2 * exceptions-arm.c: exception support for ARM
5 * Dietmar Maurer (dietmar@ximian.com)
6 * Paolo Molaro (lupus@ximian.com)
8 * (C) 2001 Ximian, Inc.
16 #ifndef MONO_CROSS_COMPILE
17 #ifdef HAVE_ASM_SIGCONTEXT_H
18 #include <asm/sigcontext.h>
19 #endif /* def HAVE_ASM_SIGCONTEXT_H */
22 #ifdef HAVE_UCONTEXT_H
24 #endif /* def HAVE_UCONTEXT_H */
26 #include <mono/arch/arm/arm-codegen.h>
27 #include <mono/arch/arm/arm-vfp-codegen.h>
28 #include <mono/metadata/appdomain.h>
29 #include <mono/metadata/tabledefs.h>
30 #include <mono/metadata/threads.h>
31 #include <mono/metadata/debug-helpers.h>
32 #include <mono/metadata/exception.h>
33 #include <mono/metadata/mono-debug.h>
37 #include "mono/utils/mono-sigcontext.h"
40 * arch_get_restore_context:
42 * Returns a pointer to a method which restores a previously saved sigcontext.
43 * The first argument in r0 is the pointer to the context.
46 mono_arch_get_restore_context (MonoTrampInfo **info, gboolean aot)
51 MonoJumpInfo *ji = NULL;
52 GSList *unwind_ops = NULL;
54 start = code = mono_global_codeman_reserve (128);
57 * Move things to their proper place so we can restore all the registers with
63 if (!mono_arch_is_soft_float ()) {
64 ARM_ADD_REG_IMM8 (code, ARMREG_IP, ctx_reg, G_STRUCT_OFFSET (MonoContext, fregs));
65 ARM_FLDMD (code, ARM_VFP_D0, 16, ARMREG_IP);
69 ARM_LDR_IMM (code, ARMREG_IP, ctx_reg, G_STRUCT_OFFSET (MonoContext, pc));
70 ARM_STR_IMM (code, ARMREG_IP, ctx_reg, G_STRUCT_OFFSET (MonoContext, regs) + (ARMREG_PC * sizeof (mgreg_t)));
72 /* restore everything */
73 ARM_ADD_REG_IMM8 (code, ARMREG_IP, ctx_reg, G_STRUCT_OFFSET(MonoContext, regs));
74 ARM_LDM (code, ARMREG_IP, 0xffff);
79 g_assert ((code - start) < 128);
81 mono_arch_flush_icache (start, code - start);
84 *info = mono_tramp_info_create ("restore_context", start, code - start, ji, unwind_ops);
90 * arch_get_call_filter:
92 * Returns a pointer to a method which calls an exception filter. We
93 * also use this function to call finally handlers (we pass NULL as
94 * @exc object in this case).
97 mono_arch_get_call_filter (MonoTrampInfo **info, gboolean aot)
102 MonoJumpInfo *ji = NULL;
103 GSList *unwind_ops = NULL;
105 /* call_filter (MonoContext *ctx, unsigned long eip, gpointer exc) */
106 start = code = mono_global_codeman_reserve (320);
108 /* save all the regs on the stack */
109 ARM_MOV_REG_REG (code, ARMREG_IP, ARMREG_SP);
110 ARM_PUSH (code, MONO_ARM_REGSAVE_MASK);
112 /* restore all the regs from ctx (in r0), but not sp, the stack pointer */
114 ARM_LDR_IMM (code, ARMREG_IP, ctx_reg, G_STRUCT_OFFSET (MonoContext, pc));
115 ARM_ADD_REG_IMM8 (code, ARMREG_LR, ctx_reg, G_STRUCT_OFFSET(MonoContext, regs) + (MONO_ARM_FIRST_SAVED_REG * sizeof (mgreg_t)));
116 ARM_LDM (code, ARMREG_LR, MONO_ARM_REGSAVE_MASK);
117 /* call handler at eip (r1) and set the first arg with the exception (r2) */
118 ARM_MOV_REG_REG (code, ARMREG_R0, ARMREG_R2);
119 ARM_MOV_REG_REG (code, ARMREG_LR, ARMREG_PC);
120 ARM_MOV_REG_REG (code, ARMREG_PC, ARMREG_R1);
123 ARM_POP_NWB (code, 0xff0 | ((1 << ARMREG_SP) | (1 << ARMREG_PC)));
125 g_assert ((code - start) < 320);
127 mono_arch_flush_icache (start, code - start);
130 *info = mono_tramp_info_create ("call_filter", start, code - start, ji, unwind_ops);
136 mono_arm_throw_exception (MonoObject *exc, mgreg_t pc, mgreg_t sp, mgreg_t *int_regs, gdouble *fp_regs)
139 gboolean rethrow = sp & 1;
141 sp &= ~1; /* clear the optional rethrow bit */
142 pc &= ~1; /* clear the thumb bit */
143 /* adjust eip so that it point into the call instruction */
146 /*printf ("stack in throw: %p\n", esp);*/
147 MONO_CONTEXT_SET_BP (&ctx, int_regs [ARMREG_FP - 4]);
148 MONO_CONTEXT_SET_SP (&ctx, sp);
149 MONO_CONTEXT_SET_IP (&ctx, pc);
150 memcpy (((guint8*)&ctx.regs) + (ARMREG_R4 * sizeof (mgreg_t)), int_regs, 8 * sizeof (mgreg_t));
151 memcpy (&ctx.fregs, fp_regs, sizeof (double) * 16);
153 if (mono_object_isinst (exc, mono_defaults.exception_class)) {
154 MonoException *mono_ex = (MonoException*)exc;
156 mono_ex->stack_trace = NULL;
158 mono_handle_exception (&ctx, exc);
159 mono_restore_context (&ctx);
160 g_assert_not_reached ();
164 mono_arm_throw_exception_by_token (guint32 type_token, mgreg_t pc, mgreg_t sp, mgreg_t *int_regs, gdouble *fp_regs)
166 /* Clear thumb bit */
169 mono_arm_throw_exception ((MonoObject*)mono_exception_from_token (mono_defaults.corlib, type_token), pc, sp, int_regs, fp_regs);
173 mono_arm_resume_unwind (guint32 dummy1, mgreg_t pc, mgreg_t sp, mgreg_t *int_regs, gdouble *fp_regs)
177 pc &= ~1; /* clear the optional rethrow bit */
178 /* adjust eip so that it point into the call instruction */
181 MONO_CONTEXT_SET_BP (&ctx, int_regs [ARMREG_FP - 4]);
182 MONO_CONTEXT_SET_SP (&ctx, sp);
183 MONO_CONTEXT_SET_IP (&ctx, pc);
184 memcpy (((guint8*)&ctx.regs) + (ARMREG_R4 * sizeof (mgreg_t)), int_regs, 8 * sizeof (mgreg_t));
186 mono_resume_unwind (&ctx);
190 * get_throw_trampoline:
192 * Returns a function pointer which can be used to raise
193 * exceptions. The returned function has the following
194 * signature: void (*func) (MonoException *exc); or
195 * void (*func) (guint32 ex_token, guint8* ip);
199 get_throw_trampoline (int size, gboolean corlib, gboolean rethrow, gboolean llvm, gboolean resume_unwind, const char *tramp_name, MonoTrampInfo **info, gboolean aot)
203 MonoJumpInfo *ji = NULL;
204 GSList *unwind_ops = NULL;
207 code = start = mono_global_codeman_reserve (size);
209 mono_add_unwind_op_def_cfa (unwind_ops, code, start, ARMREG_SP, 0);
211 /* save all the regs on the stack */
212 ARM_MOV_REG_REG (code, ARMREG_IP, ARMREG_SP);
213 ARM_PUSH (code, MONO_ARM_REGSAVE_MASK);
215 cfa_offset = MONO_ARM_NUM_SAVED_REGS * sizeof (mgreg_t);
216 mono_add_unwind_op_def_cfa (unwind_ops, code, start, ARMREG_SP, cfa_offset);
217 mono_add_unwind_op_offset (unwind_ops, code, start, ARMREG_LR, - sizeof (mgreg_t));
220 if (!mono_arch_is_soft_float ()) {
221 ARM_SUB_REG_IMM8 (code, ARMREG_SP, ARMREG_SP, sizeof (double) * 16);
222 cfa_offset += sizeof (double) * 16;
223 mono_add_unwind_op_def_cfa_offset (unwind_ops, code, start, cfa_offset);
224 ARM_FSTMD (code, ARM_VFP_D0, 16, ARMREG_SP);
228 ARM_SUB_REG_IMM8 (code, ARMREG_SP, ARMREG_SP, 8);
230 mono_add_unwind_op_def_cfa_offset (unwind_ops, code, start, cfa_offset);
232 /* call throw_exception (exc, ip, sp, int_regs, fp_regs) */
234 ARM_ADD_REG_IMM8 (code, ARMREG_R2, ARMREG_SP, cfa_offset);
235 /* we encode rethrow in sp */
237 g_assert (!resume_unwind);
239 ARM_ORR_REG_IMM8 (code, ARMREG_R2, ARMREG_R2, rethrow);
241 /* exc is already in place in r0 */
243 /* The caller ip is already in R1 */
245 /* Negate the ip adjustment done in mono_arm_throw_exception */
246 ARM_ADD_REG_IMM8 (code, ARMREG_R1, ARMREG_R1, 4);
248 ARM_MOV_REG_REG (code, ARMREG_R1, ARMREG_LR); /* caller ip */
251 ARM_ADD_REG_IMM8 (code, ARMREG_R3, ARMREG_SP, (cfa_offset - (MONO_ARM_NUM_SAVED_REGS * sizeof (mgreg_t))));
253 ARM_ADD_REG_IMM8 (code, ARMREG_LR, ARMREG_SP, 8);
254 ARM_STR_IMM (code, ARMREG_LR, ARMREG_SP, 0);
257 const char *icall_name;
260 icall_name = "mono_arm_resume_unwind";
262 icall_name = "mono_arm_throw_exception_by_token";
264 icall_name = "mono_arm_throw_exception";
266 ji = mono_patch_info_list_prepend (ji, code - start, MONO_PATCH_INFO_JIT_ICALL_ADDR, icall_name);
267 ARM_LDR_IMM (code, ARMREG_IP, ARMREG_PC, 0);
269 *(gpointer*)(gpointer)code = NULL;
271 ARM_LDR_REG_REG (code, ARMREG_IP, ARMREG_PC, ARMREG_IP);
273 code = mono_arm_emit_load_imm (code, ARMREG_IP, GPOINTER_TO_UINT (resume_unwind ? (gpointer)mono_arm_resume_unwind : (corlib ? (gpointer)mono_arm_throw_exception_by_token : (gpointer)mono_arm_throw_exception)));
275 ARM_MOV_REG_REG (code, ARMREG_LR, ARMREG_PC);
276 ARM_MOV_REG_REG (code, ARMREG_PC, ARMREG_IP);
277 /* we should never reach this breakpoint */
279 g_assert ((code - start) < size);
280 mono_arch_flush_icache (start, code - start);
283 *info = mono_tramp_info_create (tramp_name, start, code - start, ji, unwind_ops);
289 * arch_get_throw_exception:
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);
294 * For example to raise an arithmetic exception you can use:
296 * x86_push_imm (code, mono_get_exception_arithmetic ());
297 * x86_call_code (code, arch_get_throw_exception ());
301 mono_arch_get_throw_exception (MonoTrampInfo **info, gboolean aot)
303 return get_throw_trampoline (132, FALSE, FALSE, FALSE, FALSE, "throw_exception", info, aot);
307 * mono_arch_get_rethrow_exception:
309 * Returns a function pointer which can be used to rethrow
310 * exceptions. The returned function has the following
311 * signature: void (*func) (MonoException *exc);
315 mono_arch_get_rethrow_exception (MonoTrampInfo **info, gboolean aot)
317 return get_throw_trampoline (132, FALSE, TRUE, FALSE, FALSE, "rethrow_exception", info, aot);
321 * mono_arch_get_throw_corlib_exception:
323 * Returns a function pointer which can be used to raise
324 * corlib exceptions. The returned function has the following
325 * signature: void (*func) (guint32 ex_token, guint32 offset);
326 * Here, offset is the offset which needs to be substracted from the caller IP
327 * to get the IP of the throw. Passing the offset has the advantage that it
328 * needs no relocations in the caller.
329 * On ARM, the ip is passed instead of an offset.
332 mono_arch_get_throw_corlib_exception (MonoTrampInfo **info, gboolean aot)
334 return get_throw_trampoline (168, TRUE, FALSE, FALSE, FALSE, "throw_corlib_exception", info, aot);
338 mono_arm_get_exception_trampolines (gboolean aot)
341 GSList *tramps = NULL;
343 /* LLVM uses the normal trampolines, but with a different name */
344 get_throw_trampoline (168, TRUE, FALSE, FALSE, FALSE, "llvm_throw_corlib_exception_trampoline", &info, aot);
345 tramps = g_slist_prepend (tramps, info);
347 get_throw_trampoline (168, TRUE, FALSE, TRUE, FALSE, "llvm_throw_corlib_exception_abs_trampoline", &info, aot);
348 tramps = g_slist_prepend (tramps, info);
350 get_throw_trampoline (168, FALSE, FALSE, FALSE, TRUE, "llvm_resume_unwind_trampoline", &info, aot);
351 tramps = g_slist_prepend (tramps, info);
357 mono_arch_exceptions_init (void)
363 tramp = mono_aot_get_trampoline ("llvm_throw_corlib_exception_trampoline");
364 mono_register_jit_icall (tramp, "llvm_throw_corlib_exception_trampoline", NULL, TRUE);
365 tramp = mono_aot_get_trampoline ("llvm_throw_corlib_exception_abs_trampoline");
366 mono_register_jit_icall (tramp, "llvm_throw_corlib_exception_abs_trampoline", NULL, TRUE);
367 tramp = mono_aot_get_trampoline ("llvm_resume_unwind_trampoline");
368 mono_register_jit_icall (tramp, "llvm_resume_unwind_trampoline", NULL, TRUE);
370 tramps = mono_arm_get_exception_trampolines (FALSE);
371 for (l = tramps; l; l = l->next) {
372 MonoTrampInfo *info = l->data;
374 mono_register_jit_icall (info->code, g_strdup (info->name), NULL, TRUE);
375 mono_tramp_info_register (info);
377 g_slist_free (tramps);
382 * mono_arch_find_jit_info:
384 * See exceptions-amd64.c for docs;
387 mono_arch_find_jit_info (MonoDomain *domain, MonoJitTlsData *jit_tls,
388 MonoJitInfo *ji, MonoContext *ctx,
389 MonoContext *new_ctx, MonoLMF **lmf,
390 mgreg_t **save_locations,
391 StackFrameInfo *frame)
393 gpointer ip = MONO_CONTEXT_GET_IP (ctx);
395 memset (frame, 0, sizeof (StackFrameInfo));
402 gssize regs [MONO_MAX_IREGS + 1 + 8];
404 guint32 unwind_info_len;
407 frame->type = FRAME_TYPE_MANAGED;
409 unwind_info = mono_jinfo_get_unwind_info (ji, &unwind_info_len);
412 printf ("%s %p %p\n", ji->d.method->name, ji->code_start, ip);
413 mono_print_unwind_info (unwind_info, unwind_info_len);
416 for (i = 0; i < 16; ++i)
417 regs [i] = new_ctx->regs [i];
419 /* On IOS, d8..d15 are callee saved. They are mapped to 8..15 in unwind.c */
420 for (i = 0; i < 8; ++i)
421 regs [MONO_MAX_IREGS + i] = new_ctx->fregs [8 + i];
424 mono_unwind_frame (unwind_info, unwind_info_len, ji->code_start,
425 (guint8*)ji->code_start + ji->code_size,
426 ip, regs, MONO_MAX_IREGS + 8,
427 save_locations, MONO_MAX_IREGS, &cfa);
429 for (i = 0; i < 16; ++i)
430 new_ctx->regs [i] = regs [i];
431 new_ctx->pc = regs [ARMREG_LR];
432 new_ctx->regs [ARMREG_SP] = (gsize)cfa;
434 for (i = 0; i < 8; ++i)
435 new_ctx->fregs [8 + i] = regs [MONO_MAX_IREGS + i];
438 if (*lmf && (MONO_CONTEXT_GET_SP (ctx) >= (gpointer)(*lmf)->sp)) {
439 /* remove any unused lmf */
440 *lmf = (gpointer)(((gsize)(*lmf)->previous_lmf) & ~3);
443 /* Clear thumb bit */
446 /* we substract 1, so that the IP points into the call instruction */
452 if (((gsize)(*lmf)->previous_lmf) & 2) {
454 * This LMF entry is created by the soft debug code to mark transitions to
455 * managed code done during invokes.
457 MonoLMFExt *ext = (MonoLMFExt*)(*lmf);
459 g_assert (ext->debugger_invoke);
461 memcpy (new_ctx, &ext->ctx, sizeof (MonoContext));
463 *lmf = (gpointer)(((gsize)(*lmf)->previous_lmf) & ~3);
465 frame->type = FRAME_TYPE_DEBUGGER_INVOKE;
470 frame->type = FRAME_TYPE_MANAGED_TO_NATIVE;
472 if ((ji = mini_jit_info_table_find (domain, (gpointer)(*lmf)->ip, NULL))) {
477 frame->method = (*lmf)->method;
481 * The LMF is saved at the start of the method using:
482 * ARM_MOV_REG_REG (code, ARMREG_IP, ARMREG_SP)
483 * ARM_PUSH (code, 0x5ff0);
484 * So it stores the register state as it existed at the caller. We need to
485 * produce the register state which existed at the time of the call which
486 * transitioned to native call, so we save the sp/fp/ip in the LMF.
488 memcpy (&new_ctx->regs [0], &(*lmf)->iregs [0], sizeof (mgreg_t) * 13);
489 new_ctx->pc = (*lmf)->ip;
490 new_ctx->regs [ARMREG_SP] = (*lmf)->sp;
491 new_ctx->regs [ARMREG_FP] = (*lmf)->fp;
493 /* Clear thumb bit */
496 /* we substract 1, so that the IP points into the call instruction */
499 *lmf = (gpointer)(((gsize)(*lmf)->previous_lmf) & ~3);
507 #if MONO_ARCH_HAVE_SIGCTX_TO_MONOCTX
509 mono_arch_sigctx_to_monoctx (void *sigctx, MonoContext *mctx)
511 mono_sigctx_to_monoctx (sigctx, mctx);
515 mono_arch_monoctx_to_sigctx (MonoContext *mctx, void *ctx)
517 mono_monoctx_to_sigctx (mctx, ctx);
519 #endif /* MONO_ARCH_HAVE_SIGCTX_TO_MONOCTX */
524 * Called by resuming from a signal handler.
527 handle_signal_exception (gpointer obj)
529 MonoJitTlsData *jit_tls = mono_native_tls_get_value (mono_jit_tls_id);
532 memcpy (&ctx, &jit_tls->ex_ctx, sizeof (MonoContext));
534 mono_handle_exception (&ctx, obj);
536 mono_restore_context (&ctx);
540 * This works around a gcc 4.5 bug:
541 * https://bugs.launchpad.net/ubuntu/+source/gcc-4.5/+bug/721531
543 #if defined(__GNUC__)
544 __attribute__((noinline))
547 get_handle_signal_exception_addr (void)
549 return handle_signal_exception;
553 * This is the function called from the signal handler
556 mono_arch_handle_exception (void *ctx, gpointer obj)
558 #if defined(MONO_CROSS_COMPILE) || !defined(MONO_ARCH_HAVE_SIGCTX_TO_MONOCTX)
559 g_assert_not_reached ();
560 #elif defined(MONO_ARCH_USE_SIGACTION)
561 arm_ucontext *sigctx = ctx;
563 * Handling the exception in the signal handler is problematic, since the original
564 * signal is disabled, and we could run arbitrary code though the debugger. So
565 * resume into the normal stack and do most work there if possible.
567 MonoJitTlsData *jit_tls = mono_native_tls_get_value (mono_jit_tls_id);
568 guint64 sp = UCONTEXT_REG_SP (sigctx);
570 /* Pass the ctx parameter in TLS */
571 mono_arch_sigctx_to_monoctx (sigctx, &jit_tls->ex_ctx);
572 /* The others in registers */
573 UCONTEXT_REG_R0 (sigctx) = (gsize)obj;
575 /* Allocate a stack frame */
577 UCONTEXT_REG_SP (sigctx) = sp;
579 UCONTEXT_REG_PC (sigctx) = (gsize)get_handle_signal_exception_addr ();
580 #ifdef UCONTEXT_REG_CPSR
581 if ((gsize)UCONTEXT_REG_PC (sigctx) & 1)
582 /* Transition to thumb */
583 UCONTEXT_REG_CPSR (sigctx) |= (1 << 5);
585 /* Transition to ARM */
586 UCONTEXT_REG_CPSR (sigctx) &= ~(1 << 5);
594 mono_arch_sigctx_to_monoctx (ctx, &mctx);
596 result = mono_handle_exception (&mctx, obj);
597 /* restore the context so that returning from the signal handler will invoke
600 mono_arch_monoctx_to_sigctx (&mctx, ctx);
606 mono_arch_ip_from_context (void *sigctx)
608 #ifdef MONO_CROSS_COMPILE
609 g_assert_not_reached ();
610 #elif defined(__native_client__)
611 g_assert_not_reached ();
613 arm_ucontext *my_uc = sigctx;
614 return (void*) UCONTEXT_REG_PC (my_uc);
619 mono_arch_setup_async_callback (MonoContext *ctx, void (*async_cb)(void *fun), gpointer user_data)
621 mgreg_t sp = (mgreg_t)MONO_CONTEXT_GET_SP (ctx);
624 g_assert (!user_data);
626 /* Allocate a stack frame */
628 MONO_CONTEXT_SET_SP (ctx, sp);
629 MONO_CONTEXT_SET_IP (ctx, async_cb);
635 * mono_arch_setup_resume_sighandler_ctx:
637 * Setup CTX so execution continues at FUNC.
640 mono_arch_setup_resume_sighandler_ctx (MonoContext *ctx, gpointer func)
642 MONO_CONTEXT_SET_IP (ctx,func);
643 if ((mgreg_t)MONO_CONTEXT_GET_IP (ctx) & 1)
644 /* Transition to thumb */
645 ctx->cpsr |= (1 << 5);
647 /* Transition to ARM */
648 ctx->cpsr &= ~(1 << 5);