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// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
#include <errno.h>
#include <signal.h>
#include <unistd.h>
#if defined(__i386__) || defined(__x86_64__)
#include <cpuid.h>
#endif
#ifdef __linux__
#include <syscall.h>
#endif
#include "config.h"
#include "runtime.h"
#include "arch.h"
#include "array.h"
int32
runtime_atoi(const byte *p, intgo len)
{
int32 n;
n = 0;
while(len > 0 && '0' <= *p && *p <= '9') {
n = n*10 + *p++ - '0';
len--;
}
return n;
}
// A random number from the GNU/Linux auxv array.
static uint32 randomNumber;
// Set the random number from Go code.
void
setRandomNumber(uint32 r)
{
randomNumber = r;
}
#if defined(__i386__) || defined(__x86_64__) || defined (__s390__) || defined (__s390x__)
// When cputicks is just asm instructions, skip the split stack
// prologue for speed.
int64 runtime_cputicks(void) __attribute__((no_split_stack));
#endif
// Whether the processor supports SSE2.
#if defined (__i386__)
static _Bool hasSSE2;
// Force appropriate CPU level so that we can call the lfence/mfence
// builtins.
#pragma GCC push_options
#pragma GCC target("sse2")
#elif defined(__x86_64__)
#define hasSSE2 true
#endif
#if defined(__i386__) || defined(__x86_64__)
// Whether to use lfence, as opposed to mfence.
// Set based on cpuid.
static _Bool lfenceBeforeRdtsc;
#endif // defined(__i386__) || defined(__x86_64__)
int64
runtime_cputicks(void)
{
#if defined(__i386__) || defined(__x86_64__)
if (hasSSE2) {
if (lfenceBeforeRdtsc) {
__builtin_ia32_lfence();
} else {
__builtin_ia32_mfence();
}
}
return __builtin_ia32_rdtsc();
#elif defined (__s390__) || defined (__s390x__)
uint64 clock = 0;
/* stckf may not write the return variable in case of a clock error, so make
it read-write to prevent that the initialisation is optimised out.
Note: Targets below z9-109 will crash when executing store clock fast, i.e.
we don't support Go for machines older than that. */
asm volatile(".insn s,0xb27c0000,%0" /* stckf */ : "+Q" (clock) : : "cc" );
return (int64)clock;
#else
// Currently cputicks() is used in blocking profiler and to seed runtime·fastrand().
// runtime·nanotime() is a poor approximation of CPU ticks that is enough for the profiler.
// randomNumber provides better seeding of fastrand.
return runtime_nanotime1() + randomNumber;
#endif
}
#if defined(__i386__)
#pragma GCC pop_options
#endif
void
runtime_signalstack(byte *p, uintptr n)
{
stack_t st;
st.ss_sp = p;
st.ss_size = n;
st.ss_flags = 0;
if(p == nil)
st.ss_flags = SS_DISABLE;
if(sigaltstack(&st, nil) < 0)
abort();
}
int32 go_open(char *, int32, int32)
__asm__ (GOSYM_PREFIX "runtime.open");
int32
go_open(char *name, int32 mode, int32 perm)
{
return runtime_open(name, mode, perm);
}
int32 go_read(int32, void *, int32)
__asm__ (GOSYM_PREFIX "runtime.read");
int32
go_read(int32 fd, void *p, int32 n)
{
ssize_t r = runtime_read(fd, p, n);
if (r < 0)
r = - errno;
return (int32)r;
}
int32 go_write1(uintptr, void *, int32)
__asm__ (GOSYM_PREFIX "runtime.write1");
int32
go_write1(uintptr fd, void *p, int32 n)
{
ssize_t r = runtime_write(fd, p, n);
if (r < 0)
r = - errno;
return (int32)r;
}
int32 go_closefd(int32)
__asm__ (GOSYM_PREFIX "runtime.closefd");
int32
go_closefd(int32 fd)
{
return runtime_close(fd);
}
intgo go_errno(void)
__asm__ (GOSYM_PREFIX "runtime.errno");
intgo
go_errno()
{
return (intgo)errno;
}
uintptr getEnd(void)
__asm__ (GOSYM_PREFIX "runtime.getEnd");
uintptr
getEnd()
{
#ifdef _AIX
// mmap adresses range start at 0x30000000 on AIX for 32 bits processes
uintptr end = 0x30000000U;
#else
uintptr end = 0;
uintptr *pend;
pend = &__go_end;
if (pend != nil) {
end = *pend;
}
#endif
return end;
}
// Return an address that is before the read-only data section.
// Unfortunately there is no standard symbol for this so we use a text
// address.
uintptr getText(void)
__asm__ (GOSYM_PREFIX "runtime.getText");
extern void main_main(void*)
__asm__(GOSYM_PREFIX "main.main");
uintptr
getText(void)
{
return (uintptr)(const void *)(main_main);
}
// Return the end of the text segment, assumed to come after the
// read-only data section.
uintptr getEtext(void)
__asm__ (GOSYM_PREFIX "runtime.getEtext");
uintptr
getEtext(void)
{
const void *p;
p = __data_start;
if (p == nil)
p = __etext;
if (p == nil)
p = _etext;
return (uintptr)(p);
}
// Return the start of the BSS section.
uintptr getBSS(void)
__asm__ (GOSYM_PREFIX "runtime.getBSS");
uintptr
getBSS(void)
{
const void *p;
p = __edata;
if (p == NULL)
p = _edata;
if (p == NULL)
p = __bss_start;
return (uintptr)(p);
}
// CPU-specific initialization.
// Fetch CPUID info on x86.
void
runtime_cpuinit()
{
#if defined(__i386__) || defined(__x86_64__)
unsigned int eax, ebx, ecx, edx;
if (__get_cpuid(0, &eax, &ebx, &ecx, &edx)) {
if (eax != 0
&& ebx == 0x756E6547 // "Genu"
&& edx == 0x49656E69 // "ineI"
&& ecx == 0x6C65746E) { // "ntel"
lfenceBeforeRdtsc = true;
}
}
if (__get_cpuid(1, &eax, &ebx, &ecx, &edx)) {
#if defined(__i386__)
if ((edx & bit_SSE2) != 0) {
hasSSE2 = true;
}
#endif
}
#if defined(HAVE_AS_X86_AES)
setSupportAES(true);
#endif
#endif
}
// A publication barrier: a store/store barrier.
void publicationBarrier(void)
__asm__ (GOSYM_PREFIX "runtime.publicationBarrier");
void
publicationBarrier()
{
__atomic_thread_fence(__ATOMIC_RELEASE);
}
#ifdef __linux__
/* Currently sbrk0 is only called on GNU/Linux. */
uintptr sbrk0(void)
__asm__ (GOSYM_PREFIX "runtime.sbrk0");
uintptr
sbrk0()
{
return syscall(SYS_brk, (uintptr)(0));
}
#endif /* __linux__ */
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