coredump
  55         unsigned long dsisr;
  56         unsigned long exception;// number of powerpc exception taken
  57         unsigned long pad0;     // align to 16 bytes
  58
  59         unsigned long pad1[4];  // space in PCB "just in case"
  60 } ppc_exception_state_t;
  61
  62 typedef struct ppc_vector_state {
  63         unsigned long   save_vr[32][4];
  64         unsigned long   save_vscr[4];
  65         unsigned int    save_pad5[4];
  66         unsigned int    save_vrvalid;                   // VRs that have been saved
  67         unsigned int    save_pad6[7];
  68 } ppc_vector_state_t;
  69
  70 typedef struct ppc_float_state {
  71         double  fpregs[32];
  72
  73         unsigned int fpscr_pad; // fpscr is 64 bits, 32 bits of rubbish
  74         unsigned int fpscr;     // floating point status register
  75 } ppc_float_state_t;
  76
  77 typedef struct ppc_thread_state {
  78         unsigned int srr0;      // Instruction address register (PC)
  79         unsigned int srr1;      // Machine state register (supervisor)
  80         unsigned int r0;
  81         unsigned int r1;
  82         unsigned int r2;
  83         ...
  84         unsigned int r31;
  85         unsigned int cr;        // Condition register
  86         unsigned int xer;       // User's integer exception register
  87         unsigned int lr;        // Link register
  88         unsigned int ctr;       // Count register
  89         unsigned int mq;        // MQ register (601 only)
  90
  91         unsigned int vrsave;    // Vector Save Register
  92 } ppc_thread_state_t;
  93
  94 struct mcontext {
  95         ppc_exception_state_t   es;
  96         ppc_thread_state_t      ss;
  97         ppc_float_state_t       fs;
  98         ppc_vector_state_t      vs;
  99 };
 100
 101 typedef struct mcontext  * mcontext_t;
 102
 103 Linux/PPC instead has:
 104 struct sigcontext {
 105         unsigned long   _unused[4];
 106         int             signal;
 107         unsigned long   handler;
 108         unsigned long   oldmask;
 109         struct pt_regs  *regs;
 110 };
 111 struct pt_regs {
 112         unsigned long gpr[32];
 113         unsigned long nip;
 114         unsigned long msr;
 115         unsigned long orig_gpr3;        // Used for restarting system calls
 116         unsigned long ctr;
 117         unsigned long link;
 118         unsigned long xer;
 119         unsigned long ccr;
 120         unsigned long mq;               // 601 only (not used at present)
 121                                         // Used on APUS to hold IPL value.
 122         unsigned long trap;             // Reason for being here
 123         // N.B. for critical exceptions on 4xx, the dar and dsisr
 124         // fields are overloaded to hold srr0 and srr1.
 125         unsigned long dar;              // Fault registers
 126         unsigned long dsisr;            // on 4xx/Book-E used for ESR
 127         unsigned long result;           // Result of a system call
 128 };
 129 struct mcontext {
 130         elf_gregset_t   mc_gregs;
 131         elf_fpregset_t  mc_fregs;
 132         unsigned long   mc_pad[2];
 133         elf_vrregset_t  mc_vregs __attribute__((__aligned__(16)));
 134 };
 135
 136 struct ucontext {
 137         unsigned long    uc_flags;
 138         struct ucontext *uc_link;
 139         stack_t          uc_stack;
 140         int              uc_pad[7];
 141         struct mcontext *uc_regs;       // points to uc_mcontext field
 142         sigset_t         uc_sigmask;
 143         // glibc has 1024-bit signal masks, ours are 64-bit
 144         int              uc_maskext[30];
 145         int              uc_pad2[3];
 146         struct mcontext  uc_mcontext;
 147 };
 148
 149 #define ELF_NGREG       48      // includes nip, msr, lr, etc.
 150 #define ELF_NFPREG      33      // includes fpscr
 151
 152 // General registers
 153 typedef unsigned long elf_greg_t;
 154 typedef elf_greg_t elf_gregset_t[ELF_NGREG];
 155
 156 // Floating point registers
 157 typedef double elf_fpreg_t;
 158 typedef elf_fpreg_t elf_fpregset_t[ELF_NFPREG];
 159
 160
 161 */
 162
 163
 164 #define restore_regs_from_context(ctx_reg,ip_reg,tmp_reg) do {  \
 165                 int reg;        \
 166                 ppc_load_reg (code, ip_reg, G_STRUCT_OFFSET (MonoContext, sc_ir), ctx_reg);     \
 167                 ppc_load_multiple_regs (code, ppc_r13, G_STRUCT_OFFSET (MonoContext, regs), ctx_reg);   \
 168                 for (reg = 0; reg < MONO_SAVED_FREGS; ++reg) {  \
 169                         ppc_lfd (code, (14 + reg),      \
 170                                 G_STRUCT_OFFSET(MonoContext, fregs) + reg * sizeof (gdouble), ctx_reg); \
 171                 }       \
 172         } while (0)
 173
 174 /* nothing to do */
 175 #define setup_context(ctx)
 176
 177 #ifdef PPC_USES_FUNCTION_DESCRIPTOR
 178 guint8*
 179 mono_ppc_create_pre_code_ftnptr (guint8 *code)
 180 {
 181         MonoPPCFunctionDescriptor *ftnptr = (MonoPPCFunctionDescriptor*)code;
 182
 183         code += sizeof (MonoPPCFunctionDescriptor);
 184         ftnptr->code = code;
 185         ftnptr->toc = NULL;
 186         ftnptr->env = NULL;
 187
 188         return code;
 189 }
 190 #endif
 191
 192 /*
 193  * arch_get_restore_context:
 194  *
 195  * Returns a pointer to a method which restores a previously saved sigcontext.
 196  * The first argument in r3 is the pointer to the context.
 197  */
 198 gpointer
 199 mono_arch_get_restore_context (void)
 200 {
 201         static guint8 *start = NULL;
 202
 203         guint8 *code;
 204         int size = MONO_PPC_32_64_CASE (128, 172) + PPC_FTNPTR_SIZE;
 205
 206         if (start)
 207                 return start;
 208
 209         code = start = mono_global_codeman_reserve (size);
 210         code = mono_ppc_create_pre_code_ftnptr (code);
 211         restore_regs_from_context (ppc_r3, ppc_r4, ppc_r5);
 212         /* restore also the stack pointer */
 213         ppc_load_reg (code, ppc_sp, G_STRUCT_OFFSET (MonoContext, sc_sp), ppc_r3);
 214         //ppc_break (code);
 215         /* jump to the saved IP */
 216         ppc_mtctr (code, ppc_r4);
 217         ppc_bcctr (code, PPC_BR_ALWAYS, 0);
 218         /* never reached */
 219         ppc_break (code);
 220
 221         g_assert ((code - start) <= size);
 222         mono_arch_flush_icache (start, code - start);
 223         return start;
 224 }
 225
 226 #define SAVED_REGS_LENGTH               (sizeof (gdouble) * MONO_SAVED_FREGS + sizeof (gpointer) * MONO_SAVED_GREGS)
 227 #define ALIGN_STACK_FRAME_SIZE(s)       (((s) + MONO_ARCH_FRAME_ALIGNMENT - 1) & ~(MONO_ARCH_FRAME_ALIGNMENT - 1))
 228 /* The 64 bytes here are for outgoing arguments and a bit of spare.
 229    We don't use it all, but it doesn't hurt. */
 230 #define REG_SAVE_STACK_FRAME_SIZE       (ALIGN_STACK_FRAME_SIZE (SAVED_REGS_LENGTH + PPC_MINIMAL_STACK_SIZE + 64))
 231
 232 static guint8*
 233 emit_save_saved_regs (guint8 *code, int pos)
 234 {
 235         int i;
 236
 237         for (i = 31; i >= 14; --i) {
 238                 pos -= sizeof (gdouble);
 239                 ppc_stfd (code, i, pos, ppc_sp);
 240         }
 241         pos -= sizeof (gpointer) * MONO_SAVED_GREGS;
 242         ppc_store_multiple_regs (code, ppc_r13, pos, ppc_sp);
 243
 244         return code;
 245 }
 246
 247 /*
 248  * mono_arch_get_call_filter:
 249  *
 250  * Returns a pointer to a method which calls an exception filter. We
 251  * also use this function to call finally handlers (we pass NULL as
 252  * @exc object in this case).
 253  */
 254 gpointer
 255 mono_arch_get_call_filter (void)
 256 {
 257         static guint8 *start = NULL;
 258
 259         guint8 *code;
 260         int alloc_size, pos, i;
 261         int size = MONO_PPC_32_64_CASE (320, 500) + PPC_FTNPTR_SIZE;
 262
 263         if (start)
 264                 return start;
 265
 266         /* call_filter (MonoContext *ctx, unsigned long eip, gpointer exc) */
 267         code = start = mono_global_codeman_reserve (size);
 268         code = mono_ppc_create_pre_code_ftnptr (code);
 269
 270         /* store ret addr */
 271         ppc_mflr (code, ppc_r0);
 272         ppc_store_reg (code, ppc_r0, PPC_RET_ADDR_OFFSET, ppc_sp);
 273
 274         alloc_size = REG_SAVE_STACK_FRAME_SIZE;
 275
 276         /* allocate stack frame and set link from sp in ctx */
 277         g_assert ((alloc_size & (MONO_ARCH_FRAME_ALIGNMENT-1)) == 0);
 278         ppc_load_reg (code, ppc_r0, G_STRUCT_OFFSET (MonoContext, sc_sp), ppc_r3);
 279         ppc_load_reg_indexed (code, ppc_r0, ppc_r0, ppc_r0);
 280         ppc_store_reg_update (code, ppc_r0, -alloc_size, ppc_sp);
 281
 282         code = emit_save_saved_regs (code, alloc_size);
 283
 284         /* restore all the regs from ctx (in r3), but not r1, the stack pointer */
 285         restore_regs_from_context (ppc_r3, ppc_r6, ppc_r7);
 286         /* call handler at eip (r4) and set the first arg with the exception (r5) */
 287         ppc_mtctr (code, ppc_r4);
 288         ppc_mr (code, ppc_r3, ppc_r5);
 289         ppc_bcctrl (code, PPC_BR_ALWAYS, 0);
 290
 291         /* epilog */
 292         ppc_load_reg (code, ppc_r0, alloc_size + PPC_RET_ADDR_OFFSET, ppc_sp);
 293         ppc_mtlr (code, ppc_r0);
 294
 295         /* restore all the regs from the stack */
 296         pos = alloc_size;
 297         for (i = 31; i >= 14; --i) {
 298                 pos -= sizeof (gdouble);
 299                 ppc_lfd (code, i, pos, ppc_sp);
 300         }
 301         pos -= sizeof (gpointer) * MONO_SAVED_GREGS;
 302         ppc_load_multiple_regs (code, ppc_r13, pos, ppc_sp);
 303
 304         ppc_addic (code, ppc_sp, ppc_sp, alloc_size);
 305         ppc_blr (code);
 306
 307         g_assert ((code - start) < size);
 308         mono_arch_flush_icache (start, code - start);
 309         return start;
 310 }
 311
 312 static void
 313 throw_exception (MonoObject *exc, unsigned long eip, unsigned long esp, gulong *int_regs, gdouble *fp_regs, gboolean rethrow)
 314 {
 315         static void (*restore_context) (MonoContext *);
 316         MonoContext ctx;
 317
 318         if (!restore_context)
 319                 restore_context = mono_arch_get_restore_context ();
 320
 321         /* adjust eip so that it point into the call instruction */
 322         eip -= 4;
 323
 324         setup_context (&ctx);
 325
 326         /*printf ("stack in throw: %p\n", esp);*/
 327         MONO_CONTEXT_SET_BP (&ctx, esp);
 328         MONO_CONTEXT_SET_IP (&ctx, eip);
 329         memcpy (&ctx.regs, int_regs, sizeof (gulong) * MONO_SAVED_GREGS);
 330         memcpy (&ctx.fregs, fp_regs, sizeof (double) * MONO_SAVED_FREGS);
 331
 332         if (mono_object_isinst (exc, mono_defaults.exception_class)) {
 333                 MonoException *mono_ex = (MonoException*)exc;
 334                 if (!rethrow)
 335                         mono_ex->stack_trace = NULL;
 336         }
 337         mono_handle_exception (&ctx, exc, (gpointer)eip, FALSE);
 338         restore_context (&ctx);
 339
 340         g_assert_not_reached ();
 341 }
 342
 343 /**
 344  * arch_get_throw_exception_generic:
 345  *
 346  * Returns a function pointer which can be used to raise
 347  * exceptions. The returned function has the following
 348  * signature: void (*func) (MonoException *exc); or
 349  * void (*func) (char *exc_name);
 350  *
 351  */
 352 static gpointer
 353 mono_arch_get_throw_exception_generic (guint8 *start, int size, int by_name, gboolean rethrow)
 354 {
 355         guint8 *code;
 356         int alloc_size, pos;
 357
 358         code = mono_ppc_create_pre_code_ftnptr (start);
 359
 360         /* store ret addr */
 361         ppc_mflr (code, ppc_r0);
 362         ppc_store_reg (code, ppc_r0, PPC_RET_ADDR_OFFSET, ppc_sp);
 363
 364         alloc_size = REG_SAVE_STACK_FRAME_SIZE;
 365
 366         g_assert ((alloc_size & (MONO_ARCH_FRAME_ALIGNMENT-1)) == 0);
 367         ppc_store_reg_update (code, ppc_sp, -alloc_size, ppc_sp);
 368
 369         code = emit_save_saved_regs (code, alloc_size);
 370
 371         //ppc_break (code);
 372         if (by_name) {
 373                 ppc_mr (code, ppc_r5, ppc_r3);
 374                 ppc_load (code, ppc_r3, (gulong)mono_defaults.corlib);
 375                 ppc_load (code, ppc_r4, "System");
 376                 ppc_load_func (code, ppc_r0, mono_exception_from_name);
 377                 ppc_mtctr (code, ppc_r0);
 378                 ppc_bcctrl (code, PPC_BR_ALWAYS, 0);
 379         }
 380
 381         /* call throw_exception (exc, ip, sp, int_regs, fp_regs) */
 382         /* caller sp */
 383         ppc_load_reg (code, ppc_r5, 0, ppc_sp);
 384         /* exc is already in place in r3 */
 385         if (by_name)
 386                 ppc_load_reg (code, ppc_r4, PPC_RET_ADDR_OFFSET, ppc_r5);
 387         else
 388                 ppc_mr (code, ppc_r4, ppc_r0); /* caller ip */
 389         /* pointer to the saved fp regs */
 390         pos = alloc_size - sizeof (gdouble) * MONO_SAVED_FREGS;
 391         ppc_addi (code, ppc_r7, ppc_sp, pos);
 392         /* pointer to the saved int regs */
 393         pos -= sizeof (gpointer) * MONO_SAVED_GREGS;
 394         ppc_addi (code, ppc_r6, ppc_sp, pos);
 395         ppc_li (code, ppc_r8, rethrow);
 396
 397         ppc_load_func (code, ppc_r0, throw_exception);
 398         ppc_mtctr (code, ppc_r0);
 399         ppc_bcctrl (code, PPC_BR_ALWAYS, 0);
 400         /* we should never reach this breakpoint */
 401         ppc_break (code);
 402         g_assert ((code - start) <= size);
 403         mono_arch_flush_icache (start, code - start);
 404         return start;
 405 }
 406
 407 /**
 408  * mono_arch_get_rethrow_exception:
 409  *
 410  * Returns a function pointer which can be used to rethrow
 411  * exceptions. The returned function has the following
 412  * signature: void (*func) (MonoException *exc);
 413  *
 414  */
 415 gpointer
 416 mono_arch_get_rethrow_exception (void)
 417 {
 418         static guint8 *start = NULL;
 419         static int inited = 0;
 420
 421         guint8 *code;
 422         int size = MONO_PPC_32_64_CASE (132, 224) + PPC_FTNPTR_SIZE;
 423
 424         if (inited)
 425                 return start;
 426         code = mono_global_codeman_reserve (size);
 427         start = mono_arch_get_throw_exception_generic (code, size, FALSE, TRUE);
 428         inited = 1;
 429         return start;
 430 }
 431 /**
 432  * arch_get_throw_exception:
 433  *
 434  * Returns a function pointer which can be used to raise
 435  * exceptions. The returned function has the following
 436  * signature: void (*func) (MonoException *exc);
 437  * For example to raise an arithmetic exception you can use:
 438  *
 439  * x86_push_imm (code, mono_get_exception_arithmetic ());
 440  * x86_call_code (code, arch_get_throw_exception ());
 441  *
 442  */
 443 gpointer
 444 mono_arch_get_throw_exception (void)
 445 {
 446         static guint8 *start = NULL;
 447         static int inited = 0;
 448
 449         guint8 *code;
 450         int size = MONO_PPC_32_64_CASE (132, 224) + PPC_FTNPTR_SIZE;
 451
 452         if (inited)
 453                 return start;
 454         code = mono_global_codeman_reserve (size);
 455         start = mono_arch_get_throw_exception_generic (code, size, FALSE, FALSE);
 456         inited = 1;
 457         return start;
 458 }
 459
 460 /**
 461  * arch_get_throw_exception_by_name:
 462  *
 463  * Returns a function pointer which can be used to raise
 464  * corlib exceptions. The returned function has the following
 465  * signature: void (*func) (char *exc_name);
 466  * For example to raise an arithmetic exception you can use:
 467  *
 468  * x86_push_imm (code, "ArithmeticException");
 469  * x86_call_code (code, arch_get_throw_exception_by_name ());
 470  *
 471  */
 472 gpointer
 473 mono_arch_get_throw_exception_by_name (void)
 474 {
 475         static guint8 *start = NULL;
 476         static int inited = 0;
 477
 478         guint8 *code;
 479         int size = MONO_PPC_32_64_CASE (168, 304) + PPC_FTNPTR_SIZE;
 480
 481         if (inited)
 482                 return start;
 483         code = mono_global_codeman_reserve (size);
 484         start = mono_arch_get_throw_exception_generic (code, size, TRUE, FALSE);
 485         inited = 1;
 486         return start;
 487 }
 488
 489 /* mono_arch_find_jit_info:
 490  *
 491  * This function is used to gather information from @ctx. It return the
 492  * MonoJitInfo of the corresponding function, unwinds one stack frame and
 493  * stores the resulting context into @new_ctx. It also stores a string
 494  * describing the stack location into @trace (if not NULL), and modifies
 495  * the @lmf if necessary. @native_offset return the IP offset from the
 496  * start of the function or -1 if that info is not available.
 497  */
 498 MonoJitInfo *
 499 mono_arch_find_jit_info (MonoDomain *domain, MonoJitTlsData *jit_tls, MonoJitInfo *res, MonoJitInfo *prev_ji, MonoContext *ctx,
 500                                                  MonoContext *new_ctx, MonoLMF **lmf, gboolean *managed)
 501 {
 502         MonoJitInfo *ji;
 503         gpointer ip = MONO_CONTEXT_GET_IP (ctx);
 504         MonoPPCStackFrame *sframe;
 505
 506         /* Avoid costly table lookup during stack overflow */
 507         if (prev_ji && (ip > prev_ji->code_start && ((guint8*)ip < ((guint8*)prev_ji->code_start) + prev_ji->code_size)))
 508                 ji = prev_ji;
 509         else
 510                 ji = mono_jit_info_table_find (domain, ip);
 511
 512         if (managed)
 513                 *managed = FALSE;
 514
 515         if (ji != NULL) {
 516                 gint32 address;
 517                 int offset, i;
 518
 519                 *new_ctx = *ctx;
 520                 setup_context (new_ctx);
 521
 522                 if (*lmf && (MONO_CONTEXT_GET_SP (ctx) >= (gpointer)(*lmf)->ebp)) {
 523                         /* remove any unused lmf */
 524                         *lmf = (*lmf)->previous_lmf;
 525                 }
 526
 527                 address = (char *)ip - (char *)ji->code_start;
 528
 529                 if (managed)
 530                         if (!ji->method->wrapper_type)
 531                                 *managed = TRUE;
 532
 533                 sframe = (MonoPPCStackFrame*)MONO_CONTEXT_GET_SP (ctx);
 534                 MONO_CONTEXT_SET_BP (new_ctx, sframe->sp);
 535                 if (ji->method->save_lmf) {
 536                         memcpy (&new_ctx->fregs, (char*)sframe->sp - sizeof (double) * MONO_SAVED_FREGS, sizeof (double) * MONO_SAVED_FREGS);
 537                         memcpy (&new_ctx->regs, (char*)sframe->sp - sizeof (double) * MONO_SAVED_FREGS - sizeof (gulong) * MONO_SAVED_GREGS, sizeof (gulong) * MONO_SAVED_GREGS);
 538                 } else if (ji->used_regs) {
 539                         /* keep updated with emit_prolog in mini-ppc.c */
 540                         offset = 0;
 541                         /* FIXME handle floating point args
 542                         for (i = 31; i >= 14; --i) {
 543                                 if (ji->used_fregs & (1 << i)) {
 544                                         offset += sizeof (double);
 545                                         new_ctx->fregs [i - 14] = *(gulong*)((char*)sframe->sp - offset);
 546                                 }
 547                         }*/
 548                         for (i = 31; i >= 13; --i) {
 549                                 if (ji->used_regs & (1 << i)) {
 550                                         offset += sizeof (gulong);
 551                                         new_ctx->regs [i - 13] = *(gulong*)((char*)sframe->sp - offset);
 552                                 }
 553                         }
 554                 }
 555                 /* the calling IP is in the parent frame */
 556                 sframe = (MonoPPCStackFrame*)sframe->sp;
 557                 /* we substract 4, so that the IP points into the call instruction */
 558                 MONO_CONTEXT_SET_IP (new_ctx, sframe->lr - 4);
 559
 560                 return ji;
 561         } else if (*lmf) {
 562
 563                 *new_ctx = *ctx;
 564                 setup_context (new_ctx);
 565
 566                 if ((ji = mono_jit_info_table_find (domain, (gpointer)(*lmf)->eip))) {
 567                 } else {
 568                         if (!(*lmf)->method)
 569                                 return (gpointer)-1;
 570
 571                         memset (res, 0, sizeof (MonoJitInfo));
 572                         res->method = (*lmf)->method;
 573                 }
 574
 575                 /*sframe = (MonoPPCStackFrame*)MONO_CONTEXT_GET_SP (ctx);
 576                 MONO_CONTEXT_SET_BP (new_ctx, sframe->sp);
 577                 MONO_CONTEXT_SET_IP (new_ctx, sframe->lr);*/
 578                 MONO_CONTEXT_SET_BP (new_ctx, (*lmf)->ebp);
 579                 MONO_CONTEXT_SET_IP (new_ctx, (*lmf)->eip);
 580                 memcpy (&new_ctx->regs, (*lmf)->iregs, sizeof (gulong) * MONO_SAVED_GREGS);
 581                 memcpy (&new_ctx->fregs, (*lmf)->fregs, sizeof (double) * MONO_SAVED_FREGS);
 582
 583                 /* FIXME: what about trampoline LMF frames?  see exceptions-x86.c */
 584
 585                 *lmf = (*lmf)->previous_lmf;
 586
 587                 return ji ? ji : res;
 588         }
 589
 590         return NULL;
 591 }
 592
 593 /*
 594  * This is the function called from the signal handler
 595  */
 596 void
 597 mono_arch_sigctx_to_monoctx (void *ctx, MonoContext *mctx)
 598 {
 599         os_ucontext *uc = ctx;
 600
 601         mctx->sc_ir = UCONTEXT_REG_NIP(uc);
 602         mctx->sc_sp = UCONTEXT_REG_Rn(uc, 1);
 603         memcpy (&mctx->regs, &UCONTEXT_REG_Rn(uc, 13), sizeof (gulong) * MONO_SAVED_GREGS);
 604         memcpy (&mctx->fregs, &UCONTEXT_REG_FPRn(uc, 14), sizeof (double) * MONO_SAVED_FREGS);
 605 }
 606
 607 void
 608 mono_arch_monoctx_to_sigctx (MonoContext *mctx, void *ctx)
 609 {
 610         os_ucontext *uc = ctx;
 611
 612         UCONTEXT_REG_NIP(uc) = mctx->sc_ir;
 613         UCONTEXT_REG_Rn(uc, 1) = mctx->sc_sp;
 614         memcpy (&UCONTEXT_REG_Rn(uc, 13), &mctx->regs, sizeof (gulong) * MONO_SAVED_GREGS);
 615         memcpy (&UCONTEXT_REG_FPRn(uc, 14), &mctx->fregs, sizeof (double) * MONO_SAVED_FREGS);
 616 }
 617
 618 gpointer
 619 mono_arch_ip_from_context (void *sigctx)
 620 {
 621         os_ucontext *uc = sigctx;
 622         return (gpointer)UCONTEXT_REG_NIP(uc);
 623 }
 624
 625 static void
 626 altstack_handle_and_restore (void *sigctx, gpointer obj, gboolean test_only)
 627 {
 628         void (*restore_context) (MonoContext *);
 629         MonoContext mctx;
 630
 631         restore_context = mono_arch_get_restore_context ();
 632         mono_arch_sigctx_to_monoctx (sigctx, &mctx);
 633         mono_handle_exception (&mctx, obj, (gpointer)mctx.sc_ir, test_only);
 634         restore_context (&mctx);
 635 }
 636
 637 void
 638 mono_arch_handle_altstack_exception (void *sigctx, gpointer fault_addr, gboolean stack_ovf)
 639 {
 640 #ifdef MONO_ARCH_USE_SIGACTION
 641         os_ucontext *uc = (ucontext_t*)sigctx;
 642         os_ucontext *uc_copy;
 643         MonoJitInfo *ji = mono_jit_info_table_find (mono_domain_get (), mono_arch_ip_from_context (sigctx));
 644         gpointer *sp;
 645         int frame_size;
 646
 647         if (stack_ovf) {
 648                 const char *method;
 649                 /* we don't do much now, but we can warn the user with a useful message */
 650                 fprintf (stderr, "Stack overflow: IP: %p, SP: %p\n", mono_arch_ip_from_context (sigctx), (gpointer)UCONTEXT_REG_Rn(uc, 1));
 651                 if (ji && ji->method)
 652                         method = mono_method_full_name (ji->method, TRUE);
 653                 else
 654                         method = "Unmanaged";
 655                 fprintf (stderr, "At %s\n", method);
 656                 abort ();
 657         }
 658         if (!ji)
 659                 mono_handle_native_sigsegv (SIGSEGV, sigctx);
 660         /* setup a call frame on the real stack so that control is returned there
 661          * and exception handling can continue.
 662          * The frame looks like:
 663          *   ucontext struct
 664          *   ...
 665          * 224 is the size of the red zone
 666          */
 667         frame_size = sizeof (ucontext_t) + sizeof (gpointer) * 16 + 224;
 668         frame_size += 15;
 669         frame_size &= ~15;
 670         sp = (gpointer)(UCONTEXT_REG_Rn(uc, 1) & ~15);
 671         sp = (gpointer)((char*)sp - frame_size);
 672         /* may need to adjust pointers in the new struct copy, depending on the OS */
 673         uc_copy = (ucontext_t*)(sp + 16);
 674         memcpy (uc_copy, uc, sizeof (os_ucontext));
 675 #if defined(__linux__) && !defined(__mono_ppc64__)
 676         uc_copy->uc_mcontext.uc_regs = (gpointer)((char*)uc_copy + ((char*)uc->uc_mcontext.uc_regs - (char*)uc));
 677 #endif
 678         g_assert (mono_arch_ip_from_context (uc) == mono_arch_ip_from_context (uc_copy));
 679         /* at the return form the signal handler execution starts in altstack_handle_and_restore() */
 680         UCONTEXT_REG_LNK(uc) = UCONTEXT_REG_NIP(uc);
 681 #ifdef PPC_USES_FUNCTION_DESCRIPTOR
 682         {
 683                 MonoPPCFunctionDescriptor *handler_ftnptr = (MonoPPCFunctionDescriptor*)altstack_handle_and_restore;
 684
 685                 UCONTEXT_REG_NIP(uc) = (gulong)handler_ftnptr->code;
 686                 UCONTEXT_REG_Rn(uc, 2) = (gulong)handler_ftnptr->toc;
 687         }
 688 #else
 689         UCONTEXT_REG_NIP(uc) = (unsigned long)altstack_handle_and_restore;
 690 #endif
 691         UCONTEXT_REG_Rn(uc, 1) = (unsigned long)sp;
 692         UCONTEXT_REG_Rn(uc, PPC_FIRST_ARG_REG) = (unsigned long)(sp + 16);
 693         UCONTEXT_REG_Rn(uc, PPC_FIRST_ARG_REG + 1) = 0;
 694         UCONTEXT_REG_Rn(uc, PPC_FIRST_ARG_REG + 2) = 0;
 695 #endif
 696 }
 697
 698 gboolean
 699 mono_arch_handle_exception (void *ctx, gpointer obj, gboolean test_only)
 700 {
 701         MonoContext mctx;
 702         gboolean result;
 703
 704         mono_arch_sigctx_to_monoctx (ctx, &mctx);
 705
 706         result = mono_handle_exception (&mctx, obj, (gpointer)mctx.sc_ir, test_only);
 707         /* restore the context so that returning from the signal handler will invoke
 708          * the catch clause
 709          */
 710         mono_arch_monoctx_to_sigctx (&mctx, ctx);
 711         return result;
 712 }
 713
 714 gboolean
 715 mono_arch_has_unwind_info (gconstpointer addr)
 716 {
 717         return FALSE;
 718 }
 719