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/abi-details.h>
29 #include <mono/metadata/appdomain.h>
30 #include <mono/metadata/tabledefs.h>
31 #include <mono/metadata/threads.h>
32 #include <mono/metadata/debug-helpers.h>
33 #include <mono/metadata/exception.h>
34 #include <mono/metadata/mono-debug.h>
38 #include "mono/utils/mono-sigcontext.h"
39 #include "mono/utils/mono-compiler.h"
42 * arch_get_restore_context:
44 * Returns a pointer to a method which restores a previously saved sigcontext.
45 * The first argument in r0 is the pointer to the context.
48 mono_arch_get_restore_context (MonoTrampInfo **info, gboolean aot)
53 MonoJumpInfo *ji = NULL;
54 GSList *unwind_ops = NULL;
56 start = code = mono_global_codeman_reserve (128);
59 * Move things to their proper place so we can restore all the registers with
65 if (!mono_arch_is_soft_float ()) {
66 ARM_ADD_REG_IMM8 (code, ARMREG_IP, ctx_reg, MONO_STRUCT_OFFSET (MonoContext, fregs));
67 ARM_FLDMD (code, ARM_VFP_D0, 16, ARMREG_IP);
71 ARM_LDR_IMM (code, ARMREG_IP, ctx_reg, MONO_STRUCT_OFFSET (MonoContext, pc));
72 ARM_STR_IMM (code, ARMREG_IP, ctx_reg, MONO_STRUCT_OFFSET (MonoContext, regs) + (ARMREG_PC * sizeof (mgreg_t)));
74 /* restore everything */
75 ARM_ADD_REG_IMM8 (code, ARMREG_IP, ctx_reg, MONO_STRUCT_OFFSET(MonoContext, regs));
76 ARM_LDM (code, ARMREG_IP, 0xffff);
81 g_assert ((code - start) < 128);
83 mono_arch_flush_icache (start, code - start);
86 *info = mono_tramp_info_create ("restore_context", start, code - start, ji, unwind_ops);
92 * arch_get_call_filter:
94 * Returns a pointer to a method which calls an exception filter. We
95 * also use this function to call finally handlers (we pass NULL as
96 * @exc object in this case).
99 mono_arch_get_call_filter (MonoTrampInfo **info, gboolean aot)
104 MonoJumpInfo *ji = NULL;
105 GSList *unwind_ops = NULL;
107 /* call_filter (MonoContext *ctx, unsigned long eip, gpointer exc) */
108 start = code = mono_global_codeman_reserve (320);
110 /* save all the regs on the stack */
111 ARM_MOV_REG_REG (code, ARMREG_IP, ARMREG_SP);
112 ARM_PUSH (code, MONO_ARM_REGSAVE_MASK);
114 /* restore all the regs from ctx (in r0), but not sp, the stack pointer */
116 ARM_LDR_IMM (code, ARMREG_IP, ctx_reg, MONO_STRUCT_OFFSET (MonoContext, pc));
117 ARM_ADD_REG_IMM8 (code, ARMREG_LR, ctx_reg, MONO_STRUCT_OFFSET(MonoContext, regs) + (MONO_ARM_FIRST_SAVED_REG * sizeof (mgreg_t)));
118 ARM_LDM (code, ARMREG_LR, MONO_ARM_REGSAVE_MASK);
119 /* call handler at eip (r1) and set the first arg with the exception (r2) */
120 ARM_MOV_REG_REG (code, ARMREG_R0, ARMREG_R2);
121 ARM_MOV_REG_REG (code, ARMREG_LR, ARMREG_PC);
122 ARM_MOV_REG_REG (code, ARMREG_PC, ARMREG_R1);
125 ARM_POP_NWB (code, 0xff0 | ((1 << ARMREG_SP) | (1 << ARMREG_PC)));
127 g_assert ((code - start) < 320);
129 mono_arch_flush_icache (start, code - start);
132 *info = mono_tramp_info_create ("call_filter", start, code - start, ji, unwind_ops);
138 mono_arm_throw_exception (MonoObject *exc, mgreg_t pc, mgreg_t sp, mgreg_t *int_regs, gdouble *fp_regs)
141 gboolean rethrow = sp & 1;
143 sp &= ~1; /* clear the optional rethrow bit */
144 pc &= ~1; /* clear the thumb bit */
145 /* adjust eip so that it point into the call instruction */
148 /*printf ("stack in throw: %p\n", esp);*/
149 MONO_CONTEXT_SET_BP (&ctx, int_regs [ARMREG_FP - 4]);
150 MONO_CONTEXT_SET_SP (&ctx, sp);
151 MONO_CONTEXT_SET_IP (&ctx, pc);
152 memcpy (((guint8*)&ctx.regs) + (ARMREG_R4 * sizeof (mgreg_t)), int_regs, 8 * sizeof (mgreg_t));
153 memcpy (&ctx.fregs, fp_regs, sizeof (double) * 16);
155 if (mono_object_isinst (exc, mono_defaults.exception_class)) {
156 MonoException *mono_ex = (MonoException*)exc;
158 mono_ex->stack_trace = NULL;
159 mono_ex->trace_ips = NULL;
162 mono_handle_exception (&ctx, exc);
163 mono_restore_context (&ctx);
164 g_assert_not_reached ();
168 mono_arm_throw_exception_by_token (guint32 type_token, mgreg_t pc, mgreg_t sp, mgreg_t *int_regs, gdouble *fp_regs)
170 /* Clear thumb bit */
173 mono_arm_throw_exception ((MonoObject*)mono_exception_from_token (mono_defaults.corlib, type_token), pc, sp, int_regs, fp_regs);
177 mono_arm_resume_unwind (guint32 dummy1, mgreg_t pc, mgreg_t sp, mgreg_t *int_regs, gdouble *fp_regs)
181 pc &= ~1; /* clear the optional rethrow bit */
182 /* adjust eip so that it point into the call instruction */
185 MONO_CONTEXT_SET_BP (&ctx, int_regs [ARMREG_FP - 4]);
186 MONO_CONTEXT_SET_SP (&ctx, sp);
187 MONO_CONTEXT_SET_IP (&ctx, pc);
188 memcpy (((guint8*)&ctx.regs) + (ARMREG_R4 * sizeof (mgreg_t)), int_regs, 8 * sizeof (mgreg_t));
190 mono_resume_unwind (&ctx);
194 * get_throw_trampoline:
196 * Returns a function pointer which can be used to raise
197 * exceptions. The returned function has the following
198 * signature: void (*func) (MonoException *exc); or
199 * void (*func) (guint32 ex_token, guint8* ip);
203 get_throw_trampoline (int size, gboolean corlib, gboolean rethrow, gboolean llvm, gboolean resume_unwind, const char *tramp_name, MonoTrampInfo **info, gboolean aot)
207 MonoJumpInfo *ji = NULL;
208 GSList *unwind_ops = NULL;
211 code = start = mono_global_codeman_reserve (size);
213 mono_add_unwind_op_def_cfa (unwind_ops, code, start, ARMREG_SP, 0);
215 /* save all the regs on the stack */
216 ARM_MOV_REG_REG (code, ARMREG_IP, ARMREG_SP);
217 ARM_PUSH (code, MONO_ARM_REGSAVE_MASK);
219 cfa_offset = MONO_ARM_NUM_SAVED_REGS * sizeof (mgreg_t);
220 mono_add_unwind_op_def_cfa (unwind_ops, code, start, ARMREG_SP, cfa_offset);
221 mono_add_unwind_op_offset (unwind_ops, code, start, ARMREG_LR, - sizeof (mgreg_t));
224 if (!mono_arch_is_soft_float ()) {
225 ARM_SUB_REG_IMM8 (code, ARMREG_SP, ARMREG_SP, sizeof (double) * 16);
226 cfa_offset += sizeof (double) * 16;
227 mono_add_unwind_op_def_cfa_offset (unwind_ops, code, start, cfa_offset);
228 ARM_FSTMD (code, ARM_VFP_D0, 16, ARMREG_SP);
232 ARM_SUB_REG_IMM8 (code, ARMREG_SP, ARMREG_SP, 8);
234 mono_add_unwind_op_def_cfa_offset (unwind_ops, code, start, cfa_offset);
236 /* call throw_exception (exc, ip, sp, int_regs, fp_regs) */
238 ARM_ADD_REG_IMM8 (code, ARMREG_R2, ARMREG_SP, cfa_offset);
239 /* we encode rethrow in sp */
241 g_assert (!resume_unwind);
243 ARM_ORR_REG_IMM8 (code, ARMREG_R2, ARMREG_R2, rethrow);
245 /* exc is already in place in r0 */
247 /* The caller ip is already in R1 */
249 /* Negate the ip adjustment done in mono_arm_throw_exception */
250 ARM_ADD_REG_IMM8 (code, ARMREG_R1, ARMREG_R1, 4);
252 ARM_MOV_REG_REG (code, ARMREG_R1, ARMREG_LR); /* caller ip */
255 ARM_ADD_REG_IMM8 (code, ARMREG_R3, ARMREG_SP, (cfa_offset - (MONO_ARM_NUM_SAVED_REGS * sizeof (mgreg_t))));
257 ARM_ADD_REG_IMM8 (code, ARMREG_LR, ARMREG_SP, 8);
258 ARM_STR_IMM (code, ARMREG_LR, ARMREG_SP, 0);
261 const char *icall_name;
264 icall_name = "mono_arm_resume_unwind";
266 icall_name = "mono_arm_throw_exception_by_token";
268 icall_name = "mono_arm_throw_exception";
270 ji = mono_patch_info_list_prepend (ji, code - start, MONO_PATCH_INFO_JIT_ICALL_ADDR, icall_name);
271 ARM_LDR_IMM (code, ARMREG_IP, ARMREG_PC, 0);
273 *(gpointer*)(gpointer)code = NULL;
275 ARM_LDR_REG_REG (code, ARMREG_IP, ARMREG_PC, ARMREG_IP);
277 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)));
279 ARM_MOV_REG_REG (code, ARMREG_LR, ARMREG_PC);
280 ARM_MOV_REG_REG (code, ARMREG_PC, ARMREG_IP);
281 /* we should never reach this breakpoint */
283 g_assert ((code - start) < size);
284 mono_arch_flush_icache (start, code - start);
287 *info = mono_tramp_info_create (tramp_name, start, code - start, ji, unwind_ops);
293 * arch_get_throw_exception:
295 * Returns a function pointer which can be used to raise
296 * exceptions. The returned function has the following
297 * signature: void (*func) (MonoException *exc);
298 * For example to raise an arithmetic exception you can use:
300 * x86_push_imm (code, mono_get_exception_arithmetic ());
301 * x86_call_code (code, arch_get_throw_exception ());
305 mono_arch_get_throw_exception (MonoTrampInfo **info, gboolean aot)
307 return get_throw_trampoline (132, FALSE, FALSE, FALSE, FALSE, "throw_exception", info, aot);
311 * mono_arch_get_rethrow_exception:
313 * Returns a function pointer which can be used to rethrow
314 * exceptions. The returned function has the following
315 * signature: void (*func) (MonoException *exc);
319 mono_arch_get_rethrow_exception (MonoTrampInfo **info, gboolean aot)
321 return get_throw_trampoline (132, FALSE, TRUE, FALSE, FALSE, "rethrow_exception", info, aot);
325 * mono_arch_get_throw_corlib_exception:
327 * Returns a function pointer which can be used to raise
328 * corlib exceptions. The returned function has the following
329 * signature: void (*func) (guint32 ex_token, guint32 offset);
330 * Here, offset is the offset which needs to be substracted from the caller IP
331 * to get the IP of the throw. Passing the offset has the advantage that it
332 * needs no relocations in the caller.
333 * On ARM, the ip is passed instead of an offset.
336 mono_arch_get_throw_corlib_exception (MonoTrampInfo **info, gboolean aot)
338 return get_throw_trampoline (168, TRUE, FALSE, FALSE, FALSE, "throw_corlib_exception", info, aot);
342 mono_arm_get_exception_trampolines (gboolean aot)
345 GSList *tramps = NULL;
347 /* LLVM uses the normal trampolines, but with a different name */
348 get_throw_trampoline (168, TRUE, FALSE, FALSE, FALSE, "llvm_throw_corlib_exception_trampoline", &info, aot);
349 tramps = g_slist_prepend (tramps, info);
351 get_throw_trampoline (168, TRUE, FALSE, TRUE, FALSE, "llvm_throw_corlib_exception_abs_trampoline", &info, aot);
352 tramps = g_slist_prepend (tramps, info);
354 get_throw_trampoline (168, FALSE, FALSE, FALSE, TRUE, "llvm_resume_unwind_trampoline", &info, aot);
355 tramps = g_slist_prepend (tramps, info);
361 mono_arch_exceptions_init (void)
367 tramp = mono_aot_get_trampoline ("llvm_throw_corlib_exception_trampoline");
368 mono_register_jit_icall (tramp, "llvm_throw_corlib_exception_trampoline", NULL, TRUE);
369 tramp = mono_aot_get_trampoline ("llvm_throw_corlib_exception_abs_trampoline");
370 mono_register_jit_icall (tramp, "llvm_throw_corlib_exception_abs_trampoline", NULL, TRUE);
371 tramp = mono_aot_get_trampoline ("llvm_resume_unwind_trampoline");
372 mono_register_jit_icall (tramp, "llvm_resume_unwind_trampoline", NULL, TRUE);
374 tramps = mono_arm_get_exception_trampolines (FALSE);
375 for (l = tramps; l; l = l->next) {
376 MonoTrampInfo *info = l->data;
378 mono_register_jit_icall (info->code, g_strdup (info->name), NULL, TRUE);
379 mono_tramp_info_register (info);
381 g_slist_free (tramps);
386 * mono_arch_unwind_frame:
388 * See exceptions-amd64.c for docs;
391 mono_arch_unwind_frame (MonoDomain *domain, MonoJitTlsData *jit_tls,
392 MonoJitInfo *ji, MonoContext *ctx,
393 MonoContext *new_ctx, MonoLMF **lmf,
394 mgreg_t **save_locations,
395 StackFrameInfo *frame)
397 gpointer ip = MONO_CONTEXT_GET_IP (ctx);
399 memset (frame, 0, sizeof (StackFrameInfo));
406 mono_unwind_reg_t regs [MONO_MAX_IREGS + 1 + 8];
408 guint32 unwind_info_len;
411 frame->type = FRAME_TYPE_MANAGED;
413 unwind_info = mono_jinfo_get_unwind_info (ji, &unwind_info_len);
416 printf ("%s %p %p\n", ji->d.method->name, ji->code_start, ip);
417 mono_print_unwind_info (unwind_info, unwind_info_len);
420 for (i = 0; i < 16; ++i)
421 regs [i] = new_ctx->regs [i];
423 /* On IOS, d8..d15 are callee saved. They are mapped to 8..15 in unwind.c */
424 for (i = 0; i < 8; ++i)
425 regs [MONO_MAX_IREGS + i] = *(guint64*)&(new_ctx->fregs [8 + i]);
428 mono_unwind_frame (unwind_info, unwind_info_len, ji->code_start,
429 (guint8*)ji->code_start + ji->code_size,
430 ip, NULL, regs, MONO_MAX_IREGS + 8,
431 save_locations, MONO_MAX_IREGS, &cfa);
433 for (i = 0; i < 16; ++i)
434 new_ctx->regs [i] = regs [i];
435 new_ctx->pc = regs [ARMREG_LR];
436 new_ctx->regs [ARMREG_SP] = (gsize)cfa;
438 for (i = 0; i < 8; ++i)
439 new_ctx->fregs [8 + i] = *(double*)&(regs [MONO_MAX_IREGS + i]);
442 /* Clear thumb bit */
445 /* we substract 1, so that the IP points into the call instruction */
451 if (((gsize)(*lmf)->previous_lmf) & 2) {
453 * This LMF entry is created by the soft debug code to mark transitions to
454 * managed code done during invokes.
456 MonoLMFExt *ext = (MonoLMFExt*)(*lmf);
458 g_assert (ext->debugger_invoke);
460 memcpy (new_ctx, &ext->ctx, sizeof (MonoContext));
462 *lmf = (gpointer)(((gsize)(*lmf)->previous_lmf) & ~3);
464 frame->type = FRAME_TYPE_DEBUGGER_INVOKE;
469 frame->type = FRAME_TYPE_MANAGED_TO_NATIVE;
471 if ((ji = mini_jit_info_table_find (domain, (gpointer)(*lmf)->ip, NULL))) {
476 frame->method = (*lmf)->method;
480 * The LMF is saved at the start of the method using:
481 * ARM_MOV_REG_REG (code, ARMREG_IP, ARMREG_SP)
482 * ARM_PUSH (code, 0x5ff0);
483 * So it stores the register state as it existed at the caller. We need to
484 * produce the register state which existed at the time of the call which
485 * transitioned to native call, so we save the sp/fp/ip in the LMF.
487 memcpy (&new_ctx->regs [0], &(*lmf)->iregs [0], sizeof (mgreg_t) * 13);
488 new_ctx->pc = (*lmf)->ip;
489 new_ctx->regs [ARMREG_SP] = (*lmf)->sp;
490 new_ctx->regs [ARMREG_FP] = (*lmf)->fp;
492 /* Clear thumb bit */
495 /* we substract 1, so that the IP points into the call instruction */
498 *lmf = (gpointer)(((gsize)(*lmf)->previous_lmf) & ~3);
509 * Called by resuming from a signal handler.
512 handle_signal_exception (gpointer obj)
514 MonoJitTlsData *jit_tls = mono_native_tls_get_value (mono_jit_tls_id);
517 memcpy (&ctx, &jit_tls->ex_ctx, sizeof (MonoContext));
519 mono_handle_exception (&ctx, obj);
521 mono_restore_context (&ctx);
525 * This works around a gcc 4.5 bug:
526 * https://bugs.launchpad.net/ubuntu/+source/gcc-4.5/+bug/721531
528 static MONO_NEVER_INLINE gpointer
529 get_handle_signal_exception_addr (void)
531 return handle_signal_exception;
535 * This is the function called from the signal handler
538 mono_arch_handle_exception (void *ctx, gpointer obj)
540 #if defined(MONO_CROSS_COMPILE) || !defined(MONO_ARCH_HAVE_SIGCTX_TO_MONOCTX)
541 g_assert_not_reached ();
542 #elif defined(MONO_ARCH_USE_SIGACTION)
543 arm_ucontext *sigctx = ctx;
545 * Handling the exception in the signal handler is problematic, since the original
546 * signal is disabled, and we could run arbitrary code though the debugger. So
547 * resume into the normal stack and do most work there if possible.
549 MonoJitTlsData *jit_tls = mono_native_tls_get_value (mono_jit_tls_id);
550 guint64 sp = UCONTEXT_REG_SP (sigctx);
552 /* Pass the ctx parameter in TLS */
553 mono_sigctx_to_monoctx (sigctx, &jit_tls->ex_ctx);
554 /* The others in registers */
555 UCONTEXT_REG_R0 (sigctx) = (gsize)obj;
557 /* Allocate a stack frame */
559 UCONTEXT_REG_SP (sigctx) = sp;
561 UCONTEXT_REG_PC (sigctx) = (gsize)get_handle_signal_exception_addr ();
562 #ifdef UCONTEXT_REG_CPSR
563 if ((gsize)UCONTEXT_REG_PC (sigctx) & 1)
564 /* Transition to thumb */
565 UCONTEXT_REG_CPSR (sigctx) |= (1 << 5);
567 /* Transition to ARM */
568 UCONTEXT_REG_CPSR (sigctx) &= ~(1 << 5);
576 mono_sigctx_to_monoctx (ctx, &mctx);
578 result = mono_handle_exception (&mctx, obj);
579 /* restore the context so that returning from the signal handler will invoke
582 mono_monoctx_to_sigctx (&mctx, ctx);
588 mono_arch_ip_from_context (void *sigctx)
590 #ifdef MONO_CROSS_COMPILE
591 g_assert_not_reached ();
592 #elif defined(__native_client__)
593 g_assert_not_reached ();
595 arm_ucontext *my_uc = sigctx;
596 return (void*) UCONTEXT_REG_PC (my_uc);
601 mono_arch_setup_async_callback (MonoContext *ctx, void (*async_cb)(void *fun), gpointer user_data)
603 mgreg_t sp = (mgreg_t)MONO_CONTEXT_GET_SP (ctx);
606 g_assert (!user_data);
608 /* Allocate a stack frame */
610 MONO_CONTEXT_SET_SP (ctx, sp);
612 mono_arch_setup_resume_sighandler_ctx (ctx, async_cb);
616 * mono_arch_setup_resume_sighandler_ctx:
618 * Setup CTX so execution continues at FUNC.
621 mono_arch_setup_resume_sighandler_ctx (MonoContext *ctx, gpointer func)
623 MONO_CONTEXT_SET_IP (ctx,func);
624 if ((mgreg_t)MONO_CONTEXT_GET_IP (ctx) & 1)
625 /* Transition to thumb */
626 ctx->cpsr |= (1 << 5);
628 /* Transition to ARM */
629 ctx->cpsr &= ~(1 << 5);