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