add walltime for linux amd64/arm64

walltime.go

@@ -0,0 +1,5 @@
+//go:build (linux && amd64) || (linux && arm64)
+
+package log
+
+func walltime() (sec int64, nsec int32)

walltime.s

@@ -0,0 +1,26 @@
+#include "textflag.h"
+
+#ifdef GOOS_linux
+#ifdef GOARCH_amd64
+// func walltime() (sec int64, nsec int32)
+TEXT ·walltime(SB), NOSPLIT, $24-12
+	CALL	runtime·nanotime1(SB)
+	MOVQ	AX, ret+0(FP)  // sec
+	MOVL	DX, ret+8(FP)  // nsec
+	RET
+#endif
+#endif
+
+#ifdef GOOS_linux
+#ifdef GOARCH_arm64
+// func walltime() (sec int64, nsec int32)
+TEXT ·walltime(SB), NOSPLIT, $24-12
+    // Call runtime.walltime
+    CALL      runtime·walltime(SB)
+    // Get the return values
+    MOVD    R3, ret+0(FP)  // sec
+    MOVW    R5, ret+8(FP)  // nsec
+    RET
+#endif
+#endif
+

walltime_safe.go

@@ -0,0 +1,16 @@
+//go:build !((linux && amd64) || (linux && arm64))
+
+package log
+
+import (
+	_ "unsafe"
+)
+
+//go:noescape
+//go:linkname time_now time.now
+func time_now() (sec int64, nsec int32, mono int64)
+
+func walltime() (sec int64, nsec int32) {
+	sec, nsec, _ = time_now()
+	return
+}

walltime_test.go

@@ -0,0 +1,11 @@
+package log
+
+import (
+	"testing"
+	"time"
+)
+
+func TestWalltime(t *testing.T) {
+	sec, nsec := walltime()
+	t.Log(time.Unix(sec, int64(nsec)))
+}