CPU affinity configuration fixes

- if no affinity was set for a new thread before calling
  Cpu_session::start(), the CPU session's affinity gets set for this
  thread
- documentation fix: <affinity_space> -> <affinity-space>

Fixes #873.

base-linux/src/core/include/platform_thread.h

@@ -114,7 +114,19 @@ namespace Genode {
 			}
 
 			const char   *name() { return _name; }
-			void          affinity(Affinity::Location) { }
+
+			/**
+			 * Set the executing CPU for this thread
+			 *
+			 * SMP is currently not directly supported on Genode/Linux
+			 * (but indirectly by the Linux kernel).
+			 */
+			void affinity(Affinity::Location) { }
+
+			/**
+			 * Request the affinity of this thread
+			 */
+			Affinity::Location affinity() { return Affinity::Location(); }
 
 			/**
 			 * Register process ID and thread ID of thread

base/src/core/cpu_session_component.cc

@@ -122,6 +122,13 @@ int Cpu_session_component::start(Thread_capability thread_cap,
 	 */
 	thread->update_exception_sigh();
 
+	/*
+	 * If no affinity location was set for this specific thread before,
+	 * we set the one which was defined for the whole CPU session.
+	 */
+	if (!thread->platform_thread()->affinity().valid())
+		thread->platform_thread()->affinity(_location);
+
 	return thread->platform_thread()->start((void *)ip, (void *)sp);
 }
 

doc/release_notes-13-08.txt

@@ -564,7 +564,7 @@ declaration describes an affinity space of 4x2:
 
 ! <config>
 !   ...
-!   <affinity_space width="4" height="2" />
+!   <affinity-space width="4" height="2" />
 !   ...
 ! </config>
 

os/doc/init.txt

@@ -263,7 +263,7 @@ example, the following declaration describes an affinity space of 4x2:
 
 ! <config>
 !   ...
-!   <affinity_space width="4" height="2" />
+!   <affinity-space width="4" height="2" />
 !   ...
 ! </config>