...
Run Format

Source file src/runtime/os_freebsd.go

Documentation: runtime

     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  	"runtime/internal/sys"
     9  	"unsafe"
    10  )
    11  
    12  type mOS struct{}
    13  
    14  //go:noescape
    15  func thr_new(param *thrparam, size int32) int32
    16  
    17  //go:noescape
    18  func sigaltstack(new, old *stackt)
    19  
    20  //go:noescape
    21  func sigprocmask(how int32, new, old *sigset)
    22  
    23  //go:noescape
    24  func setitimer(mode int32, new, old *itimerval)
    25  
    26  //go:noescape
    27  func sysctl(mib *uint32, miblen uint32, out *byte, size *uintptr, dst *byte, ndst uintptr) int32
    28  
    29  func raise(sig uint32)
    30  func raiseproc(sig uint32)
    31  
    32  //go:noescape
    33  func sys_umtx_op(addr *uint32, mode int32, val uint32, uaddr1 uintptr, ut *umtx_time) int32
    34  
    35  func osyield()
    36  
    37  func kqueue() int32
    38  
    39  //go:noescape
    40  func kevent(kq int32, ch *keventt, nch int32, ev *keventt, nev int32, ts *timespec) int32
    41  func closeonexec(fd int32)
    42  
    43  // From FreeBSD's <sys/sysctl.h>
    44  const (
    45  	_CTL_HW      = 6
    46  	_HW_PAGESIZE = 7
    47  )
    48  
    49  var sigset_all = sigset{[4]uint32{^uint32(0), ^uint32(0), ^uint32(0), ^uint32(0)}}
    50  
    51  // Undocumented numbers from FreeBSD's lib/libc/gen/sysctlnametomib.c.
    52  const (
    53  	_CTL_QUERY     = 0
    54  	_CTL_QUERY_MIB = 3
    55  )
    56  
    57  // sysctlnametomib fill mib with dynamically assigned sysctl entries of name,
    58  // return count of effected mib slots, return 0 on error.
    59  func sysctlnametomib(name []byte, mib *[_CTL_MAXNAME]uint32) uint32 {
    60  	oid := [2]uint32{_CTL_QUERY, _CTL_QUERY_MIB}
    61  	miblen := uintptr(_CTL_MAXNAME)
    62  	if sysctl(&oid[0], 2, (*byte)(unsafe.Pointer(mib)), &miblen, (*byte)(unsafe.Pointer(&name[0])), (uintptr)(len(name))) < 0 {
    63  		return 0
    64  	}
    65  	miblen /= unsafe.Sizeof(uint32(0))
    66  	if miblen <= 0 {
    67  		return 0
    68  	}
    69  	return uint32(miblen)
    70  }
    71  
    72  const (
    73  	_CPU_CURRENT_PID = -1 // Current process ID.
    74  )
    75  
    76  //go:noescape
    77  func cpuset_getaffinity(level int, which int, id int64, size int, mask *byte) int32
    78  
    79  //go:systemstack
    80  func getncpu() int32 {
    81  	// Use a large buffer for the CPU mask. We're on the system
    82  	// stack, so this is fine, and we can't allocate memory for a
    83  	// dynamically-sized buffer at this point.
    84  	const maxCPUs = 64 * 1024
    85  	var mask [maxCPUs / 8]byte
    86  	var mib [_CTL_MAXNAME]uint32
    87  
    88  	// According to FreeBSD's /usr/src/sys/kern/kern_cpuset.c,
    89  	// cpuset_getaffinity return ERANGE when provided buffer size exceed the limits in kernel.
    90  	// Querying kern.smp.maxcpus to calculate maximum buffer size.
    91  	// See https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=200802
    92  
    93  	// Variable kern.smp.maxcpus introduced at Dec 23 2003, revision 123766,
    94  	// with dynamically assigned sysctl entries.
    95  	miblen := sysctlnametomib([]byte("kern.smp.maxcpus"), &mib)
    96  	if miblen == 0 {
    97  		return 1
    98  	}
    99  
   100  	// Query kern.smp.maxcpus.
   101  	dstsize := uintptr(4)
   102  	maxcpus := uint32(0)
   103  	if sysctl(&mib[0], miblen, (*byte)(unsafe.Pointer(&maxcpus)), &dstsize, nil, 0) != 0 {
   104  		return 1
   105  	}
   106  
   107  	maskSize := int(maxcpus+7) / 8
   108  	if maskSize < sys.PtrSize {
   109  		maskSize = sys.PtrSize
   110  	}
   111  	if maskSize > len(mask) {
   112  		maskSize = len(mask)
   113  	}
   114  
   115  	if cpuset_getaffinity(_CPU_LEVEL_WHICH, _CPU_WHICH_PID, _CPU_CURRENT_PID,
   116  		maskSize, (*byte)(unsafe.Pointer(&mask[0]))) != 0 {
   117  		return 1
   118  	}
   119  	n := int32(0)
   120  	for _, v := range mask[:maskSize] {
   121  		for v != 0 {
   122  			n += int32(v & 1)
   123  			v >>= 1
   124  		}
   125  	}
   126  	if n == 0 {
   127  		return 1
   128  	}
   129  	return n
   130  }
   131  
   132  func getPageSize() uintptr {
   133  	mib := [2]uint32{_CTL_HW, _HW_PAGESIZE}
   134  	out := uint32(0)
   135  	nout := unsafe.Sizeof(out)
   136  	ret := sysctl(&mib[0], 2, (*byte)(unsafe.Pointer(&out)), &nout, nil, 0)
   137  	if ret >= 0 {
   138  		return uintptr(out)
   139  	}
   140  	return 0
   141  }
   142  
   143  // FreeBSD's umtx_op syscall is effectively the same as Linux's futex, and
   144  // thus the code is largely similar. See Linux implementation
   145  // and lock_futex.go for comments.
   146  
   147  //go:nosplit
   148  func futexsleep(addr *uint32, val uint32, ns int64) {
   149  	systemstack(func() {
   150  		futexsleep1(addr, val, ns)
   151  	})
   152  }
   153  
   154  func futexsleep1(addr *uint32, val uint32, ns int64) {
   155  	var utp *umtx_time
   156  	if ns >= 0 {
   157  		var ut umtx_time
   158  		ut._clockid = _CLOCK_MONOTONIC
   159  		ut._timeout.set_sec(int64(timediv(ns, 1000000000, (*int32)(unsafe.Pointer(&ut._timeout.tv_nsec)))))
   160  		utp = &ut
   161  	}
   162  	ret := sys_umtx_op(addr, _UMTX_OP_WAIT_UINT_PRIVATE, val, unsafe.Sizeof(*utp), utp)
   163  	if ret >= 0 || ret == -_EINTR {
   164  		return
   165  	}
   166  	print("umtx_wait addr=", addr, " val=", val, " ret=", ret, "\n")
   167  	*(*int32)(unsafe.Pointer(uintptr(0x1005))) = 0x1005
   168  }
   169  
   170  //go:nosplit
   171  func futexwakeup(addr *uint32, cnt uint32) {
   172  	ret := sys_umtx_op(addr, _UMTX_OP_WAKE_PRIVATE, cnt, 0, nil)
   173  	if ret >= 0 {
   174  		return
   175  	}
   176  
   177  	systemstack(func() {
   178  		print("umtx_wake_addr=", addr, " ret=", ret, "\n")
   179  	})
   180  }
   181  
   182  func thr_start()
   183  
   184  // May run with m.p==nil, so write barriers are not allowed.
   185  //go:nowritebarrier
   186  func newosproc(mp *m) {
   187  	stk := unsafe.Pointer(mp.g0.stack.hi)
   188  	if false {
   189  		print("newosproc stk=", stk, " m=", mp, " g=", mp.g0, " thr_start=", funcPC(thr_start), " id=", mp.id, " ostk=", &mp, "\n")
   190  	}
   191  
   192  	param := thrparam{
   193  		start_func: funcPC(thr_start),
   194  		arg:        unsafe.Pointer(mp),
   195  		stack_base: mp.g0.stack.lo,
   196  		stack_size: uintptr(stk) - mp.g0.stack.lo,
   197  		child_tid:  unsafe.Pointer(&mp.procid),
   198  		parent_tid: nil,
   199  		tls_base:   unsafe.Pointer(&mp.tls[0]),
   200  		tls_size:   unsafe.Sizeof(mp.tls),
   201  	}
   202  
   203  	var oset sigset
   204  	sigprocmask(_SIG_SETMASK, &sigset_all, &oset)
   205  	// TODO: Check for error.
   206  	ret := thr_new(&param, int32(unsafe.Sizeof(param)))
   207  	sigprocmask(_SIG_SETMASK, &oset, nil)
   208  	if ret < 0 {
   209  		print("runtime: failed to create new OS thread (have ", mcount(), " already; errno=", -ret, ")\n")
   210  		throw("newosproc")
   211  	}
   212  }
   213  
   214  // Version of newosproc that doesn't require a valid G.
   215  //go:nosplit
   216  func newosproc0(stacksize uintptr, fn unsafe.Pointer) {
   217  	stack := sysAlloc(stacksize, &memstats.stacks_sys)
   218  	if stack == nil {
   219  		write(2, unsafe.Pointer(&failallocatestack[0]), int32(len(failallocatestack)))
   220  		exit(1)
   221  	}
   222  	// This code "knows" it's being called once from the library
   223  	// initialization code, and so it's using the static m0 for the
   224  	// tls and procid (thread) pointers. thr_new() requires the tls
   225  	// pointers, though the tid pointers can be nil.
   226  	// However, newosproc0 is currently unreachable because builds
   227  	// utilizing c-shared/c-archive force external linking.
   228  	param := thrparam{
   229  		start_func: funcPC(fn),
   230  		arg:        nil,
   231  		stack_base: uintptr(stack), //+stacksize?
   232  		stack_size: stacksize,
   233  		child_tid:  unsafe.Pointer(&m0.procid),
   234  		parent_tid: nil,
   235  		tls_base:   unsafe.Pointer(&m0.tls[0]),
   236  		tls_size:   unsafe.Sizeof(m0.tls),
   237  	}
   238  
   239  	var oset sigset
   240  	sigprocmask(_SIG_SETMASK, &sigset_all, &oset)
   241  	ret := thr_new(&param, int32(unsafe.Sizeof(param)))
   242  	sigprocmask(_SIG_SETMASK, &oset, nil)
   243  	if ret < 0 {
   244  		write(2, unsafe.Pointer(&failthreadcreate[0]), int32(len(failthreadcreate)))
   245  		exit(1)
   246  	}
   247  }
   248  
   249  var failallocatestack = []byte("runtime: failed to allocate stack for the new OS thread\n")
   250  var failthreadcreate = []byte("runtime: failed to create new OS thread\n")
   251  
   252  // Called to do synchronous initialization of Go code built with
   253  // -buildmode=c-archive or -buildmode=c-shared.
   254  // None of the Go runtime is initialized.
   255  //go:nosplit
   256  //go:nowritebarrierrec
   257  func libpreinit() {
   258  	initsig(true)
   259  }
   260  
   261  func osinit() {
   262  	ncpu = getncpu()
   263  	if physPageSize == 0 {
   264  		physPageSize = getPageSize()
   265  	}
   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  	// m.procid is a uint64, but thr_new writes a uint32 on 32-bit systems.
   293  	// Fix it up. (Only matters on big-endian, but be clean anyway.)
   294  	if sys.PtrSize == 4 {
   295  		_g_ := getg()
   296  		_g_.m.procid = uint64(*(*uint32)(unsafe.Pointer(&_g_.m.procid)))
   297  	}
   298  
   299  	// On FreeBSD before about April 2017 there was a bug such
   300  	// that calling execve from a thread other than the main
   301  	// thread did not reset the signal stack. That would confuse
   302  	// minitSignals, which calls minitSignalStack, which checks
   303  	// whether there is currently a signal stack and uses it if
   304  	// present. To avoid this confusion, explicitly disable the
   305  	// signal stack on the main thread when not running in a
   306  	// library. This can be removed when we are confident that all
   307  	// FreeBSD users are running a patched kernel. See issue #15658.
   308  	if gp := getg(); !isarchive && !islibrary && gp.m == &m0 && gp == gp.m.g0 {
   309  		st := stackt{ss_flags: _SS_DISABLE}
   310  		sigaltstack(&st, nil)
   311  	}
   312  
   313  	minitSignals()
   314  }
   315  
   316  // Called from dropm to undo the effect of an minit.
   317  //go:nosplit
   318  func unminit() {
   319  	unminitSignals()
   320  }
   321  
   322  func sigtramp()
   323  
   324  type sigactiont struct {
   325  	sa_handler uintptr
   326  	sa_flags   int32
   327  	sa_mask    sigset
   328  }
   329  
   330  // See os_freebsd2.go, os_freebsd_amd64.go for setsig function
   331  
   332  //go:nosplit
   333  //go:nowritebarrierrec
   334  func setsigstack(i uint32) {
   335  	var sa sigactiont
   336  	sigaction(i, nil, &sa)
   337  	if sa.sa_flags&_SA_ONSTACK != 0 {
   338  		return
   339  	}
   340  	sa.sa_flags |= _SA_ONSTACK
   341  	sigaction(i, &sa, nil)
   342  }
   343  
   344  //go:nosplit
   345  //go:nowritebarrierrec
   346  func getsig(i uint32) uintptr {
   347  	var sa sigactiont
   348  	sigaction(i, nil, &sa)
   349  	return sa.sa_handler
   350  }
   351  
   352  // setSignaltstackSP sets the ss_sp field of a stackt.
   353  //go:nosplit
   354  func setSignalstackSP(s *stackt, sp uintptr) {
   355  	s.ss_sp = sp
   356  }
   357  
   358  //go:nosplit
   359  //go:nowritebarrierrec
   360  func sigaddset(mask *sigset, i int) {
   361  	mask.__bits[(i-1)/32] |= 1 << ((uint32(i) - 1) & 31)
   362  }
   363  
   364  func sigdelset(mask *sigset, i int) {
   365  	mask.__bits[(i-1)/32] &^= 1 << ((uint32(i) - 1) & 31)
   366  }
   367  
   368  func (c *sigctxt) fixsigcode(sig uint32) {
   369  }
   370  
   371  func sysargs(argc int32, argv **byte) {
   372  	n := argc + 1
   373  
   374  	// skip over argv, envp to get to auxv
   375  	for argv_index(argv, n) != nil {
   376  		n++
   377  	}
   378  
   379  	// skip NULL separator
   380  	n++
   381  
   382  	// now argv+n is auxv
   383  	auxv := (*[1 << 28]uintptr)(add(unsafe.Pointer(argv), uintptr(n)*sys.PtrSize))
   384  	sysauxv(auxv[:])
   385  }
   386  
   387  const (
   388  	_AT_NULL     = 0  // Terminates the vector
   389  	_AT_PAGESZ   = 6  // Page size in bytes
   390  	_AT_TIMEKEEP = 22 // Pointer to timehands.
   391  	_AT_HWCAP    = 25 // CPU feature flags
   392  )
   393  
   394  func sysauxv(auxv []uintptr) {
   395  	for i := 0; auxv[i] != _AT_NULL; i += 2 {
   396  		tag, val := auxv[i], auxv[i+1]
   397  		switch tag {
   398  		// _AT_NCPUS from auxv shouldn't be used due to golang.org/issue/15206
   399  		case _AT_PAGESZ:
   400  			physPageSize = val
   401  		case _AT_TIMEKEEP:
   402  			timekeepSharedPage = (*vdsoTimekeep)(unsafe.Pointer(val))
   403  		}
   404  
   405  		archauxv(tag, val)
   406  	}
   407  }
   408  
   409  // sysSigaction calls the sigaction system call.
   410  //go:nosplit
   411  func sysSigaction(sig uint32, new, old *sigactiont) {
   412  	// Use system stack to avoid split stack overflow on amd64
   413  	if asmSigaction(uintptr(sig), new, old) != 0 {
   414  		systemstack(func() {
   415  			throw("sigaction failed")
   416  		})
   417  	}
   418  }
   419  
   420  // asmSigaction is implemented in assembly.
   421  //go:noescape
   422  func asmSigaction(sig uintptr, new, old *sigactiont) int32
   423  

View as plain text