runtime: make nanotime use monotonic clock in Solaris

nanotime() currently uses the REALTIME clock to get the elapsed
time in Solaris. This commit changes it to use the MONOTONIC clock
instead, similar to how it's done in Linux and other OSs. Also changed
nanotime() and walltime() to call clock_gettime() library function
directly from Go code rather than from assembly.

Fixes #33674

Change-Id: Ie4a687b17d2140998ecd97af6ce048c86cf5fc02
Reviewed-on: https://go-review.googlesource.com/c/go/+/199502
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Aram Hăvărneanu <aram@mgk.ro>

1 files changed, 13 insertions, 2 deletions

diff --git a/src/runtime/os3_solaris.go b/src/runtime/os3_solaris.go
index afda44295b..cdec190de5 100644
--- a/src/runtime/os3_solaris.go
+++ b/src/runtime/os3_solaris.go
@@ -393,11 +393,16 @@ func munmap(addr unsafe.Pointer, n uintptr) {
 	sysvicall2(&libc_munmap, uintptr(addr), uintptr(n))
 }
 
-func nanotime2()
+const (
+	_CLOCK_REALTIME  = 3
+	_CLOCK_MONOTONIC = 4
+)
 
 //go:nosplit
 func nanotime1() int64 {
-	return int64(sysvicall0((*libcFunc)(unsafe.Pointer(funcPC(nanotime2)))))
+	var ts mts
+	sysvicall2(&libc_clock_gettime, _CLOCK_MONOTONIC, uintptr(unsafe.Pointer(&ts)))
+	return ts.tv_sec*1e9 + ts.tv_nsec
 }
 
 //go:nosplit
@@ -498,6 +503,12 @@ func usleep(µs uint32) {
 	usleep1(µs)
 }
 
+func walltime1() (sec int64, nsec int32) {
+	var ts mts
+	sysvicall2(&libc_clock_gettime, _CLOCK_REALTIME, uintptr(unsafe.Pointer(&ts)))
+	return ts.tv_sec, int32(ts.tv_nsec)
+}
+
 //go:nosplit
 func write1(fd uintptr, buf unsafe.Pointer, nbyte int32) int32 {
 	return int32(sysvicall3(&libc_write, uintptr(fd), uintptr(buf), uintptr(nbyte)))