os_freebsd.go

     1  // Copyright 2011 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  	"unsafe"
    11  )
    12  
    13  type mOS struct {
    14  	waitsema uint32 // semaphore for parking on locks
    15  }
    16  
    17  //go:noescape
    18  func thr_new(param *thrparam, size int32) int32
    19  
    20  //go:noescape
    21  func sigaltstack(new, old *stackt)
    22  
    23  //go:noescape
    24  func sigprocmask(how int32, new, old *sigset)
    25  
    26  //go:noescape
    27  func setitimer(mode int32, new, old *itimerval)
    28  
    29  //go:noescape
    30  func sysctl(mib *uint32, miblen uint32, out *byte, size *uintptr, dst *byte, ndst uintptr) int32
    31  
    32  func raiseproc(sig uint32)
    33  
    34  func thr_self() thread
    35  func thr_kill(tid thread, sig int)
    36  
    37  //go:noescape
    38  func sys_umtx_op(addr *uint32, mode int32, val uint32, uaddr1 uintptr, ut *umtx_time) int32
    39  
    40  func osyield()
    41  
    42  //go:nosplit
    43  func osyield_no_g() {
    44  	osyield()
    45  }
    46  
    47  func kqueue() int32
    48  
    49  //go:noescape
    50  func kevent(kq int32, ch *keventt, nch int32, ev *keventt, nev int32, ts *timespec) int32
    51  
    52  func pipe2(flags int32) (r, w int32, errno int32)
    53  func fcntl(fd, cmd, arg int32) (ret int32, errno int32)
    54  
    55  func issetugid() int32
    56  
    57  // From FreeBSD's <sys/sysctl.h>
    58  const (
    59  	_CTL_HW      = 6
    60  	_HW_PAGESIZE = 7
    61  )
    62  
    63  var sigset_all = sigset{[4]uint32{^uint32(0), ^uint32(0), ^uint32(0), ^uint32(0)}}
    64  
    65  // Undocumented numbers from FreeBSD's lib/libc/gen/sysctlnametomib.c.
    66  const (
    67  	_CTL_QUERY     = 0
    68  	_CTL_QUERY_MIB = 3
    69  )
    70  
    71  // sysctlnametomib fill mib with dynamically assigned sysctl entries of name,
    72  // return count of effected mib slots, return 0 on error.
    73  func sysctlnametomib(name []byte, mib *[_CTL_MAXNAME]uint32) uint32 {
    74  	oid := [2]uint32{_CTL_QUERY, _CTL_QUERY_MIB}
    75  	miblen := uintptr(_CTL_MAXNAME)
    76  	if sysctl(&oid[0], 2, (*byte)(unsafe.Pointer(mib)), &miblen, (*byte)(unsafe.Pointer(&name[0])), (uintptr)(len(name))) < 0 {
    77  		return 0
    78  	}
    79  	miblen /= unsafe.Sizeof(uint32(0))
    80  	if miblen <= 0 {
    81  		return 0
    82  	}
    83  	return uint32(miblen)
    84  }
    85  
    86  const (
    87  	_CPU_CURRENT_PID = -1 // Current process ID.
    88  )
    89  
    90  //go:noescape
    91  func cpuset_getaffinity(level int, which int, id int64, size int, mask *byte) int32
    92  
    93  //go:systemstack
    94  func getncpu() int32 {
    95  	// Use a large buffer for the CPU mask. We're on the system
    96  	// stack, so this is fine, and we can't allocate memory for a
    97  	// dynamically-sized buffer at this point.
    98  	const maxCPUs = 64 * 1024
    99  	var mask [maxCPUs / 8]byte
   100  	var mib [_CTL_MAXNAME]uint32
   101  
   102  	// According to FreeBSD's /usr/src/sys/kern/kern_cpuset.c,
   103  	// cpuset_getaffinity return ERANGE when provided buffer size exceed the limits in kernel.
   104  	// Querying kern.smp.maxcpus to calculate maximum buffer size.
   105  	// See https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=200802
   106  
   107  	// Variable kern.smp.maxcpus introduced at Dec 23 2003, revision 123766,
   108  	// with dynamically assigned sysctl entries.
   109  	miblen := sysctlnametomib([]byte("kern.smp.maxcpus"), &mib)
   110  	if miblen == 0 {
   111  		return 1
   112  	}
   113  
   114  	// Query kern.smp.maxcpus.
   115  	dstsize := uintptr(4)
   116  	maxcpus := uint32(0)
   117  	if sysctl(&mib[0], miblen, (*byte)(unsafe.Pointer(&maxcpus)), &dstsize, nil, 0) != 0 {
   118  		return 1
   119  	}
   120  
   121  	maskSize := int(maxcpus+7) / 8
   122  	if maskSize < goarch.PtrSize {
   123  		maskSize = goarch.PtrSize
   124  	}
   125  	if maskSize > len(mask) {
   126  		maskSize = len(mask)
   127  	}
   128  
   129  	if cpuset_getaffinity(_CPU_LEVEL_WHICH, _CPU_WHICH_PID, _CPU_CURRENT_PID,
   130  		maskSize, (*byte)(unsafe.Pointer(&mask[0]))) != 0 {
   131  		return 1
   132  	}
   133  	n := int32(0)
   134  	for _, v := range mask[:maskSize] {
   135  		for v != 0 {
   136  			n += int32(v & 1)
   137  			v >>= 1
   138  		}
   139  	}
   140  	if n == 0 {
   141  		return 1
   142  	}
   143  	return n
   144  }
   145  
   146  func getPageSize() uintptr {
   147  	mib := [2]uint32{_CTL_HW, _HW_PAGESIZE}
   148  	out := uint32(0)
   149  	nout := unsafe.Sizeof(out)
   150  	ret := sysctl(&mib[0], 2, (*byte)(unsafe.Pointer(&out)), &nout, nil, 0)
   151  	if ret >= 0 {
   152  		return uintptr(out)
   153  	}
   154  	return 0
   155  }
   156  
   157  // FreeBSD's umtx_op syscall is effectively the same as Linux's futex, and
   158  // thus the code is largely similar. See Linux implementation
   159  // and lock_futex.go for comments.
   160  
   161  //go:nosplit
   162  func futexsleep(addr *uint32, val uint32, ns int64) {
   163  	systemstack(func() {
   164  		futexsleep1(addr, val, ns)
   165  	})
   166  }
   167  
   168  func futexsleep1(addr *uint32, val uint32, ns int64) {
   169  	var utp *umtx_time
   170  	if ns >= 0 {
   171  		var ut umtx_time
   172  		ut._clockid = _CLOCK_MONOTONIC
   173  		ut._timeout.setNsec(ns)
   174  		utp = &ut
   175  	}
   176  	ret := sys_umtx_op(addr, _UMTX_OP_WAIT_UINT_PRIVATE, val, unsafe.Sizeof(*utp), utp)
   177  	if ret >= 0 || ret == -_EINTR || ret == -_ETIMEDOUT {
   178  		return
   179  	}
   180  	print("umtx_wait addr=", addr, " val=", val, " ret=", ret, "\n")
   181  	*(*int32)(unsafe.Pointer(uintptr(0x1005))) = 0x1005
   182  }
   183  
   184  //go:nosplit
   185  func futexwakeup(addr *uint32, cnt uint32) {
   186  	ret := sys_umtx_op(addr, _UMTX_OP_WAKE_PRIVATE, cnt, 0, nil)
   187  	if ret >= 0 {
   188  		return
   189  	}
   190  
   191  	systemstack(func() {
   192  		print("umtx_wake_addr=", addr, " ret=", ret, "\n")
   193  	})
   194  }
   195  
   196  func thr_start()
   197  
   198  // May run with m.p==nil, so write barriers are not allowed.
   199  //
   200  //go:nowritebarrier
   201  func newosproc(mp *m) {
   202  	stk := unsafe.Pointer(mp.g0.stack.hi)
   203  	if false {
   204  		print("newosproc stk=", stk, " m=", mp, " g=", mp.g0, " thr_start=", abi.FuncPCABI0(thr_start), " id=", mp.id, " ostk=", &mp, "\n")
   205  	}
   206  
   207  	param := thrparam{
   208  		start_func: abi.FuncPCABI0(thr_start),
   209  		arg:        unsafe.Pointer(mp),
   210  		stack_base: mp.g0.stack.lo,
   211  		stack_size: uintptr(stk) - mp.g0.stack.lo,
   212  		child_tid:  nil, // minit will record tid
   213  		parent_tid: nil,
   214  		tls_base:   unsafe.Pointer(&mp.tls[0]),
   215  		tls_size:   unsafe.Sizeof(mp.tls),
   216  	}
   217  
   218  	var oset sigset
   219  	sigprocmask(_SIG_SETMASK, &sigset_all, &oset)
   220  	ret := retryOnEAGAIN(func() int32 {
   221  		errno := thr_new(&param, int32(unsafe.Sizeof(param)))
   222  		// thr_new returns negative errno
   223  		return -errno
   224  	})
   225  	sigprocmask(_SIG_SETMASK, &oset, nil)
   226  	if ret != 0 {
   227  		print("runtime: failed to create new OS thread (have ", mcount(), " already; errno=", ret, ")\n")
   228  		throw("newosproc")
   229  	}
   230  }
   231  
   232  // Version of newosproc that doesn't require a valid G.
   233  //
   234  //go:nosplit
   235  func newosproc0(stacksize uintptr, fn unsafe.Pointer) {
   236  	stack := sysAlloc(stacksize, &memstats.stacks_sys)
   237  	if stack == nil {
   238  		writeErrStr(failallocatestack)
   239  		exit(1)
   240  	}
   241  	// This code "knows" it's being called once from the library
   242  	// initialization code, and so it's using the static m0 for the
   243  	// tls and procid (thread) pointers. thr_new() requires the tls
   244  	// pointers, though the tid pointers can be nil.
   245  	// However, newosproc0 is currently unreachable because builds
   246  	// utilizing c-shared/c-archive force external linking.
   247  	param := thrparam{
   248  		start_func: uintptr(fn),
   249  		arg:        nil,
   250  		stack_base: uintptr(stack), //+stacksize?
   251  		stack_size: stacksize,
   252  		child_tid:  nil, // minit will record tid
   253  		parent_tid: nil,
   254  		tls_base:   unsafe.Pointer(&m0.tls[0]),
   255  		tls_size:   unsafe.Sizeof(m0.tls),
   256  	}
   257  
   258  	var oset sigset
   259  	sigprocmask(_SIG_SETMASK, &sigset_all, &oset)
   260  	ret := thr_new(&param, int32(unsafe.Sizeof(param)))
   261  	sigprocmask(_SIG_SETMASK, &oset, nil)
   262  	if ret < 0 {
   263  		writeErrStr(failthreadcreate)
   264  		exit(1)
   265  	}
   266  }
   267  
   268  // Called to do synchronous initialization of Go code built with
   269  // -buildmode=c-archive or -buildmode=c-shared.
   270  // None of the Go runtime is initialized.
   271  //
   272  //go:nosplit
   273  //go:nowritebarrierrec
   274  func libpreinit() {
   275  	initsig(true)
   276  }
   277  
   278  func osinit() {
   279  	ncpu = getncpu()
   280  	if physPageSize == 0 {
   281  		physPageSize = getPageSize()
   282  	}
   283  }
   284  
   285  var urandom_dev = []byte("/dev/urandom\x00")
   286  
   287  //go:nosplit
   288  func readRandom(r []byte) int {
   289  	fd := open(&urandom_dev[0], 0 /* O_RDONLY */, 0)
   290  	n := read(fd, unsafe.Pointer(&r[0]), int32(len(r)))
   291  	closefd(fd)
   292  	return int(n)
   293  }
   294  
   295  func goenvs() {
   296  	goenvs_unix()
   297  }
   298  
   299  // Called to initialize a new m (including the bootstrap m).
   300  // Called on the parent thread (main thread in case of bootstrap), can allocate memory.
   301  func mpreinit(mp *m) {
   302  	mp.gsignal = malg(32 * 1024)
   303  	mp.gsignal.m = mp
   304  }
   305  
   306  // Called to initialize a new m (including the bootstrap m).
   307  // Called on the new thread, cannot allocate memory.
   308  func minit() {
   309  	getg().m.procid = uint64(thr_self())
   310  
   311  	// On FreeBSD before about April 2017 there was a bug such
   312  	// that calling execve from a thread other than the main
   313  	// thread did not reset the signal stack. That would confuse
   314  	// minitSignals, which calls minitSignalStack, which checks
   315  	// whether there is currently a signal stack and uses it if
   316  	// present. To avoid this confusion, explicitly disable the
   317  	// signal stack on the main thread when not running in a
   318  	// library. This can be removed when we are confident that all
   319  	// FreeBSD users are running a patched kernel. See issue #15658.
   320  	if gp := getg(); !isarchive && !islibrary && gp.m == &m0 && gp == gp.m.g0 {
   321  		st := stackt{ss_flags: _SS_DISABLE}
   322  		sigaltstack(&st, nil)
   323  	}
   324  
   325  	minitSignals()
   326  }
   327  
   328  // Called from dropm to undo the effect of an minit.
   329  //
   330  //go:nosplit
   331  func unminit() {
   332  	unminitSignals()
   333  	getg().m.procid = 0
   334  }
   335  
   336  // Called from exitm, but not from drop, to undo the effect of thread-owned
   337  // resources in minit, semacreate, or elsewhere. Do not take locks after calling this.
   338  func mdestroy(mp *m) {
   339  }
   340  
   341  func sigtramp()
   342  
   343  type sigactiont struct {
   344  	sa_handler uintptr
   345  	sa_flags   int32
   346  	sa_mask    sigset
   347  }
   348  
   349  // See os_freebsd2.go, os_freebsd_amd64.go for setsig function
   350  
   351  //go:nosplit
   352  //go:nowritebarrierrec
   353  func setsigstack(i uint32) {
   354  	var sa sigactiont
   355  	sigaction(i, nil, &sa)
   356  	if sa.sa_flags&_SA_ONSTACK != 0 {
   357  		return
   358  	}
   359  	sa.sa_flags |= _SA_ONSTACK
   360  	sigaction(i, &sa, nil)
   361  }
   362  
   363  //go:nosplit
   364  //go:nowritebarrierrec
   365  func getsig(i uint32) uintptr {
   366  	var sa sigactiont
   367  	sigaction(i, nil, &sa)
   368  	return sa.sa_handler
   369  }
   370  
   371  // setSignalstackSP sets the ss_sp field of a stackt.
   372  //
   373  //go:nosplit
   374  func setSignalstackSP(s *stackt, sp uintptr) {
   375  	s.ss_sp = sp
   376  }
   377  
   378  //go:nosplit
   379  //go:nowritebarrierrec
   380  func sigaddset(mask *sigset, i int) {
   381  	mask.__bits[(i-1)/32] |= 1 << ((uint32(i) - 1) & 31)
   382  }
   383  
   384  func sigdelset(mask *sigset, i int) {
   385  	mask.__bits[(i-1)/32] &^= 1 << ((uint32(i) - 1) & 31)
   386  }
   387  
   388  //go:nosplit
   389  func (c *sigctxt) fixsigcode(sig uint32) {
   390  }
   391  
   392  func setProcessCPUProfiler(hz int32) {
   393  	setProcessCPUProfilerTimer(hz)
   394  }
   395  
   396  func setThreadCPUProfiler(hz int32) {
   397  	setThreadCPUProfilerHz(hz)
   398  }
   399  
   400  //go:nosplit
   401  func validSIGPROF(mp *m, c *sigctxt) bool {
   402  	return true
   403  }
   404  
   405  func sysargs(argc int32, argv **byte) {
   406  	n := argc + 1
   407  
   408  	// skip over argv, envp to get to auxv
   409  	for argv_index(argv, n) != nil {
   410  		n++
   411  	}
   412  
   413  	// skip NULL separator
   414  	n++
   415  
   416  	// now argv+n is auxv
   417  	auxvp := (*[1 << 28]uintptr)(add(unsafe.Pointer(argv), uintptr(n)*goarch.PtrSize))
   418  	pairs := sysauxv(auxvp[:])
   419  	auxv = auxvp[: pairs*2 : pairs*2]
   420  }
   421  
   422  const (
   423  	_AT_NULL     = 0  // Terminates the vector
   424  	_AT_PAGESZ   = 6  // Page size in bytes
   425  	_AT_PLATFORM = 15 // string identifying platform
   426  	_AT_TIMEKEEP = 22 // Pointer to timehands.
   427  	_AT_HWCAP    = 25 // CPU feature flags
   428  	_AT_HWCAP2   = 26 // CPU feature flags 2
   429  )
   430  
   431  func sysauxv(auxv []uintptr) (pairs int) {
   432  	var i int
   433  	for i = 0; auxv[i] != _AT_NULL; i += 2 {
   434  		tag, val := auxv[i], auxv[i+1]
   435  		switch tag {
   436  		// _AT_NCPUS from auxv shouldn't be used due to golang.org/issue/15206
   437  		case _AT_PAGESZ:
   438  			physPageSize = val
   439  		case _AT_TIMEKEEP:
   440  			timekeepSharedPage = (*vdsoTimekeep)(unsafe.Pointer(val))
   441  		}
   442  
   443  		archauxv(tag, val)
   444  	}
   445  	return i / 2
   446  }
   447  
   448  // sysSigaction calls the sigaction system call.
   449  //
   450  //go:nosplit
   451  func sysSigaction(sig uint32, new, old *sigactiont) {
   452  	// Use system stack to avoid split stack overflow on amd64
   453  	if asmSigaction(uintptr(sig), new, old) != 0 {
   454  		systemstack(func() {
   455  			throw("sigaction failed")
   456  		})
   457  	}
   458  }
   459  
   460  // asmSigaction is implemented in assembly.
   461  //
   462  //go:noescape
   463  func asmSigaction(sig uintptr, new, old *sigactiont) int32
   464  
   465  // raise sends a signal to the calling thread.
   466  //
   467  // It must be nosplit because it is used by the signal handler before
   468  // it definitely has a Go stack.
   469  //
   470  //go:nosplit
   471  func raise(sig uint32) {
   472  	thr_kill(thr_self(), int(sig))
   473  }
   474  
   475  func signalM(mp *m, sig int) {
   476  	thr_kill(thread(mp.procid), sig)
   477  }
   478  
   479  // sigPerThreadSyscall is only used on linux, so we assign a bogus signal
   480  // number.
   481  const sigPerThreadSyscall = 1 << 31
   482  
   483  //go:nosplit
   484  func runPerThreadSyscall() {
   485  	throw("runPerThreadSyscall only valid on linux")
   486  }
   487
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