hw: increase timing accuracy of kernel (fix #3081)

* Introduce 64-bit tick counter
* Let the timer always count when possible, also if it already fired
* Simplify the kernel syscall API to have one current time call,
  which returns the elapsed microseconds since boot

repos/base-hw/include/kernel/interface.h

@@ -40,7 +40,6 @@ namespace Kernel
 	constexpr Call_arg call_id_ack_cap()                  { return 14; }
 	constexpr Call_arg call_id_delete_cap()               { return 15; }
 	constexpr Call_arg call_id_timeout()                  { return 16; }
-	constexpr Call_arg call_id_timeout_age_us()           { return 17; }
 	constexpr Call_arg call_id_timeout_max_us()           { return 18; }
 	constexpr Call_arg call_id_time()                     { return 19; }
 
@@ -80,6 +79,8 @@ namespace Kernel
 	              Call_arg arg_4,
 	              Call_arg arg_5);
 
+	Call_ret_64 call64(Call_arg arg_0);
+
 
 	/**
 	 * Install timeout for calling thread
@@ -90,23 +91,12 @@ namespace Kernel
 	 * This call always overwrites the last timeout installed by the thread
 	 * if any.
 	 */
-	inline int timeout(time_t const duration_us, capid_t const sigid)
+	inline int timeout(timeout_t const duration_us, capid_t const sigid)
 	{
 		return call(call_id_timeout(), duration_us, sigid);
 	}
 
 
-	/**
-	 * Return time in microseconds since the caller installed its last timeout
-	 *
-	 * Must not be called if the installation is older than 'timeout_max_us'.
-	 */
-	inline time_t timeout_age_us()
-	{
-		return call(call_id_timeout_age_us());
-	}
-
-
 	/**
 	 * Return value of a free-running, uniform counter
 	 *
@@ -115,7 +105,7 @@ namespace Kernel
 	 */
 	inline time_t time()
 	{
-		return call(call_id_time());
+		return call64(call_id_time());
 	}
 
 
@@ -127,7 +117,7 @@ namespace Kernel
 	 */
 	inline time_t timeout_max_us()
 	{
-		return call(call_id_timeout_max_us());
+		return call64(call_id_timeout_max_us());
 	}
 
 

repos/base-hw/include/kernel/types.h

@@ -20,10 +20,11 @@
 
 namespace Kernel
 {
-	using addr_t  = Genode::addr_t;
-	using size_t  = Genode::size_t;
-	using capid_t = Genode::uint16_t;
-	using time_t  = unsigned long;
+	using addr_t    = Genode::addr_t;
+	using size_t    = Genode::size_t;
+	using capid_t   = Genode::uint16_t;
+	using time_t    = Genode::uint64_t;
+	using timeout_t = Genode::uint32_t;
 
 	constexpr capid_t cap_id_invalid() { return 0; }
 }

repos/base-hw/include/spec/arm/kernel/interface_support.h

@@ -21,6 +21,7 @@ namespace Kernel
 {
 	typedef Genode::uint32_t Call_arg;
 	typedef Genode::uint32_t Call_ret;
+	typedef Genode::uint64_t Call_ret_64;
 }
 
 #endif /* _INCLUDE__SPEC__ARM__KERNEL__INTERFACE_SUPPORT_H_ */

repos/base-hw/include/spec/riscv/kernel/interface_support.h

@@ -21,6 +21,7 @@ namespace Kernel
 {
 	typedef Genode::uint64_t Call_arg;
 	typedef Genode::uint64_t Call_ret;
+	typedef Genode::uint64_t Call_ret_64;
 }
 
 #endif /* _KERNEL__INTERFACE_SUPPORT_H_ */

repos/base-hw/include/spec/x86_64/kernel/interface_support.h

@@ -21,6 +21,7 @@ namespace Kernel
 {
 	typedef Genode::uint64_t Call_arg;
 	typedef Genode::uint64_t Call_ret;
+	typedef Genode::uint64_t Call_ret_64;
 }
 
 #endif /* _INCLUDE__SPEC__X86_64__KERNEL__INTERFACE_SUPPORT_H_ */