1 files changed, 92 insertions, 0 deletions
diff --git a/src/runtime/vdso_freebsd_x86.go b/src/runtime/vdso_freebsd_x86.go
new file mode 100644
index 0000000..5324a3d
--- /dev/null
+++ b/src/runtime/vdso_freebsd_x86.go
@@ -0,0 +1,92 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build freebsd && (386 || amd64)
+
+package runtime
+
+import (
+	"runtime/internal/atomic"
+	"unsafe"
+)
+
+const (
+	_VDSO_TH_ALGO_X86_TSC  = 1
+	_VDSO_TH_ALGO_X86_HPET = 2
+)
+
+const (
+	_HPET_DEV_MAP_MAX  = 10
+	_HPET_MAIN_COUNTER = 0xf0 /* Main counter register */
+
+	hpetDevPath = "/dev/hpetX\x00"
+)
+
+var hpetDevMap [_HPET_DEV_MAP_MAX]uintptr
+
+//go:nosplit
+func (th *vdsoTimehands) getTSCTimecounter() uint32 {
+	tsc := cputicks()
+	if th.x86_shift > 0 {
+		tsc >>= th.x86_shift
+	}
+	return uint32(tsc)
+}
+
+//go:systemstack
+func (th *vdsoTimehands) getHPETTimecounter() (uint32, bool) {
+	const digits = "0123456789"
+
+	idx := int(th.x86_hpet_idx)
+	if idx >= len(hpetDevMap) {
+		return 0, false
+	}
+
+	p := atomic.Loaduintptr(&hpetDevMap[idx])
+	if p == 0 {
+		var devPath [len(hpetDevPath)]byte
+		copy(devPath[:], hpetDevPath)
+		devPath[9] = digits[idx]
+
+		fd := open(&devPath[0], 0 /* O_RDONLY */, 0)
+		if fd < 0 {
+			atomic.Casuintptr(&hpetDevMap[idx], 0, ^uintptr(0))
+			return 0, false
+		}
+
+		addr, mmapErr := mmap(nil, physPageSize, _PROT_READ, _MAP_SHARED, fd, 0)
+		closefd(fd)
+		newP := uintptr(addr)
+		if mmapErr != 0 {
+			newP = ^uintptr(0)
+		}
+		if !atomic.Casuintptr(&hpetDevMap[idx], 0, newP) && mmapErr == 0 {
+			munmap(addr, physPageSize)
+		}
+		p = atomic.Loaduintptr(&hpetDevMap[idx])
+	}
+	if p == ^uintptr(0) {
+		return 0, false
+	}
+	return *(*uint32)(unsafe.Pointer(p + _HPET_MAIN_COUNTER)), true
+}
+
+//go:nosplit
+func (th *vdsoTimehands) getTimecounter() (uint32, bool) {
+	switch th.algo {
+	case _VDSO_TH_ALGO_X86_TSC:
+		return th.getTSCTimecounter(), true
+	case _VDSO_TH_ALGO_X86_HPET:
+		var (
+			tc uint32
+			ok bool
+		)
+		systemstack(func() {
+			tc, ok = th.getHPETTimecounter()
+		})
+		return tc, ok
+	default:
+		return 0, false
+	}
+}