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_ldptr (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_full (guint32 *code_size, MonoJumpInfo **ji, gboolean aot)
 200 {
 201         guint8 *start, *code;
 202         int size = MONO_PPC_32_64_CASE (128, 172) + PPC_FTNPTR_SIZE;
 203
 204         code = start = mono_global_codeman_reserve (size);
 205         *ji = NULL;
 206         if (!aot)
 207                 code = mono_ppc_create_pre_code_ftnptr (code);
 208         restore_regs_from_context (ppc_r3, ppc_r4, ppc_r5);
 209         /* restore also the stack pointer */
 210         ppc_ldptr (code, ppc_sp, G_STRUCT_OFFSET (MonoContext, sc_sp), ppc_r3);
 211         //ppc_break (code);
 212         /* jump to the saved IP */
 213         ppc_mtctr (code, ppc_r4);
 214         ppc_bcctr (code, PPC_BR_ALWAYS, 0);
 215         /* never reached */
 216         ppc_break (code);
 217
 218         g_assert ((code - start) <= size);
 219         mono_arch_flush_icache (start, code - start);
 220
 221         *code_size = code - start;
 222
 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_full (guint32 *code_size, MonoJumpInfo **ji, gboolean aot)
 256 {
 257         guint8 *start, *code;
 258         int alloc_size, pos, i;
 259         int size = MONO_PPC_32_64_CASE (320, 500) + PPC_FTNPTR_SIZE;
 260
 261         *ji = NULL;
 262
 263         /* call_filter (MonoContext *ctx, unsigned long eip, gpointer exc) */
 264         code = start = mono_global_codeman_reserve (size);
 265         if (!aot)
 266                 code = mono_ppc_create_pre_code_ftnptr (code);
 267
 268         /* store ret addr */
 269         ppc_mflr (code, ppc_r0);
 270         ppc_stptr (code, ppc_r0, PPC_RET_ADDR_OFFSET, ppc_sp);
 271
 272         alloc_size = REG_SAVE_STACK_FRAME_SIZE;
 273
 274         /* allocate stack frame and set link from sp in ctx */
 275         g_assert ((alloc_size & (MONO_ARCH_FRAME_ALIGNMENT-1)) == 0);
 276         ppc_ldptr (code, ppc_r0, G_STRUCT_OFFSET (MonoContext, sc_sp), ppc_r3);
 277         ppc_ldptr_indexed (code, ppc_r0, ppc_r0, ppc_r0);
 278         ppc_stptr_update (code, ppc_r0, -alloc_size, ppc_sp);
 279
 280         code = emit_save_saved_regs (code, alloc_size);
 281
 282         /* restore all the regs from ctx (in r3), but not r1, the stack pointer */
 283         restore_regs_from_context (ppc_r3, ppc_r6, ppc_r7);
 284         /* call handler at eip (r4) and set the first arg with the exception (r5) */
 285         ppc_mtctr (code, ppc_r4);
 286         ppc_mr (code, ppc_r3, ppc_r5);
 287         ppc_bcctrl (code, PPC_BR_ALWAYS, 0);
 288
 289         /* epilog */
 290         ppc_ldptr (code, ppc_r0, alloc_size + PPC_RET_ADDR_OFFSET, ppc_sp);
 291         ppc_mtlr (code, ppc_r0);
 292
 293         /* restore all the regs from the stack */
 294         pos = alloc_size;
 295         for (i = 31; i >= 14; --i) {
 296                 pos -= sizeof (gdouble);
 297                 ppc_lfd (code, i, pos, ppc_sp);
 298         }
 299         pos -= sizeof (gpointer) * MONO_SAVED_GREGS;
 300         ppc_load_multiple_regs (code, ppc_r13, pos, ppc_sp);
 301
 302         ppc_addic (code, ppc_sp, ppc_sp, alloc_size);
 303         ppc_blr (code);
 304
 305         g_assert ((code - start) < size);
 306         mono_arch_flush_icache (start, code - start);
 307
 308         *code_size = code - start;
 309
 310         return start;
 311 }
 312
 313 void
 314 mono_ppc_throw_exception (MonoObject *exc, unsigned long eip, unsigned long esp, mgreg_t *int_regs, gdouble *fp_regs, gboolean rethrow)
 315 {
 316         static void (*restore_context) (MonoContext *);
 317         MonoContext ctx;
 318
 319         if (!restore_context)
 320                 restore_context = mono_get_restore_context ();
 321
 322         /* adjust eip so that it point into the call instruction */
 323         eip -= 4;
 324
 325         setup_context (&ctx);
 326
 327         /*printf ("stack in throw: %p\n", esp);*/
 328         MONO_CONTEXT_SET_BP (&ctx, esp);
 329         MONO_CONTEXT_SET_IP (&ctx, eip);
 330         memcpy (&ctx.regs, int_regs, sizeof (mgreg_t) * MONO_SAVED_GREGS);
 331         memcpy (&ctx.fregs, fp_regs, sizeof (double) * MONO_SAVED_FREGS);
 332
 333         if (mono_object_isinst (exc, mono_defaults.exception_class)) {
 334                 MonoException *mono_ex = (MonoException*)exc;
 335                 if (!rethrow)
 336                         mono_ex->stack_trace = NULL;
 337         }
 338         mono_handle_exception (&ctx, exc, (gpointer)eip, FALSE);
 339         restore_context (&ctx);
 340
 341         g_assert_not_reached ();
 342 }
 343
 344 /**
 345  * arch_get_throw_exception_generic:
 346  *
 347  * Returns a function pointer which can be used to raise
 348  * exceptions. The returned function has the following
 349  * signature: void (*func) (MonoException *exc); or
 350  * void (*func) (guint32 ex_token, gpointer ip)
 351  *
 352  */
 353 static gpointer
 354 mono_arch_get_throw_exception_generic (int size, guint32 *code_size, MonoJumpInfo **ji, int corlib, gboolean rethrow, gboolean aot)
 355 {
 356         guint8 *start, *code;
 357         int alloc_size, pos;
 358
 359         *ji = NULL;
 360
 361         code = start = mono_global_codeman_reserve (size);
 362         if (!aot)
 363                 code = mono_ppc_create_pre_code_ftnptr (code);
 364
 365         /* store ret addr */
 366         if (corlib)
 367                 ppc_mr (code, ppc_r0, ppc_r4);
 368         else
 369                 ppc_mflr (code, ppc_r0);
 370         ppc_stptr (code, ppc_r0, PPC_RET_ADDR_OFFSET, ppc_sp);
 371
 372         alloc_size = REG_SAVE_STACK_FRAME_SIZE;
 373
 374         g_assert ((alloc_size & (MONO_ARCH_FRAME_ALIGNMENT-1)) == 0);
 375         ppc_stptr_update (code, ppc_sp, -alloc_size, ppc_sp);
 376
 377         code = emit_save_saved_regs (code, alloc_size);
 378
 379         //ppc_break (code);
 380         if (corlib) {
 381                 ppc_mr (code, ppc_r4, ppc_r3);
 382
 383                 if (aot) {
 384                         code = mono_arch_emit_load_aotconst (start, code, ji, MONO_PATCH_INFO_IMAGE, mono_defaults.corlib);
 385                         ppc_mr (code, ppc_r3, ppc_r11);
 386                         code = mono_arch_emit_load_aotconst (start, code, ji, MONO_PATCH_INFO_JIT_ICALL_ADDR, "mono_exception_from_token");
 387 #ifdef PPC_USES_FUNCTION_DESCRIPTOR
 388                         ppc_ldptr (code, ppc_r2, sizeof (gpointer), ppc_r11);
 389                         ppc_ldptr (code, ppc_r11, 0, ppc_r11);
 390 #endif
 391                         ppc_mtctr (code, ppc_r11);
 392                         ppc_bcctrl (code, PPC_BR_ALWAYS, 0);
 393                 } else {
 394                         ppc_load (code, ppc_r3, (gulong)mono_defaults.corlib);
 395                         ppc_load_func (code, ppc_r0, mono_exception_from_token);
 396                         ppc_mtctr (code, ppc_r0);
 397                         ppc_bcctrl (code, PPC_BR_ALWAYS, 0);
 398                 }
 399         }
 400
 401         /* call throw_exception (exc, ip, sp, int_regs, fp_regs) */
 402         /* caller sp */
 403         ppc_ldptr (code, ppc_r5, 0, ppc_sp);
 404         /* exc is already in place in r3 */
 405         if (corlib)
 406                 ppc_ldptr (code, ppc_r4, PPC_RET_ADDR_OFFSET, ppc_r5);
 407         else
 408                 ppc_mr (code, ppc_r4, ppc_r0); /* caller ip */
 409         /* pointer to the saved fp regs */
 410         pos = alloc_size - sizeof (gdouble) * MONO_SAVED_FREGS;
 411         ppc_addi (code, ppc_r7, ppc_sp, pos);
 412         /* pointer to the saved int regs */
 413         pos -= sizeof (gpointer) * MONO_SAVED_GREGS;
 414         ppc_addi (code, ppc_r6, ppc_sp, pos);
 415         ppc_li (code, ppc_r8, rethrow);
 416
 417         if (aot) {
 418                 // This can be called from runtime code, which can't guarantee that
 419                 // r30 contains the got address.
 420                 // So emit the got address loading code too
 421                 code = mono_arch_emit_load_got_addr (start, code, NULL, ji);
 422                 code = mono_arch_emit_load_aotconst (start, code, ji, MONO_PATCH_INFO_JIT_ICALL_ADDR, "mono_ppc_throw_exception");
 423 #ifdef PPC_USES_FUNCTION_DESCRIPTOR
 424                 ppc_ldptr (code, ppc_r2, sizeof (gpointer), ppc_r11);
 425                 ppc_ldptr (code, ppc_r11, 0, ppc_r11);
 426 #endif
 427                 ppc_mtctr (code, ppc_r11);
 428                 ppc_bcctrl (code, PPC_BR_ALWAYS, 0);
 429         } else {
 430                 ppc_load_func (code, ppc_r0, mono_ppc_throw_exception);
 431                 ppc_mtctr (code, ppc_r0);
 432                 ppc_bcctrl (code, PPC_BR_ALWAYS, 0);
 433         }
 434         /* we should never reach this breakpoint */
 435         ppc_break (code);
 436         g_assert ((code - start) <= size);
 437         mono_arch_flush_icache (start, code - start);
 438
 439         *code_size = code - start;
 440
 441         return start;
 442 }
 443
 444 /**
 445  * mono_arch_get_rethrow_exception:
 446  *
 447  * Returns a function pointer which can be used to rethrow
 448  * exceptions. The returned function has the following
 449  * signature: void (*func) (MonoException *exc);
 450  *
 451  */
 452 gpointer
 453 mono_arch_get_rethrow_exception_full (guint32 *code_size, MonoJumpInfo **ji, gboolean aot)
 454 {
 455         int size = MONO_PPC_32_64_CASE (132, 224) + PPC_FTNPTR_SIZE;
 456
 457         if (aot)
 458                 size += 64;
 459         return mono_arch_get_throw_exception_generic (size, code_size, ji, FALSE, TRUE, aot);
 460 }
 461
 462 /**
 463  * arch_get_throw_exception:
 464  *
 465  * Returns a function pointer which can be used to raise
 466  * exceptions. The returned function has the following
 467  * signature: void (*func) (MonoException *exc);
 468  * For example to raise an arithmetic exception you can use:
 469  *
 470  * x86_push_imm (code, mono_get_exception_arithmetic ());
 471  * x86_call_code (code, arch_get_throw_exception ());
 472  *
 473  */
 474 gpointer
 475 mono_arch_get_throw_exception_full (guint32 *code_size, MonoJumpInfo **ji, gboolean aot)
 476 {
 477         int size = MONO_PPC_32_64_CASE (132, 224) + PPC_FTNPTR_SIZE;
 478
 479         if (aot)
 480                 size += 64;
 481         return mono_arch_get_throw_exception_generic (size, code_size, ji, FALSE, FALSE, aot);
 482 }
 483
 484 /**
 485  * mono_arch_get_throw_corlib_exception:
 486  *
 487  * Returns a function pointer which can be used to raise
 488  * corlib exceptions. The returned function has the following
 489  * signature: void (*func) (guint32 ex_token, guint32 offset);
 490  * On PPC, we pass the ip instead of the offset
 491  */
 492 gpointer
 493 mono_arch_get_throw_corlib_exception_full (guint32 *code_size, MonoJumpInfo **ji, gboolean aot)
 494 {
 495         int size = MONO_PPC_32_64_CASE (168, 304) + PPC_FTNPTR_SIZE;
 496
 497         if (aot)
 498                 size += 64;
 499         return mono_arch_get_throw_exception_generic (size, code_size, ji, TRUE, FALSE, aot);
 500 }
 501
 502 /*
 503  * mono_arch_find_jit_info_ext:
 504  *
 505  * See exceptions-amd64.c for docs.
 506  */
 507 gboolean
 508 mono_arch_find_jit_info_ext (MonoDomain *domain, MonoJitTlsData *jit_tls,
 509                                                          MonoJitInfo *ji, MonoContext *ctx,
 510                                                          MonoContext *new_ctx, MonoLMF **lmf,
 511                                                          StackFrameInfo *frame)
 512 {
 513         gpointer ip = MONO_CONTEXT_GET_IP (ctx);
 514         MonoPPCStackFrame *sframe;
 515
 516         memset (frame, 0, sizeof (StackFrameInfo));
 517         frame->ji = ji;
 518         frame->managed = FALSE;
 519
 520         *new_ctx = *ctx;
 521         setup_context (new_ctx);
 522
 523         if (ji != NULL) {
 524                 int i;
 525                 mgreg_t regs [ppc_lr + 1];
 526                 guint8 *cfa;
 527                 guint32 unwind_info_len;
 528                 guint8 *unwind_info;
 529
 530                 frame->type = FRAME_TYPE_MANAGED;
 531
 532                 if (!ji->method->wrapper_type || ji->method->wrapper_type == MONO_WRAPPER_DYNAMIC_METHOD)
 533                         frame->managed = TRUE;
 534
 535                 if (ji->from_aot)
 536                         unwind_info = mono_aot_get_unwind_info (ji, &unwind_info_len);
 537                 else
 538                         unwind_info = mono_get_cached_unwind_info (ji->used_regs, &unwind_info_len);
 539
 540                 sframe = (MonoPPCStackFrame*)MONO_CONTEXT_GET_SP (ctx);
 541                 MONO_CONTEXT_SET_BP (new_ctx, sframe->sp);
 542                 if (ji->method->save_lmf) {
 543                         /* sframe->sp points just past the end of the LMF */
 544                         guint8 *lmf_addr = (guint8*)sframe->sp - sizeof (MonoLMF);
 545                         memcpy (&new_ctx->fregs, lmf_addr + G_STRUCT_OFFSET (MonoLMF, fregs), sizeof (double) * MONO_SAVED_FREGS);
 546                         memcpy (&new_ctx->regs, lmf_addr + G_STRUCT_OFFSET (MonoLMF, iregs), sizeof (mgreg_t) * MONO_SAVED_GREGS);
 547                         /* the calling IP is in the parent frame */
 548                         sframe = (MonoPPCStackFrame*)sframe->sp;
 549                         /* we substract 4, so that the IP points into the call instruction */
 550                         MONO_CONTEXT_SET_IP (new_ctx, sframe->lr - 4);
 551                 } else {
 552                         regs [ppc_lr] = ctx->sc_ir;
 553                         regs [ppc_sp] = ctx->sc_sp;
 554                         for (i = 0; i < MONO_SAVED_GREGS; ++i)
 555                                 regs [ppc_r13 + i] = ctx->regs [i];
 556
 557                         mono_unwind_frame (unwind_info, unwind_info_len, ji->code_start,
 558                                                            (guint8*)ji->code_start + ji->code_size,
 559                                                            ip, regs, ppc_lr + 1, &cfa);
 560
 561                         /* we substract 4, so that the IP points into the call instruction */
 562                         MONO_CONTEXT_SET_IP (new_ctx, regs [ppc_lr] - 4);
 563                         MONO_CONTEXT_SET_BP (new_ctx, cfa);
 564
 565                         for (i = 0; i < MONO_SAVED_GREGS; ++i)
 566                                 new_ctx->regs [i] = regs [ppc_r13 + i];
 567                 }
 568
 569                 if (*lmf && (MONO_CONTEXT_GET_SP (ctx) >= (gpointer)(*lmf)->ebp)) {
 570                         /* remove any unused lmf */
 571                         *lmf = (*lmf)->previous_lmf;
 572                 }
 573
 574                 return TRUE;
 575         } else if (*lmf) {
 576
 577                 if ((ji = mini_jit_info_table_find (domain, (gpointer)(*lmf)->eip, NULL))) {
 578                 } else {
 579                         if (!(*lmf)->method)
 580                                 return FALSE;
 581
 582                         /* Trampoline lmf frame */
 583                         frame->method = (*lmf)->method;
 584                 }
 585
 586                 /*sframe = (MonoPPCStackFrame*)MONO_CONTEXT_GET_SP (ctx);
 587                 MONO_CONTEXT_SET_BP (new_ctx, sframe->sp);
 588                 MONO_CONTEXT_SET_IP (new_ctx, sframe->lr);*/
 589                 MONO_CONTEXT_SET_BP (new_ctx, (*lmf)->ebp);
 590                 MONO_CONTEXT_SET_IP (new_ctx, (*lmf)->eip);
 591                 memcpy (&new_ctx->regs, (*lmf)->iregs, sizeof (mgreg_t) * MONO_SAVED_GREGS);
 592                 memcpy (&new_ctx->fregs, (*lmf)->fregs, sizeof (double) * MONO_SAVED_FREGS);
 593
 594                 frame->ji = ji;
 595                 frame->type = FRAME_TYPE_MANAGED_TO_NATIVE;
 596
 597                 /* FIXME: what about trampoline LMF frames?  see exceptions-x86.c */
 598
 599                 *lmf = (*lmf)->previous_lmf;
 600
 601                 return TRUE;
 602         }
 603
 604         return FALSE;
 605 }
 606
 607 /*
 608  * This is the function called from the signal handler
 609  */
 610 void
 611 mono_arch_sigctx_to_monoctx (void *ctx, MonoContext *mctx)
 612 {
 613 #ifdef MONO_CROSS_COMPILE
 614         g_assert_not_reached ();
 615 #else
 616         os_ucontext *uc = ctx;
 617
 618         mctx->sc_ir = UCONTEXT_REG_NIP(uc);
 619         mctx->sc_sp = UCONTEXT_REG_Rn(uc, 1);
 620         memcpy (&mctx->regs, &UCONTEXT_REG_Rn(uc, 13), sizeof (mgreg_t) * MONO_SAVED_GREGS);
 621         memcpy (&mctx->fregs, &UCONTEXT_REG_FPRn(uc, 14), sizeof (double) * MONO_SAVED_FREGS);
 622 #endif
 623 }
 624
 625 void
 626 mono_arch_monoctx_to_sigctx (MonoContext *mctx, void *ctx)
 627 {
 628 #ifdef MONO_CROSS_COMPILE
 629         g_assert_not_reached ();
 630 #else
 631         os_ucontext *uc = ctx;
 632
 633         UCONTEXT_REG_NIP(uc) = mctx->sc_ir;
 634         UCONTEXT_REG_Rn(uc, 1) = mctx->sc_sp;
 635         memcpy (&UCONTEXT_REG_Rn(uc, 13), &mctx->regs, sizeof (mgreg_t) * MONO_SAVED_GREGS);
 636         memcpy (&UCONTEXT_REG_FPRn(uc, 14), &mctx->fregs, sizeof (double) * MONO_SAVED_FREGS);
 637 #endif
 638 }
 639
 640 gpointer
 641 mono_arch_ip_from_context (void *sigctx)
 642 {
 643 #ifdef MONO_CROSS_COMPILE
 644         g_assert_not_reached ();
 645 #else
 646         os_ucontext *uc = sigctx;
 647         return (gpointer)UCONTEXT_REG_NIP(uc);
 648 #endif
 649 }
 650
 651 void
 652 mono_ppc_set_func_into_sigctx (void *sigctx, void *func)
 653 {
 654 #ifdef MONO_CROSS_COMPILE
 655         g_assert_not_reached ();
 656 #elif defined(PPC_USES_FUNCTION_DESCRIPTOR)
 657         /* Have to set both the ip and the TOC reg */
 658         os_ucontext *uc = sigctx;
 659
 660         UCONTEXT_REG_NIP(uc) = ((gsize*)func) [0];
 661         UCONTEXT_REG_Rn (uc, 2) = ((gsize*)func)[1];
 662 #else
 663         g_assert_not_reached ();
 664 #endif
 665 }
 666
 667 static void
 668 altstack_handle_and_restore (void *sigctx, gpointer obj, gboolean test_only)
 669 {
 670         void (*restore_context) (MonoContext *);
 671         MonoContext mctx;
 672
 673         restore_context = mono_get_restore_context ();
 674         mono_arch_sigctx_to_monoctx (sigctx, &mctx);
 675         mono_handle_exception (&mctx, obj, (gpointer)mctx.sc_ir, test_only);
 676         restore_context (&mctx);
 677 }
 678
 679 void
 680 mono_arch_handle_altstack_exception (void *sigctx, gpointer fault_addr, gboolean stack_ovf)
 681 {
 682 #ifdef MONO_CROSS_COMPILE
 683         g_assert_not_reached ();
 684 #else
 685 #ifdef MONO_ARCH_USE_SIGACTION
 686         os_ucontext *uc = (ucontext_t*)sigctx;
 687         os_ucontext *uc_copy;
 688         MonoJitInfo *ji = mini_jit_info_table_find (mono_domain_get (), mono_arch_ip_from_context (sigctx), NULL);
 689         gpointer *sp;
 690         int frame_size;
 691
 692         if (stack_ovf) {
 693                 const char *method;
 694                 /* we don't do much now, but we can warn the user with a useful message */
 695                 fprintf (stderr, "Stack overflow: IP: %p, SP: %p\n", mono_arch_ip_from_context (sigctx), (gpointer)UCONTEXT_REG_Rn(uc, 1));
 696                 if (ji && ji->method)
 697                         method = mono_method_full_name (ji->method, TRUE);
 698                 else
 699                         method = "Unmanaged";
 700                 fprintf (stderr, "At %s\n", method);
 701                 abort ();
 702         }
 703         if (!ji)
 704                 mono_handle_native_sigsegv (SIGSEGV, sigctx);
 705         /* setup a call frame on the real stack so that control is returned there
 706          * and exception handling can continue.
 707          * The frame looks like:
 708          *   ucontext struct
 709          *   ...
 710          * 224 is the size of the red zone
 711          */
 712         frame_size = sizeof (ucontext_t) + sizeof (gpointer) * 16 + 224;
 713         frame_size += 15;
 714         frame_size &= ~15;
 715         sp = (gpointer)(UCONTEXT_REG_Rn(uc, 1) & ~15);
 716         sp = (gpointer)((char*)sp - frame_size);
 717         /* may need to adjust pointers in the new struct copy, depending on the OS */
 718         uc_copy = (ucontext_t*)(sp + 16);
 719         memcpy (uc_copy, uc, sizeof (os_ucontext));
 720 #if defined(__linux__) && !defined(__mono_ppc64__)
 721         uc_copy->uc_mcontext.uc_regs = (gpointer)((char*)uc_copy + ((char*)uc->uc_mcontext.uc_regs - (char*)uc));
 722 #endif
 723         g_assert (mono_arch_ip_from_context (uc) == mono_arch_ip_from_context (uc_copy));
 724         /* at the return form the signal handler execution starts in altstack_handle_and_restore() */
 725         UCONTEXT_REG_LNK(uc) = UCONTEXT_REG_NIP(uc);
 726 #ifdef PPC_USES_FUNCTION_DESCRIPTOR
 727         {
 728                 MonoPPCFunctionDescriptor *handler_ftnptr = (MonoPPCFunctionDescriptor*)altstack_handle_and_restore;
 729
 730                 UCONTEXT_REG_NIP(uc) = (gulong)handler_ftnptr->code;
 731                 UCONTEXT_REG_Rn(uc, 2) = (gulong)handler_ftnptr->toc;
 732         }
 733 #else
 734         UCONTEXT_REG_NIP(uc) = (unsigned long)altstack_handle_and_restore;
 735 #endif
 736         UCONTEXT_REG_Rn(uc, 1) = (unsigned long)sp;
 737         UCONTEXT_REG_Rn(uc, PPC_FIRST_ARG_REG) = (unsigned long)(sp + 16);
 738         UCONTEXT_REG_Rn(uc, PPC_FIRST_ARG_REG + 1) = 0;
 739         UCONTEXT_REG_Rn(uc, PPC_FIRST_ARG_REG + 2) = 0;
 740 #endif
 741
 742 #endif /* !MONO_CROSS_COMPILE */
 743 }
 744
 745 gboolean
 746 mono_arch_handle_exception (void *ctx, gpointer obj, gboolean test_only)
 747 {
 748         MonoContext mctx;
 749         gboolean result;
 750
 751         mono_arch_sigctx_to_monoctx (ctx, &mctx);
 752
 753         result = mono_handle_exception (&mctx, obj, (gpointer)mctx.sc_ir, test_only);
 754         /* restore the context so that returning from the signal handler will invoke
 755          * the catch clause
 756          */
 757         mono_arch_monoctx_to_sigctx (&mctx, ctx);
 758         return result;
 759 }
 760
 761 gboolean
 762 mono_arch_has_unwind_info (gconstpointer addr)
 763 {
 764         return FALSE;
 765 }
 766