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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)
    16  
    17  //go:noescape
    18  func sigaltstack(new, old *stackt)
    19  
    20  //go:noescape
    21  func sigaction(sig uint32, new, old *sigactiont)
    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  //go:noescape
    33  func getrlimit(kind int32, limit unsafe.Pointer) int32
    34  func raise(sig uint32)
    35  func raiseproc(sig uint32)
    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  // From FreeBSD's <sys/sysctl.h>
    43  const (
    44  	_CTL_HW      = 6
    45  	_HW_PAGESIZE = 7
    46  )
    47  
    48  var sigset_all = sigset{[4]uint32{^uint32(0), ^uint32(0), ^uint32(0), ^uint32(0)}}
    49  
    50  // Undocumented numbers from FreeBSD's lib/libc/gen/sysctlnametomib.c.
    51  const (
    52  	_CTL_QUERY     = 0
    53  	_CTL_QUERY_MIB = 3
    54  )
    55  
    56  // sysctlnametomib fill mib with dynamically assigned sysctl entries of name,
    57  // return count of effected mib slots, return 0 on error.
    58  func sysctlnametomib(name []byte, mib *[_CTL_MAXNAME]uint32) uint32 {
    59  	oid := [2]uint32{_CTL_QUERY, _CTL_QUERY_MIB}
    60  	miblen := uintptr(_CTL_MAXNAME)
    61  	if sysctl(&oid[0], 2, (*byte)(unsafe.Pointer(mib)), &miblen, (*byte)(unsafe.Pointer(&name[0])), (uintptr)(len(name))) < 0 {
    62  		return 0
    63  	}
    64  	miblen /= unsafe.Sizeof(uint32(0))
    65  	if miblen <= 0 {
    66  		return 0
    67  	}
    68  	return uint32(miblen)
    69  }
    70  
    71  const (
    72  	_CPU_CURRENT_PID = -1 // Current process ID.
    73  )
    74  
    75  //go:noescape
    76  func cpuset_getaffinity(level int, which int, id int64, size int, mask *byte) int32
    77  
    78  //go:systemstack
    79  func getncpu() int32 {
    80  	// Use a large buffer for the CPU mask. We're on the system
    81  	// stack, so this is fine, and we can't allocate memory for a
    82  	// dynamically-sized buffer at this point.
    83  	const maxCPUs = 64 * 1024
    84  	var mask [maxCPUs / 8]byte
    85  	var mib [_CTL_MAXNAME]uint32
    86  
    87  	// According to FreeBSD's /usr/src/sys/kern/kern_cpuset.c,
    88  	// cpuset_getaffinity return ERANGE when provided buffer size exceed the limits in kernel.
    89  	// Querying kern.smp.maxcpus to calculate maximum buffer size.
    90  	// See https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=200802
    91  
    92  	// Variable kern.smp.maxcpus introduced at Dec 23 2003, revision 123766,
    93  	// with dynamically assigned sysctl entries.
    94  	miblen := sysctlnametomib([]byte("kern.smp.maxcpus"), &mib)
    95  	if miblen == 0 {
    96  		return 1
    97  	}
    98  
    99  	// Query kern.smp.maxcpus.
   100  	dstsize := uintptr(4)
   101  	maxcpus := uint32(0)
   102  	if sysctl(&mib[0], miblen, (*byte)(unsafe.Pointer(&maxcpus)), &dstsize, nil, 0) != 0 {
   103  		return 1
   104  	}
   105  
   106  	maskSize := int(maxcpus+7) / 8
   107  	if maskSize < sys.PtrSize {
   108  		maskSize = sys.PtrSize
   109  	}
   110  	if maskSize > len(mask) {
   111  		maskSize = len(mask)
   112  	}
   113  
   114  	if cpuset_getaffinity(_CPU_LEVEL_WHICH, _CPU_WHICH_PID, _CPU_CURRENT_PID,
   115  		maskSize, (*byte)(unsafe.Pointer(&mask[0]))) != 0 {
   116  		return 1
   117  	}
   118  	n := int32(0)
   119  	for _, v := range mask[:maskSize] {
   120  		for v != 0 {
   121  			n += int32(v & 1)
   122  			v >>= 1
   123  		}
   124  	}
   125  	if n == 0 {
   126  		return 1
   127  	}
   128  	return n
   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  // FreeBSD's umtx_op syscall is effectively the same as Linux's futex, and
   143  // thus the code is largely similar. See Linux implementation
   144  // and lock_futex.go for comments.
   145  
   146  //go:nosplit
   147  func futexsleep(addr *uint32, val uint32, ns int64) {
   148  	systemstack(func() {
   149  		futexsleep1(addr, val, ns)
   150  	})
   151  }
   152  
   153  func futexsleep1(addr *uint32, val uint32, ns int64) {
   154  	var utp *umtx_time
   155  	if ns >= 0 {
   156  		var ut umtx_time
   157  		ut._clockid = _CLOCK_MONOTONIC
   158  		ut._timeout.set_sec(int64(timediv(ns, 1000000000, (*int32)(unsafe.Pointer(&ut._timeout.tv_nsec)))))
   159  		utp = &ut
   160  	}
   161  	ret := sys_umtx_op(addr, _UMTX_OP_WAIT_UINT_PRIVATE, val, unsafe.Sizeof(*utp), utp)
   162  	if ret >= 0 || ret == -_EINTR {
   163  		return
   164  	}
   165  	print("umtx_wait addr=", addr, " val=", val, " ret=", ret, "\n")
   166  	*(*int32)(unsafe.Pointer(uintptr(0x1005))) = 0x1005
   167  }
   168  
   169  //go:nosplit
   170  func futexwakeup(addr *uint32, cnt uint32) {
   171  	ret := sys_umtx_op(addr, _UMTX_OP_WAKE_PRIVATE, cnt, 0, nil)
   172  	if ret >= 0 {
   173  		return
   174  	}
   175  
   176  	systemstack(func() {
   177  		print("umtx_wake_addr=", addr, " ret=", ret, "\n")
   178  	})
   179  }
   180  
   181  func thr_start()
   182  
   183  // May run with m.p==nil, so write barriers are not allowed.
   184  //go:nowritebarrier
   185  func newosproc(mp *m, stk unsafe.Pointer) {
   186  	if false {
   187  		print("newosproc stk=", stk, " m=", mp, " g=", mp.g0, " thr_start=", funcPC(thr_start), " id=", mp.id, " ostk=", &mp, "\n")
   188  	}
   189  
   190  	// NOTE(rsc): This code is confused. stackbase is the top of the stack
   191  	// and is equal to stk. However, it's working, so I'm not changing it.
   192  	param := thrparam{
   193  		start_func: funcPC(thr_start),
   194  		arg:        unsafe.Pointer(mp),
   195  		stack_base: mp.g0.stack.hi,
   196  		stack_size: uintptr(stk) - mp.g0.stack.hi,
   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  	thr_new(&param, int32(unsafe.Sizeof(param)))
   207  	sigprocmask(_SIG_SETMASK, &oset, nil)
   208  }
   209  
   210  func osinit() {
   211  	ncpu = getncpu()
   212  	physPageSize = getPageSize()
   213  }
   214  
   215  var urandom_dev = []byte("/dev/urandom\x00")
   216  
   217  //go:nosplit
   218  func getRandomData(r []byte) {
   219  	fd := open(&urandom_dev[0], 0 /* O_RDONLY */, 0)
   220  	n := read(fd, unsafe.Pointer(&r[0]), int32(len(r)))
   221  	closefd(fd)
   222  	extendRandom(r, int(n))
   223  }
   224  
   225  func goenvs() {
   226  	goenvs_unix()
   227  }
   228  
   229  // Called to initialize a new m (including the bootstrap m).
   230  // Called on the parent thread (main thread in case of bootstrap), can allocate memory.
   231  func mpreinit(mp *m) {
   232  	mp.gsignal = malg(32 * 1024)
   233  	mp.gsignal.m = mp
   234  }
   235  
   236  // Called to initialize a new m (including the bootstrap m).
   237  // Called on the new thread, cannot allocate memory.
   238  func minit() {
   239  	// m.procid is a uint64, but thr_new writes a uint32 on 32-bit systems.
   240  	// Fix it up. (Only matters on big-endian, but be clean anyway.)
   241  	if sys.PtrSize == 4 {
   242  		_g_ := getg()
   243  		_g_.m.procid = uint64(*(*uint32)(unsafe.Pointer(&_g_.m.procid)))
   244  	}
   245  
   246  	// On FreeBSD before about April 2017 there was a bug such
   247  	// that calling execve from a thread other than the main
   248  	// thread did not reset the signal stack. That would confuse
   249  	// minitSignals, which calls minitSignalStack, which checks
   250  	// whether there is currently a signal stack and uses it if
   251  	// present. To avoid this confusion, explicitly disable the
   252  	// signal stack on the main thread when not running in a
   253  	// library. This can be removed when we are confident that all
   254  	// FreeBSD users are running a patched kernel. See issue #15658.
   255  	if gp := getg(); !isarchive && !islibrary && gp.m == &m0 && gp == gp.m.g0 {
   256  		st := stackt{ss_flags: _SS_DISABLE}
   257  		sigaltstack(&st, nil)
   258  	}
   259  
   260  	minitSignals()
   261  }
   262  
   263  // Called from dropm to undo the effect of an minit.
   264  //go:nosplit
   265  func unminit() {
   266  	unminitSignals()
   267  }
   268  
   269  func memlimit() uintptr {
   270  	/*
   271  		TODO: Convert to Go when something actually uses the result.
   272  		Rlimit rl;
   273  		extern byte runtime·text[], runtime·end[];
   274  		uintptr used;
   275  
   276  		if(runtime·getrlimit(RLIMIT_AS, &rl) != 0)
   277  			return 0;
   278  		if(rl.rlim_cur >= 0x7fffffff)
   279  			return 0;
   280  
   281  		// Estimate our VM footprint excluding the heap.
   282  		// Not an exact science: use size of binary plus
   283  		// some room for thread stacks.
   284  		used = runtime·end - runtime·text + (64<<20);
   285  		if(used >= rl.rlim_cur)
   286  			return 0;
   287  
   288  		// If there's not at least 16 MB left, we're probably
   289  		// not going to be able to do much. Treat as no limit.
   290  		rl.rlim_cur -= used;
   291  		if(rl.rlim_cur < (16<<20))
   292  			return 0;
   293  
   294  		return rl.rlim_cur - used;
   295  	*/
   296  
   297  	return 0
   298  }
   299  
   300  func sigtramp()
   301  
   302  type sigactiont struct {
   303  	sa_handler uintptr
   304  	sa_flags   int32
   305  	sa_mask    sigset
   306  }
   307  
   308  //go:nosplit
   309  //go:nowritebarrierrec
   310  func setsig(i uint32, fn uintptr) {
   311  	var sa sigactiont
   312  	sa.sa_flags = _SA_SIGINFO | _SA_ONSTACK | _SA_RESTART
   313  	sa.sa_mask = sigset_all
   314  	if fn == funcPC(sighandler) {
   315  		fn = funcPC(sigtramp)
   316  	}
   317  	sa.sa_handler = fn
   318  	sigaction(i, &sa, nil)
   319  }
   320  
   321  //go:nosplit
   322  //go:nowritebarrierrec
   323  func setsigstack(i uint32) {
   324  	throw("setsigstack")
   325  }
   326  
   327  //go:nosplit
   328  //go:nowritebarrierrec
   329  func getsig(i uint32) uintptr {
   330  	var sa sigactiont
   331  	sigaction(i, nil, &sa)
   332  	return sa.sa_handler
   333  }
   334  
   335  // setSignaltstackSP sets the ss_sp field of a stackt.
   336  //go:nosplit
   337  func setSignalstackSP(s *stackt, sp uintptr) {
   338  	s.ss_sp = sp
   339  }
   340  
   341  //go:nosplit
   342  //go:nowritebarrierrec
   343  func sigaddset(mask *sigset, i int) {
   344  	mask.__bits[(i-1)/32] |= 1 << ((uint32(i) - 1) & 31)
   345  }
   346  
   347  func sigdelset(mask *sigset, i int) {
   348  	mask.__bits[(i-1)/32] &^= 1 << ((uint32(i) - 1) & 31)
   349  }
   350  
   351  func (c *sigctxt) fixsigcode(sig uint32) {
   352  }
   353  

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