libgo/runtime/runtime_c.c

   1 // Copyright 2009 The Go Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style
   3 // license that can be found in the LICENSE file.
   4
   5 #include <errno.h>
   6 #include <signal.h>
   7 #include <unistd.h>
   8
   9 #if defined(__i386__) || defined(__x86_64__)
  10 #include <cpuid.h>
  11 #endif
  12
  13 #ifdef __linux__
  14 #include <syscall.h>
  15 #endif
  16
  17 #include "config.h"
  18
  19 #include "runtime.h"
  20 #include "arch.h"
  21 #include "array.h"
  22
  23 int32
  24 runtime_atoi(const byte *p, intgo len)
  25 {
  26         int32 n;
  27
  28         n = 0;
  29         while(len > 0 && '0' <= *p && *p <= '9') {
  30                 n = n*10 + *p++ - '0';
  31                 len--;
  32         }
  33         return n;
  34 }
  35
  36 int64
  37 runtime_cputicks(void)
  38 {
  39 #if defined(__386__) || defined(__x86_64__)
  40   uint32 low, high;
  41   asm("rdtsc" : "=a" (low), "=d" (high));
  42   return (int64)(((uint64)high << 32) | (uint64)low);
  43 #elif defined (__s390__) || defined (__s390x__)
  44   uint64 clock = 0;
  45   /* stckf may not write the return variable in case of a clock error, so make
  46      it read-write to prevent that the initialisation is optimised out.
  47      Note: Targets below z9-109 will crash when executing store clock fast, i.e.
  48      we don't support Go for machines older than that.  */
  49   asm volatile(".insn s,0xb27c0000,%0" /* stckf */ : "+Q" (clock) : : "cc" );
  50   return (int64)clock;
  51 #else
  52   // Currently cputicks() is used in blocking profiler and to seed runtime·fastrand().
  53   // runtime·nanotime() is a poor approximation of CPU ticks that is enough for the profiler.
  54   // TODO: need more entropy to better seed fastrand.
  55   return runtime_nanotime();
  56 #endif
  57 }
  58
  59 void
  60 runtime_signalstack(byte *p, uintptr n)
  61 {
  62         stack_t st;
  63
  64         st.ss_sp = p;
  65         st.ss_size = n;
  66         st.ss_flags = 0;
  67         if(p == nil)
  68                 st.ss_flags = SS_DISABLE;
  69         if(sigaltstack(&st, nil) < 0)
  70                 *(int *)0xf1 = 0xf1;
  71 }
  72
  73 int32 go_open(char *, int32, int32)
  74   __asm__ (GOSYM_PREFIX "runtime.open");
  75
  76 int32
  77 go_open(char *name, int32 mode, int32 perm)
  78 {
  79   return runtime_open(name, mode, perm);
  80 }
  81
  82 int32 go_read(int32, void *, int32)
  83   __asm__ (GOSYM_PREFIX "runtime.read");
  84
  85 int32
  86 go_read(int32 fd, void *p, int32 n)
  87 {
  88   return runtime_read(fd, p, n);
  89 }
  90
  91 int32 go_write(uintptr, void *, int32)
  92   __asm__ (GOSYM_PREFIX "runtime.write");
  93
  94 int32
  95 go_write(uintptr fd, void *p, int32 n)
  96 {
  97   return runtime_write(fd, p, n);
  98 }
  99
 100 int32 go_closefd(int32)
 101   __asm__ (GOSYM_PREFIX "runtime.closefd");
 102
 103 int32
 104 go_closefd(int32 fd)
 105 {
 106   return runtime_close(fd);
 107 }
 108
 109 intgo go_errno(void)
 110   __asm__ (GOSYM_PREFIX "runtime.errno");
 111
 112 intgo
 113 go_errno()
 114 {
 115   return (intgo)errno;
 116 }
 117
 118 uintptr getEnd(void)
 119   __asm__ (GOSYM_PREFIX "runtime.getEnd");
 120
 121 uintptr
 122 getEnd()
 123 {
 124 #ifdef _AIX
 125   // mmap adresses range start at 0x30000000 on AIX for 32 bits processes
 126   uintptr end = 0x30000000U;
 127 #else
 128   uintptr end = 0;
 129   uintptr *pend;
 130
 131   pend = &__go_end;
 132   if (pend != nil) {
 133     end = *pend;
 134   }
 135 #endif
 136
 137   return end;
 138 }
 139
 140 // CPU-specific initialization.
 141 // Fetch CPUID info on x86.
 142
 143 void
 144 runtime_cpuinit()
 145 {
 146 #if defined(__i386__) || defined(__x86_64__)
 147         unsigned int eax, ebx, ecx, edx;
 148
 149         if (__get_cpuid(1, &eax, &ebx, &ecx, &edx)) {
 150                 setCpuidECX(ecx);
 151         }
 152
 153 #if defined(HAVE_AS_X86_AES)
 154         setSupportAES(true);
 155 #endif
 156 #endif
 157 }
 158
 159 // A publication barrier: a store/store barrier.
 160
 161 void publicationBarrier(void)
 162   __asm__ (GOSYM_PREFIX "runtime.publicationBarrier");
 163
 164 void
 165 publicationBarrier()
 166 {
 167   __atomic_thread_fence(__ATOMIC_RELEASE);
 168 }
 169
 170 #ifdef __linux__
 171
 172 /* Currently sbrk0 is only called on GNU/Linux.  */
 173
 174 uintptr sbrk0(void)
 175   __asm__ (GOSYM_PREFIX "runtime.sbrk0");
 176
 177 uintptr
 178 sbrk0()
 179 {
 180   return syscall(SYS_brk, (uintptr)(0));
 181 }
 182
 183 #endif /* __linux__ */