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, pc));
64 ARM_STR_IMM (code, ARMREG_IP, ctx_reg, G_STRUCT_OFFSET (MonoContext, regs) + (ARMREG_PC * sizeof (mgreg_t)));
66 /* restore everything */
67 ARM_ADD_REG_IMM8 (code, ARMREG_IP, ctx_reg, G_STRUCT_OFFSET(MonoContext, regs));
68 ARM_LDM (code, ARMREG_IP, 0xffff);
73 g_assert ((code - start) < 128);
75 mono_arch_flush_icache (start, code - start);
78 *info = mono_tramp_info_create (g_strdup_printf ("restore_context"), start, code - start, ji, unwind_ops);
84 * arch_get_call_filter:
86 * Returns a pointer to a method which calls an exception filter. We
87 * also use this function to call finally handlers (we pass NULL as
88 * @exc object in this case).
91 mono_arch_get_call_filter (MonoTrampInfo **info, gboolean aot)
96 MonoJumpInfo *ji = NULL;
97 GSList *unwind_ops = NULL;
99 /* call_filter (MonoContext *ctx, unsigned long eip, gpointer exc) */
100 start = code = mono_global_codeman_reserve (320);
102 /* save all the regs on the stack */
103 ARM_MOV_REG_REG (code, ARMREG_IP, ARMREG_SP);
104 ARM_PUSH (code, MONO_ARM_REGSAVE_MASK);
106 /* restore all the regs from ctx (in r0), but not sp, the stack pointer */
108 ARM_LDR_IMM (code, ARMREG_IP, ctx_reg, G_STRUCT_OFFSET (MonoContext, pc));
109 ARM_ADD_REG_IMM8 (code, ARMREG_LR, ctx_reg, G_STRUCT_OFFSET(MonoContext, regs) + (MONO_ARM_FIRST_SAVED_REG * sizeof (mgreg_t)));
110 ARM_LDM (code, ARMREG_LR, MONO_ARM_REGSAVE_MASK);
111 /* call handler at eip (r1) and set the first arg with the exception (r2) */
112 ARM_MOV_REG_REG (code, ARMREG_R0, ARMREG_R2);
113 ARM_MOV_REG_REG (code, ARMREG_LR, ARMREG_PC);
114 ARM_MOV_REG_REG (code, ARMREG_PC, ARMREG_R1);
117 ARM_POP_NWB (code, 0xff0 | ((1 << ARMREG_SP) | (1 << ARMREG_PC)));
119 g_assert ((code - start) < 320);
121 mono_arch_flush_icache (start, code - start);
124 *info = mono_tramp_info_create (g_strdup_printf ("call_filter"), start, code - start, ji, unwind_ops);
130 mono_arm_throw_exception (MonoObject *exc, mgreg_t pc, mgreg_t sp, mgreg_t *int_regs, gdouble *fp_regs)
132 static void (*restore_context) (MonoContext *);
134 gboolean rethrow = pc & 1;
136 if (!restore_context)
137 restore_context = mono_get_restore_context ();
139 pc &= ~1; /* clear the optional rethrow bit */
140 /* adjust eip so that it point into the call instruction */
143 /*printf ("stack in throw: %p\n", esp);*/
144 MONO_CONTEXT_SET_BP (&ctx, int_regs [ARMREG_FP - 4]);
145 MONO_CONTEXT_SET_SP (&ctx, sp);
146 MONO_CONTEXT_SET_IP (&ctx, pc);
147 memcpy (((guint8*)&ctx.regs) + (ARMREG_R4 * sizeof (mgreg_t)), int_regs, 8 * sizeof (mgreg_t));
148 /* memcpy (&ctx.fregs, fp_regs, sizeof (double) * MONO_SAVED_FREGS); */
150 if (mono_object_isinst (exc, mono_defaults.exception_class)) {
151 MonoException *mono_ex = (MonoException*)exc;
153 mono_ex->stack_trace = NULL;
155 mono_handle_exception (&ctx, exc);
156 restore_context (&ctx);
157 g_assert_not_reached ();
161 mono_arm_throw_exception_by_token (guint32 type_token, mgreg_t pc, mgreg_t sp, mgreg_t *int_regs, gdouble *fp_regs)
163 /* Clear thumb bit */
166 mono_arm_throw_exception ((MonoObject*)mono_exception_from_token (mono_defaults.corlib, type_token), pc, sp, int_regs, fp_regs);
170 mono_arm_resume_unwind (guint32 dummy1, mgreg_t pc, mgreg_t sp, mgreg_t *int_regs, gdouble *fp_regs)
174 pc &= ~1; /* clear the optional rethrow bit */
175 /* adjust eip so that it point into the call instruction */
178 MONO_CONTEXT_SET_BP (&ctx, int_regs [ARMREG_FP - 4]);
179 MONO_CONTEXT_SET_SP (&ctx, sp);
180 MONO_CONTEXT_SET_IP (&ctx, pc);
181 memcpy (((guint8*)&ctx.regs) + (ARMREG_R4 * sizeof (mgreg_t)), int_regs, 8 * sizeof (mgreg_t));
183 mono_resume_unwind (&ctx);
187 * get_throw_trampoline:
189 * Returns a function pointer which can be used to raise
190 * exceptions. The returned function has the following
191 * signature: void (*func) (MonoException *exc); or
192 * void (*func) (guint32 ex_token, guint8* ip);
196 get_throw_trampoline (int size, gboolean corlib, gboolean rethrow, gboolean llvm, gboolean resume_unwind, const char *tramp_name, MonoTrampInfo **info, gboolean aot)
200 MonoJumpInfo *ji = NULL;
201 GSList *unwind_ops = NULL;
203 code = start = mono_global_codeman_reserve (size);
205 mono_add_unwind_op_def_cfa (unwind_ops, code, start, ARMREG_SP, 0);
207 /* save all the regs on the stack */
208 ARM_MOV_REG_REG (code, ARMREG_IP, ARMREG_SP);
209 ARM_PUSH (code, MONO_ARM_REGSAVE_MASK);
211 mono_add_unwind_op_def_cfa (unwind_ops, code, start, ARMREG_SP, MONO_ARM_NUM_SAVED_REGS * sizeof (mgreg_t));
212 mono_add_unwind_op_offset (unwind_ops, code, start, ARMREG_LR, - sizeof (mgreg_t));
214 /* call throw_exception (exc, ip, sp, int_regs, fp_regs) */
216 ARM_ADD_REG_IMM8 (code, ARMREG_R2, ARMREG_SP, MONO_ARM_NUM_SAVED_REGS * sizeof (mgreg_t));
217 /* exc is already in place in r0 */
219 /* The caller ip is already in R1 */
221 /* Negate the ip adjustment done in mono_arm_throw_exception */
222 ARM_ADD_REG_IMM8 (code, ARMREG_R1, ARMREG_R1, 4);
224 ARM_MOV_REG_REG (code, ARMREG_R1, ARMREG_LR); /* caller ip */
226 /* FIXME: pointer to the saved fp regs */
227 /*pos = alloc_size - sizeof (double) * MONO_SAVED_FREGS;
228 ppc_addi (code, ppc_r7, ppc_sp, pos);*/
229 /* pointer to the saved int regs */
230 ARM_MOV_REG_REG (code, ARMREG_R3, ARMREG_SP); /* the pushed regs */
231 /* we encode rethrow in the ip, so we avoid args on the stack */
232 ARM_ORR_REG_IMM8 (code, ARMREG_R1, ARMREG_R1, rethrow);
235 const char *icall_name;
238 icall_name = "mono_arm_resume_unwind";
240 icall_name = "mono_arm_throw_exception_by_token";
242 icall_name = "mono_arm_throw_exception";
244 ji = mono_patch_info_list_prepend (ji, code - start, MONO_PATCH_INFO_JIT_ICALL_ADDR, icall_name);
245 ARM_LDR_IMM (code, ARMREG_IP, ARMREG_PC, 0);
247 *(gpointer*)(gpointer)code = NULL;
249 ARM_LDR_REG_REG (code, ARMREG_IP, ARMREG_PC, ARMREG_IP);
251 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)));
253 ARM_MOV_REG_REG (code, ARMREG_LR, ARMREG_PC);
254 ARM_MOV_REG_REG (code, ARMREG_PC, ARMREG_IP);
255 /* we should never reach this breakpoint */
257 g_assert ((code - start) < size);
258 mono_arch_flush_icache (start, code - start);
261 *info = mono_tramp_info_create (g_strdup_printf (tramp_name), start, code - start, ji, unwind_ops);
267 * arch_get_throw_exception:
269 * Returns a function pointer which can be used to raise
270 * exceptions. The returned function has the following
271 * signature: void (*func) (MonoException *exc);
272 * For example to raise an arithmetic exception you can use:
274 * x86_push_imm (code, mono_get_exception_arithmetic ());
275 * x86_call_code (code, arch_get_throw_exception ());
279 mono_arch_get_throw_exception (MonoTrampInfo **info, gboolean aot)
281 return get_throw_trampoline (132, FALSE, FALSE, FALSE, FALSE, "throw_exception", info, aot);
285 * mono_arch_get_rethrow_exception:
287 * Returns a function pointer which can be used to rethrow
288 * exceptions. The returned function has the following
289 * signature: void (*func) (MonoException *exc);
293 mono_arch_get_rethrow_exception (MonoTrampInfo **info, gboolean aot)
295 return get_throw_trampoline (132, FALSE, TRUE, FALSE, FALSE, "rethrow_exception", info, aot);
299 * mono_arch_get_throw_corlib_exception:
301 * Returns a function pointer which can be used to raise
302 * corlib exceptions. The returned function has the following
303 * signature: void (*func) (guint32 ex_token, guint32 offset);
304 * Here, offset is the offset which needs to be substracted from the caller IP
305 * to get the IP of the throw. Passing the offset has the advantage that it
306 * needs no relocations in the caller.
307 * On ARM, the ip is passed instead of an offset.
310 mono_arch_get_throw_corlib_exception (MonoTrampInfo **info, gboolean aot)
312 return get_throw_trampoline (168, TRUE, FALSE, FALSE, FALSE, "throw_corlib_exception", info, aot);
316 mono_arm_get_exception_trampolines (gboolean aot)
319 GSList *tramps = NULL;
321 /* LLVM uses the normal trampolines, but with a different name */
322 get_throw_trampoline (168, TRUE, FALSE, FALSE, FALSE, "llvm_throw_corlib_exception_trampoline", &info, aot);
323 tramps = g_slist_prepend (tramps, info);
325 get_throw_trampoline (168, TRUE, FALSE, TRUE, FALSE, "llvm_throw_corlib_exception_abs_trampoline", &info, aot);
326 tramps = g_slist_prepend (tramps, info);
328 get_throw_trampoline (168, FALSE, FALSE, FALSE, TRUE, "llvm_resume_unwind_trampoline", &info, aot);
329 tramps = g_slist_prepend (tramps, info);
335 mono_arch_exceptions_init (void)
341 tramp = mono_aot_get_trampoline ("llvm_throw_corlib_exception_trampoline");
342 mono_register_jit_icall (tramp, "llvm_throw_corlib_exception_trampoline", NULL, TRUE);
343 tramp = mono_aot_get_trampoline ("llvm_throw_corlib_exception_abs_trampoline");
344 mono_register_jit_icall (tramp, "llvm_throw_corlib_exception_abs_trampoline", NULL, TRUE);
345 tramp = mono_aot_get_trampoline ("llvm_resume_unwind_trampoline");
346 mono_register_jit_icall (tramp, "llvm_resume_unwind_trampoline", NULL, TRUE);
348 tramps = mono_arm_get_exception_trampolines (FALSE);
349 for (l = tramps; l; l = l->next) {
350 MonoTrampInfo *info = l->data;
352 mono_register_jit_icall (info->code, g_strdup (info->name), NULL, TRUE);
353 mono_save_trampoline_xdebug_info (info);
354 mono_tramp_info_free (info);
356 g_slist_free (tramps);
361 * mono_arch_find_jit_info:
363 * See exceptions-amd64.c for docs;
366 mono_arch_find_jit_info (MonoDomain *domain, MonoJitTlsData *jit_tls,
367 MonoJitInfo *ji, MonoContext *ctx,
368 MonoContext *new_ctx, MonoLMF **lmf,
369 mgreg_t **save_locations,
370 StackFrameInfo *frame)
372 gpointer ip = MONO_CONTEXT_GET_IP (ctx);
374 memset (frame, 0, sizeof (StackFrameInfo));
381 gssize regs [MONO_MAX_IREGS + 1];
383 guint32 unwind_info_len;
386 frame->type = FRAME_TYPE_MANAGED;
389 unwind_info = mono_aot_get_unwind_info (ji, &unwind_info_len);
391 unwind_info = mono_get_cached_unwind_info (ji->used_regs, &unwind_info_len);
393 for (i = 0; i < 16; ++i)
394 regs [i] = new_ctx->regs [i];
396 mono_unwind_frame (unwind_info, unwind_info_len, ji->code_start,
397 (guint8*)ji->code_start + ji->code_size,
398 ip, regs, MONO_MAX_IREGS,
399 save_locations, MONO_MAX_IREGS, &cfa);
401 for (i = 0; i < 16; ++i)
402 new_ctx->regs [i] = regs [i];
403 new_ctx->pc = regs [ARMREG_LR];
404 new_ctx->regs [ARMREG_SP] = (gsize)cfa;
406 if (*lmf && (MONO_CONTEXT_GET_SP (ctx) >= (gpointer)(*lmf)->sp)) {
407 /* remove any unused lmf */
408 *lmf = (gpointer)(((gsize)(*lmf)->previous_lmf) & ~3);
411 /* Clear thumb bit */
414 /* we substract 1, so that the IP points into the call instruction */
420 if (((gsize)(*lmf)->previous_lmf) & 2) {
422 * This LMF entry is created by the soft debug code to mark transitions to
423 * managed code done during invokes.
425 MonoLMFExt *ext = (MonoLMFExt*)(*lmf);
427 g_assert (ext->debugger_invoke);
429 memcpy (new_ctx, &ext->ctx, sizeof (MonoContext));
431 *lmf = (gpointer)(((gsize)(*lmf)->previous_lmf) & ~3);
433 frame->type = FRAME_TYPE_DEBUGGER_INVOKE;
438 frame->type = FRAME_TYPE_MANAGED_TO_NATIVE;
440 if ((ji = mini_jit_info_table_find (domain, (gpointer)(*lmf)->ip, NULL))) {
445 frame->method = (*lmf)->method;
449 * The LMF is saved at the start of the method using:
450 * ARM_MOV_REG_REG (code, ARMREG_IP, ARMREG_SP)
451 * ARM_PUSH (code, 0x5ff0);
452 * So it stores the register state as it existed at the caller. We need to
453 * produce the register state which existed at the time of the call which
454 * transitioned to native call, so we save the sp/fp/ip in the LMF.
456 memcpy (&new_ctx->regs [0], &(*lmf)->iregs [0], sizeof (mgreg_t) * 13);
457 new_ctx->pc = (*lmf)->ip;
458 new_ctx->regs [ARMREG_SP] = (*lmf)->sp;
459 new_ctx->regs [ARMREG_FP] = (*lmf)->fp;
461 /* Clear thumb bit */
464 /* we substract 1, so that the IP points into the call instruction */
467 *lmf = (gpointer)(((gsize)(*lmf)->previous_lmf) & ~3);
476 mono_arch_sigctx_to_monoctx (void *sigctx, MonoContext *mctx)
478 mono_sigctx_to_monoctx (sigctx, mctx);
482 mono_arch_monoctx_to_sigctx (MonoContext *mctx, void *ctx)
484 mono_monoctx_to_sigctx (mctx, ctx);
490 * Called by resuming from a signal handler.
493 handle_signal_exception (gpointer obj)
495 MonoJitTlsData *jit_tls = mono_native_tls_get_value (mono_jit_tls_id);
497 static void (*restore_context) (MonoContext *);
499 if (!restore_context)
500 restore_context = mono_get_restore_context ();
502 memcpy (&ctx, &jit_tls->ex_ctx, sizeof (MonoContext));
504 mono_handle_exception (&ctx, obj);
506 restore_context (&ctx);
510 * This works around a gcc 4.5 bug:
511 * https://bugs.launchpad.net/ubuntu/+source/gcc-4.5/+bug/721531
513 #if defined(__GNUC__)
514 __attribute__((noinline))
517 get_handle_signal_exception_addr (void)
519 return handle_signal_exception;
523 * This is the function called from the signal handler
526 mono_arch_handle_exception (void *ctx, gpointer obj)
528 #if defined(MONO_CROSS_COMPILE)
529 g_assert_not_reached ();
530 #elif defined(MONO_ARCH_USE_SIGACTION)
531 arm_ucontext *sigctx = ctx;
533 * Handling the exception in the signal handler is problematic, since the original
534 * signal is disabled, and we could run arbitrary code though the debugger. So
535 * resume into the normal stack and do most work there if possible.
537 MonoJitTlsData *jit_tls = mono_native_tls_get_value (mono_jit_tls_id);
538 guint64 sp = UCONTEXT_REG_SP (sigctx);
540 /* Pass the ctx parameter in TLS */
541 mono_arch_sigctx_to_monoctx (sigctx, &jit_tls->ex_ctx);
542 /* The others in registers */
543 UCONTEXT_REG_R0 (sigctx) = (gsize)obj;
545 /* Allocate a stack frame */
547 UCONTEXT_REG_SP (sigctx) = sp;
549 UCONTEXT_REG_PC (sigctx) = (gsize)get_handle_signal_exception_addr ();
550 #ifdef UCONTEXT_REG_CPSR
551 if ((gsize)UCONTEXT_REG_PC (sigctx) & 1)
552 /* Transition to thumb */
553 UCONTEXT_REG_CPSR (sigctx) |= (1 << 5);
555 /* Transition to ARM */
556 UCONTEXT_REG_CPSR (sigctx) &= ~(1 << 5);
564 mono_arch_sigctx_to_monoctx (ctx, &mctx);
566 result = mono_handle_exception (&mctx, obj);
567 /* restore the context so that returning from the signal handler will invoke
570 mono_arch_monoctx_to_sigctx (&mctx, ctx);
576 mono_arch_ip_from_context (void *sigctx)
578 #ifdef MONO_CROSS_COMPILE
579 g_assert_not_reached ();
581 arm_ucontext *my_uc = sigctx;
582 return (void*) UCONTEXT_REG_PC (my_uc);
587 mono_arch_setup_async_callback (MonoContext *ctx, void (*async_cb)(void *fun), gpointer user_data)
589 mgreg_t sp = (mgreg_t)MONO_CONTEXT_GET_SP (ctx);
592 g_assert (!user_data);
594 /* Allocate a stack frame */
596 MONO_CONTEXT_SET_SP (ctx, sp);
597 MONO_CONTEXT_SET_IP (ctx, async_cb);
603 * mono_arch_setup_resume_sighandler_ctx:
605 * Setup CTX so execution continues at FUNC.
608 mono_arch_setup_resume_sighandler_ctx (MonoContext *ctx, gpointer func)
610 MONO_CONTEXT_SET_IP (ctx,func);
611 if ((mgreg_t)MONO_CONTEXT_GET_IP (ctx) & 1)
612 /* Transition to thumb */
613 ctx->cpsr |= (1 << 5);
615 /* Transition to ARM */
616 ctx->cpsr &= ~(1 << 5);