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[pf3gnuchains/gcc-fork.git] / libjava / include / powerpc-signal.h
1 // powerpc-signal.h - Catch runtime signals and turn them into exceptions
2 // on a powerpc based Linux system.
3
4 /* Copyright (C) 2003  Free Software Foundation
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
13 #ifndef JAVA_SIGNAL_H
14 #define JAVA_SIGNAL_H 1
15
16 #include <signal.h>
17 #include <sys/syscall.h>
18
19 #define HANDLE_SEGV 1
20 #undef HANDLE_FPE
21
22 #define SIGNAL_HANDLER(_name)                                           \
23   static void _name (int /* _signal */, struct sigcontext *_sc)
24
25 /* PPC either leaves PC pointing at a faulting instruction or the
26    following instruction, depending on the signal.  SEGV always does
27    the former, so we adjust the saved PC to point to the following
28    instruction. This is what the handler in libgcc expects.  */
29
30 #define MAKE_THROW_FRAME(_exception)                                    \
31 do                                                                      \
32   {                                                                     \
33     _sc->regs->nip += 4;                                                \
34   }                                                                     \
35 while (0)
36   
37 /* For an explanation why we cannot simply use sigaction to
38    install the handlers, see i386-signal.h.  */
39
40 /* We use kernel_old_sigaction here because we're calling the kernel
41    directly rather than via glibc. The sigaction structure that the
42    syscall uses is a different shape from the one in userland and not
43    visible to us in a header file so we define it here.
44    Additionally we want a proper prototype for the handler function
45    with the struct sigcontext pointer passed by the kernel as the 2nd
46    argument, which isn't there in userland headers.
47
48    Note that we explicitly avoid the SA_SIGINFO flag in INIT_SEGV and
49    INIT_FPE below. Using the ucontext pointer passed as 3rd argument
50    of a SA_SIGINFO type handler would need complicated backwards
51    compatibility hacks in MAKE_THROW_FRAME, as the ucontext layout
52    on PPC changed during the 2.5 kernel series.  */
53
54 #ifndef __powerpc64__
55 struct kernel_old_sigaction {
56   void (*k_sa_handler) (int, struct sigcontext *);
57   unsigned long k_sa_mask;
58   unsigned long k_sa_flags;
59   void (*k_sa_restorer) (void);
60 };
61
62 #define INIT_SEGV                                                       \
63 do                                                                      \
64   {                                                                     \
65     struct kernel_old_sigaction kact;                                   \
66     kact.k_sa_handler = catch_segv;                                     \
67     kact.k_sa_mask = 0;                                                 \
68     kact.k_sa_flags = 0;                                                \
69     if (syscall (SYS_sigaction, SIGSEGV, &kact, NULL) != 0)             \
70       __asm__ __volatile__ (".long 0");                                 \
71   }                                                                     \
72 while (0)  
73
74 #define INIT_FPE                                                        \
75 do                                                                      \
76   {                                                                     \
77     struct kernel_old_sigaction kact;                                   \
78     kact.k_sa_handler = catch_fpe;                                      \
79     kact.k_sa_mask = 0;                                                 \
80     kact.k_sa_flags = 0;                                                \
81     if (syscall (SYS_sigaction, SIGFPE, &kact, NULL) != 0)              \
82       __asm__ __volatile__ (".long 0");                                 \
83   }                                                                     \
84 while (0)
85
86 #else /* powerpc64 */
87
88 struct kernel_sigaction
89 {
90   void (*k_sa_handler) (int, struct sigcontext *);
91   unsigned long k_sa_flags;
92   void (*k_sa_restorer)(void);
93   unsigned long k_sa_mask;
94 };
95
96 #define INIT_SEGV                                                       \
97 do                                                                      \
98   {                                                                     \
99     struct kernel_sigaction kact;                                       \
100     memset (&kact, 0, sizeof (kact));                                   \
101     kact.k_sa_handler = catch_segv;                                     \
102     if (syscall (SYS_rt_sigaction, SIGSEGV, &kact, NULL, 8) != 0)       \
103       __asm__ __volatile__ (".long 0");                                 \
104   }                                                                     \
105 while (0)  
106
107 #define INIT_FPE                                                        \
108 do                                                                      \
109   {                                                                     \
110     struct kernel_sigaction kact;                                       \
111     memset (&kact, 0, sizeof (kact));                                   \
112     kact.k_sa_handler = catch_fpe;                                      \
113     if (syscall (SYS_rt_sigaction, SIGFPE, &kact, NULL, 8) != 0)        \
114       __asm__ __volatile__ (".long 0");                                 \
115   }                                                                     \
116 while (0)
117 #endif
118
119 #endif /* JAVA_SIGNAL_H */