]>
Commit | Line | Data |
---|---|---|
4e1fff64 | 1 | // x86_64-signal.h - Catch runtime signals and turn them into exceptions |
2 | // on an x86_64 based GNU/Linux system. | |
3 | ||
71e45bc2 | 4 | /* Copyright (C) 2003, 2006, 2007, 2012 Free Software Foundation |
4e1fff64 | 5 | |
6 | This file is part of libgcj. | |
7 | ||
8 | This software is copyrighted work licensed under the terms of the | |
9 | Libgcj License. Please consult the file "LIBGCJ_LICENSE" for | |
10 | details. */ | |
11 | ||
12 | ||
a4fe931d | 13 | #ifdef __x86_64__ |
14 | ||
4e1fff64 | 15 | #ifndef JAVA_SIGNAL_H |
16 | #define JAVA_SIGNAL_H 1 | |
17 | ||
18 | #include <signal.h> | |
19 | #include <sys/syscall.h> | |
20 | ||
21 | #define HANDLE_SEGV 1 | |
70f661cc | 22 | #define HANDLE_FPE 1 |
23 | ||
24 | #define SIGNAL_HANDLER(_name) \ | |
25 | static void _Jv_##_name (int, siginfo_t *, \ | |
26 | void *_p __attribute__ ((__unused__))) | |
27 | ||
28 | #define HANDLE_DIVIDE_OVERFLOW \ | |
29 | do \ | |
30 | { \ | |
31 | struct ucontext *_uc = (struct ucontext *)_p; \ | |
a1fefa1d | 32 | gregset_t &_gregs = _uc->uc_mcontext.gregs; \ |
33 | unsigned char *_rip = (unsigned char *)_gregs[REG_RIP]; \ | |
70f661cc | 34 | \ |
35 | /* According to the JVM spec, "if the dividend is the negative \ | |
36 | * integer of largest possible magnitude for the type and the \ | |
37 | * divisor is -1, then overflow occurs and the result is equal to \ | |
38 | * the dividend. Despite the overflow, no exception occurs". \ | |
39 | \ | |
40 | * We handle this by inspecting the instruction which generated the \ | |
41 | * signal and advancing ip to point to the following instruction. \ | |
42 | * As the instructions are variable length it is necessary to do a \ | |
43 | * little calculation to figure out where the following instruction \ | |
44 | * actually is. \ | |
45 | \ | |
46 | */ \ | |
47 | \ | |
48 | bool _is_64_bit = false; \ | |
49 | \ | |
b64804e9 | 50 | /* Skip 67h address size prefix. */ \ |
0e02c032 | 51 | if (_rip[0] == 0x67) \ |
aea51dc8 | 52 | _rip++; \ |
53 | \ | |
70f661cc | 54 | if ((_rip[0] & 0xf0) == 0x40) /* REX byte present. */ \ |
55 | { \ | |
56 | unsigned char _rex = _rip[0] & 0x0f; \ | |
57 | _is_64_bit = (_rex & 0x08) != 0; \ | |
58 | _rip++; \ | |
59 | } \ | |
60 | \ | |
61 | /* Detect a signed division of Integer.MIN_VALUE or Long.MIN_VALUE. */ \ | |
62 | if (_rip[0] == 0xf7) \ | |
63 | { \ | |
64 | bool _min_value_dividend = false; \ | |
65 | unsigned char _modrm = _rip[1]; \ | |
66 | \ | |
67 | if (((_modrm >> 3) & 7) == 7) \ | |
68 | { \ | |
69 | if (_is_64_bit) \ | |
a1fefa1d | 70 | _min_value_dividend = \ |
aea51dc8 | 71 | _gregs[REG_RAX] == (greg_t)0x8000000000000000ULL; \ |
70f661cc | 72 | else \ |
a1fefa1d | 73 | _min_value_dividend = \ |
aea51dc8 | 74 | (_gregs[REG_RAX] & 0xffffffff) == (greg_t)0x80000000ULL; \ |
70f661cc | 75 | } \ |
76 | \ | |
77 | if (_min_value_dividend) \ | |
78 | { \ | |
79 | unsigned char _rm = _modrm & 7; \ | |
a1fefa1d | 80 | _gregs[REG_RDX] = 0; /* the remainder is zero */ \ |
70f661cc | 81 | switch (_modrm >> 6) \ |
82 | { \ | |
83 | case 0: /* register indirect */ \ | |
84 | if (_rm == 5) /* 32-bit displacement */ \ | |
85 | _rip += 4; \ | |
86 | if (_rm == 4) /* A SIB byte follows the ModR/M byte */ \ | |
87 | _rip += 1; \ | |
88 | break; \ | |
89 | case 1: /* register indirect + 8-bit displacement */ \ | |
90 | _rip += 1; \ | |
91 | if (_rm == 4) /* A SIB byte follows the ModR/M byte */ \ | |
92 | _rip += 1; \ | |
93 | break; \ | |
94 | case 2: /* register indirect + 32-bit displacement */ \ | |
95 | _rip += 4; \ | |
96 | if (_rm == 4) /* A SIB byte follows the ModR/M byte */ \ | |
97 | _rip += 1; \ | |
98 | break; \ | |
99 | case 3: \ | |
100 | break; \ | |
101 | } \ | |
102 | _rip += 2; \ | |
a1fefa1d | 103 | _gregs[REG_RIP] = (greg_t)_rip; \ |
70f661cc | 104 | return; \ |
105 | } \ | |
106 | } \ | |
107 | } \ | |
108 | while (0) | |
4e1fff64 | 109 | |
110 | extern "C" | |
111 | { | |
112 | struct kernel_sigaction | |
113 | { | |
114 | void (*k_sa_sigaction)(int,siginfo_t *,void *); | |
115 | unsigned long k_sa_flags; | |
116 | void (*k_sa_restorer) (void); | |
117 | sigset_t k_sa_mask; | |
118 | }; | |
119 | } | |
120 | ||
15c73eb7 | 121 | #define MAKE_THROW_FRAME(_exception) |
4e1fff64 | 122 | |
123 | #define RESTORE(name, syscall) RESTORE2 (name, syscall) | |
124 | #define RESTORE2(name, syscall) \ | |
125 | asm \ | |
126 | ( \ | |
ccc173db | 127 | ".text\n" \ |
4e1fff64 | 128 | ".byte 0 # Yes, this really is necessary\n" \ |
129 | ".align 16\n" \ | |
130 | "__" #name ":\n" \ | |
131 | " movq $" #syscall ", %rax\n" \ | |
132 | " syscall\n" \ | |
133 | ); | |
134 | ||
135 | /* The return code for realtime-signals. */ | |
136 | RESTORE (restore_rt, __NR_rt_sigreturn) | |
fdcfb10d | 137 | void restore_rt (void) asm ("__restore_rt") |
138 | __attribute__ ((visibility ("hidden"))); | |
4e1fff64 | 139 | |
140 | #define INIT_SEGV \ | |
141 | do \ | |
142 | { \ | |
4e1fff64 | 143 | struct kernel_sigaction act; \ |
144 | act.k_sa_sigaction = _Jv_catch_segv; \ | |
145 | sigemptyset (&act.k_sa_mask); \ | |
146 | act.k_sa_flags = SA_SIGINFO|0x4000000; \ | |
147 | act.k_sa_restorer = restore_rt; \ | |
148 | syscall (SYS_rt_sigaction, SIGSEGV, &act, NULL, _NSIG / 8); \ | |
149 | } \ | |
150 | while (0) | |
151 | ||
70f661cc | 152 | #define INIT_FPE \ |
153 | do \ | |
154 | { \ | |
155 | struct kernel_sigaction act; \ | |
156 | act.k_sa_sigaction = _Jv_catch_fpe; \ | |
157 | sigemptyset (&act.k_sa_mask); \ | |
158 | act.k_sa_flags = SA_SIGINFO|0x4000000; \ | |
159 | act.k_sa_restorer = restore_rt; \ | |
160 | syscall (SYS_rt_sigaction, SIGFPE, &act, NULL, _NSIG / 8); \ | |
161 | } \ | |
162 | while (0) | |
163 | ||
164 | /* You might wonder why we use syscall(SYS_sigaction) in INIT_FPE | |
165 | * instead of the standard sigaction(). This is necessary because of | |
166 | * the shenanigans above where we increment the PC saved in the | |
167 | * context and then return. This trick will only work when we are | |
168 | * called _directly_ by the kernel, because linuxthreads wraps signal | |
169 | * handlers and its wrappers do not copy the sigcontext struct back | |
170 | * when returning from a signal handler. If we return from our divide | |
171 | * handler to a linuxthreads wrapper, we will lose the PC adjustment | |
172 | * we made and return to the faulting instruction again. Using | |
173 | * syscall(SYS_sigaction) causes our handler to be called directly | |
174 | * by the kernel, bypassing any wrappers. */ | |
4e1fff64 | 175 | |
a4fe931d | 176 | #endif /* JAVA_SIGNAL_H */ |
d8a53361 | 177 | |
a4fe931d | 178 | #else /* __x86_64__ */ |
d8a53361 | 179 | |
42b36080 | 180 | /* This is for the 32-bit subsystem on x86-64. */ |
d8a53361 | 181 | |
a4fe931d | 182 | #define sigcontext_struct sigcontext |
183 | #include <java-signal-aux.h> | |
d8a53361 | 184 | |
185 | #endif /* __x86_64__ */ |