From 57d025c338bbff7250b2d91e159f8a63aeb70469 Mon Sep 17 00:00:00 2001
From: "George V. Neville-Neil" <gnn@FreeBSD.org>
Date: Mon, 16 Jul 2012 20:17:19 +0000
Subject: [PATCH] Add support for walltimestamp in DTrace.

Submitted by:	Fabian Keil
MFC after:	2 weeks
---
 sys/cddl/dev/dtrace/amd64/dtrace_subr.c |  9 +++++++--
 sys/cddl/dev/dtrace/i386/dtrace_subr.c  |  9 +++++++--
 sys/kern/kern_tc.c                      | 20 ++++++++++++++++++++
 3 files changed, 34 insertions(+), 4 deletions(-)

diff --git a/sys/cddl/dev/dtrace/amd64/dtrace_subr.c b/sys/cddl/dev/dtrace/amd64/dtrace_subr.c
index 48952314ecf8..00e3e2480bf6 100644
--- a/sys/cddl/dev/dtrace/amd64/dtrace_subr.c
+++ b/sys/cddl/dev/dtrace/amd64/dtrace_subr.c
@@ -47,6 +47,8 @@
 extern uintptr_t 	dtrace_in_probe_addr;
 extern int		dtrace_in_probe;
 
+extern void dtrace_getnanotime(struct timespec *tsp);
+
 int dtrace_invop(uintptr_t, uintptr_t *, uintptr_t);
 
 typedef struct dtrace_invop_hdlr {
@@ -461,8 +463,11 @@ dtrace_gethrtime()
 uint64_t
 dtrace_gethrestime(void)
 {
-	printf("%s(%d): XXX\n",__func__,__LINE__);
-	return (0);
+	struct timespec current_time;
+
+	dtrace_getnanotime(&current_time);
+
+	return (current_time.tv_sec * 1000000000UL + current_time.tv_nsec);
 }
 
 /* Function to handle DTrace traps during probes. See amd64/amd64/trap.c */
diff --git a/sys/cddl/dev/dtrace/i386/dtrace_subr.c b/sys/cddl/dev/dtrace/i386/dtrace_subr.c
index e8384bf66edf..551e0353a424 100644
--- a/sys/cddl/dev/dtrace/i386/dtrace_subr.c
+++ b/sys/cddl/dev/dtrace/i386/dtrace_subr.c
@@ -49,6 +49,8 @@ extern uintptr_t 	kernelbase;
 extern uintptr_t 	dtrace_in_probe_addr;
 extern int		dtrace_in_probe;
 
+extern void dtrace_getnanotime(struct timespec *tsp);
+
 int dtrace_invop(uintptr_t, uintptr_t *, uintptr_t);
 
 typedef struct dtrace_invop_hdlr {
@@ -462,8 +464,11 @@ dtrace_gethrtime()
 uint64_t
 dtrace_gethrestime(void)
 {
-	printf("%s(%d): XXX\n",__func__,__LINE__);
-	return (0);
+	struct timespec current_time;
+
+	dtrace_getnanotime(&current_time);
+
+	return (current_time.tv_sec * 1000000000UL + current_time.tv_nsec);
 }
 
 /* Function to handle DTrace traps during probes. See i386/i386/trap.c */
diff --git a/sys/kern/kern_tc.c b/sys/kern/kern_tc.c
index 4a75af550764..a08b218cd19c 100644
--- a/sys/kern/kern_tc.c
+++ b/sys/kern/kern_tc.c
@@ -122,6 +122,8 @@ SYSCTL_INT(_kern_timecounter, OID_AUTO, stepwarnings, CTLFLAG_RW,
 static void tc_windup(void);
 static void cpu_tick_calibrate(int);
 
+void dtrace_getnanotime(struct timespec *tsp);
+
 static int
 sysctl_kern_boottime(SYSCTL_HANDLER_ARGS)
 {
@@ -959,6 +961,24 @@ getmicrotime(struct timeval *tvp)
 
 #endif /* FFCLOCK */
 
+/*
+ * This is a clone of getnanotime and used for walltimestamps.
+ * The dtrace_ prefix prevents fbt from creating probes for
+ * it so walltimestamp can be safely used in all fbt probes.
+ */
+void
+dtrace_getnanotime(struct timespec *tsp)
+{
+	struct timehands *th;
+	u_int gen;
+
+	do {
+		th = timehands;
+		gen = th->th_generation;
+		*tsp = th->th_nanotime;
+	} while (gen == 0 || gen != th->th_generation);
+}
+
 /*
  * System clock currently providing time to the system. Modifiable via sysctl
  * when the FFCLOCK option is defined.