| // x86_64-signal.h - Catch runtime signals and turn them into exceptions |
| // on an x86_64 based GNU/Linux system. |
| |
| /* Copyright (C) 2003, 2006, 2007, 2012 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 __x86_64__ |
| |
| #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 *_rip = (unsigned char *)_gregs[REG_RIP]; \ |
| \ |
| /* 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. \ |
| \ |
| */ \ |
| \ |
| bool _is_64_bit = false; \ |
| \ |
| /* Skip 67h address size prefix. */ \ |
| if (_rip[0] == 0x67) \ |
| _rip++; \ |
| \ |
| if ((_rip[0] & 0xf0) == 0x40) /* REX byte present. */ \ |
| { \ |
| unsigned char _rex = _rip[0] & 0x0f; \ |
| _is_64_bit = (_rex & 0x08) != 0; \ |
| _rip++; \ |
| } \ |
| \ |
| /* Detect a signed division of Integer.MIN_VALUE or Long.MIN_VALUE. */ \ |
| if (_rip[0] == 0xf7) \ |
| { \ |
| bool _min_value_dividend = false; \ |
| unsigned char _modrm = _rip[1]; \ |
| \ |
| if (((_modrm >> 3) & 7) == 7) \ |
| { \ |
| if (_is_64_bit) \ |
| _min_value_dividend = \ |
| _gregs[REG_RAX] == (greg_t)0x8000000000000000ULL; \ |
| else \ |
| _min_value_dividend = \ |
| (_gregs[REG_RAX] & 0xffffffff) == (greg_t)0x80000000ULL; \ |
| } \ |
| \ |
| if (_min_value_dividend) \ |
| { \ |
| unsigned char _rm = _modrm & 7; \ |
| _gregs[REG_RDX] = 0; /* the remainder is zero */ \ |
| switch (_modrm >> 6) \ |
| { \ |
| case 0: /* register indirect */ \ |
| if (_rm == 5) /* 32-bit displacement */ \ |
| _rip += 4; \ |
| if (_rm == 4) /* A SIB byte follows the ModR/M byte */ \ |
| _rip += 1; \ |
| break; \ |
| case 1: /* register indirect + 8-bit displacement */ \ |
| _rip += 1; \ |
| if (_rm == 4) /* A SIB byte follows the ModR/M byte */ \ |
| _rip += 1; \ |
| break; \ |
| case 2: /* register indirect + 32-bit displacement */ \ |
| _rip += 4; \ |
| if (_rm == 4) /* A SIB byte follows the ModR/M byte */ \ |
| _rip += 1; \ |
| break; \ |
| case 3: \ |
| break; \ |
| } \ |
| _rip += 2; \ |
| _gregs[REG_RIP] = (greg_t)_rip; \ |
| return; \ |
| } \ |
| } \ |
| } \ |
| while (0) |
| |
| 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" \ |
| " movq $" #syscall ", %rax\n" \ |
| " syscall\n" \ |
| ); |
| |
| /* 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. */ |
| |
| #endif /* JAVA_SIGNAL_H */ |
| |
| #else /* __x86_64__ */ |
| |
| /* This is for the 32-bit subsystem on x86-64. */ |
| |
| #define sigcontext_struct sigcontext |
| #include <java-signal-aux.h> |
| |
| #endif /* __x86_64__ */ |