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;
160 mono_handle_exception (&ctx, exc);
161 mono_restore_context (&ctx);
162 g_assert_not_reached ();
166 mono_arm_throw_exception_by_token (guint32 type_token, mgreg_t pc, mgreg_t sp, mgreg_t *int_regs, gdouble *fp_regs)
168 /* Clear thumb bit */
171 mono_arm_throw_exception ((MonoObject*)mono_exception_from_token (mono_defaults.corlib, type_token), pc, sp, int_regs, fp_regs);
175 mono_arm_resume_unwind (guint32 dummy1, mgreg_t pc, mgreg_t sp, mgreg_t *int_regs, gdouble *fp_regs)
179 pc &= ~1; /* clear the optional rethrow bit */
180 /* adjust eip so that it point into the call instruction */
183 MONO_CONTEXT_SET_BP (&ctx, int_regs [ARMREG_FP - 4]);
184 MONO_CONTEXT_SET_SP (&ctx, sp);
185 MONO_CONTEXT_SET_IP (&ctx, pc);
186 memcpy (((guint8*)&ctx.regs) + (ARMREG_R4 * sizeof (mgreg_t)), int_regs, 8 * sizeof (mgreg_t));
188 mono_resume_unwind (&ctx);
192 * get_throw_trampoline:
194 * Returns a function pointer which can be used to raise
195 * exceptions. The returned function has the following
196 * signature: void (*func) (MonoException *exc); or
197 * void (*func) (guint32 ex_token, guint8* ip);
201 get_throw_trampoline (int size, gboolean corlib, gboolean rethrow, gboolean llvm, gboolean resume_unwind, const char *tramp_name, MonoTrampInfo **info, gboolean aot)
205 MonoJumpInfo *ji = NULL;
206 GSList *unwind_ops = NULL;
209 code = start = mono_global_codeman_reserve (size);
211 mono_add_unwind_op_def_cfa (unwind_ops, code, start, ARMREG_SP, 0);
213 /* save all the regs on the stack */
214 ARM_MOV_REG_REG (code, ARMREG_IP, ARMREG_SP);
215 ARM_PUSH (code, MONO_ARM_REGSAVE_MASK);
217 cfa_offset = MONO_ARM_NUM_SAVED_REGS * sizeof (mgreg_t);
218 mono_add_unwind_op_def_cfa (unwind_ops, code, start, ARMREG_SP, cfa_offset);
219 mono_add_unwind_op_offset (unwind_ops, code, start, ARMREG_LR, - sizeof (mgreg_t));
222 if (!mono_arch_is_soft_float ()) {
223 ARM_SUB_REG_IMM8 (code, ARMREG_SP, ARMREG_SP, sizeof (double) * 16);
224 cfa_offset += sizeof (double) * 16;
225 mono_add_unwind_op_def_cfa_offset (unwind_ops, code, start, cfa_offset);
226 ARM_FSTMD (code, ARM_VFP_D0, 16, ARMREG_SP);
230 ARM_SUB_REG_IMM8 (code, ARMREG_SP, ARMREG_SP, 8);
232 mono_add_unwind_op_def_cfa_offset (unwind_ops, code, start, cfa_offset);
234 /* call throw_exception (exc, ip, sp, int_regs, fp_regs) */
236 ARM_ADD_REG_IMM8 (code, ARMREG_R2, ARMREG_SP, cfa_offset);
237 /* we encode rethrow in sp */
239 g_assert (!resume_unwind);
241 ARM_ORR_REG_IMM8 (code, ARMREG_R2, ARMREG_R2, rethrow);
243 /* exc is already in place in r0 */
245 /* The caller ip is already in R1 */
247 /* Negate the ip adjustment done in mono_arm_throw_exception */
248 ARM_ADD_REG_IMM8 (code, ARMREG_R1, ARMREG_R1, 4);
250 ARM_MOV_REG_REG (code, ARMREG_R1, ARMREG_LR); /* caller ip */
253 ARM_ADD_REG_IMM8 (code, ARMREG_R3, ARMREG_SP, (cfa_offset - (MONO_ARM_NUM_SAVED_REGS * sizeof (mgreg_t))));
255 ARM_ADD_REG_IMM8 (code, ARMREG_LR, ARMREG_SP, 8);
256 ARM_STR_IMM (code, ARMREG_LR, ARMREG_SP, 0);
259 const char *icall_name;
262 icall_name = "mono_arm_resume_unwind";
264 icall_name = "mono_arm_throw_exception_by_token";
266 icall_name = "mono_arm_throw_exception";
268 ji = mono_patch_info_list_prepend (ji, code - start, MONO_PATCH_INFO_JIT_ICALL_ADDR, icall_name);
269 ARM_LDR_IMM (code, ARMREG_IP, ARMREG_PC, 0);
271 *(gpointer*)(gpointer)code = NULL;
273 ARM_LDR_REG_REG (code, ARMREG_IP, ARMREG_PC, ARMREG_IP);
275 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)));
277 ARM_MOV_REG_REG (code, ARMREG_LR, ARMREG_PC);
278 ARM_MOV_REG_REG (code, ARMREG_PC, ARMREG_IP);
279 /* we should never reach this breakpoint */
281 g_assert ((code - start) < size);
282 mono_arch_flush_icache (start, code - start);
285 *info = mono_tramp_info_create (tramp_name, start, code - start, ji, unwind_ops);
291 * arch_get_throw_exception:
293 * Returns a function pointer which can be used to raise
294 * exceptions. The returned function has the following
295 * signature: void (*func) (MonoException *exc);
296 * For example to raise an arithmetic exception you can use:
298 * x86_push_imm (code, mono_get_exception_arithmetic ());
299 * x86_call_code (code, arch_get_throw_exception ());
303 mono_arch_get_throw_exception (MonoTrampInfo **info, gboolean aot)
305 return get_throw_trampoline (132, FALSE, FALSE, FALSE, FALSE, "throw_exception", info, aot);
309 * mono_arch_get_rethrow_exception:
311 * Returns a function pointer which can be used to rethrow
312 * exceptions. The returned function has the following
313 * signature: void (*func) (MonoException *exc);
317 mono_arch_get_rethrow_exception (MonoTrampInfo **info, gboolean aot)
319 return get_throw_trampoline (132, FALSE, TRUE, FALSE, FALSE, "rethrow_exception", info, aot);
323 * mono_arch_get_throw_corlib_exception:
325 * Returns a function pointer which can be used to raise
326 * corlib exceptions. The returned function has the following
327 * signature: void (*func) (guint32 ex_token, guint32 offset);
328 * Here, offset is the offset which needs to be substracted from the caller IP
329 * to get the IP of the throw. Passing the offset has the advantage that it
330 * needs no relocations in the caller.
331 * On ARM, the ip is passed instead of an offset.
334 mono_arch_get_throw_corlib_exception (MonoTrampInfo **info, gboolean aot)
336 return get_throw_trampoline (168, TRUE, FALSE, FALSE, FALSE, "throw_corlib_exception", info, aot);
340 mono_arm_get_exception_trampolines (gboolean aot)
343 GSList *tramps = NULL;
345 /* LLVM uses the normal trampolines, but with a different name */
346 get_throw_trampoline (168, TRUE, FALSE, FALSE, FALSE, "llvm_throw_corlib_exception_trampoline", &info, aot);
347 tramps = g_slist_prepend (tramps, info);
349 get_throw_trampoline (168, TRUE, FALSE, TRUE, FALSE, "llvm_throw_corlib_exception_abs_trampoline", &info, aot);
350 tramps = g_slist_prepend (tramps, info);
352 get_throw_trampoline (168, FALSE, FALSE, FALSE, TRUE, "llvm_resume_unwind_trampoline", &info, aot);
353 tramps = g_slist_prepend (tramps, info);
359 mono_arch_exceptions_init (void)
365 tramp = mono_aot_get_trampoline ("llvm_throw_corlib_exception_trampoline");
366 mono_register_jit_icall (tramp, "llvm_throw_corlib_exception_trampoline", NULL, TRUE);
367 tramp = mono_aot_get_trampoline ("llvm_throw_corlib_exception_abs_trampoline");
368 mono_register_jit_icall (tramp, "llvm_throw_corlib_exception_abs_trampoline", NULL, TRUE);
369 tramp = mono_aot_get_trampoline ("llvm_resume_unwind_trampoline");
370 mono_register_jit_icall (tramp, "llvm_resume_unwind_trampoline", NULL, TRUE);
372 tramps = mono_arm_get_exception_trampolines (FALSE);
373 for (l = tramps; l; l = l->next) {
374 MonoTrampInfo *info = l->data;
376 mono_register_jit_icall (info->code, g_strdup (info->name), NULL, TRUE);
377 mono_tramp_info_register (info);
379 g_slist_free (tramps);
384 * mono_arch_find_jit_info:
386 * See exceptions-amd64.c for docs;
389 mono_arch_find_jit_info (MonoDomain *domain, MonoJitTlsData *jit_tls,
390 MonoJitInfo *ji, MonoContext *ctx,
391 MonoContext *new_ctx, MonoLMF **lmf,
392 mgreg_t **save_locations,
393 StackFrameInfo *frame)
395 gpointer ip = MONO_CONTEXT_GET_IP (ctx);
397 memset (frame, 0, sizeof (StackFrameInfo));
404 gssize regs [MONO_MAX_IREGS + 1 + 8];
406 guint32 unwind_info_len;
409 frame->type = FRAME_TYPE_MANAGED;
411 unwind_info = mono_jinfo_get_unwind_info (ji, &unwind_info_len);
414 printf ("%s %p %p\n", ji->d.method->name, ji->code_start, ip);
415 mono_print_unwind_info (unwind_info, unwind_info_len);
418 for (i = 0; i < 16; ++i)
419 regs [i] = new_ctx->regs [i];
421 /* On IOS, d8..d15 are callee saved. They are mapped to 8..15 in unwind.c */
422 for (i = 0; i < 8; ++i)
423 regs [MONO_MAX_IREGS + i] = new_ctx->fregs [8 + i];
426 mono_unwind_frame (unwind_info, unwind_info_len, ji->code_start,
427 (guint8*)ji->code_start + ji->code_size,
428 ip, NULL, regs, MONO_MAX_IREGS + 8,
429 save_locations, MONO_MAX_IREGS, &cfa);
431 for (i = 0; i < 16; ++i)
432 new_ctx->regs [i] = regs [i];
433 new_ctx->pc = regs [ARMREG_LR];
434 new_ctx->regs [ARMREG_SP] = (gsize)cfa;
436 for (i = 0; i < 8; ++i)
437 new_ctx->fregs [8 + i] = regs [MONO_MAX_IREGS + i];
440 /* Clear thumb bit */
443 /* we substract 1, so that the IP points into the call instruction */
449 if (((gsize)(*lmf)->previous_lmf) & 2) {
451 * This LMF entry is created by the soft debug code to mark transitions to
452 * managed code done during invokes.
454 MonoLMFExt *ext = (MonoLMFExt*)(*lmf);
456 g_assert (ext->debugger_invoke);
458 memcpy (new_ctx, &ext->ctx, sizeof (MonoContext));
460 *lmf = (gpointer)(((gsize)(*lmf)->previous_lmf) & ~3);
462 frame->type = FRAME_TYPE_DEBUGGER_INVOKE;
467 frame->type = FRAME_TYPE_MANAGED_TO_NATIVE;
469 if ((ji = mini_jit_info_table_find (domain, (gpointer)(*lmf)->ip, NULL))) {
474 frame->method = (*lmf)->method;
478 * The LMF is saved at the start of the method using:
479 * ARM_MOV_REG_REG (code, ARMREG_IP, ARMREG_SP)
480 * ARM_PUSH (code, 0x5ff0);
481 * So it stores the register state as it existed at the caller. We need to
482 * produce the register state which existed at the time of the call which
483 * transitioned to native call, so we save the sp/fp/ip in the LMF.
485 memcpy (&new_ctx->regs [0], &(*lmf)->iregs [0], sizeof (mgreg_t) * 13);
486 new_ctx->pc = (*lmf)->ip;
487 new_ctx->regs [ARMREG_SP] = (*lmf)->sp;
488 new_ctx->regs [ARMREG_FP] = (*lmf)->fp;
490 /* Clear thumb bit */
493 /* we substract 1, so that the IP points into the call instruction */
496 *lmf = (gpointer)(((gsize)(*lmf)->previous_lmf) & ~3);
507 * Called by resuming from a signal handler.
510 handle_signal_exception (gpointer obj)
512 MonoJitTlsData *jit_tls = mono_native_tls_get_value (mono_jit_tls_id);
515 memcpy (&ctx, &jit_tls->ex_ctx, sizeof (MonoContext));
517 mono_handle_exception (&ctx, obj);
519 mono_restore_context (&ctx);
523 * This works around a gcc 4.5 bug:
524 * https://bugs.launchpad.net/ubuntu/+source/gcc-4.5/+bug/721531
526 static MONO_NEVER_INLINE gpointer
527 get_handle_signal_exception_addr (void)
529 return handle_signal_exception;
533 * This is the function called from the signal handler
536 mono_arch_handle_exception (void *ctx, gpointer obj)
538 #if defined(MONO_CROSS_COMPILE) || !defined(MONO_ARCH_HAVE_SIGCTX_TO_MONOCTX)
539 g_assert_not_reached ();
540 #elif defined(MONO_ARCH_USE_SIGACTION)
541 arm_ucontext *sigctx = ctx;
543 * Handling the exception in the signal handler is problematic, since the original
544 * signal is disabled, and we could run arbitrary code though the debugger. So
545 * resume into the normal stack and do most work there if possible.
547 MonoJitTlsData *jit_tls = mono_native_tls_get_value (mono_jit_tls_id);
548 guint64 sp = UCONTEXT_REG_SP (sigctx);
550 /* Pass the ctx parameter in TLS */
551 mono_sigctx_to_monoctx (sigctx, &jit_tls->ex_ctx);
552 /* The others in registers */
553 UCONTEXT_REG_R0 (sigctx) = (gsize)obj;
555 /* Allocate a stack frame */
557 UCONTEXT_REG_SP (sigctx) = sp;
559 UCONTEXT_REG_PC (sigctx) = (gsize)get_handle_signal_exception_addr ();
560 #ifdef UCONTEXT_REG_CPSR
561 if ((gsize)UCONTEXT_REG_PC (sigctx) & 1)
562 /* Transition to thumb */
563 UCONTEXT_REG_CPSR (sigctx) |= (1 << 5);
565 /* Transition to ARM */
566 UCONTEXT_REG_CPSR (sigctx) &= ~(1 << 5);
574 mono_sigctx_to_monoctx (ctx, &mctx);
576 result = mono_handle_exception (&mctx, obj);
577 /* restore the context so that returning from the signal handler will invoke
580 mono_monoctx_to_sigctx (&mctx, ctx);
586 mono_arch_ip_from_context (void *sigctx)
588 #ifdef MONO_CROSS_COMPILE
589 g_assert_not_reached ();
590 #elif defined(__native_client__)
591 g_assert_not_reached ();
593 arm_ucontext *my_uc = sigctx;
594 return (void*) UCONTEXT_REG_PC (my_uc);
599 mono_arch_setup_async_callback (MonoContext *ctx, void (*async_cb)(void *fun), gpointer user_data)
601 mgreg_t sp = (mgreg_t)MONO_CONTEXT_GET_SP (ctx);
604 g_assert (!user_data);
606 /* Allocate a stack frame */
608 MONO_CONTEXT_SET_SP (ctx, sp);
609 MONO_CONTEXT_SET_IP (ctx, async_cb);
615 * mono_arch_setup_resume_sighandler_ctx:
617 * Setup CTX so execution continues at FUNC.
620 mono_arch_setup_resume_sighandler_ctx (MonoContext *ctx, gpointer func)
622 MONO_CONTEXT_SET_IP (ctx,func);
623 if ((mgreg_t)MONO_CONTEXT_GET_IP (ctx) & 1)
624 /* Transition to thumb */
625 ctx->cpsr |= (1 << 5);
627 /* Transition to ARM */
628 ctx->cpsr &= ~(1 << 5);