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/metadata/appdomain.h>
28 #include <mono/metadata/tabledefs.h>
29 #include <mono/metadata/threads.h>
30 #include <mono/metadata/debug-helpers.h>
31 #include <mono/metadata/exception.h>
32 #include <mono/metadata/mono-debug.h>
36 #include "mono/utils/mono-sigcontext.h"
39 * arch_get_restore_context:
41 * Returns a pointer to a method which restores a previously saved sigcontext.
42 * The first argument in r0 is the pointer to the context.
45 mono_arch_get_restore_context (MonoTrampInfo **info, gboolean aot)
50 MonoJumpInfo *ji = NULL;
51 GSList *unwind_ops = NULL;
53 start = code = mono_global_codeman_reserve (128);
56 * Move things to their proper place so we can restore all the registers with
63 ARM_LDR_IMM (code, ARMREG_IP, ctx_reg, G_STRUCT_OFFSET (MonoContext, eip));
64 ARM_STR_IMM (code, ARMREG_IP, ctx_reg, G_STRUCT_OFFSET (MonoContext, regs) + (ARMREG_PC * sizeof (mgreg_t)));
66 ARM_LDR_IMM (code, ARMREG_IP, ctx_reg, G_STRUCT_OFFSET (MonoContext, esp));
67 ARM_STR_IMM (code, ARMREG_IP, ctx_reg, G_STRUCT_OFFSET (MonoContext, regs) + (ARMREG_SP * sizeof (mgreg_t)));
69 /* restore everything */
70 ARM_ADD_REG_IMM8 (code, ARMREG_IP, ctx_reg, G_STRUCT_OFFSET(MonoContext, regs));
71 ARM_LDM (code, ARMREG_IP, 0xffff);
76 g_assert ((code - start) < 128);
78 mono_arch_flush_icache (start, code - start);
81 *info = mono_tramp_info_create (g_strdup_printf ("restore_context"), start, code - start, ji, unwind_ops);
87 * arch_get_call_filter:
89 * Returns a pointer to a method which calls an exception filter. We
90 * also use this function to call finally handlers (we pass NULL as
91 * @exc object in this case).
94 mono_arch_get_call_filter (MonoTrampInfo **info, gboolean aot)
99 MonoJumpInfo *ji = NULL;
100 GSList *unwind_ops = NULL;
102 /* call_filter (MonoContext *ctx, unsigned long eip, gpointer exc) */
103 start = code = mono_global_codeman_reserve (320);
105 /* save all the regs on the stack */
106 ARM_MOV_REG_REG (code, ARMREG_IP, ARMREG_SP);
107 ARM_PUSH (code, MONO_ARM_REGSAVE_MASK);
109 /* restore all the regs from ctx (in r0), but not sp, the stack pointer */
111 ARM_LDR_IMM (code, ARMREG_IP, ctx_reg, G_STRUCT_OFFSET (MonoContext, eip));
112 ARM_ADD_REG_IMM8 (code, ARMREG_LR, ctx_reg, G_STRUCT_OFFSET(MonoContext, regs) + (MONO_ARM_FIRST_SAVED_REG * sizeof (mgreg_t)));
113 ARM_LDM (code, ARMREG_LR, MONO_ARM_REGSAVE_MASK);
114 /* call handler at eip (r1) and set the first arg with the exception (r2) */
115 ARM_MOV_REG_REG (code, ARMREG_R0, ARMREG_R2);
116 ARM_MOV_REG_REG (code, ARMREG_LR, ARMREG_PC);
117 ARM_MOV_REG_REG (code, ARMREG_PC, ARMREG_R1);
120 ARM_POP_NWB (code, 0xff0 | ((1 << ARMREG_SP) | (1 << ARMREG_PC)));
122 g_assert ((code - start) < 320);
124 mono_arch_flush_icache (start, code - start);
127 *info = mono_tramp_info_create (g_strdup_printf ("call_filter"), start, code - start, ji, unwind_ops);
133 mono_arm_throw_exception (MonoObject *exc, unsigned long eip, unsigned long esp, gulong *int_regs, gdouble *fp_regs)
135 static void (*restore_context) (MonoContext *);
137 gboolean rethrow = eip & 1;
139 if (!restore_context)
140 restore_context = mono_get_restore_context ();
142 eip &= ~1; /* clear the optional rethrow 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, esp);
149 MONO_CONTEXT_SET_IP (&ctx, eip);
150 memcpy (((guint8*)&ctx.regs) + (ARMREG_R4 * sizeof (mgreg_t)), int_regs, 8 * sizeof (mgreg_t));
151 /* memcpy (&ctx.fregs, fp_regs, sizeof (double) * MONO_SAVED_FREGS); */
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 restore_context (&ctx);
160 g_assert_not_reached ();
164 mono_arm_throw_exception_by_token (guint32 type_token, unsigned long eip, unsigned long esp, gulong *int_regs, gdouble *fp_regs)
166 /* Clear thumb bit */
169 mono_arm_throw_exception ((MonoObject*)mono_exception_from_token (mono_defaults.corlib, type_token), eip, esp, int_regs, fp_regs);
173 mono_arm_resume_unwind (guint32 dummy1, unsigned long eip, unsigned long esp, gulong *int_regs, gdouble *fp_regs)
177 eip &= ~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, esp);
183 MONO_CONTEXT_SET_IP (&ctx, eip);
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;
206 code = start = mono_global_codeman_reserve (size);
208 mono_add_unwind_op_def_cfa (unwind_ops, code, start, ARMREG_SP, 0);
210 /* save all the regs on the stack */
211 ARM_MOV_REG_REG (code, ARMREG_IP, ARMREG_SP);
212 ARM_PUSH (code, MONO_ARM_REGSAVE_MASK);
214 mono_add_unwind_op_def_cfa (unwind_ops, code, start, ARMREG_SP, MONO_ARM_NUM_SAVED_REGS * sizeof (mgreg_t));
215 mono_add_unwind_op_offset (unwind_ops, code, start, ARMREG_LR, - sizeof (mgreg_t));
217 /* call throw_exception (exc, ip, sp, int_regs, fp_regs) */
219 ARM_ADD_REG_IMM8 (code, ARMREG_R2, ARMREG_SP, MONO_ARM_NUM_SAVED_REGS * sizeof (mgreg_t));
220 /* exc is already in place in r0 */
222 /* The caller ip is already in R1 */
224 /* Negate the ip adjustment done in mono_arm_throw_exception */
225 ARM_ADD_REG_IMM8 (code, ARMREG_R1, ARMREG_R1, 4);
227 ARM_MOV_REG_REG (code, ARMREG_R1, ARMREG_LR); /* caller ip */
229 /* FIXME: pointer to the saved fp regs */
230 /*pos = alloc_size - sizeof (double) * MONO_SAVED_FREGS;
231 ppc_addi (code, ppc_r7, ppc_sp, pos);*/
232 /* pointer to the saved int regs */
233 ARM_MOV_REG_REG (code, ARMREG_R3, ARMREG_SP); /* the pushed regs */
234 /* we encode rethrow in the ip, so we avoid args on the stack */
235 ARM_ORR_REG_IMM8 (code, ARMREG_R1, ARMREG_R1, rethrow);
238 const char *icall_name;
241 icall_name = "mono_arm_resume_unwind";
243 icall_name = "mono_arm_throw_exception_by_token";
245 icall_name = "mono_arm_throw_exception";
247 ji = mono_patch_info_list_prepend (ji, code - start, MONO_PATCH_INFO_JIT_ICALL_ADDR, icall_name);
248 ARM_LDR_IMM (code, ARMREG_IP, ARMREG_PC, 0);
250 *(gpointer*)(gpointer)code = NULL;
252 ARM_LDR_REG_REG (code, ARMREG_IP, ARMREG_PC, ARMREG_IP);
254 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)));
256 ARM_MOV_REG_REG (code, ARMREG_LR, ARMREG_PC);
257 ARM_MOV_REG_REG (code, ARMREG_PC, ARMREG_IP);
258 /* we should never reach this breakpoint */
260 g_assert ((code - start) < size);
261 mono_arch_flush_icache (start, code - start);
264 *info = mono_tramp_info_create (g_strdup_printf (tramp_name), start, code - start, ji, unwind_ops);
270 * arch_get_throw_exception:
272 * Returns a function pointer which can be used to raise
273 * exceptions. The returned function has the following
274 * signature: void (*func) (MonoException *exc);
275 * For example to raise an arithmetic exception you can use:
277 * x86_push_imm (code, mono_get_exception_arithmetic ());
278 * x86_call_code (code, arch_get_throw_exception ());
282 mono_arch_get_throw_exception (MonoTrampInfo **info, gboolean aot)
284 return get_throw_trampoline (132, FALSE, FALSE, FALSE, FALSE, "throw_exception", info, aot);
288 * mono_arch_get_rethrow_exception:
290 * Returns a function pointer which can be used to rethrow
291 * exceptions. The returned function has the following
292 * signature: void (*func) (MonoException *exc);
296 mono_arch_get_rethrow_exception (MonoTrampInfo **info, gboolean aot)
298 return get_throw_trampoline (132, FALSE, TRUE, FALSE, FALSE, "rethrow_exception", info, aot);
302 * mono_arch_get_throw_corlib_exception:
304 * Returns a function pointer which can be used to raise
305 * corlib exceptions. The returned function has the following
306 * signature: void (*func) (guint32 ex_token, guint32 offset);
307 * Here, offset is the offset which needs to be substracted from the caller IP
308 * to get the IP of the throw. Passing the offset has the advantage that it
309 * needs no relocations in the caller.
310 * On ARM, the ip is passed instead of an offset.
313 mono_arch_get_throw_corlib_exception (MonoTrampInfo **info, gboolean aot)
315 return get_throw_trampoline (168, TRUE, FALSE, FALSE, FALSE, "throw_corlib_exception", info, aot);
319 mono_arm_get_exception_trampolines (gboolean aot)
322 GSList *tramps = NULL;
324 /* LLVM uses the normal trampolines, but with a different name */
325 get_throw_trampoline (168, TRUE, FALSE, FALSE, FALSE, "llvm_throw_corlib_exception_trampoline", &info, aot);
326 tramps = g_slist_prepend (tramps, info);
328 get_throw_trampoline (168, TRUE, FALSE, TRUE, FALSE, "llvm_throw_corlib_exception_abs_trampoline", &info, aot);
329 tramps = g_slist_prepend (tramps, info);
331 get_throw_trampoline (168, FALSE, FALSE, FALSE, TRUE, "llvm_resume_unwind_trampoline", &info, aot);
332 tramps = g_slist_prepend (tramps, info);
338 mono_arch_exceptions_init (void)
344 tramp = mono_aot_get_trampoline ("llvm_throw_corlib_exception_trampoline");
345 mono_register_jit_icall (tramp, "llvm_throw_corlib_exception_trampoline", NULL, TRUE);
346 tramp = mono_aot_get_trampoline ("llvm_throw_corlib_exception_abs_trampoline");
347 mono_register_jit_icall (tramp, "llvm_throw_corlib_exception_abs_trampoline", NULL, TRUE);
348 tramp = mono_aot_get_trampoline ("llvm_resume_unwind_trampoline");
349 mono_register_jit_icall (tramp, "llvm_resume_unwind_trampoline", NULL, TRUE);
351 tramps = mono_arm_get_exception_trampolines (FALSE);
352 for (l = tramps; l; l = l->next) {
353 MonoTrampInfo *info = l->data;
355 mono_register_jit_icall (info->code, g_strdup (info->name), NULL, TRUE);
356 mono_save_trampoline_xdebug_info (info);
357 mono_tramp_info_free (info);
359 g_slist_free (tramps);
364 * mono_arch_find_jit_info:
366 * See exceptions-amd64.c for docs;
369 mono_arch_find_jit_info (MonoDomain *domain, MonoJitTlsData *jit_tls,
370 MonoJitInfo *ji, MonoContext *ctx,
371 MonoContext *new_ctx, MonoLMF **lmf,
372 mgreg_t **save_locations,
373 StackFrameInfo *frame)
375 gpointer ip = MONO_CONTEXT_GET_IP (ctx);
377 memset (frame, 0, sizeof (StackFrameInfo));
384 gssize regs [MONO_MAX_IREGS + 1];
386 guint32 unwind_info_len;
389 frame->type = FRAME_TYPE_MANAGED;
392 unwind_info = mono_aot_get_unwind_info (ji, &unwind_info_len);
394 unwind_info = mono_get_cached_unwind_info (ji->used_regs, &unwind_info_len);
396 for (i = 0; i < 16; ++i)
397 regs [i] = new_ctx->regs [i];
398 regs [ARMREG_SP] = new_ctx->esp;
400 mono_unwind_frame (unwind_info, unwind_info_len, ji->code_start,
401 (guint8*)ji->code_start + ji->code_size,
402 ip, regs, MONO_MAX_IREGS,
403 save_locations, MONO_MAX_IREGS, &cfa);
405 for (i = 0; i < 16; ++i)
406 new_ctx->regs [i] = regs [i];
407 new_ctx->eip = regs [ARMREG_LR];
408 new_ctx->esp = (gsize)cfa;
410 if (*lmf && (MONO_CONTEXT_GET_SP (ctx) >= (gpointer)(*lmf)->sp)) {
411 /* remove any unused lmf */
412 *lmf = (gpointer)(((gsize)(*lmf)->previous_lmf) & ~3);
415 /* Clear thumb bit */
418 /* we substract 1, so that the IP points into the call instruction */
424 if (((gsize)(*lmf)->previous_lmf) & 2) {
426 * This LMF entry is created by the soft debug code to mark transitions to
427 * managed code done during invokes.
429 MonoLMFExt *ext = (MonoLMFExt*)(*lmf);
431 g_assert (ext->debugger_invoke);
433 memcpy (new_ctx, &ext->ctx, sizeof (MonoContext));
435 *lmf = (gpointer)(((gsize)(*lmf)->previous_lmf) & ~3);
437 frame->type = FRAME_TYPE_DEBUGGER_INVOKE;
442 frame->type = FRAME_TYPE_MANAGED_TO_NATIVE;
444 if ((ji = mini_jit_info_table_find (domain, (gpointer)(*lmf)->ip, NULL))) {
449 frame->method = (*lmf)->method;
453 * The LMF is saved at the start of the method using:
454 * ARM_MOV_REG_REG (code, ARMREG_IP, ARMREG_SP)
455 * ARM_PUSH (code, 0x5ff0);
456 * So it stores the register state as it existed at the caller. We need to
457 * produce the register state which existed at the time of the call which
458 * transitioned to native call, so we save the sp/fp/ip in the LMF.
460 memcpy (&new_ctx->regs [0], &(*lmf)->iregs [0], sizeof (mgreg_t) * 13);
461 new_ctx->esp = (*lmf)->sp;
462 new_ctx->eip = (*lmf)->ip;
463 new_ctx->regs [ARMREG_FP] = (*lmf)->fp;
465 /* Clear thumb bit */
468 /* we substract 1, so that the IP points into the call instruction */
471 *lmf = (gpointer)(((gsize)(*lmf)->previous_lmf) & ~3);
480 mono_arch_sigctx_to_monoctx (void *sigctx, MonoContext *mctx)
482 #ifdef MONO_CROSS_COMPILE
483 g_assert_not_reached ();
485 g_assert_not_reached ();
487 arm_ucontext *my_uc = sigctx;
489 mctx->eip = UCONTEXT_REG_PC (my_uc);
490 mctx->esp = UCONTEXT_REG_SP (my_uc);
491 memcpy (&mctx->regs, &UCONTEXT_REG_R0 (my_uc), sizeof (mgreg_t) * 16);
496 mono_arch_monoctx_to_sigctx (MonoContext *mctx, void *ctx)
498 #ifdef MONO_CROSS_COMPILE
499 g_assert_not_reached ();
501 g_assert_not_reached ();
503 arm_ucontext *my_uc = ctx;
505 UCONTEXT_REG_PC (my_uc) = mctx->eip;
506 UCONTEXT_REG_SP (my_uc) = mctx->regs [ARMREG_FP];
507 /* The upper registers are not guaranteed to be valid */
508 memcpy (&UCONTEXT_REG_R0 (my_uc), &mctx->regs, sizeof (mgreg_t) * 12);
515 * Called by resuming from a signal handler.
518 handle_signal_exception (gpointer obj)
520 MonoJitTlsData *jit_tls = mono_native_tls_get_value (mono_jit_tls_id);
522 static void (*restore_context) (MonoContext *);
524 if (!restore_context)
525 restore_context = mono_get_restore_context ();
527 memcpy (&ctx, &jit_tls->ex_ctx, sizeof (MonoContext));
529 mono_handle_exception (&ctx, obj);
531 restore_context (&ctx);
535 * This works around a gcc 4.5 bug:
536 * https://bugs.launchpad.net/ubuntu/+source/gcc-4.5/+bug/721531
538 #if defined(__GNUC__)
539 __attribute__((noinline))
542 get_handle_signal_exception_addr (void)
544 return handle_signal_exception;
548 * This is the function called from the signal handler
551 mono_arch_handle_exception (void *ctx, gpointer obj)
553 #if defined(MONO_CROSS_COMPILE)
554 g_assert_not_reached ();
555 #elif defined(MONO_ARCH_USE_SIGACTION)
556 arm_ucontext *sigctx = ctx;
558 * Handling the exception in the signal handler is problematic, since the original
559 * signal is disabled, and we could run arbitrary code though the debugger. So
560 * resume into the normal stack and do most work there if possible.
562 MonoJitTlsData *jit_tls = mono_native_tls_get_value (mono_jit_tls_id);
563 guint64 sp = UCONTEXT_REG_SP (sigctx);
565 /* Pass the ctx parameter in TLS */
566 mono_arch_sigctx_to_monoctx (sigctx, &jit_tls->ex_ctx);
567 /* The others in registers */
568 UCONTEXT_REG_R0 (sigctx) = (gsize)obj;
570 /* Allocate a stack frame */
572 UCONTEXT_REG_SP (sigctx) = sp;
574 UCONTEXT_REG_PC (sigctx) = (gsize)get_handle_signal_exception_addr ();
575 #ifdef UCONTEXT_REG_CPSR
576 if ((gsize)UCONTEXT_REG_PC (sigctx) & 1)
577 /* Transition to thumb */
578 UCONTEXT_REG_CPSR (sigctx) |= (1 << 5);
580 /* Transition to ARM */
581 UCONTEXT_REG_CPSR (sigctx) &= ~(1 << 5);
589 mono_arch_sigctx_to_monoctx (ctx, &mctx);
591 result = mono_handle_exception (&mctx, obj);
592 /* restore the context so that returning from the signal handler will invoke
595 mono_arch_monoctx_to_sigctx (&mctx, ctx);
601 mono_arch_ip_from_context (void *sigctx)
603 #ifdef MONO_CROSS_COMPILE
604 g_assert_not_reached ();
606 g_assert_not_reached ();
608 arm_ucontext *my_uc = sigctx;
609 return (void*) UCONTEXT_REG_PC (my_uc);