os_netbsd.go

     1  // Copyright 2014 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  package runtime
     6  
     7  import (
     8  	"internal/abi"
     9  	"internal/goarch"
    10  	"runtime/internal/atomic"
    11  	"unsafe"
    12  )
    13  
    14  const (
    15  	_SS_DISABLE  = 4
    16  	_SIG_BLOCK   = 1
    17  	_SIG_UNBLOCK = 2
    18  	_SIG_SETMASK = 3
    19  	_NSIG        = 33
    20  	_SI_USER     = 0
    21  
    22  	// From NetBSD's <sys/ucontext.h>
    23  	_UC_SIGMASK = 0x01
    24  	_UC_CPU     = 0x04
    25  
    26  	// From <sys/lwp.h>
    27  	_LWP_DETACHED = 0x00000040
    28  )
    29  
    30  type mOS struct {
    31  	waitsemacount uint32
    32  }
    33  
    34  //go:noescape
    35  func setitimer(mode int32, new, old *itimerval)
    36  
    37  //go:noescape
    38  func sigaction(sig uint32, new, old *sigactiont)
    39  
    40  //go:noescape
    41  func sigaltstack(new, old *stackt)
    42  
    43  //go:noescape
    44  func sigprocmask(how int32, new, old *sigset)
    45  
    46  //go:noescape
    47  func sysctl(mib *uint32, miblen uint32, out *byte, size *uintptr, dst *byte, ndst uintptr) int32
    48  
    49  func lwp_tramp()
    50  
    51  func raiseproc(sig uint32)
    52  
    53  func lwp_kill(tid int32, sig int)
    54  
    55  //go:noescape
    56  func getcontext(ctxt unsafe.Pointer)
    57  
    58  //go:noescape
    59  func lwp_create(ctxt unsafe.Pointer, flags uintptr, lwpid unsafe.Pointer) int32
    60  
    61  //go:noescape
    62  func lwp_park(clockid, flags int32, ts *timespec, unpark int32, hint, unparkhint unsafe.Pointer) int32
    63  
    64  //go:noescape
    65  func lwp_unpark(lwp int32, hint unsafe.Pointer) int32
    66  
    67  func lwp_self() int32
    68  
    69  func osyield()
    70  
    71  //go:nosplit
    72  func osyield_no_g() {
    73  	osyield()
    74  }
    75  
    76  func kqueue() int32
    77  
    78  //go:noescape
    79  func kevent(kq int32, ch *keventt, nch int32, ev *keventt, nev int32, ts *timespec) int32
    80  
    81  func pipe2(flags int32) (r, w int32, errno int32)
    82  func closeonexec(fd int32)
    83  
    84  const (
    85  	_ESRCH     = 3
    86  	_ETIMEDOUT = 60
    87  
    88  	// From NetBSD's <sys/time.h>
    89  	_CLOCK_REALTIME  = 0
    90  	_CLOCK_VIRTUAL   = 1
    91  	_CLOCK_PROF      = 2
    92  	_CLOCK_MONOTONIC = 3
    93  
    94  	_TIMER_RELTIME = 0
    95  	_TIMER_ABSTIME = 1
    96  )
    97  
    98  var sigset_all = sigset{[4]uint32{^uint32(0), ^uint32(0), ^uint32(0), ^uint32(0)}}
    99  
   100  // From NetBSD's <sys/sysctl.h>
   101  const (
   102  	_CTL_KERN   = 1
   103  	_KERN_OSREV = 3
   104  
   105  	_CTL_HW        = 6
   106  	_HW_NCPU       = 3
   107  	_HW_PAGESIZE   = 7
   108  	_HW_NCPUONLINE = 16
   109  )
   110  
   111  func sysctlInt(mib []uint32) (int32, bool) {
   112  	var out int32
   113  	nout := unsafe.Sizeof(out)
   114  	ret := sysctl(&mib[0], uint32(len(mib)), (*byte)(unsafe.Pointer(&out)), &nout, nil, 0)
   115  	if ret < 0 {
   116  		return 0, false
   117  	}
   118  	return out, true
   119  }
   120  
   121  func getncpu() int32 {
   122  	if n, ok := sysctlInt([]uint32{_CTL_HW, _HW_NCPUONLINE}); ok {
   123  		return int32(n)
   124  	}
   125  	if n, ok := sysctlInt([]uint32{_CTL_HW, _HW_NCPU}); ok {
   126  		return int32(n)
   127  	}
   128  	return 1
   129  }
   130  
   131  func getPageSize() uintptr {
   132  	mib := [2]uint32{_CTL_HW, _HW_PAGESIZE}
   133  	out := uint32(0)
   134  	nout := unsafe.Sizeof(out)
   135  	ret := sysctl(&mib[0], 2, (*byte)(unsafe.Pointer(&out)), &nout, nil, 0)
   136  	if ret >= 0 {
   137  		return uintptr(out)
   138  	}
   139  	return 0
   140  }
   141  
   142  func getOSRev() int {
   143  	if osrev, ok := sysctlInt([]uint32{_CTL_KERN, _KERN_OSREV}); ok {
   144  		return int(osrev)
   145  	}
   146  	return 0
   147  }
   148  
   149  //go:nosplit
   150  func semacreate(mp *m) {
   151  }
   152  
   153  //go:nosplit
   154  func semasleep(ns int64) int32 {
   155  	_g_ := getg()
   156  	var deadline int64
   157  	if ns >= 0 {
   158  		deadline = nanotime() + ns
   159  	}
   160  
   161  	for {
   162  		v := atomic.Load(&_g_.m.waitsemacount)
   163  		if v > 0 {
   164  			if atomic.Cas(&_g_.m.waitsemacount, v, v-1) {
   165  				return 0 // semaphore acquired
   166  			}
   167  			continue
   168  		}
   169  
   170  		// Sleep until unparked by semawakeup or timeout.
   171  		var tsp *timespec
   172  		var ts timespec
   173  		if ns >= 0 {
   174  			wait := deadline - nanotime()
   175  			if wait <= 0 {
   176  				return -1
   177  			}
   178  			ts.setNsec(wait)
   179  			tsp = &ts
   180  		}
   181  		ret := lwp_park(_CLOCK_MONOTONIC, _TIMER_RELTIME, tsp, 0, unsafe.Pointer(&_g_.m.waitsemacount), nil)
   182  		if ret == _ETIMEDOUT {
   183  			return -1
   184  		}
   185  	}
   186  }
   187  
   188  //go:nosplit
   189  func semawakeup(mp *m) {
   190  	atomic.Xadd(&mp.waitsemacount, 1)
   191  	// From NetBSD's _lwp_unpark(2) manual:
   192  	// "If the target LWP is not currently waiting, it will return
   193  	// immediately upon the next call to _lwp_park()."
   194  	ret := lwp_unpark(int32(mp.procid), unsafe.Pointer(&mp.waitsemacount))
   195  	if ret != 0 && ret != _ESRCH {
   196  		// semawakeup can be called on signal stack.
   197  		systemstack(func() {
   198  			print("thrwakeup addr=", &mp.waitsemacount, " sem=", mp.waitsemacount, " ret=", ret, "\n")
   199  		})
   200  	}
   201  }
   202  
   203  // May run with m.p==nil, so write barriers are not allowed.
   204  //
   205  //go:nowritebarrier
   206  func newosproc(mp *m) {
   207  	stk := unsafe.Pointer(mp.g0.stack.hi)
   208  	if false {
   209  		print("newosproc stk=", stk, " m=", mp, " g=", mp.g0, " id=", mp.id, " ostk=", &mp, "\n")
   210  	}
   211  
   212  	var uc ucontextt
   213  	getcontext(unsafe.Pointer(&uc))
   214  
   215  	// _UC_SIGMASK does not seem to work here.
   216  	// It would be nice if _UC_SIGMASK and _UC_STACK
   217  	// worked so that we could do all the work setting
   218  	// the sigmask and the stack here, instead of setting
   219  	// the mask here and the stack in netbsdMstart.
   220  	// For now do the blocking manually.
   221  	uc.uc_flags = _UC_SIGMASK | _UC_CPU
   222  	uc.uc_link = nil
   223  	uc.uc_sigmask = sigset_all
   224  
   225  	var oset sigset
   226  	sigprocmask(_SIG_SETMASK, &sigset_all, &oset)
   227  
   228  	lwp_mcontext_init(&uc.uc_mcontext, stk, mp, mp.g0, abi.FuncPCABI0(netbsdMstart))
   229  
   230  	ret := lwp_create(unsafe.Pointer(&uc), _LWP_DETACHED, unsafe.Pointer(&mp.procid))
   231  	sigprocmask(_SIG_SETMASK, &oset, nil)
   232  	if ret < 0 {
   233  		print("runtime: failed to create new OS thread (have ", mcount()-1, " already; errno=", -ret, ")\n")
   234  		if ret == -_EAGAIN {
   235  			println("runtime: may need to increase max user processes (ulimit -p)")
   236  		}
   237  		throw("runtime.newosproc")
   238  	}
   239  }
   240  
   241  // mstart is the entry-point for new Ms.
   242  // It is written in assembly, uses ABI0, is marked TOPFRAME, and calls netbsdMstart0.
   243  func netbsdMstart()
   244  
   245  // netbsdMStart0 is the function call that starts executing a newly
   246  // created thread. On NetBSD, a new thread inherits the signal stack
   247  // of the creating thread. That confuses minit, so we remove that
   248  // signal stack here before calling the regular mstart. It's a bit
   249  // baroque to remove a signal stack here only to add one in minit, but
   250  // it's a simple change that keeps NetBSD working like other OS's.
   251  // At this point all signals are blocked, so there is no race.
   252  //
   253  //go:nosplit
   254  func netbsdMstart0() {
   255  	st := stackt{ss_flags: _SS_DISABLE}
   256  	sigaltstack(&st, nil)
   257  	mstart0()
   258  }
   259  
   260  func osinit() {
   261  	ncpu = getncpu()
   262  	if physPageSize == 0 {
   263  		physPageSize = getPageSize()
   264  	}
   265  	needSysmonWorkaround = getOSRev() < 902000000 // NetBSD 9.2
   266  }
   267  
   268  var urandom_dev = []byte("/dev/urandom\x00")
   269  
   270  //go:nosplit
   271  func getRandomData(r []byte) {
   272  	fd := open(&urandom_dev[0], 0 /* O_RDONLY */, 0)
   273  	n := read(fd, unsafe.Pointer(&r[0]), int32(len(r)))
   274  	closefd(fd)
   275  	extendRandom(r, int(n))
   276  }
   277  
   278  func goenvs() {
   279  	goenvs_unix()
   280  }
   281  
   282  // Called to initialize a new m (including the bootstrap m).
   283  // Called on the parent thread (main thread in case of bootstrap), can allocate memory.
   284  func mpreinit(mp *m) {
   285  	mp.gsignal = malg(32 * 1024)
   286  	mp.gsignal.m = mp
   287  }
   288  
   289  // Called to initialize a new m (including the bootstrap m).
   290  // Called on the new thread, cannot allocate memory.
   291  func minit() {
   292  	_g_ := getg()
   293  	_g_.m.procid = uint64(lwp_self())
   294  
   295  	// On NetBSD a thread created by pthread_create inherits the
   296  	// signal stack of the creating thread. We always create a
   297  	// new signal stack here, to avoid having two Go threads using
   298  	// the same signal stack. This breaks the case of a thread
   299  	// created in C that calls sigaltstack and then calls a Go
   300  	// function, because we will lose track of the C code's
   301  	// sigaltstack, but it's the best we can do.
   302  	signalstack(&_g_.m.gsignal.stack)
   303  	_g_.m.newSigstack = true
   304  
   305  	minitSignalMask()
   306  }
   307  
   308  // Called from dropm to undo the effect of an minit.
   309  //
   310  //go:nosplit
   311  func unminit() {
   312  	unminitSignals()
   313  }
   314  
   315  // Called from exitm, but not from drop, to undo the effect of thread-owned
   316  // resources in minit, semacreate, or elsewhere. Do not take locks after calling this.
   317  func mdestroy(mp *m) {
   318  }
   319  
   320  func sigtramp()
   321  
   322  type sigactiont struct {
   323  	sa_sigaction uintptr
   324  	sa_mask      sigset
   325  	sa_flags     int32
   326  }
   327  
   328  //go:nosplit
   329  //go:nowritebarrierrec
   330  func setsig(i uint32, fn uintptr) {
   331  	var sa sigactiont
   332  	sa.sa_flags = _SA_SIGINFO | _SA_ONSTACK | _SA_RESTART
   333  	sa.sa_mask = sigset_all
   334  	if fn == abi.FuncPCABIInternal(sighandler) { // abi.FuncPCABIInternal(sighandler) matches the callers in signal_unix.go
   335  		fn = abi.FuncPCABI0(sigtramp)
   336  	}
   337  	sa.sa_sigaction = fn
   338  	sigaction(i, &sa, nil)
   339  }
   340  
   341  //go:nosplit
   342  //go:nowritebarrierrec
   343  func setsigstack(i uint32) {
   344  	throw("setsigstack")
   345  }
   346  
   347  //go:nosplit
   348  //go:nowritebarrierrec
   349  func getsig(i uint32) uintptr {
   350  	var sa sigactiont
   351  	sigaction(i, nil, &sa)
   352  	return sa.sa_sigaction
   353  }
   354  
   355  // setSignaltstackSP sets the ss_sp field of a stackt.
   356  //
   357  //go:nosplit
   358  func setSignalstackSP(s *stackt, sp uintptr) {
   359  	s.ss_sp = sp
   360  }
   361  
   362  //go:nosplit
   363  //go:nowritebarrierrec
   364  func sigaddset(mask *sigset, i int) {
   365  	mask.__bits[(i-1)/32] |= 1 << ((uint32(i) - 1) & 31)
   366  }
   367  
   368  func sigdelset(mask *sigset, i int) {
   369  	mask.__bits[(i-1)/32] &^= 1 << ((uint32(i) - 1) & 31)
   370  }
   371  
   372  //go:nosplit
   373  func (c *sigctxt) fixsigcode(sig uint32) {
   374  }
   375  
   376  func setProcessCPUProfiler(hz int32) {
   377  	setProcessCPUProfilerTimer(hz)
   378  }
   379  
   380  func setThreadCPUProfiler(hz int32) {
   381  	setThreadCPUProfilerHz(hz)
   382  }
   383  
   384  //go:nosplit
   385  func validSIGPROF(mp *m, c *sigctxt) bool {
   386  	return true
   387  }
   388  
   389  func sysargs(argc int32, argv **byte) {
   390  	n := argc + 1
   391  
   392  	// skip over argv, envp to get to auxv
   393  	for argv_index(argv, n) != nil {
   394  		n++
   395  	}
   396  
   397  	// skip NULL separator
   398  	n++
   399  
   400  	// now argv+n is auxv
   401  	auxv := (*[1 << 28]uintptr)(add(unsafe.Pointer(argv), uintptr(n)*goarch.PtrSize))
   402  	sysauxv(auxv[:])
   403  }
   404  
   405  const (
   406  	_AT_NULL   = 0 // Terminates the vector
   407  	_AT_PAGESZ = 6 // Page size in bytes
   408  )
   409  
   410  func sysauxv(auxv []uintptr) {
   411  	for i := 0; auxv[i] != _AT_NULL; i += 2 {
   412  		tag, val := auxv[i], auxv[i+1]
   413  		switch tag {
   414  		case _AT_PAGESZ:
   415  			physPageSize = val
   416  		}
   417  	}
   418  }
   419  
   420  // raise sends signal to the calling thread.
   421  //
   422  // It must be nosplit because it is used by the signal handler before
   423  // it definitely has a Go stack.
   424  //
   425  //go:nosplit
   426  func raise(sig uint32) {
   427  	lwp_kill(lwp_self(), int(sig))
   428  }
   429  
   430  func signalM(mp *m, sig int) {
   431  	lwp_kill(int32(mp.procid), sig)
   432  }
   433  
   434  // sigPerThreadSyscall is only used on linux, so we assign a bogus signal
   435  // number.
   436  const sigPerThreadSyscall = 1 << 31
   437  
   438  //go:nosplit
   439  func runPerThreadSyscall() {
   440  	throw("runPerThreadSyscall only valid on linux")
   441  }
   442
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