Add new test case
[official-gcc.git] / libjava / include / i386-signal.h
blobc2409b0e30101b51624d7ee4d2c8aec5eb9ebdda
1 // i386-signal.h - Catch runtime signals and turn them into exceptions
2 // on an i386 based Linux system.
4 /* Copyright (C) 1998, 1999, 2001, 2002, 2006, 2007, 2011
5 Free Software Foundation
7 This file is part of libgcj.
9 This software is copyrighted work licensed under the terms of the
10 Libgcj License. Please consult the file "LIBGCJ_LICENSE" for
11 details. */
14 #ifdef __i386__
16 #ifndef JAVA_SIGNAL_H
17 #define JAVA_SIGNAL_H 1
19 #include <signal.h>
20 #include <sys/syscall.h>
22 #define HANDLE_SEGV 1
23 #define HANDLE_FPE 1
25 #define SIGNAL_HANDLER(_name) \
26 static void _Jv_##_name (int, siginfo_t *, \
27 void *_p __attribute__ ((__unused__)))
29 #define HANDLE_DIVIDE_OVERFLOW \
30 do \
31 { \
32 struct ucontext *_uc = (struct ucontext *)_p; \
33 gregset_t &_gregs = _uc->uc_mcontext.gregs; \
34 unsigned char *_eip = (unsigned char *)_gregs[REG_EIP]; \
36 /* According to the JVM spec, "if the dividend is the negative \
37 * integer of largest possible magnitude for the type and the \
38 * divisor is -1, then overflow occurs and the result is equal to \
39 * the dividend. Despite the overflow, no exception occurs". \
41 * We handle this by inspecting the instruction which generated the \
42 * signal and advancing ip to point to the following instruction. \
43 * As the instructions are variable length it is necessary to do a \
44 * little calculation to figure out where the following instruction \
45 * actually is. \
47 */ \
49 /* Detect a signed division of Integer.MIN_VALUE. */ \
50 if (_eip[0] == 0xf7) \
51 { \
52 bool _min_value_dividend = false; \
53 unsigned char _modrm = _eip[1]; \
55 if (((_modrm >> 3) & 7) == 7) /* Signed divide */ \
56 { \
57 _min_value_dividend = \
58 _gregs[REG_EAX] == (greg_t)0x80000000UL; \
59 } \
61 if (_min_value_dividend) \
62 { \
63 unsigned char _rm = _modrm & 7; \
64 _gregs[REG_EDX] = 0; /* the remainder is zero */ \
65 switch (_modrm >> 6) \
66 { \
67 case 0: /* register indirect */ \
68 if (_rm == 5) /* 32-bit displacement */ \
69 _eip += 4; \
70 if (_rm == 4) /* A SIB byte follows the ModR/M byte */ \
71 _eip += 1; \
72 break; \
73 case 1: /* register indirect + 8-bit displacement */ \
74 _eip += 1; \
75 if (_rm == 4) /* A SIB byte follows the ModR/M byte */ \
76 _eip += 1; \
77 break; \
78 case 2: /* register indirect + 32-bit displacement */ \
79 _eip += 4; \
80 if (_rm == 4) /* A SIB byte follows the ModR/M byte */ \
81 _eip += 1; \
82 break; \
83 case 3: \
84 break; \
85 } \
86 _eip += 2; \
87 _gregs[REG_EIP] = (greg_t)_eip; \
88 return; \
89 } \
90 } \
91 } \
92 while (0)
94 /* We use kernel_sigaction here because we're calling the kernel
95 directly rather than via glibc. The sigaction structure that the
96 syscall uses is a different shape from the one in userland and not
97 visible to us in a header file so we define it here. */
99 extern "C"
101 struct kernel_sigaction
103 void (*k_sa_sigaction)(int,siginfo_t *,void *);
104 unsigned long k_sa_flags;
105 void (*k_sa_restorer) (void);
106 sigset_t k_sa_mask;
110 #define MAKE_THROW_FRAME(_exception)
112 #define RESTORE(name, syscall) RESTORE2 (name, syscall)
113 #define RESTORE2(name, syscall) \
114 asm \
116 ".text\n" \
117 ".byte 0 # Yes, this really is necessary\n" \
118 " .align 16\n" \
119 "__" #name ":\n" \
120 " movl $" #syscall ", %eax\n" \
121 " int $0x80" \
124 /* The return code for realtime-signals. */
125 RESTORE (restore_rt, __NR_rt_sigreturn)
126 void restore_rt (void) asm ("__restore_rt")
127 __attribute__ ((visibility ("hidden")));
129 #define INIT_SEGV \
130 do \
132 struct kernel_sigaction act; \
133 act.k_sa_sigaction = _Jv_catch_segv; \
134 sigemptyset (&act.k_sa_mask); \
135 act.k_sa_flags = SA_SIGINFO|0x4000000; \
136 act.k_sa_restorer = restore_rt; \
137 syscall (SYS_rt_sigaction, SIGSEGV, &act, NULL, _NSIG / 8); \
139 while (0)
141 #define INIT_FPE \
142 do \
144 struct kernel_sigaction act; \
145 act.k_sa_sigaction = _Jv_catch_fpe; \
146 sigemptyset (&act.k_sa_mask); \
147 act.k_sa_flags = SA_SIGINFO|0x4000000; \
148 act.k_sa_restorer = restore_rt; \
149 syscall (SYS_rt_sigaction, SIGFPE, &act, NULL, _NSIG / 8); \
151 while (0)
153 /* You might wonder why we use syscall(SYS_sigaction) in INIT_FPE
154 * instead of the standard sigaction(). This is necessary because of
155 * the shenanigans above where we increment the PC saved in the
156 * context and then return. This trick will only work when we are
157 * called _directly_ by the kernel, because linuxthreads wraps signal
158 * handlers and its wrappers do not copy the sigcontext struct back
159 * when returning from a signal handler. If we return from our divide
160 * handler to a linuxthreads wrapper, we will lose the PC adjustment
161 * we made and return to the faulting instruction again. Using
162 * syscall(SYS_sigaction) causes our handler to be called directly
163 * by the kernel, bypassing any wrappers.
165 * Also, there may not be any unwind info in the linuxthreads
166 * library's signal handlers and so we can't unwind through them
167 * anyway. */
169 #endif /* JAVA_SIGNAL_H */
171 #else /* __i386__ */
173 /* This is for the 64-bit subsystem on i386. */
175 #define sigcontext_struct sigcontext
176 #include <java-signal-aux.h>
178 #endif /* __i386__ */