libjava/include/dwarf2-signal.h

   1 // dwarf2-signal.h - Catch runtime signals and turn them into exceptions.
   2
   3 /* Copyright (C) 2000, 2001  Free Software Foundation
   4
   5    This file is part of libgcj.
   6
   7    Use this file for a target for which the dwarf2 unwinder in libgcc
   8    can unwind through signal handlers.
   9
  10 This software is copyrighted work licensed under the terms of the
  11 Libgcj License.  Please consult the file "LIBGCJ_LICENSE" for
  12 details.  */
  13
  14 #ifndef JAVA_SIGNAL_H
  15 #define JAVA_SIGNAL_H 1
  16
  17 #include <signal.h>
  18 #include <sys/syscall.h>
  19
  20 #define HANDLE_SEGV 1
  21 #undef HANDLE_FPE
  22
  23 #define SIGNAL_HANDLER(_name)   \
  24 static void _Jv_##_name (int, siginfo_t *_sip, void *_p)
  25
  26 class java::lang::Throwable;
  27
  28 // Unwind the stack to the point at which the signal was generated and
  29 // then throw an exception.  With the dwarf2 unwinder we don't usually
  30 // need to do anything, with some minor exceptions.
  31
  32 #ifdef __alpha__
  33 #define MAKE_THROW_FRAME(_exception)                                    \
  34 do                                                                      \
  35 {                                                                       \
  36   /* Alpha either leaves PC pointing at a faulting instruction or the   \
  37    following instruction, depending on the signal.  SEGV always does    \
  38    the former, so we adjust the saved PC to point to the following      \
  39    instruction; this is what the handler in libgcc expects.  */         \
  40   struct sigcontext *_sc = (struct sigcontext *)_p;                     \
  41   _sc->sc_pc += 4;                                                      \
  42 }                                                                       \
  43 while (0)
  44
  45 #elif defined(__ia64__)
  46
  47 #define MAKE_THROW_FRAME(_exception)                                    \
  48 do                                                                      \
  49 {                                                                       \
  50   /* IA-64 either leaves PC pointing at a faulting instruction or the   \
  51    following instruction, depending on the signal.  SEGV always does    \
  52    the former, so we adjust the saved PC to point to the following      \
  53    instruction; this is what the handler in libgcc expects.  */         \
  54   /* Note that we are lying to the unwinder here, which expects the     \
  55    faulting pc, not pc+1.  But we claim the unwind information can't    \
  56    be changed by such a ld or st instruction, so it doesn't matter. */  \
  57   struct sigcontext *_sc = (struct sigcontext *)_p;                     \
  58   _sc->sc_ip++;                                                         \
  59 }                                                                       \
  60 while (0)
  61 #elif defined(__sparc__)
  62 /* We could do the unwind of the signal frame quickly by hand here like
  63    sparc-signal.h does under Solaris, but that makes debugging unwind
  64    failures almost impossible.  */
  65 #if !defined(__arch64__)
  66 #define MAKE_THROW_FRAME(_exception)                                    \
  67 do                                                                      \
  68 {                                                                       \
  69   /* Sparc-32 leaves PC pointing at a faulting instruction              \
  70    always.                                                              \
  71    We advance the PC one instruction past the exception causing PC.     \
  72    This is done because FDEs are found with "context->ra - 1" in the    \
  73    unwinder.                                                            \
  74    Also, the dwarf2 unwind machinery is going to add 8 to the           \
  75    PC it uses on Sparc.  So we adjust the PC here.  We do it here       \
  76    because we run once for such an exception, however the Sparc specific\
  77    unwind can run multiple times for the same exception and it would    \
  78    adjust the PC more than once resulting in a bogus value.  */         \
  79   struct sig_regs {                                                     \
  80     unsigned int psr, pc, npc, y, u_regs[16];                           \
  81   } *regp;                                                              \
  82   unsigned int insn;                                                    \
  83   __asm__ __volatile__("ld [%%i7 + 8], %0" : "=r" (insn));              \
  84   /* mov __NR_sigaction, %g1; Old signal stack layout */                \
  85   if (insn == 0x821020d8)                                               \
  86     regp = (struct sig_regs *) _sip;                                    \
  87   else                                                                  \
  88     /* mov __NR_rt_sigaction, %g1; New signal stack layout */           \
  89     regp = (struct sig_regs *) (_sip + 1);                              \
  90   regp->pc = ((regp->pc + 4) - 8);                                      \
  91 }                                                                       \
  92 while (0)
  93 #else
  94 #define MAKE_THROW_FRAME(_exception)                                    \
  95 do                                                                      \
  96 {                                                                       \
  97   /* Sparc-64 leaves PC pointing at a faulting instruction              \
  98    always.                                                              \
  99    We advance the PC one instruction past the exception causing PC.     \
 100    This is done because FDEs are found with "context->ra - 1" in the    \
 101    unwinder.                                                            \
 102    Also, the dwarf2 unwind machinery is going to add 8 to the           \
 103    PC it uses on Sparc.  So we adjust the PC here.  We do it here       \
 104    because we run once for such an exception, however the Sparc specific\
 105    unwind can run multiple times for the same exception and it would    \
 106    adjust the PC more than once resulting in a bogus value.  */         \
 107   struct pt_regs {                                                      \
 108     unsigned long u_regs[16];                                           \
 109     unsigned long tstate, tpc, tnpc;                                    \
 110     unsigned int y, fprs;                                               \
 111   } *regp = (struct pt_regs *) (_sip + 1);                              \
 112   regp->tpc = ((regp->tpc + 4) - 8);                                    \
 113 }                                                                       \
 114 while (0)
 115 #endif
 116 #else
 117 #define MAKE_THROW_FRAME(_exception)            \
 118 do                                              \
 119 {                                               \
 120   (void)_p;                                     \
 121 }                                               \
 122 while (0)
 123 #endif
 124
 125 #if defined(__sparc__)
 126 #if defined(__arch64__)
 127 extern "C" {
 128     static void __rt_sigreturn_stub(void)
 129     {
 130       __asm__("mov %0, %%g1\n\t"
 131               "ta  0x6d\n\t"
 132               : /* no outputs */
 133               : "i" (__NR_rt_sigreturn));
 134     }
 135     struct kernel_sigaction
 136     {
 137       void (*k_sa_sigaction)(int,siginfo_t *,void *);
 138       unsigned long k_sa_flags;
 139       void (*k_sa_restorer)(void);
 140       sigset_t k_sa_mask;
 141     };
 142 }
 143 #define INIT_SEGV                                               \
 144 do                                                              \
 145   {                                                             \
 146     struct kernel_sigaction act;                                \
 147     unsigned long stub = ((unsigned long)&__rt_sigreturn_stub); \
 148     act.k_sa_sigaction = _Jv_catch_segv;                        \
 149     sigemptyset (&act.k_sa_mask);                               \
 150     act.k_sa_flags = SA_SIGINFO;                                \
 151     act.k_sa_restorer = NULL;                                   \
 152     syscall (SYS_rt_sigaction, SIGSEGV, &act, NULL,             \
 153              stub - 8, _NSIG / 8);                              \
 154   }                                                             \
 155 while (0)
 156
 157 #define INIT_FPE                                                \
 158 do                                                              \
 159   {                                                             \
 160     struct kernel_sigaction act;                                \
 161     unsigned long stub = ((unsigned long)&__rt_sigreturn_stub); \
 162     act.k_sa_sigaction = _Jv_catch_fpe;                         \
 163     sigemptyset (&act.k_sa_mask);                               \
 164     act.k_sa_flags = SA_SIGINFO;                                \
 165     act.k_sa_restorer = NULL;                                   \
 166     syscall (SYS_rt_sigaction, SIGFPE, &act, NULL,              \
 167              stub - 8, _NSIG / 8);                              \
 168   }                                                             \
 169 while (0)
 170 #else /* __arch64__ */
 171
 172 extern "C" {
 173     struct kernel_sigaction
 174     {
 175       void (*k_sa_sigaction)(int,siginfo_t *,void *);
 176       unsigned long k_sa_mask, k_sa_flags;
 177       void (*k_sa_restorer)(void);
 178     };
 179 }
 180
 181 #define INIT_SEGV                                               \
 182 do                                                              \
 183   {                                                             \
 184     struct kernel_sigaction act;                                \
 185     act.k_sa_sigaction = _Jv_catch_segv;                        \
 186     act.k_sa_mask = 0;                                          \
 187     act.k_sa_flags = SA_SIGINFO;                                \
 188     act.k_sa_restorer = NULL;                                   \
 189     syscall (SYS_sigaction, -SIGSEGV, &act, NULL);              \
 190   }                                                             \
 191 while (0)
 192
 193 #define INIT_FPE                                                \
 194 do                                                              \
 195   {                                                             \
 196     struct kernel_sigaction act;                                \
 197     act.k_sa_sigaction = _Jv_catch_fpe;                         \
 198     act.k_sa_mask = 0;                                          \
 199     act.k_sa_flags = SA_SIGINFO;                                \
 200     act.k_sa_restorer = NULL;                                   \
 201     syscall (SYS_sigaction, -SIGFPE, &act, NULL);               \
 202   }                                                             \
 203 while (0)
 204 #endif
 205 #elif !defined(__ia64__)
 206 #define INIT_SEGV                                               \
 207 do                                                              \
 208   {                                                             \
 209     struct sigaction act;                                       \
 210     act.sa_sigaction = _Jv_catch_segv;                          \
 211     sigemptyset (&act.sa_mask);                                 \
 212     act.sa_flags = SA_SIGINFO;                                  \
 213     syscall (SYS_sigaction, SIGSEGV, &act, NULL);               \
 214   }                                                             \
 215 while (0)
 216
 217 #define INIT_FPE                                                \
 218 do                                                              \
 219   {                                                             \
 220     struct sigaction act;                                       \
 221     act.sa_sigaction = _Jv_catch_fpe;                           \
 222     sigemptyset (&act.sa_mask);                                 \
 223     act.sa_flags = SA_SIGINFO;                                  \
 224     syscall (SYS_sigaction, SIGFPE, &act, NULL);                \
 225   }                                                             \
 226 while (0)
 227
 228 /* We use syscall(SYS_sigaction) in INIT_SEGV and INIT_FPE instead of
 229  * sigaction() because on some systems the pthreads wrappers for
 230  * signal handlers are not compiled with unwind information, so it's
 231  * not possible to unwind through them.  This is a problem that will
 232  * go away once all systems have pthreads libraries that are
 233  * compiled with full unwind info.  */
 234
 235 #else  /* __ia64__ */
 236
 237 // On IA64, unwind information is mandatory, so we can unwind
 238 // correctly through glibc frames.  Thus we call the ordinary
 239 // sigaction.
 240
 241 #define INIT_SEGV                                               \
 242 do                                                              \
 243   {                                                             \
 244     struct sigaction act;                                       \
 245     act.sa_sigaction = _Jv_catch_segv;                          \
 246     sigemptyset (&act.sa_mask);                                 \
 247     act.sa_flags = SA_SIGINFO;                                  \
 248     sigaction (SIGSEGV, &act, NULL);                            \
 249   }                                                             \
 250 while (0)
 251
 252 #define INIT_FPE                                                \
 253 do                                                              \
 254   {                                                             \
 255     struct sigaction act;                                       \
 256     act.sa_sigaction = _Jv_catch_fpe;                           \
 257     sigemptyset (&act.sa_mask);                                 \
 258     act.sa_flags = SA_SIGINFO;                                  \
 259     sigaction (SIGFPE, &act, NULL);                             \
 260   }                                                             \
 261 while (0)
 262 #endif /* __ia64__ || __sparc__ */
 263 #endif /* JAVA_SIGNAL_H */