mirror of
https://github.com/autc04/Retro68.git
synced 2024-09-08 20:55:01 +00:00
179 lines
5.5 KiB
C
179 lines
5.5 KiB
C
// i386-signal.h - Catch runtime signals and turn them into exceptions
|
|
// on an i386 based Linux system.
|
|
|
|
/* Copyright (C) 1998, 1999, 2001, 2002, 2006, 2007, 2011
|
|
Free Software Foundation
|
|
|
|
This file is part of libgcj.
|
|
|
|
This software is copyrighted work licensed under the terms of the
|
|
Libgcj License. Please consult the file "LIBGCJ_LICENSE" for
|
|
details. */
|
|
|
|
|
|
#ifdef __i386__
|
|
|
|
#ifndef JAVA_SIGNAL_H
|
|
#define JAVA_SIGNAL_H 1
|
|
|
|
#include <signal.h>
|
|
#include <sys/syscall.h>
|
|
|
|
#define HANDLE_SEGV 1
|
|
#define HANDLE_FPE 1
|
|
|
|
#define SIGNAL_HANDLER(_name) \
|
|
static void _Jv_##_name (int, siginfo_t *, \
|
|
void *_p __attribute__ ((__unused__)))
|
|
|
|
#define HANDLE_DIVIDE_OVERFLOW \
|
|
do \
|
|
{ \
|
|
struct ucontext *_uc = (struct ucontext *)_p; \
|
|
gregset_t &_gregs = _uc->uc_mcontext.gregs; \
|
|
unsigned char *_eip = (unsigned char *)_gregs[REG_EIP]; \
|
|
\
|
|
/* According to the JVM spec, "if the dividend is the negative \
|
|
* integer of largest possible magnitude for the type and the \
|
|
* divisor is -1, then overflow occurs and the result is equal to \
|
|
* the dividend. Despite the overflow, no exception occurs". \
|
|
\
|
|
* We handle this by inspecting the instruction which generated the \
|
|
* signal and advancing ip to point to the following instruction. \
|
|
* As the instructions are variable length it is necessary to do a \
|
|
* little calculation to figure out where the following instruction \
|
|
* actually is. \
|
|
\
|
|
*/ \
|
|
\
|
|
/* Detect a signed division of Integer.MIN_VALUE. */ \
|
|
if (_eip[0] == 0xf7) \
|
|
{ \
|
|
bool _min_value_dividend = false; \
|
|
unsigned char _modrm = _eip[1]; \
|
|
\
|
|
if (((_modrm >> 3) & 7) == 7) /* Signed divide */ \
|
|
{ \
|
|
_min_value_dividend = \
|
|
_gregs[REG_EAX] == (greg_t)0x80000000UL; \
|
|
} \
|
|
\
|
|
if (_min_value_dividend) \
|
|
{ \
|
|
unsigned char _rm = _modrm & 7; \
|
|
_gregs[REG_EDX] = 0; /* the remainder is zero */ \
|
|
switch (_modrm >> 6) \
|
|
{ \
|
|
case 0: /* register indirect */ \
|
|
if (_rm == 5) /* 32-bit displacement */ \
|
|
_eip += 4; \
|
|
if (_rm == 4) /* A SIB byte follows the ModR/M byte */ \
|
|
_eip += 1; \
|
|
break; \
|
|
case 1: /* register indirect + 8-bit displacement */ \
|
|
_eip += 1; \
|
|
if (_rm == 4) /* A SIB byte follows the ModR/M byte */ \
|
|
_eip += 1; \
|
|
break; \
|
|
case 2: /* register indirect + 32-bit displacement */ \
|
|
_eip += 4; \
|
|
if (_rm == 4) /* A SIB byte follows the ModR/M byte */ \
|
|
_eip += 1; \
|
|
break; \
|
|
case 3: \
|
|
break; \
|
|
} \
|
|
_eip += 2; \
|
|
_gregs[REG_EIP] = (greg_t)_eip; \
|
|
return; \
|
|
} \
|
|
} \
|
|
} \
|
|
while (0)
|
|
|
|
/* We use kernel_sigaction here because we're calling the kernel
|
|
directly rather than via glibc. The sigaction structure that the
|
|
syscall uses is a different shape from the one in userland and not
|
|
visible to us in a header file so we define it here. */
|
|
|
|
extern "C"
|
|
{
|
|
struct kernel_sigaction
|
|
{
|
|
void (*k_sa_sigaction)(int,siginfo_t *,void *);
|
|
unsigned long k_sa_flags;
|
|
void (*k_sa_restorer) (void);
|
|
sigset_t k_sa_mask;
|
|
};
|
|
}
|
|
|
|
#define MAKE_THROW_FRAME(_exception)
|
|
|
|
#define RESTORE(name, syscall) RESTORE2 (name, syscall)
|
|
#define RESTORE2(name, syscall) \
|
|
asm \
|
|
( \
|
|
".text\n" \
|
|
".byte 0 # Yes, this really is necessary\n" \
|
|
" .align 16\n" \
|
|
"__" #name ":\n" \
|
|
" movl $" #syscall ", %eax\n" \
|
|
" int $0x80" \
|
|
);
|
|
|
|
/* The return code for realtime-signals. */
|
|
RESTORE (restore_rt, __NR_rt_sigreturn)
|
|
void restore_rt (void) asm ("__restore_rt")
|
|
__attribute__ ((visibility ("hidden")));
|
|
|
|
#define INIT_SEGV \
|
|
do \
|
|
{ \
|
|
struct kernel_sigaction act; \
|
|
act.k_sa_sigaction = _Jv_catch_segv; \
|
|
sigemptyset (&act.k_sa_mask); \
|
|
act.k_sa_flags = SA_SIGINFO|0x4000000; \
|
|
act.k_sa_restorer = restore_rt; \
|
|
syscall (SYS_rt_sigaction, SIGSEGV, &act, NULL, _NSIG / 8); \
|
|
} \
|
|
while (0)
|
|
|
|
#define INIT_FPE \
|
|
do \
|
|
{ \
|
|
struct kernel_sigaction act; \
|
|
act.k_sa_sigaction = _Jv_catch_fpe; \
|
|
sigemptyset (&act.k_sa_mask); \
|
|
act.k_sa_flags = SA_SIGINFO|0x4000000; \
|
|
act.k_sa_restorer = restore_rt; \
|
|
syscall (SYS_rt_sigaction, SIGFPE, &act, NULL, _NSIG / 8); \
|
|
} \
|
|
while (0)
|
|
|
|
/* You might wonder why we use syscall(SYS_sigaction) in INIT_FPE
|
|
* instead of the standard sigaction(). This is necessary because of
|
|
* the shenanigans above where we increment the PC saved in the
|
|
* context and then return. This trick will only work when we are
|
|
* called _directly_ by the kernel, because linuxthreads wraps signal
|
|
* handlers and its wrappers do not copy the sigcontext struct back
|
|
* when returning from a signal handler. If we return from our divide
|
|
* handler to a linuxthreads wrapper, we will lose the PC adjustment
|
|
* we made and return to the faulting instruction again. Using
|
|
* syscall(SYS_sigaction) causes our handler to be called directly
|
|
* by the kernel, bypassing any wrappers.
|
|
|
|
* Also, there may not be any unwind info in the linuxthreads
|
|
* library's signal handlers and so we can't unwind through them
|
|
* anyway. */
|
|
|
|
#endif /* JAVA_SIGNAL_H */
|
|
|
|
#else /* __i386__ */
|
|
|
|
/* This is for the 64-bit subsystem on i386. */
|
|
|
|
#define sigcontext_struct sigcontext
|
|
#include <java-signal-aux.h>
|
|
|
|
#endif /* __i386__ */
|