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|
/**
* \file
* exception support for x86
*
* Authors:
* Dietmar Maurer (dietmar@ximian.com)
*
* (C) 2001 Ximian, Inc.
*/
#include <config.h>
#include <glib.h>
#include <signal.h>
#include <string.h>
#ifdef HAVE_UCONTEXT_H
#include <ucontext.h>
#endif
#include <mono/metadata/abi-details.h>
#include <mono/arch/x86/x86-codegen.h>
#include <mono/metadata/appdomain.h>
#include <mono/metadata/tabledefs.h>
#include <mono/metadata/threads.h>
#include <mono/metadata/debug-helpers.h>
#include <mono/metadata/exception.h>
#include <mono/metadata/gc-internals.h>
#include <mono/metadata/mono-debug.h>
#include <mono/utils/mono-mmap.h>
#include <mono/utils/mono-state.h>
#include "mini.h"
#include "mini-x86.h"
#include "mini-runtime.h"
#include "tasklets.h"
#include "aot-runtime.h"
#include "mono/utils/mono-tls-inline.h"
static gpointer signal_exception_trampoline;
gpointer
mono_x86_get_signal_exception_trampoline (MonoTrampInfo **info, gboolean aot);
#ifdef TARGET_WIN32
static void (*restore_stack) (void *);
static MonoW32ExceptionHandler fpe_handler;
static MonoW32ExceptionHandler ill_handler;
static MonoW32ExceptionHandler segv_handler;
LPTOP_LEVEL_EXCEPTION_FILTER mono_old_win_toplevel_exception_filter;
gpointer mono_win_vectored_exception_handle;
extern int (*gUnhandledExceptionHandler)(EXCEPTION_POINTERS*);
#ifndef PROCESS_CALLBACK_FILTER_ENABLED
# define PROCESS_CALLBACK_FILTER_ENABLED 1
#endif
#define W32_SEH_HANDLE_EX(_ex) \
if (_ex##_handler) _ex##_handler(er->ExceptionCode, &info, ctx)
static LONG CALLBACK seh_unhandled_exception_filter(EXCEPTION_POINTERS* ep)
{
#ifndef MONO_CROSS_COMPILE
if (mono_old_win_toplevel_exception_filter) {
return (*mono_old_win_toplevel_exception_filter)(ep);
}
#endif
if (mono_dump_start ())
mono_handle_native_crash (mono_get_signame (SIGSEGV), NULL, NULL);
return EXCEPTION_CONTINUE_SEARCH;
}
/*
* mono_win32_get_handle_stackoverflow (void):
*
* Returns a pointer to a method which restores the current context stack
* and calls handle_exceptions, when done restores the original stack.
*/
static gpointer
mono_win32_get_handle_stackoverflow (void)
{
static guint8 *start = NULL;
guint8 *code;
if (start)
return start;
const int size = 128;
/* restore_contect (void *sigctx) */
start = code = mono_global_codeman_reserve (size);
/* load context into ebx */
x86_mov_reg_membase (code, X86_EBX, X86_ESP, 4, 4);
/* move current stack into edi for later restore */
x86_mov_reg_reg (code, X86_EDI, X86_ESP);
/* use the new freed stack from sigcontext */
/* XXX replace usage of struct sigcontext with MonoContext so we can use MONO_STRUCT_OFFSET */
x86_mov_reg_membase (code, X86_ESP, X86_EBX, G_STRUCT_OFFSET (struct sigcontext, esp), 4);
/* get the current domain */
x86_call_code (code, mono_domain_get);
/* get stack overflow exception from domain object */
x86_mov_reg_membase (code, X86_EAX, X86_EAX, G_STRUCT_OFFSET (MonoDomain, stack_overflow_ex), 4);
/* call mono_arch_handle_exception (sctx, stack_overflow_exception_obj) */
x86_push_reg (code, X86_EAX);
x86_push_reg (code, X86_EBX);
x86_call_code (code, mono_arch_handle_exception);
/* restore the SEH handler stack */
x86_mov_reg_reg (code, X86_ESP, X86_EDI);
/* return */
x86_ret (code);
g_assertf ((code - start) <= size, "%d %d", (int)(code - start), size);
mono_arch_flush_icache (start, code - start);
MONO_PROFILER_RAISE (jit_code_buffer, (start, code - start, MONO_PROFILER_CODE_BUFFER_EXCEPTION_HANDLING, NULL));
return start;
}
/* Special hack to workaround the fact that the
* when the SEH handler is called the stack is
* to small to recover.
*
* Stack walking part of this method is from mono_handle_exception
*
* The idea is simple;
* - walk the stack to free some space (64k)
* - set esp to new stack location
* - call mono_arch_handle_exception with stack overflow exception
* - set esp to SEH handlers stack
* - done
*/
static void
win32_handle_stack_overflow (EXCEPTION_POINTERS* ep, CONTEXT *sctx)
{
MonoDomain *domain = mono_domain_get ();
MonoJitInfo rji;
MonoJitTlsData *jit_tls = mono_tls_get_jit_tls ();
MonoLMF *lmf = jit_tls->lmf;
MonoContext initial_ctx;
MonoContext ctx;
guint32 free_stack = 0;
StackFrameInfo frame;
mono_sigctx_to_monoctx (sctx, &ctx);
/* Let's walk the stack to recover
* the needed stack space (if possible)
*/
memset (&rji, 0, sizeof (rji));
initial_ctx = ctx;
free_stack = (guint8*)(MONO_CONTEXT_GET_BP (&ctx)) - (guint8*)(MONO_CONTEXT_GET_BP (&initial_ctx));
/* try to free 64kb from our stack */
do {
MonoContext new_ctx;
mono_arch_unwind_frame (domain, jit_tls, &rji, &ctx, &new_ctx, &lmf, NULL, &frame);
if (!frame.ji) {
g_warning ("Exception inside function without unwind info");
g_assert_not_reached ();
}
if (frame.ji != (gpointer)-1) {
free_stack = (guint8*)(MONO_CONTEXT_GET_BP (&ctx)) - (guint8*)(MONO_CONTEXT_GET_BP (&initial_ctx));
}
/* todo: we should call abort if ji is -1 */
ctx = new_ctx;
} while (free_stack < 64 * 1024 && frame.ji != (gpointer) -1);
mono_monoctx_to_sigctx (&ctx, sctx);
/* todo: install new stack-guard page */
/* use the new stack and call mono_arch_handle_exception () */
restore_stack (sctx);
}
/*
* Unhandled Exception Filter
* Top-level per-process exception handler.
*/
static LONG CALLBACK seh_vectored_exception_handler(EXCEPTION_POINTERS* ep)
{
EXCEPTION_RECORD* er;
CONTEXT* ctx;
LONG res;
MonoJitTlsData *jit_tls = mono_tls_get_jit_tls ();
MonoWindowsSigHandlerInfo info = { TRUE, ep };
/* If the thread is not managed by the runtime return early */
if (!jit_tls)
return EXCEPTION_CONTINUE_SEARCH;
res = EXCEPTION_CONTINUE_EXECUTION;
er = ep->ExceptionRecord;
ctx = ep->ContextRecord;
switch (er->ExceptionCode) {
case EXCEPTION_STACK_OVERFLOW:
win32_handle_stack_overflow (ep, ctx);
break;
case EXCEPTION_ACCESS_VIOLATION:
W32_SEH_HANDLE_EX(segv);
break;
case EXCEPTION_ILLEGAL_INSTRUCTION:
W32_SEH_HANDLE_EX(ill);
break;
case EXCEPTION_INT_DIVIDE_BY_ZERO:
case EXCEPTION_INT_OVERFLOW:
case EXCEPTION_FLT_DIVIDE_BY_ZERO:
case EXCEPTION_FLT_OVERFLOW:
case EXCEPTION_FLT_UNDERFLOW:
case EXCEPTION_FLT_INEXACT_RESULT:
W32_SEH_HANDLE_EX(fpe);
break;
default:
info.handled = FALSE;
break;
}
if (!info.handled) {
/* Don't copy context back if we chained exception
* as the handler may have modfied the EXCEPTION_POINTERS
* directly. We don't pass sigcontext to chained handlers.
* Return continue search so the UnhandledExceptionFilter
* can correctly chain the exception.
*/
res = EXCEPTION_CONTINUE_SEARCH;
}
return res;
}
void win32_seh_init()
{
/* install restore stack helper */
if (!restore_stack)
restore_stack = (void (*) (void*))mono_win32_get_handle_stackoverflow ();
mono_old_win_toplevel_exception_filter = SetUnhandledExceptionFilter(seh_unhandled_exception_filter);
mono_win_vectored_exception_handle = AddVectoredExceptionHandler (1, seh_vectored_exception_handler);
}
void win32_seh_cleanup()
{
if (mono_old_win_toplevel_exception_filter)
SetUnhandledExceptionFilter(mono_old_win_toplevel_exception_filter);
RemoveVectoredExceptionHandler (mono_win_vectored_exception_handle);
}
void win32_seh_set_handler(int type, MonoW32ExceptionHandler handler)
{
switch (type) {
case SIGFPE:
fpe_handler = handler;
break;
case SIGILL:
ill_handler = handler;
break;
case SIGSEGV:
segv_handler = handler;
break;
default:
break;
}
}
#endif /* TARGET_WIN32 */
/*
* mono_arch_get_restore_context:
*
* Returns a pointer to a method which restores a previously saved sigcontext.
*/
gpointer
mono_arch_get_restore_context (MonoTrampInfo **info, gboolean aot)
{
guint8 *start = NULL;
guint8 *code;
MonoJumpInfo *ji = NULL;
GSList *unwind_ops = NULL;
/* restore_contect (MonoContext *ctx) */
const int size = 128;
start = code = mono_global_codeman_reserve (size);
/* load ctx */
x86_mov_reg_membase (code, X86_EAX, X86_ESP, 4, 4);
/* restore EBX */
x86_mov_reg_membase (code, X86_EBX, X86_EAX, MONO_STRUCT_OFFSET (MonoContext, ebx), 4);
/* restore EDI */
x86_mov_reg_membase (code, X86_EDI, X86_EAX, MONO_STRUCT_OFFSET (MonoContext, edi), 4);
/* restore ESI */
x86_mov_reg_membase (code, X86_ESI, X86_EAX, MONO_STRUCT_OFFSET (MonoContext, esi), 4);
/* restore EDX */
x86_mov_reg_membase (code, X86_EDX, X86_EAX, MONO_STRUCT_OFFSET (MonoContext, edx), 4);
/*
* The context resides on the stack, in the stack frame of the
* caller of this function. The stack pointer that we need to
* restore is potentially many stack frames higher up, so the
* distance between them can easily be more than the red zone
* size. Hence the stack pointer can be restored only after
* we have finished loading everything from the context.
*/
/* load ESP into EBP */
x86_mov_reg_membase (code, X86_EBP, X86_EAX, MONO_STRUCT_OFFSET (MonoContext, esp), 4);
/* load return address into ECX */
x86_mov_reg_membase (code, X86_ECX, X86_EAX, MONO_STRUCT_OFFSET (MonoContext, eip), 4);
/* save the return addr to the restored stack - 4 */
x86_mov_membase_reg (code, X86_EBP, -4, X86_ECX, 4);
/* load EBP into ECX */
x86_mov_reg_membase (code, X86_ECX, X86_EAX, MONO_STRUCT_OFFSET (MonoContext, ebp), 4);
/* save EBP to the restored stack - 8 */
x86_mov_membase_reg (code, X86_EBP, -8, X86_ECX, 4);
/* load EAX into ECX */
x86_mov_reg_membase (code, X86_ECX, X86_EAX, MONO_STRUCT_OFFSET (MonoContext, eax), 4);
/* save EAX to the restored stack - 12 */
x86_mov_membase_reg (code, X86_EBP, -12, X86_ECX, 4);
/* restore ECX */
x86_mov_reg_membase (code, X86_ECX, X86_EAX, MONO_STRUCT_OFFSET (MonoContext, ecx), 4);
/* restore ESP - 12 */
x86_lea_membase (code, X86_ESP, X86_EBP, -12);
/* restore EAX */
x86_pop_reg (code, X86_EAX);
/* restore EBP */
x86_pop_reg (code, X86_EBP);
/* jump to the saved IP */
x86_ret (code);
if (info)
*info = mono_tramp_info_create ("restore_context", start, code - start, ji, unwind_ops);
else {
GSList *l;
for (l = unwind_ops; l; l = l->next)
g_free (l->data);
g_slist_free (unwind_ops);
}
g_assertf ((code - start) <= size, "%d %d", (int)(code - start), size);
mono_arch_flush_icache (start, code - start);
MONO_PROFILER_RAISE (jit_code_buffer, (start, code - start, MONO_PROFILER_CODE_BUFFER_EXCEPTION_HANDLING, NULL));
return start;
}
/*
* mono_arch_get_call_filter:
*
* Returns a pointer to a method which calls an exception filter. We
* also use this function to call finally handlers (we pass NULL as
* @exc object in this case).
*/
gpointer
mono_arch_get_call_filter (MonoTrampInfo **info, gboolean aot)
{
guint8* start;
guint8 *code;
MonoJumpInfo *ji = NULL;
GSList *unwind_ops = NULL;
const int kMaxCodeSize = 64;
/* call_filter (MonoContext *ctx, unsigned long eip) */
start = code = mono_global_codeman_reserve (kMaxCodeSize);
x86_push_reg (code, X86_EBP);
x86_mov_reg_reg (code, X86_EBP, X86_ESP);
x86_push_reg (code, X86_EBX);
x86_push_reg (code, X86_EDI);
x86_push_reg (code, X86_ESI);
/* load ctx */
x86_mov_reg_membase (code, X86_EAX, X86_EBP, 8, 4);
/* load eip */
x86_mov_reg_membase (code, X86_ECX, X86_EBP, 12, 4);
/* save EBP */
x86_push_reg (code, X86_EBP);
/* set new EBP */
x86_mov_reg_membase (code, X86_EBP, X86_EAX, MONO_STRUCT_OFFSET (MonoContext, ebp), 4);
/* restore registers used by global register allocation (EBX & ESI) */
x86_mov_reg_membase (code, X86_EBX, X86_EAX, MONO_STRUCT_OFFSET (MonoContext, ebx), 4);
x86_mov_reg_membase (code, X86_ESI, X86_EAX, MONO_STRUCT_OFFSET (MonoContext, esi), 4);
x86_mov_reg_membase (code, X86_EDI, X86_EAX, MONO_STRUCT_OFFSET (MonoContext, edi), 4);
/* align stack and save ESP */
x86_mov_reg_reg (code, X86_EDX, X86_ESP);
x86_alu_reg_imm (code, X86_AND, X86_ESP, -MONO_ARCH_FRAME_ALIGNMENT);
g_assert (MONO_ARCH_FRAME_ALIGNMENT >= 8);
x86_alu_reg_imm (code, X86_SUB, X86_ESP, MONO_ARCH_FRAME_ALIGNMENT - 8);
x86_push_reg (code, X86_EDX);
/* call the handler */
x86_call_reg (code, X86_ECX);
/* restore ESP */
x86_pop_reg (code, X86_ESP);
/* restore EBP */
x86_pop_reg (code, X86_EBP);
/* restore saved regs */
x86_pop_reg (code, X86_ESI);
x86_pop_reg (code, X86_EDI);
x86_pop_reg (code, X86_EBX);
x86_leave (code);
x86_ret (code);
if (info)
*info = mono_tramp_info_create ("call_filter", start, code - start, ji, unwind_ops);
else {
GSList *l;
for (l = unwind_ops; l; l = l->next)
g_free (l->data);
g_slist_free (unwind_ops);
}
mono_arch_flush_icache (start, code - start);
MONO_PROFILER_RAISE (jit_code_buffer, (start, code - start, MONO_PROFILER_CODE_BUFFER_EXCEPTION_HANDLING, NULL));
g_assertf ((code - start) <= kMaxCodeSize, "%d %d", (int)(code - start), kMaxCodeSize);
return start;
}
/*
* mono_x86_throw_exception:
*
* C function called from the throw trampolines.
*/
void
mono_x86_throw_exception (host_mgreg_t *regs, MonoObject *exc,
host_mgreg_t eip, gboolean rethrow, gboolean preserve_ips)
{
ERROR_DECL (error);
MonoContext ctx;
ctx.esp = regs [X86_ESP];
ctx.eip = eip;
ctx.ebp = regs [X86_EBP];
ctx.edi = regs [X86_EDI];
ctx.esi = regs [X86_ESI];
ctx.ebx = regs [X86_EBX];
ctx.edx = regs [X86_EDX];
ctx.ecx = regs [X86_ECX];
ctx.eax = regs [X86_EAX];
#ifdef __APPLE__
/* The OSX ABI specifies 16 byte alignment at call sites */
g_assert ((ctx.esp % MONO_ARCH_FRAME_ALIGNMENT) == 0);
#endif
if (mono_object_isinst_checked (exc, mono_defaults.exception_class, error)) {
MonoException *mono_ex = (MonoException*)exc;
if (!rethrow && !mono_ex->caught_in_unmanaged) {
mono_ex->stack_trace = NULL;
mono_ex->trace_ips = NULL;
} else if (preserve_ips) {
mono_ex->caught_in_unmanaged = TRUE;
}
}
mono_error_assert_ok (error);
/* adjust eip so that it point into the call instruction */
ctx.eip -= 1;
mono_handle_exception (&ctx, exc);
mono_restore_context (&ctx);
g_assert_not_reached ();
}
void
mono_x86_throw_corlib_exception (host_mgreg_t *regs, guint32 ex_token_index,
host_mgreg_t eip, gint32 pc_offset)
{
guint32 ex_token = MONO_TOKEN_TYPE_DEF | ex_token_index;
MonoException *ex;
ex = mono_exception_from_token (m_class_get_image (mono_defaults.exception_class), ex_token);
eip -= pc_offset;
/* Negate the ip adjustment done in mono_x86_throw_exception () */
eip += 1;
mono_x86_throw_exception (regs, (MonoObject*)ex, eip, FALSE, FALSE);
}
static void
mono_x86_resume_unwind (host_mgreg_t *regs, MonoObject *exc,
host_mgreg_t eip, gboolean rethrow)
{
MonoContext ctx;
ctx.esp = regs [X86_ESP];
ctx.eip = eip;
ctx.ebp = regs [X86_EBP];
ctx.edi = regs [X86_EDI];
ctx.esi = regs [X86_ESI];
ctx.ebx = regs [X86_EBX];
ctx.edx = regs [X86_EDX];
ctx.ecx = regs [X86_ECX];
ctx.eax = regs [X86_EAX];
mono_resume_unwind (&ctx);
}
/*
* get_throw_trampoline:
*
* Generate a call to mono_x86_throw_exception/
* mono_x86_throw_corlib_exception.
* If LLVM is true, generate code which assumes the caller is LLVM generated code,
* which doesn't push the arguments.
*/
static guint8*
get_throw_trampoline (const char *name, gboolean rethrow, gboolean llvm, gboolean corlib, gboolean llvm_abs, gboolean resume_unwind, MonoTrampInfo **info, gboolean aot, gboolean preserve_ips)
{
guint8 *start, *code, *labels [16];
int i, stack_size, stack_offset, arg_offsets [5], regs_offset;
MonoJumpInfo *ji = NULL;
GSList *unwind_ops = NULL;
const int kMaxCodeSize = 192;
start = code = mono_global_codeman_reserve (kMaxCodeSize);
stack_size = 128;
/*
* On apple, the stack is misaligned by the pushing of the return address.
*/
if (!llvm && corlib)
/* On OSX, we don't generate alignment code to save space */
stack_size += 4;
else
stack_size += MONO_ARCH_FRAME_ALIGNMENT - 4;
/*
* The stack looks like this:
* <pc offset> (only if corlib is TRUE)
* <exception object>/<type token>
* <return addr> <- esp (unaligned on apple)
*/
unwind_ops = mono_arch_get_cie_program ();
/* Alloc frame */
x86_alu_reg_imm (code, X86_SUB, X86_ESP, stack_size);
mono_add_unwind_op_def_cfa_offset (unwind_ops, code, start, stack_size + 4);
arg_offsets [0] = 0;
arg_offsets [1] = 4;
arg_offsets [2] = 8;
arg_offsets [3] = 12;
arg_offsets [4] = 16;
regs_offset = 20;
/* Save registers */
for (i = 0; i < X86_NREG; ++i)
if (i != X86_ESP)
x86_mov_membase_reg (code, X86_ESP, regs_offset + (i * 4), i, 4);
/* Calculate the offset between the current sp and the sp of the caller */
if (llvm) {
/* LLVM doesn't push the arguments */
stack_offset = stack_size + 4;
} else {
if (corlib) {
/* Two arguments */
stack_offset = stack_size + 4 + 8;
#ifdef __APPLE__
/* We don't generate stack alignment code on osx to save space */
#endif
} else {
/* One argument + stack alignment */
stack_offset = stack_size + 4 + 4;
#ifdef __APPLE__
/* Pop the alignment added by OP_THROW too */
stack_offset += MONO_ARCH_FRAME_ALIGNMENT - 4;
#else
if (mono_do_x86_stack_align)
stack_offset += MONO_ARCH_FRAME_ALIGNMENT - 4;
#endif
}
}
/* Save ESP */
x86_lea_membase (code, X86_EAX, X86_ESP, stack_offset);
x86_mov_membase_reg (code, X86_ESP, regs_offset + (X86_ESP * 4), X86_EAX, 4);
/* Clear fp stack */
labels [0] = code;
x86_fnstsw (code);
x86_shift_reg_imm (code, X86_SHR, X86_EAX, 11);
x86_alu_reg_imm (code, X86_AND, X86_EAX, 7);
x86_alu_reg_imm (code, X86_CMP, X86_EAX, 0);
labels [1] = code;
x86_branch8 (code, X86_CC_EQ, 0, FALSE);
x86_fstp (code, 0);
x86_jump_code (code, labels [0]);
mono_x86_patch (labels [1], code);
/* Set arg1 == regs */
x86_lea_membase (code, X86_EAX, X86_ESP, regs_offset);
x86_mov_membase_reg (code, X86_ESP, arg_offsets [0], X86_EAX, 4);
/* Set arg2 == exc/ex_token_index */
if (resume_unwind)
x86_mov_reg_imm (code, X86_EAX, 0);
else
x86_mov_reg_membase (code, X86_EAX, X86_ESP, stack_size + 4, 4);
x86_mov_membase_reg (code, X86_ESP, arg_offsets [1], X86_EAX, 4);
/* Set arg3 == eip */
if (llvm_abs)
x86_alu_reg_reg (code, X86_XOR, X86_EAX, X86_EAX);
else
x86_mov_reg_membase (code, X86_EAX, X86_ESP, stack_size, 4);
x86_mov_membase_reg (code, X86_ESP, arg_offsets [2], X86_EAX, 4);
/* Set arg4 == rethrow/pc_offset */
if (resume_unwind) {
x86_mov_membase_imm (code, X86_ESP, arg_offsets [3], 0, 4);
} else if (corlib) {
x86_mov_reg_membase (code, X86_EAX, X86_ESP, stack_size + 8, 4);
if (llvm_abs) {
/*
* The caller is LLVM code which passes the absolute address not a pc offset,
* so compensate by passing 0 as 'ip' and passing the negated abs address as
* the pc offset.
*/
x86_neg_reg (code, X86_EAX);
}
x86_mov_membase_reg (code, X86_ESP, arg_offsets [3], X86_EAX, 4);
} else {
x86_mov_membase_imm (code, X86_ESP, arg_offsets [3], rethrow, 4);
/* Set arg4 == preserve_ips */
x86_mov_membase_imm (code, X86_ESP, arg_offsets [4], preserve_ips, 4);
}
/* Make the call */
if (aot) {
// This can be called from runtime code, which can't guarantee that
// ebx contains the got address.
// So emit the got address loading code too
code = mono_arch_emit_load_got_addr (start, code, NULL, &ji);
code = mono_arch_emit_load_aotconst (start, code, &ji, MONO_PATCH_INFO_JIT_ICALL_ADDR, GUINT_TO_POINTER (corlib ? MONO_JIT_ICALL_mono_x86_throw_corlib_exception : MONO_JIT_ICALL_mono_x86_throw_exception));
x86_call_reg (code, X86_EAX);
} else {
x86_call_code (code, resume_unwind ? (gpointer)(mono_x86_resume_unwind) : (corlib ? (gpointer)mono_x86_throw_corlib_exception : (gpointer)mono_x86_throw_exception));
}
x86_breakpoint (code);
g_assertf ((code - start) <= kMaxCodeSize, "%d %d", (int)(code - start), kMaxCodeSize);
if (info)
*info = mono_tramp_info_create (name, start, code - start, ji, unwind_ops);
else {
GSList *l;
for (l = unwind_ops; l; l = l->next)
g_free (l->data);
g_slist_free (unwind_ops);
}
mono_arch_flush_icache (start, code - start);
MONO_PROFILER_RAISE (jit_code_buffer, (start, code - start, MONO_PROFILER_CODE_BUFFER_EXCEPTION_HANDLING, NULL));
return start;
}
/**
* mono_arch_get_throw_exception:
* \returns a function pointer which can be used to raise
* exceptions. The returned function has the following
* signature: void (*func) (MonoException *exc);
* For example to raise an arithmetic exception you can use:
*
* x86_push_imm (code, mono_get_exception_arithmetic ());
* x86_call_code (code, arch_get_throw_exception ());
*
*/
gpointer
mono_arch_get_throw_exception (MonoTrampInfo **info, gboolean aot)
{
return get_throw_trampoline ("throw_exception", FALSE, FALSE, FALSE, FALSE, FALSE, info, aot, FALSE);
}
gpointer
mono_arch_get_rethrow_exception (MonoTrampInfo **info, gboolean aot)
{
return get_throw_trampoline ("rethrow_exception", TRUE, FALSE, FALSE, FALSE, FALSE, info, aot, FALSE);
}
gpointer
mono_arch_get_rethrow_preserve_exception (MonoTrampInfo **info, gboolean aot)
{
return get_throw_trampoline ("rethrow_preserve_exception", TRUE, FALSE, FALSE, FALSE, FALSE, info, aot, TRUE);
}
/**
* mono_arch_get_throw_corlib_exception:
* \returns a function pointer which can be used to raise
* corlib exceptions. The returned function has the following
* signature: void (*func) (guint32 ex_token, guint32 offset);
* Here, offset is the offset which needs to be substracted from the caller IP
* to get the IP of the throw. Passing the offset has the advantage that it
* needs no relocations in the caller.
*/
gpointer
mono_arch_get_throw_corlib_exception (MonoTrampInfo **info, gboolean aot)
{
return get_throw_trampoline ("throw_corlib_exception", FALSE, FALSE, TRUE, FALSE, FALSE, info, aot, FALSE);
}
void
mono_arch_exceptions_init (void)
{
guint8 *tramp;
MonoTrampInfo *tinfo;
/*
* If we're running WoW64, we need to set the usermode exception policy
* for SEHs to behave. This requires hotfix http://support.microsoft.com/kb/976038
* or (eventually) Windows 7 SP1.
*/
#ifdef TARGET_WIN32
HMODULE kernel32 = LoadLibraryW (L"kernel32.dll");
if (kernel32) {
typedef BOOL (WINAPI * SetProcessUserModeExceptionPolicy_t) (DWORD dwFlags);
typedef BOOL (WINAPI * GetProcessUserModeExceptionPolicy_t) (PDWORD dwFlags);
GetProcessUserModeExceptionPolicy_t const getter = (GetProcessUserModeExceptionPolicy_t)GetProcAddress (kernel32, "GetProcessUserModeExceptionPolicy");
if (getter) {
SetProcessUserModeExceptionPolicy_t const setter = (SetProcessUserModeExceptionPolicy_t)GetProcAddress (kernel32, "SetProcessUserModeExceptionPolicy");
if (setter) {
DWORD flags = 0;
if (getter (&flags))
setter (flags & ~PROCESS_CALLBACK_FILTER_ENABLED);
}
}
}
#endif
if (mono_aot_only) {
signal_exception_trampoline = mono_aot_get_trampoline ("x86_signal_exception_trampoline");
return;
}
// FIXME Macroize.
/* LLVM needs different throw trampolines */
tramp = get_throw_trampoline ("llvm_throw_exception_trampoline", FALSE, TRUE, FALSE, FALSE, FALSE, &tinfo, FALSE, FALSE);
mono_register_jit_icall_info (&mono_get_jit_icall_info ()->mono_llvm_throw_exception_trampoline, tramp, "llvm_throw_exception_trampoline", NULL, TRUE, NULL);
mono_tramp_info_register (tinfo, NULL);
tramp = get_throw_trampoline ("llvm_rethrow_exception_trampoline", TRUE, TRUE, FALSE, FALSE, FALSE, &tinfo, FALSE, FALSE);
mono_register_jit_icall_info (&mono_get_jit_icall_info ()->mono_llvm_rethrow_exception_trampoline, tramp, "llvm_rethrow_exception_trampoline", NULL, TRUE, NULL);
mono_tramp_info_register (tinfo, NULL);
tramp = get_throw_trampoline ("llvm_throw_corlib_exception_trampoline", FALSE, TRUE, TRUE, FALSE, FALSE, &tinfo, FALSE, FALSE);
mono_register_jit_icall_info (&mono_get_jit_icall_info ()->mono_llvm_throw_corlib_exception_trampoline, tramp, "llvm_throw_corlib_exception_trampoline", NULL, TRUE, NULL);
mono_tramp_info_register (tinfo, NULL);
tramp = get_throw_trampoline ("llvm_throw_corlib_exception_abs_trampoline", FALSE, TRUE, TRUE, TRUE, FALSE, &tinfo, FALSE, FALSE);
mono_register_jit_icall_info (&mono_get_jit_icall_info ()->mono_llvm_throw_corlib_exception_abs_trampoline, tramp, "llvm_throw_corlib_exception_abs_trampoline", NULL, TRUE, NULL);
mono_tramp_info_register (tinfo, NULL);
tramp = get_throw_trampoline ("llvm_resume_unwind_trampoline", FALSE, FALSE, FALSE, FALSE, TRUE, &tinfo, FALSE, FALSE);
mono_register_jit_icall_info (&mono_get_jit_icall_info ()->mono_llvm_resume_unwind_trampoline, tramp, "llvm_resume_unwind_trampoline", NULL, TRUE, NULL);
mono_tramp_info_register (tinfo, NULL);
signal_exception_trampoline = mono_x86_get_signal_exception_trampoline (&tinfo, FALSE);
mono_tramp_info_register (tinfo, NULL);
}
/*
* mono_arch_unwind_frame:
*
* See exceptions-amd64.c for docs.
*/
gboolean
mono_arch_unwind_frame (MonoDomain *domain, MonoJitTlsData *jit_tls,
MonoJitInfo *ji, MonoContext *ctx,
MonoContext *new_ctx, MonoLMF **lmf,
host_mgreg_t **save_locations,
StackFrameInfo *frame)
{
gpointer ip = MONO_CONTEXT_GET_IP (ctx);
memset (frame, 0, sizeof (StackFrameInfo));
frame->ji = ji;
*new_ctx = *ctx;
if (ji != NULL) {
host_mgreg_t regs [MONO_MAX_IREGS + 1];
guint8 *cfa;
guint32 unwind_info_len;
guint8 *unwind_info;
if (ji->is_trampoline)
frame->type = FRAME_TYPE_TRAMPOLINE;
else
frame->type = FRAME_TYPE_MANAGED;
unwind_info = mono_jinfo_get_unwind_info (ji, &unwind_info_len);
regs [X86_EAX] = new_ctx->eax;
regs [X86_EBX] = new_ctx->ebx;
regs [X86_ECX] = new_ctx->ecx;
regs [X86_EDX] = new_ctx->edx;
regs [X86_ESP] = new_ctx->esp;
regs [X86_EBP] = new_ctx->ebp;
regs [X86_ESI] = new_ctx->esi;
regs [X86_EDI] = new_ctx->edi;
regs [X86_NREG] = new_ctx->eip;
gboolean success = mono_unwind_frame ((guint8*)unwind_info, unwind_info_len, (guint8*)ji->code_start,
(guint8*)ji->code_start + ji->code_size,
(guint8*)ip, NULL, regs, MONO_MAX_IREGS + 1,
save_locations, MONO_MAX_IREGS, &cfa);
if (!success)
return FALSE;
new_ctx->eax = regs [X86_EAX];
new_ctx->ebx = regs [X86_EBX];
new_ctx->ecx = regs [X86_ECX];
new_ctx->edx = regs [X86_EDX];
new_ctx->esp = regs [X86_ESP];
new_ctx->ebp = regs [X86_EBP];
new_ctx->esi = regs [X86_ESI];
new_ctx->edi = regs [X86_EDI];
new_ctx->eip = regs [X86_NREG];
/* The CFA becomes the new SP value */
new_ctx->esp = (gssize)cfa;
/* Adjust IP */
new_ctx->eip --;
return TRUE;
} else if (*lmf) {
g_assert ((((gsize)(*lmf)->previous_lmf) & 2) == 0);
if ((ji = mini_jit_info_table_find (domain, (gpointer)(uintptr_t)(*lmf)->eip, NULL))) {
frame->ji = ji;
} else {
if (!(*lmf)->method)
return FALSE;
frame->method = (*lmf)->method;
}
new_ctx->esi = (*lmf)->esi;
new_ctx->edi = (*lmf)->edi;
new_ctx->ebx = (*lmf)->ebx;
new_ctx->ebp = (*lmf)->ebp;
new_ctx->eip = (*lmf)->eip;
/* Adjust IP */
new_ctx->eip --;
frame->type = FRAME_TYPE_MANAGED_TO_NATIVE;
/* Check if we are in a trampoline LMF frame */
if ((gsize)((*lmf)->previous_lmf) & 1) {
/* lmf->esp is set by the trampoline code */
new_ctx->esp = (*lmf)->esp;
}
else
/* the lmf is always stored on the stack, so the following
* expression points to a stack location which can be used as ESP */
new_ctx->esp = (gsize)&((*lmf)->eip);
*lmf = (MonoLMF*)(((gsize)(*lmf)->previous_lmf) & ~3);
return TRUE;
}
return FALSE;
}
gpointer
mono_arch_ip_from_context (void *sigctx)
{
#if defined(HOST_WATCHOS)
printf("WARNING: mono_arch_ip_from_context() called!\n");
return (NULL);
#elif defined(MONO_CROSS_COMPILE)
g_assert_not_reached ();
return NULL;
#elif defined(MONO_ARCH_USE_SIGACTION)
ucontext_t *ctx = (ucontext_t*)sigctx;
return (gpointer)UCONTEXT_REG_EIP (ctx);
#elif defined(HOST_WIN32)
return (gpointer)((CONTEXT*)sigctx)->Eip;
#else
struct sigcontext *ctx = sigctx;
return (gpointer)ctx->SC_EIP;
#endif
}
/*
* handle_exception:
*
* Called by resuming from a signal handler.
*/
static void
handle_signal_exception (gpointer obj)
{
MonoJitTlsData *jit_tls = mono_tls_get_jit_tls ();
MonoContext ctx;
memcpy (&ctx, &jit_tls->ex_ctx, sizeof (MonoContext));
mono_handle_exception (&ctx, (MonoObject*)obj);
mono_restore_context (&ctx);
}
/*
* mono_x86_get_signal_exception_trampoline:
*
* This x86 specific trampoline is used to call handle_signal_exception.
*/
gpointer
mono_x86_get_signal_exception_trampoline (MonoTrampInfo **info, gboolean aot)
{
guint8 *start, *code;
MonoJumpInfo *ji = NULL;
GSList *unwind_ops = NULL;
int stack_size;
const int size = 128;
start = code = mono_global_codeman_reserve (size);
/* FIXME no unwind before we push ip */
/* Caller ip */
x86_push_reg (code, X86_ECX);
mono_add_unwind_op_def_cfa (unwind_ops, code, start, X86_ESP, 4);
mono_add_unwind_op_offset (unwind_ops, code, start, X86_NREG, -4);
/* Fix the alignment to be what apple expects */
stack_size = 12;
x86_alu_reg_imm (code, X86_SUB, X86_ESP, stack_size);
mono_add_unwind_op_def_cfa_offset (unwind_ops, code, start, stack_size + 4);
/* Arg1 */
x86_mov_membase_reg (code, X86_ESP, 0, X86_EAX, 4);
/* Branch to target */
x86_call_reg (code, X86_EDX);
g_assertf ((code - start) <= size, "%d %d", (int)(code - start), size);
if (info)
*info = mono_tramp_info_create ("x86_signal_exception_trampoline", start, code - start, ji, unwind_ops);
else {
GSList *l;
for (l = unwind_ops; l; l = l->next)
g_free (l->data);
g_slist_free (unwind_ops);
}
g_assertf ((code - start) <= size, "%d %d", (int)(code - start), size);
mono_arch_flush_icache (start, code - start);
MONO_PROFILER_RAISE (jit_code_buffer, (start, code - start, MONO_PROFILER_CODE_BUFFER_EXCEPTION_HANDLING, NULL));
return start;
}
void
mono_arch_setup_async_callback (MonoContext *ctx, void (*async_cb)(void *fun), gpointer user_data)
{
/*
* Can't pass the obj on the stack, since we are executing on the
* same stack. Can't save it into MonoJitTlsData, since it needs GC tracking.
* So put it into a register, and branch to a trampoline which
* pushes it.
*/
ctx->eax = (host_mgreg_t)(gsize)user_data;
ctx->ecx = ctx->eip;
ctx->edx = (host_mgreg_t)(gsize)async_cb;
/*align the stack*/
ctx->esp = (ctx->esp - 16) & ~15;
ctx->eip = (host_mgreg_t)(gsize)signal_exception_trampoline;
}
gboolean
mono_arch_handle_exception (void *sigctx, gpointer obj)
{
#if defined(MONO_ARCH_USE_SIGACTION)
MonoContext mctx;
ucontext_t *ctx = (ucontext_t*)sigctx;
/*
* Handling the exception in the signal handler is problematic, since the original
* signal is disabled, and we could run arbitrary code though the debugger. So
* resume into the normal stack and do most work there if possible.
*/
MonoJitTlsData *jit_tls = mono_tls_get_jit_tls ();
/* Pass the ctx parameter in TLS */
mono_sigctx_to_monoctx (ctx, &jit_tls->ex_ctx);
mctx = jit_tls->ex_ctx;
mono_setup_async_callback (&mctx, handle_signal_exception, obj);
mono_monoctx_to_sigctx (&mctx, sigctx);
return TRUE;
#elif defined (TARGET_WIN32)
MonoContext mctx;
MonoJitTlsData *jit_tls = mono_tls_get_jit_tls ();
mono_sigctx_to_monoctx (sigctx, &jit_tls->ex_ctx);
mctx = jit_tls->ex_ctx;
mono_setup_async_callback (&mctx, handle_signal_exception, obj);
mono_monoctx_to_sigctx (&mctx, sigctx);
return TRUE;
#else
MonoContext mctx;
mono_sigctx_to_monoctx (sigctx, &mctx);
mono_handle_exception (&mctx, obj);
mono_monoctx_to_sigctx (&mctx, sigctx);
return TRUE;
#endif
}
#if defined (MONO_ARCH_USE_SIGACTION) && !defined (MONO_CROSS_COMPILE)
static MonoObject*
restore_soft_guard_pages (void)
{
MonoJitTlsData *jit_tls = mono_tls_get_jit_tls ();
if (jit_tls->stack_ovf_guard_base)
mono_mprotect (jit_tls->stack_ovf_guard_base, jit_tls->stack_ovf_guard_size, MONO_MMAP_NONE);
if (jit_tls->stack_ovf_pending) {
MonoDomain *domain = mono_domain_get ();
jit_tls->stack_ovf_pending = 0;
return (MonoObject *) domain->stack_overflow_ex;
}
return NULL;
}
/*
* this function modifies mctx so that when it is restored, it
* won't execcute starting at mctx.eip, but in a function that
* will restore the protection on the soft-guard pages and return back to
* continue at mctx.eip.
*/
static void
prepare_for_guard_pages (MonoContext *mctx)
{
gpointer *sp;
sp = (gpointer*)(mctx->esp);
sp -= 1;
/* the return addr */
sp [0] = (gpointer)(mctx->eip);
mctx->eip = (gsize)restore_soft_guard_pages;
mctx->esp = (gsize)sp;
}
static void
altstack_handle_and_restore (MonoContext *ctx, gpointer obj, gboolean stack_ovf)
{
MonoContext mctx;
mctx = *ctx;
mono_handle_exception (&mctx, (MonoObject*)obj);
if (stack_ovf) {
MonoJitTlsData *jit_tls = mono_tls_get_jit_tls ();
jit_tls->stack_ovf_pending = 1;
prepare_for_guard_pages (&mctx);
}
mono_restore_context (&mctx);
}
#endif
void
mono_arch_handle_altstack_exception (void *sigctx, MONO_SIG_HANDLER_INFO_TYPE *siginfo, gpointer fault_addr, gboolean stack_ovf)
{
#if defined (MONO_ARCH_USE_SIGACTION) && !defined (MONO_CROSS_COMPILE)
MonoException *exc = NULL;
ucontext_t *ctx = (ucontext_t*)sigctx;
MonoJitInfo *ji = mini_jit_info_table_find (mono_domain_get (), (gpointer)UCONTEXT_REG_EIP (ctx), NULL);
gpointer *sp;
int frame_size;
/* if we didn't find a managed method for the ip address and it matches the fault
* address, we assume we followed a broken pointer during an indirect call, so
* we try the lookup again with the return address pushed on the stack
*/
if (!ji && fault_addr == (gpointer)UCONTEXT_REG_EIP (ctx)) {
glong *sp = (glong*)UCONTEXT_REG_ESP (ctx);
ji = mini_jit_info_table_find (mono_domain_get (), (gpointer)sp [0], NULL);
if (ji)
UCONTEXT_REG_EIP (ctx) = sp [0];
}
if (stack_ovf)
exc = mono_domain_get ()->stack_overflow_ex;
if (!ji) {
MonoContext mctx;
mono_sigctx_to_monoctx (sigctx, &mctx);
if (mono_dump_start ())
mono_handle_native_crash (mono_get_signame (SIGSEGV), &mctx, siginfo);
else
abort ();
}
/* setup a call frame on the real stack so that control is returned there
* and exception handling can continue.
* If this was a stack overflow the caller already ensured the stack pages
* needed have been unprotected.
* The frame looks like:
* ucontext struct
* test_only arg
* exception arg
* ctx arg
* return ip
*/
// FIXME: test_only is no more.
frame_size = sizeof (MonoContext) + sizeof (gpointer) * 4;
frame_size += 15;
frame_size &= ~15;
sp = (gpointer*)(UCONTEXT_REG_ESP (ctx) & ~15);
sp = (gpointer*)((char*)sp - frame_size);
/* the incoming arguments are aligned to 16 bytes boundaries, so the return address IP
* goes at sp [-1]
*/
sp [-1] = (gpointer)UCONTEXT_REG_EIP (ctx);
sp [0] = sp + 4;
sp [1] = exc;
sp [2] = (gpointer)stack_ovf;
mono_sigctx_to_monoctx (sigctx, (MonoContext*)(sp + 4));
/* at the return form the signal handler execution starts in altstack_handle_and_restore() */
UCONTEXT_REG_EIP (ctx) = (unsigned long)altstack_handle_and_restore;
UCONTEXT_REG_ESP (ctx) = (unsigned long)(sp - 1);
#endif
}
#if MONO_SUPPORT_TASKLETS
MonoContinuationRestore
mono_tasklets_arch_restore (void)
{
static guint8* saved = NULL;
guint8 *code, *start;
if (saved)
return (MonoContinuationRestore)saved;
const int size = 48;
code = start = mono_global_codeman_reserve (size);
/* the signature is: restore (MonoContinuation *cont, int state, MonoLMF **lmf_addr) */
/* put cont in edx */
x86_mov_reg_membase (code, X86_EDX, X86_ESP, 4, 4);
/* state in eax, so it's setup as the return value */
x86_mov_reg_membase (code, X86_EAX, X86_ESP, 8, 4);
/* lmf_addr in ebx */
x86_mov_reg_membase(code, X86_EBX, X86_ESP, 0x0C, 4);
/* setup the copy of the stack */
x86_mov_reg_membase (code, X86_ECX, X86_EDX, MONO_STRUCT_OFFSET (MonoContinuation, stack_used_size), 4);
x86_shift_reg_imm (code, X86_SHR, X86_ECX, 2);
x86_cld (code);
x86_mov_reg_membase (code, X86_ESI, X86_EDX, MONO_STRUCT_OFFSET (MonoContinuation, saved_stack), 4);
x86_mov_reg_membase (code, X86_EDI, X86_EDX, MONO_STRUCT_OFFSET (MonoContinuation, return_sp), 4);
x86_prefix (code, X86_REP_PREFIX);
x86_movsl (code);
/* now restore the registers from the LMF */
x86_mov_reg_membase (code, X86_ECX, X86_EDX, MONO_STRUCT_OFFSET (MonoContinuation, lmf), 4);
x86_mov_reg_membase (code, X86_EBP, X86_ECX, MONO_STRUCT_OFFSET (MonoLMF, ebp), 4);
x86_mov_reg_membase (code, X86_ESP, X86_ECX, MONO_STRUCT_OFFSET (MonoLMF, esp), 4);
/* restore the lmf chain */
/*x86_mov_reg_membase (code, X86_ECX, X86_ESP, 12, 4);
x86_mov_membase_reg (code, X86_ECX, 0, X86_EDX, 4);*/
x86_jump_membase (code, X86_EDX, MONO_STRUCT_OFFSET (MonoContinuation, return_ip));
g_assertf ((code - start) <= size, "%d %d", (int)(code - start), size);
mono_arch_flush_icache (start, code - start);
MONO_PROFILER_RAISE (jit_code_buffer, (start, code - start, MONO_PROFILER_CODE_BUFFER_EXCEPTION_HANDLING, NULL));
g_assert ((code - start) <= 48);
saved = start;
return (MonoContinuationRestore)saved;
}
#endif
/*
* mono_arch_setup_resume_sighandler_ctx:
*
* Setup CTX so execution continues at FUNC.
*/
void
mono_arch_setup_resume_sighandler_ctx (MonoContext *ctx, gpointer func)
{
gssize align = (((gssize)MONO_CONTEXT_GET_SP (ctx)) % MONO_ARCH_FRAME_ALIGNMENT + 4);
if (align != 0)
MONO_CONTEXT_SET_SP (ctx, (gsize)MONO_CONTEXT_GET_SP (ctx) - align);
MONO_CONTEXT_SET_IP (ctx, func);
}
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