diff --git a/bench/benchctxswitch.cpp b/bench/benchctxswitch.cpp
index fa489b35..407f7e41 100644
--- a/bench/benchctxswitch.cpp
+++ b/bench/benchctxswitch.cpp
@@ -11,7 +11,7 @@ int main(int argc, char* argv[])
 
 	uintmax_t start;
 	if ( uptime(&start) ) { perror("uptime"); return 1; }
-	uintmax_t end = start + 1ULL * 1000ULL; // 1 second
+	uintmax_t end = start + 1ULL * 1000ULL * 1000ULL; // 1 second
 	size_t count = 0;
 	uintmax_t now;
 	while ( !uptime(&now) && now < end ) { usleep(0); count += 2; /* back and forth */ }
diff --git a/bench/benchsyscall.cpp b/bench/benchsyscall.cpp
index 1201b106..f78868cc 100644
--- a/bench/benchsyscall.cpp
+++ b/bench/benchsyscall.cpp
@@ -5,7 +5,7 @@ int main(int argc, char* argv[])
 {
 	uintmax_t start;
 	if ( uptime(&start) ) { perror("uptime"); return 1; }
-	uintmax_t end = start + 1ULL * 1000ULL; // 1 second
+	uintmax_t end = start + 1ULL * 1000ULL * 1000ULL; // 1 second
 	size_t count = 0;
 	uintmax_t now;
 	while ( !uptime(&now) && now < end ) { count++; }
diff --git a/libmaxsi/c/hsrc/unistd.h b/libmaxsi/c/hsrc/unistd.h
index e94182e1..8f3ccbe5 100644
--- a/libmaxsi/c/hsrc/unistd.h
+++ b/libmaxsi/c/hsrc/unistd.h
@@ -177,7 +177,7 @@ ssize_t write(int, const void*, size_t);
 
 #ifdef SORTIX_EXTENSIONS
 int memstat(size_t* memused, size_t* memtotal);
-int uptime(uintmax_t* mssinceboot);
+int uptime(uintmax_t* usecssinceboot);
 int writeall(int fd, const void* buffer, size_t len);
 #endif
 
diff --git a/libmaxsi/time.cpp b/libmaxsi/time.cpp
index 4ba2c7ae..22249da2 100644
--- a/libmaxsi/time.cpp
+++ b/libmaxsi/time.cpp
@@ -33,9 +33,9 @@ namespace Maxsi
 	{
 		DEFN_SYSCALL1(int, SysUptime, 34, uintmax_t*);
 
-		extern "C" int uptime(uintmax_t* mssinceboot)
+		extern "C" int uptime(uintmax_t* usecssinceboot)
 		{
-			return SysUptime(mssinceboot);
+			return SysUptime(usecssinceboot);
 		}
 	}
 }
diff --git a/sortix/time.cpp b/sortix/time.cpp
index 808efecf..67f18ef0 100644
--- a/sortix/time.cpp
+++ b/sortix/time.cpp
@@ -85,10 +85,10 @@ namespace Sortix
 
 		bool didUglyIRQ0Hack;
 
-		int SysUptime(uintmax_t* mssinceboot)
+		int SysUptime(uintmax_t* usecssinceboot)
 		{
-			// TODO: HACK!
-			*mssinceboot = ((size_t)microsecondssinceboot) / 1000;
+			// TODO: Validate that usecssinceboot is a valid user-space pointer.
+			*usecssinceboot = microsecondssinceboot;
 			return 0;
 		}
 
diff --git a/utils/uptime.cpp b/utils/uptime.cpp
index d2076042..7031cb09 100644
--- a/utils/uptime.cpp
+++ b/utils/uptime.cpp
@@ -1,24 +1,24 @@
 #include <stdio.h>
 #include <unistd.h>
 
-size_t Seconds(size_t ms)
+size_t Seconds(uintmax_t usecs)
 {
-	return (ms / 1000UL) % (60UL);
+	return (usecs / (1000ULL * 1000ULL)) % (60ULL);
 }
 
-size_t Minutes(size_t ms)
+size_t Minutes(uintmax_t usecs)
 {
-	return (ms / (1000UL * 60UL)) % (60UL);
+	return (usecs / (1000ULL * 1000ULL * 60ULL)) % (60ULL);
 }
 
-size_t Hours(size_t ms)
+size_t Hours(uintmax_t usecs)
 {
-	return (ms / (1000UL * 60UL * 60UL)) % (24UL);
+	return (usecs / (1000ULL * 1000ULL * 60ULL * 60ULL)) % (24ULL);
 }
 
-size_t Days(size_t ms)
+size_t Days(uintmax_t usecs)
 {
-	return (ms / (1000UL * 60UL * 60UL * 24UL)) % (24UL);
+	return usecs / (1000ULL * 1000ULL * 60ULL * 60ULL * 24ULL);
 }
 
 void PrintElement(size_t num, const char* single, const char* multiple)