Cleanup of parent-cap handling

This patch alleviates the need for a Native_capability::Dst at the API
level. The former use case of this type as argument to
Deprecated_env::reinit uses the opaque Native_capability::Raw type
instead. The 'Raw' type contains the portion of the capability that is
transferred as-is when delegating the capability (i.e., when installing
the parent capability into a new component, or when installing a new
parent capability into a new forked Noux process). This information can
be retrieved via the new Native_capability::raw method.

Furthermore, this patch moves the functions for retriving the parent
capability to base/internal/parent_cap.h, which is meant to be
implemented in platform-specific ways. It replaces the former set of
startup/internal/_main_parent_cap.h headers.

Issue #1993

repos/base-foc/include/base/native_capability.h

@@ -38,7 +38,6 @@ namespace Genode {
 
 			struct Raw
 			{
-				Dst  dst;
 				long local_name;
 			};
 
@@ -107,6 +106,8 @@ namespace Genode {
 			long  local_name() const { return _idx ? _idx->id() : 0;        }
 			Dst   dst()        const { return _idx ? Dst(_idx->kcap()) : Dst(); }
 			bool  valid()      const { return (_idx != 0) && _idx->valid(); }
+
+			Raw raw() const { return { local_name() }; }
 	};
 }
 

repos/base-foc/src/include/base/internal/parent_cap.h

@@ -0,0 +1,50 @@
+/*
+ * \brief  Interface to obtain the parent capability for the component
+ * \author Norman Feske
+ * \date   2013-09-25
+ *
+ * On Fiasco.OC, we transfer merely the 'local_name' part of the capability
+ * via the '_parent_cap' field of the ELF binary.
+ */
+
+/*
+ * Copyright (C) 2006-2013 Genode Labs GmbH
+ *
+ * This file is part of the Genode OS framework, which is distributed
+ * under the terms of the GNU General Public License version 2.
+ */
+
+#ifndef _INCLUDE__BASE__INTERNAL__PARENT_CAP_H_
+#define _INCLUDE__BASE__INTERNAL__PARENT_CAP_H_
+
+/* Genode includes */
+#include <parent/capability.h>
+#include <util/string.h>
+#include <foc/native_capability.h>
+
+/* base-internal includes */
+#include <base/internal/crt0.h>
+
+
+namespace Genode {
+
+	static inline Parent_capability parent_cap()
+	{
+		unsigned long const local_name = _parent_cap;
+
+		static Cap_index *i = cap_map()->insert(local_name,
+		                                        Fiasco::PARENT_CAP);
+		/*
+		 * Update local name after a parent capability got reloaded via
+		 * 'Platform_env::reload_parent_cap()'.
+		 */
+		if (i->id() != local_name) {
+			cap_map()->remove(i);
+			i = cap_map()->insert(local_name, Fiasco::PARENT_CAP);
+		}
+
+		return reinterpret_cap_cast<Parent>(Native_capability(i));
+	}
+}
+
+#endif /* _INCLUDE__BASE__INTERNAL__PARENT_CAP_H_ */

repos/base-foc/src/include/startup/internal/_main_parent_cap.h

@@ -1,49 +0,0 @@
-/*
- * \brief  Obtain parent capability
- * \author Norman Feske
- * \date   2010-01-26
- */
-
-/*
- * Copyright (C) 2010-2013 Genode Labs GmbH
- *
- * This file is part of the Genode OS framework, which is distributed
- * under the terms of the GNU General Public License version 2.
- */
-
-#ifndef _INCLUDE__STARTUP__INTERNAL___MAIN_PARENT_CAP_H_
-#define _INCLUDE__STARTUP__INTERNAL___MAIN_PARENT_CAP_H_
-
-/* Genode includes */
-#include <base/native_capability.h>
-#include <foc/native_capability.h>
-
-/* base-internal includes */
-#include <base/internal/crt0.h>
-
-namespace Genode {
-
-	/**
-	 * Return constructed parent capability
-	 */
-	Parent_capability parent_cap()
-	{
-		Native_capability::Raw *raw = (Native_capability::Raw *)&_parent_cap;
-
-		static Cap_index *i = cap_map()->insert(raw->local_name,
-		                                        Fiasco::PARENT_CAP);
-
-		/*
-		 * Update local name after a parent capability got reloaded via
-		 * 'Platform_env::reload_parent_cap()'.
-		 */
-		if (i->id() != raw->local_name) {
-			cap_map()->remove(i);
-			i = cap_map()->insert(raw->local_name, Fiasco::PARENT_CAP);
-		}
-
-		return reinterpret_cap_cast<Parent>(Native_capability(i));
-	}
-}
-
-#endif /* _INCLUDE__STARTUP__INTERNAL___MAIN_PARENT_CAP_H_ */

repos/base-hw/include/base/native_capability.h

@@ -36,13 +36,7 @@ class Genode::Native_capability
 
 	public:
 
-		struct Raw
+		struct Raw { };
-		{
-			Dst dst;
-
-			/* obsolete in base-hw, but still used in generic code path */
-			addr_t local_name;
-		};
 
 		/**
 		 * Create an invalid capability
@@ -90,6 +84,8 @@ class Genode::Native_capability
 			_inc();
 			return *this;
 		}
+
+		Raw raw() const { return Raw(); }
 };
 
 #endif /* _INCLUDE__BASE__NATIVE_CAPABILITY_H_ */

repos/base-hw/src/include/base/internal/parent_cap.h

@@ -0,0 +1,30 @@
+/*
+ * \brief  Interface to obtain the parent capability for the component
+ * \author Stefan Kalkowski
+ * \date   2015-04-27
+ */
+
+/*
+ * Copyright (C) 2015-2016 Genode Labs GmbH
+ *
+ * This file is part of the Genode OS framework, which is distributed
+ * under the terms of the GNU General Public License version 2.
+ */
+
+#ifndef _INCLUDE__BASE__INTERNAL__PARENT_CAP_H_
+#define _INCLUDE__BASE__INTERNAL__PARENT_CAP_H_
+
+/* Genode includes */
+#include <parent/capability.h>
+
+namespace Hw { extern Genode::Untyped_capability _parent_cap; }
+
+namespace Genode {
+
+	static inline Parent_capability parent_cap()
+	{
+		return reinterpret_cap_cast<Parent>(Hw::_parent_cap);
+	}
+}
+
+#endif /* _INCLUDE__BASE__INTERNAL__PARENT_CAP_H_ */

repos/base-hw/src/include/startup/internal/_main_parent_cap.h

@@ -1,37 +0,0 @@
-/*
- * \brief  Obtain parent capability
- * \author Stefan Kalkowski
- * \date   2015-04-27
- */
-
-/*
- * Copyright (C) 2015 Genode Labs GmbH
- *
- * This file is part of the Genode OS framework, which is distributed
- * under the terms of the GNU General Public License version 2.
- */
-
-#ifndef _INCLUDE__STARTUP__INTERNAL___MAIN_PARENT_CAP_H_
-#define _INCLUDE__STARTUP__INTERNAL___MAIN_PARENT_CAP_H_
-
-/* Genode includes */
-#include <parent/capability.h>
-
-/* base-internal includes */
-#include <base/internal/crt0.h>
-
-namespace Hw { extern Genode::Untyped_capability _parent_cap; }
-
-namespace Genode {
-
-	/**
-	 * Return constructed parent capability
-	 */
-	Parent_capability parent_cap()
-	{
-		/* assemble parent capability */
-		return reinterpret_cap_cast<Parent>(Hw::_parent_cap);
-	}
-}
-
-#endif /* _INCLUDE__STARTUP__INTERNAL___MAIN_PARENT_CAP_H_ */

repos/base-linux/src/include/base/internal/platform_env.h

@@ -90,7 +90,7 @@ class Genode::Platform_env_base : public Env_deprecated
 		Pd_session             *pd_session()      override { return &_local_pd_session; }
 		Pd_session_capability   pd_session_cap()  override { return  _pd_session_cap; }
 
-		void reinit(Native_capability::Dst, long) override;
+		void reinit(Native_capability::Raw) override;
 		void reinit_main_thread(Capability<Region_map> &) override;
 };
 

repos/base-linux/src/lib/base/env_reinit.cc

@@ -18,7 +18,7 @@
 #include <base/internal/platform_env.h>
 
 
-void Genode::Platform_env_base::reinit(Native_capability::Dst, long) { }
+void Genode::Platform_env_base::reinit(Native_capability::Raw) { }
 
 
 void Genode::Platform_env_base::reinit_main_thread(Capability<Region_map> &) { }

repos/base-nova/include/base/native_capability.h

@@ -30,16 +30,7 @@ namespace Genode {
 
 			typedef Nova::Obj_crd Dst;
 
-			struct Raw
+			struct Raw { };
-			{
-				Dst dst;
-
-				/*
-				 * It is obsolete and unused in NOVA, however still used by
-				 * generic base part
-				 */
-				addr_t local_name;
-			};
 
 		private:
 
@@ -169,6 +160,8 @@ namespace Genode {
 			{
 				return Native_capability();
 			}
+
+			Raw raw() const { return Raw(); }
 	};
 }
 

repos/base-nova/src/include/base/internal/parent_cap.h

@@ -1,5 +1,5 @@
 /*
- * \brief  Obtain parent capability
+ * \brief  Interface to obtain the parent capability for the component
  * \author Norman Feske
  * \author Alexander Boettcher
  * \date   2010-01-26
@@ -9,32 +9,29 @@
  */
 
 /*
- * Copyright (C) 2010-2013 Genode Labs GmbH
+ * Copyright (C) 2010-2016 Genode Labs GmbH
  *
  * This file is part of the Genode OS framework, which is distributed
  * under the terms of the GNU General Public License version 2.
  */
 
-#ifndef _INCLUDE__STARTUP__INTERNAL___MAIN_PARENT_CAP_H_
+#ifndef _INCLUDE__BASE__INTERNAL__PARENT_CAP_H_
-#define _INCLUDE__STARTUP__INTERNAL___MAIN_PARENT_CAP_H_
+#define _INCLUDE__BASE__INTERNAL__PARENT_CAP_H_
 
 /* Genode includes */
-#include <util/string.h>
+#include <parent/capability.h>
 
 /* NOVA includes */
 #include <nova/syscalls.h>
 
+
 namespace Genode {
 
-	/**
+	static inline Parent_capability parent_cap()
-	 * Return constructed parent capability
-	 */
-	Parent_capability parent_cap()
 	{
-		/* assemble parent capability */
 		return reinterpret_cap_cast<Parent>(
 			Native_capability(Nova::PT_SEL_PARENT));
 	}
 }
 
-#endif /* _INCLUDE__STARTUP__INTERNAL___MAIN_PARENT_CAP_H_ */
+#endif /* _INCLUDE__BASE__INTERNAL__PARENT_CAP_H_ */

repos/base-sel4/include/base/native_capability.h

@@ -23,12 +23,10 @@ namespace Genode {
 		public:
 
 			/*
-			 * XXX remove dependency in 'process.cc' and 'core_env.h' from
+			 * Platform-specific raw information of the capability that is
-			 * 'Raw', 'Dst', and the 'dst' member.
+			 * transferred as-is when the capability is delegated.
 			 */
-			typedef int Dst;
+			struct Raw { long v[4]; };
-			struct Raw { Dst dst = 0; long local_name = 0; };
-			Dst dst() const { return 0; }
 
 			/**
 			 * Forward declaration of the platform-specific internal capability
@@ -96,6 +94,8 @@ namespace Genode {
 			long local_name() const;
 
 			bool valid() const;
+
+			Raw raw() const { return { { 0, 0, 0, 0 } }; }
 	};
 }
 

repos/base-sel4/src/include/base/internal/parent_cap.h

@@ -1,31 +1,32 @@
 /*
- * \brief  Obtain parent capability
+ * \brief  Interface to obtain the parent capability for the component
  * \author Norman Feske
  * \date   2015-05-12
+ *
+ * On seL4, no information is propagated via the '_parent_cap' field of the
+ * ELF image.
  */
 
 /*
- * Copyright (C) 2015 Genode Labs GmbH
+ * Copyright (C) 2015-2016 Genode Labs GmbH
  *
  * This file is part of the Genode OS framework, which is distributed
  * under the terms of the GNU General Public License version 2.
  */
 
-#ifndef _INCLUDE__STARTUP__INTERNAL___MAIN_PARENT_CAP_H_
+#ifndef _INCLUDE__BASE__INTERNAL__PARENT_CAP_H_
-#define _INCLUDE__STARTUP__INTERNAL___MAIN_PARENT_CAP_H_
+#define _INCLUDE__BASE__INTERNAL__PARENT_CAP_H_
 
 /* Genode includes */
-#include <util/string.h>
+#include <parent/capability.h>
 
 /* base-internal includes */
 #include <base/internal/capability_space_sel4.h>
 
+
 namespace Genode {
 
-	/**
+	static inline Parent_capability parent_cap()
-	 * Return constructed parent capability
-	 */
-	Parent_capability parent_cap()
 	{
 		Capability_space::Ipc_cap_data const
 			ipc_cap_data(Rpc_obj_key(), INITIAL_SEL_PARENT);
@@ -36,4 +37,4 @@ namespace Genode {
 	}
 }
 
-#endif /* _INCLUDE__STARTUP__INTERNAL___MAIN_PARENT_CAP_H_ */
+#endif /* _INCLUDE__BASE__INTERNAL__PARENT_CAP_H_ */

repos/base/include/base/native_capability_tpl.h

@@ -113,6 +113,11 @@ class Genode::Native_capability_tpl
 		 * Return capability destination
 		 */
 		Dst dst() const { return _dst; }
+
+		/**
+		 * Return raw data representation of the capability
+		 */
+		Raw raw() const { return { _dst, _local_name }; }
 };
 
 #endif /* _INCLUDE__BASE__NATIVE_CAPABILITY_TPL_H_ */

repos/base/include/deprecated/env.h

@@ -106,7 +106,7 @@ struct Genode::Env_deprecated
 	 *
 	 * \noapi
 	 */
-	virtual void reinit(Native_capability::Dst, long) = 0;
+	virtual void reinit(Native_capability::Raw) = 0;
 
 	/**
 	 * Reinitialize main-thread object

repos/base/src/core/include/core_env.h

@@ -199,7 +199,7 @@ namespace Genode {
 				return Pd_session_capability();
 			}
 
-			void reinit(Capability<Parent>::Dst, long) override { }
+			void reinit(Capability<Parent>::Raw) override { }
 
 			void reinit_main_thread(Capability<Region_map> &) override { }
 	};

repos/base/src/include/base/internal/crt0.h

@@ -37,8 +37,9 @@ extern unsigned _stack_high;    /* upper bound of intial stack */
  ***************************************************/
 
 /*
- * The protection domain creator initializes the information about
+ * The protection domain creator initializes the information about the parent
- * the parent capability prior the execution of the main thread.
+ * capability prior the execution of the main thread. It corresponds to the
+ * '_parent_cap' symbol defined in 'src/ld/genode.ld'.
  */
 extern unsigned long _parent_cap;
 

repos/base/src/include/base/internal/parent_cap.h

@@ -2,6 +2,9 @@
  * \brief  Interface to obtain the parent capability for the component
  * \author Norman Feske
  * \date   2013-09-25
+ *
+ * This implementation is used on platforms that rely on global IDs (thread
+ * IDs, global unique object IDs) as capability representation.
  */
 
 /*
@@ -14,8 +17,22 @@
 #ifndef _INCLUDE__BASE__INTERNAL__PARENT_CAP_H_
 #define _INCLUDE__BASE__INTERNAL__PARENT_CAP_H_
 
+/* Genode includes */
 #include <parent/capability.h>
+#include <util/string.h>
 
-namespace Genode { Parent_capability parent_cap(); }
+/* base-internal includes */
+#include <base/internal/crt0.h>
+
+
+namespace Genode {
+
+	static inline Parent_capability parent_cap()
+	{
+		Parent_capability cap;
+		memcpy(&cap, (void *)&_parent_cap, sizeof(cap));
+		return Parent_capability(cap);
+	}
+}
 
 #endif /* _INCLUDE__BASE__INTERNAL__PARENT_CAP_H_ */

repos/base/src/include/base/internal/platform_env.h

@@ -108,7 +108,7 @@ class Genode::Platform_env : public Env_deprecated,
 		/*
 		 * Support functions for implementing fork on Noux.
 		 */
-		void reinit(Native_capability::Dst, long) override;
+		void reinit(Native_capability::Raw) override;
 		void reinit_main_thread(Capability<Region_map> &) override;
 
 

repos/base/src/include/startup/internal/_main_parent_cap.h

@@ -1,36 +0,0 @@
-/*
- * \brief  Obtain parent capability
- * \author Norman Feske
- * \date   2010-01-26
- *
- * This implementation is used on platforms that rely on global IDs (thread
- * IDs, global unique object IDs) as capability representation.
- */
-
-/*
- * Copyright (C) 2010-2013 Genode Labs GmbH
- *
- * This file is part of the Genode OS framework, which is distributed
- * under the terms of the GNU General Public License version 2.
- */
-
-#ifndef _INCLUDE__STARTUP__INTERNAL___MAIN_PARENT_CAP_H_
-#define _INCLUDE__STARTUP__INTERNAL___MAIN_PARENT_CAP_H_
-
-/* base-internal includes */
-#include <base/internal/crt0.h>
-
-namespace Genode {
-
-	/**
-	 * Return constructed parent capability
-	 */
-	Parent_capability parent_cap()
-	{
-		Parent_capability cap;
-		memcpy(&cap, (void *)&_parent_cap, sizeof(cap));
-		return Parent_capability(cap);
-	}
-}
-
-#endif /* _INCLUDE__STARTUP__INTERNAL___MAIN_PARENT_CAP_H_ */

repos/base/src/lib/base/child_process.cc

@@ -19,6 +19,7 @@
 
 /* base-internal includes */
 #include <base/internal/elf.h>
+#include <base/internal/parent_cap.h>
 
 using namespace Genode;
 
@@ -123,11 +124,7 @@ Child::Process::Loaded_executable::Loaded_executable(Dataspace_capability elf_ds
 			 * data segment
 			 */
 			if (!parent_info) {
-				Native_capability::Raw *raw = (Native_capability::Raw *)ptr;
+				*(Untyped_capability::Raw *)ptr = parent_cap.raw();
-
-				raw->dst        = parent_cap.dst();
-				raw->local_name = parent_cap.local_name();
-
 				parent_info = true;
 			}
 

repos/base/src/lib/base/env_reinit.cc

@@ -27,8 +27,7 @@ void reinit_main_thread();
 namespace Genode { extern bool inhibit_tracing; }
 
 
-void Genode::Platform_env::reinit(Native_capability::Dst dst,
+void Genode::Platform_env::reinit(Native_capability::Raw raw)
-                                  long local_name)
 {
 	/*
 	 * This function is unused during the normal operation of Genode. It is
@@ -54,9 +53,7 @@ void Genode::Platform_env::reinit(Native_capability::Dst dst,
 	 * Patch new parent capability into the original location as specified by
 	 * the linker script.
 	 */
-	Native_capability::Raw *raw = (Native_capability::Raw *)(&_parent_cap);
+	*(Native_capability::Raw *)(&_parent_cap) = raw;
-	raw->dst                    = dst;
-	raw->local_name             = local_name;
 
 	/*
 	 * Re-initialize 'Platform_env' members

repos/base/src/lib/startup/_main.cc

@@ -26,7 +26,7 @@
 #include <base/component.h>
 
 /* platform-specific local helper functions */
-#include <startup/internal/_main_parent_cap.h>
+#include <base/internal/parent_cap.h>
 #include <base/internal/crt0.h>
 
 

repos/ports-foc/patches/parent_cap_ld_script.patch

@@ -0,0 +1,29 @@
++++ arch/l4/kernel/arch-arm/vmlinux.lds.S
+@@ -108,6 +108,12 @@ SECTIONS
+ 		LONG(0xffffffff);
+ 		_parent_cap_local_name = .;
+ 		LONG(0xffffffff);
++		LONG(0xffffffff);
++		LONG(0xffffffff);
++		LONG(0xffffffff);
++		LONG(0xffffffff);
++		LONG(0xffffffff);
++		LONG(0xffffffff);
+ 	} : rw
+ 
+ 	. = ALIGN(4096);
++++ arch/l4/kernel/arch-x86/vmlinux.lds.S
+@@ -101,6 +101,13 @@ SECTIONS
+ 		LONG(0xffffffff);
+ 		_parent_cap_local_name = .;
+ 		LONG(0xffffffff);
++		LONG(0xffffffff);
++		LONG(0xffffffff);
++		LONG(0xffffffff);
++		LONG(0xffffffff);
++		LONG(0xffffffff);
++		LONG(0xffffffff);
++		LONG(0xffffffff);
+ 
+ 		/*
+ 		 * Platform-specific entry for Fiasco.OC.

repos/ports-foc/ports/l4android.hash

@@ -1 +1 @@
-07d72c264878024efa078d14241f1648172a39de
+1e6243ccb8f368ed15b7f42c339434e46d0062a9

repos/ports-foc/ports/l4android.port

@@ -4,6 +4,8 @@ DOWNLOADS      := l4android.git
 URL(l4android) := https://github.com/skalk/l4linux.git
 REV(l4android) := cea6e7ab97a5ad421e53d456dd940893d5a14866
 DIR(l4android) := src/l4android
+PATCHES        := patches/parent_cap_ld_script.patch
+PATCH_OPT      := -p0 -d src/l4android
 sym_link       := src/l4android/arch/l4/drivers
 
 default: $(sym_link)

repos/ports-foc/ports/l4linux.hash

@@ -1 +1 @@
-64de371ac6ca2e4c117e0d3eb827aa97216d30e7
+153fac6366d79b8380ccc97a3a7ed099cedb51b2

repos/ports-foc/ports/l4linux.port

@@ -4,6 +4,8 @@ DOWNLOADS    := l4linux.git
 URL(l4linux) := https://github.com/skalk/l4linux.git
 REV(l4linux) := 25aa4a5f25c920e18aa18899e45c71974058d813
 DIR(l4linux) := src/l4linux
+PATCHES      := patches/parent_cap_ld_script.patch
+PATCH_OPT    := -p0 -d src/l4linux
 sym_link     := src/l4linux/arch/l4/drivers
 
 default: $(sym_link)

repos/ports/src/lib/libc_noux/plugin.cc

@@ -523,7 +523,7 @@ extern "C" void fork_trampoline()
 {
 	/* reinitialize environment */
 	using namespace Genode;
-	env()->reinit(new_parent.dst, new_parent.local_name);
+	env()->reinit(new_parent);
 
 	/* reinitialize standard-output connection */
 	stdout_reconnect();

repos/ports/src/noux/child.h

@@ -453,8 +453,7 @@ namespace Noux {
 			void start_forked_main_thread(addr_t ip, addr_t sp, addr_t parent_cap_addr)
 			{
 				/* poke parent_cap_addr into child's address space */
-				Capability<Parent> const &cap = _child.parent_cap();
+				Capability<Parent>::Raw const raw = _child.parent_cap().raw();
-				Capability<Parent>::Raw   raw = { cap.dst(), cap.local_name() };
 
 				_pd.poke(parent_cap_addr, &raw, sizeof(raw));