base: remove dependency from deprecated APIs

This patch adjusts the implementation of the base library and core such
that the code no longer relies on deprecated APIs except for very few
cases, mainly to keep those deprecated APIs in tact for now.

The most prominent changes are:

- Removing the use of base/printf.h

- Removing of the log backend for printf. The 'Console' with the
  format-string parser is still there along with 'snprintf.h' because
  the latter is still used at a few places, most prominently the
  'Connection' classes.

- Removing the notion of a RAM session, which does not exist in
  Genode anymore. Still the types were preserved (by typedefs to
  PD session) to keep up compatibility. But this transition should
  come to an end now.

- Slight rennovation of core's tracing service, e.g., the use of an
  Attached_dataspace as the Argument_buffer.

- Reducing the reliance on global accessors like deprecated_env() or
  core_env(). Still there is a longish way to go to eliminate all such
  calls. A useful pattern (or at least a stop-gap solution) is to
  pass the 'Env' to the individual compilation units via init functions.

- Avoiding the use of the old 'Child_policy::resolve_session_request'
  interface that returned a 'Service' instead of a 'Route'.

Issue #1987

repos/base-nova/src/timer/nova/time_source.cc

@@ -12,9 +12,6 @@
  * under the terms of the GNU Affero General Public License version 3.
  */
 
-/* Genode includes */
-#include <base/attached_rom_dataspace.h>
-
 /* NOVA includes */
 #include <nova/native_thread.h>
 
@@ -25,17 +22,6 @@ using namespace Genode;
 using namespace Nova;
 
 
-Timer::Time_source::Time_source(Env &env) : Threaded_time_source(env)
-{
-	/* read out the tsc frequency once */
-	Attached_rom_dataspace const platform_info { env, "platform_info" };
-	Xml_node const hardware = platform_info.xml().sub_node("hardware");
-	hardware.sub_node("tsc").attribute("freq_khz").value(&_tsc_khz);
-
-	start();
-}
-
-
 void Timer::Time_source::schedule_timeout(Microseconds     duration,
                                           Timeout_handler &handler)
 {

repos/base-nova/src/timer/nova/time_source.h

@@ -17,6 +17,7 @@
 
 /* Genode includes */
 #include <trace/timestamp.h>
+#include <base/attached_rom_dataspace.h>
 
 /* local includes */
 #include <threaded_time_source.h>
@@ -28,9 +29,24 @@ class Timer::Time_source : public Threaded_time_source
 {
 	private:
 
+		/* read the tsc frequency from platform info */
+		static unsigned long _obtain_tsc_khz(Genode::Env &env)
+		{
+			try {
+				Genode::Attached_rom_dataspace info { env, "platform_info"};
+
+				return info.xml()
+				           .sub_node("hardware")
+				           .sub_node("tsc")
+				           .attribute_value("freq_khz", 0UL);
+			} catch (...) { }
+
+			return 0;
+		}
+
 		Genode::addr_t           _sem        { ~0UL };
 		unsigned long            _timeout_us { 0 };
-		unsigned long            _tsc_khz    { 0 };
+		unsigned long      const _tsc_khz;
 		Duration                 _curr_time  { Microseconds(0) };
 		Genode::Trace::Timestamp _tsc_start  { Genode::Trace::timestamp() };
 		Genode::Trace::Timestamp _tsc_last   { _tsc_start };
@@ -52,8 +68,12 @@ class Timer::Time_source : public Threaded_time_source
 
 	public:
 
-		Time_source(Genode::Env &env);
-
+		Time_source(Genode::Env &env)
+		:
+			Threaded_time_source(env), _tsc_khz(_obtain_tsc_khz(env))
+		{
+			start();
+		}
 
 		/*************************
 		 ** Genode::Time_source **