base: hide internals of the Thread API

This patch moves details about the stack allocation and organization the base-internal headers. Thereby, I replaced the notion of "thread contexts" by "stacks" as this term is much more intuitive. The fact that we place thread-specific information at the bottom of the stack is not worth introducing new terminology. Issue genodelabs#1832
chelmuth · Mar 1, 2016 · 86ccfa0 · 86ccfa0
1 parent 5f17343
commit 86ccfa0
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diff --git a/repos/base-fiasco/include/base/native_types.h b/repos/base-fiasco/include/base/native_types.h
@@ -65,7 +65,7 @@ namespace Genode {
 	/**
 	 * Empty UTCB type expected by the thread library
 	 *
-	 * On this kernel, UTCBs are not placed within the the context area. Each
+	 * On this kernel, UTCBs are not placed within the the stack area. Each
 	 * thread can request its own UTCB pointer using the kernel interface.
 	 */
 	typedef struct { } Native_utcb;
@@ -76,17 +76,17 @@ namespace Genode {
 	struct Native_config
 	{
 		/**
-		 * Thread-context area configuration.
+		 * Stack area configuration
 		 */
-		static constexpr addr_t context_area_virtual_base() {
+		static constexpr addr_t stack_area_virtual_base() {
 			return 0x40000000UL; }
-		static constexpr addr_t context_area_virtual_size() {
+		static constexpr addr_t stack_area_virtual_size() {
 			return 0x10000000UL; }
 
 		/**
-		 * Size of virtual address region holding the context of one thread
+		 * Size of virtual address region holding the stack of one thread
 		 */
-		static constexpr addr_t context_virtual_size() { return 0x00100000UL; }
+		static constexpr addr_t stack_virtual_size() { return 0x00100000UL; }
 	};
 
 	struct Native_pd_args { };

diff --git a/repos/base-fiasco/lib/mk/base-common.mk b/repos/base-fiasco/lib/mk/base-common.mk
@@ -21,7 +21,7 @@ SRC_CC += signal/signal.cc signal/common.cc signal/platform.cc
 SRC_CC += server/server.cc server/common.cc
 SRC_CC += thread/thread.cc thread/thread_bootstrap.cc thread/trace.cc
 SRC_CC += thread/myself.cc
-SRC_CC += thread/context_allocator.cc
+SRC_CC += thread/stack_allocator.cc
 SRC_CC += entrypoint/entrypoint.cc
 SRC_CC += sleep.cc
 SRC_CC += rm_session_client.cc

diff --git a/repos/base-fiasco/lib/mk/base.mk b/repos/base-fiasco/lib/mk/base.mk
@@ -8,7 +8,7 @@ LIBS += base-common
 
 SRC_CC += console/log_console.cc
 SRC_CC += cpu/cache.cc
-SRC_CC += env/env.cc env/context_area.cc env/reinitialize.cc
+SRC_CC += env/env.cc env/stack_area.cc env/reinitialize.cc
 SRC_CC += thread/thread_start.cc
 SRC_CC += irq/platform.cc
 SRC_CC += server/rpc_cap_alloc.cc

diff --git a/repos/base-fiasco/src/core/platform.cc b/repos/base-fiasco/src/core/platform.cc
@@ -306,8 +306,8 @@ void Platform::_setup_mem_alloc()
 				}
 
 				region.start = addr; region.end = addr + size;
-				if (!region.intersects(Native_config::context_area_virtual_base(),
-				                       Native_config::context_area_virtual_size())) {
+				if (!region.intersects(Native_config::stack_area_virtual_base(),
+				                       Native_config::stack_area_virtual_size())) {
 					add_region(region, _ram_alloc);
 					add_region(region, _core_address_ranges());
 				}
@@ -411,9 +411,9 @@ void Platform::_setup_basics()
 	_vm_start = _vm_start == 0 ? L4_PAGESIZE : _vm_start;
 	_region_alloc.add_range(_vm_start, _vm_size);
 
-	/* preserve context area in core's virtual address space */
-	_region_alloc.remove_range(Native_config::context_area_virtual_base(),
-	                           Native_config::context_area_virtual_size());
+	/* preserve stack area in core's virtual address space */
+	_region_alloc.remove_range(Native_config::stack_area_virtual_base(),
+	                           Native_config::stack_area_virtual_size());
 
 	/* I/O memory could be the whole user address space */
 	/* FIXME if the kernel helps to find out max address - use info here */

diff --git a/repos/base-fiasco/src/core/target.inc b/repos/base-fiasco/src/core/target.inc
@@ -2,7 +2,7 @@ TARGET       = core
 
 GEN_CORE_DIR = $(BASE_DIR)/src/core
 
-SRC_CC      += context_area.cc \
+SRC_CC      += stack_area.cc \
                core_printf.cc \
                core_rpc_cap_alloc.cc \
                cpu_session_component.cc \
@@ -62,7 +62,7 @@ vpath signal_source_component.cc  $(GEN_CORE_DIR)
 vpath trace_session_component.cc  $(GEN_CORE_DIR)
 vpath dataspace_component.cc      $(GEN_CORE_DIR)
 vpath dump_alloc.cc               $(GEN_CORE_DIR)
-vpath context_area.cc             $(GEN_CORE_DIR)
+vpath stack_area.cc               $(GEN_CORE_DIR)
 vpath pager_object.cc             $(GEN_CORE_DIR)
 vpath pager_ep.cc                 $(GEN_CORE_DIR)
 vpath core_printf.cc              $(BASE_DIR)/src/base/console

diff --git a/repos/base-fiasco/src/core/thread_start.cc b/repos/base-fiasco/src/core/thread_start.cc
@@ -15,6 +15,9 @@
 #include <base/thread.h>
 #include <base/sleep.h>
 
+/* base-internal includes */
+#include <base/internal/stack.h>
+
 /* core includes */
 #include <platform.h>
 #include <core_env.h>
@@ -35,7 +38,7 @@ void Thread_base::start()
 {
 	/* create and start platform thread */
 	_tid.pt = new(platform()->core_mem_alloc())
-		Platform_thread(0, _context->name);
+		Platform_thread(0, _stack->name().string());
 
 	platform_specific()->core_pd()->bind_thread(_tid.pt);
 

diff --git a/repos/base-foc/include/base/native_types.h b/repos/base-foc/include/base/native_types.h
@@ -82,9 +82,29 @@ namespace Fiasco {
 namespace Genode {
 
 	typedef Fiasco::l4_cap_idx_t Native_thread_id;
-	typedef Fiasco::l4_cap_idx_t Native_thread;
+
+
+	struct Native_thread
+	{
+		Fiasco::l4_cap_idx_t kcap = 0;
+
+		Native_thread() { }
+		explicit Native_thread(Fiasco::l4_cap_idx_t kcap) : kcap(kcap) { }
+	};
+
+
 	typedef Fiasco::l4_cap_idx_t Native_task;
-	typedef Fiasco::l4_utcb_t*   Native_utcb;
+
+
+	struct Native_utcb
+	{
+		/*
+		 * The 'Native_utcb' is located within the stack slot of the thread.
+		 * We merely use it for remembering a pointer to the real UTCB, which
+		 * resides somewhere in the kernel's address space.
+		 */
+		Fiasco::l4_utcb_t *foc_utcb = nullptr;
+	};
 
 
 	/**

diff --git a/repos/base-foc/include/base/thread_state.h b/repos/base-foc/include/base/thread_state.h
@@ -24,9 +24,9 @@ namespace Genode {
 
 	struct Thread_state : Thread_state_base
 	{
-		Native_thread         kcap;         /* thread's gate cap in its pd */
+		Fiasco::l4_cap_idx_t  kcap;         /* thread's gate cap in its pd */
 		int                   id;           /* id of gate capability */
-		Native_utcb           utcb;         /* thread's utcb in its pd */
+		addr_t                utcb;         /* thread's utcb in its pd */
 		unsigned              exceptions;   /* counts exceptions raised by the thread */
 		bool                  paused;       /* indicates whether thread is stopped */
 		bool                  in_exception; /* true if thread is in exception */

diff --git a/repos/base-foc/include/signal_source/client.h b/repos/base-foc/include/signal_source/client.h
@@ -53,7 +53,7 @@ namespace Genode {
 				_sem = call<Rpc_request_semaphore>();
 
 				l4_msgtag_t tag = l4_irq_attach(_sem.dst(), 0,
-				                                Thread_base::myself()->tid());
+				                                Thread_base::myself()->tid().kcap);
 				if (l4_error(tag))
 					PERR("l4_irq_attach failed with %ld!", l4_error(tag));
 			}

diff --git a/repos/base-foc/include/spec/arm/base/native_config.h b/repos/base-foc/include/spec/arm/base/native_config.h
@@ -1,5 +1,5 @@
 /*
- * \brief  Platform-specific context area definitions
+ * \brief  Platform-specific stack area definitions
  * \author Stefan Kalkowski
  * \date   2014-01-24
  */
@@ -21,17 +21,17 @@ namespace Genode {
 	struct Native_config
 	{
 		/**
-		 * Thread-context area configuration
+		 * Stack area configuration
 		 */
-		static constexpr addr_t context_area_virtual_base() {
+		static constexpr addr_t stack_area_virtual_base() {
 			return 0x20000000UL; }
-		static constexpr addr_t context_area_virtual_size() {
+		static constexpr addr_t stack_area_virtual_size() {
 			return 0x10000000UL; }
 
 		/**
-		 * Size of virtual address region holding the context of one thread
+		 * Size of virtual address region holding the stack of one thread
 		 */
-		static constexpr addr_t context_virtual_size() { return 0x00100000UL; }
+		static constexpr addr_t stack_virtual_size() { return 0x00100000UL; }
 	};
 }
 

diff --git a/repos/base-foc/include/spec/x86/base/native_config.h b/repos/base-foc/include/spec/x86/base/native_config.h
@@ -1,5 +1,5 @@
 /*
- * \brief  Platform-specific context area definitions
+ * \brief  Platform-specific stack area definitions
  * \author Stefan Kalkowski
  * \date   2014-01-24
  */
@@ -21,17 +21,17 @@ namespace Genode {
 	struct Native_config
 	{
 		/**
-		 * Thread-context area configuration
+		 * Stack area configuration
 		 */
-		static constexpr addr_t context_area_virtual_base() {
+		static constexpr addr_t stack_area_virtual_base() {
 			return 0x40000000UL; }
-		static constexpr addr_t context_area_virtual_size() {
+		static constexpr addr_t stack_area_virtual_size() {
 			return 0x10000000UL; }
 
 		/**
-		 * Size of virtual address region holding the context of one thread
+		 * Size of virtual address region holding the stack of one thread
 		 */
-		static constexpr addr_t context_virtual_size() { return 0x00100000UL; }
+		static constexpr addr_t stack_virtual_size() { return 0x00100000UL; }
 	};
 }
 

diff --git a/repos/base-foc/lib/mk/base-common.mk b/repos/base-foc/lib/mk/base-common.mk
@@ -21,7 +21,8 @@ SRC_CC += signal/signal.cc signal/common.cc signal/platform.cc
 SRC_CC += server/server.cc server/common.cc
 SRC_CC += thread/thread.cc thread/thread_bootstrap.cc thread/trace.cc
 SRC_CC += thread/myself.cc
-SRC_CC += thread/context_allocator.cc
+SRC_CC += thread/stack_allocator.cc
+SRC_CC += thread/thread_utcb.cc
 SRC_CC += entrypoint/entrypoint.cc
 SRC_CC += sleep.cc
 SRC_CC += rm_session_client.cc

diff --git a/repos/base-foc/lib/mk/base.mk b/repos/base-foc/lib/mk/base.mk
@@ -8,7 +8,7 @@ LIBS += base-common
 
 SRC_CC += console/log_console.cc
 SRC_CC += cpu/cache.cc
-SRC_CC += env/env.cc env/context_area.cc env/reinitialize.cc \
+SRC_CC += env/env.cc env/stack_area.cc env/reinitialize.cc \
           env/cap_map_remove.cc env/cap_alloc.cc
 SRC_CC += thread/thread_start.cc
 SRC_CC += irq/platform.cc

diff --git a/repos/base-foc/src/base/thread/thread_start.cc b/repos/base-foc/src/base/thread/thread_start.cc
@@ -19,6 +19,9 @@
 #include <base/sleep.h>
 #include <base/env.h>
 
+/* base-internal includes */
+#include <base/internal/stack.h>
+
 namespace Fiasco {
 #include <l4/sys/utcb.h>
 }
@@ -30,8 +33,8 @@ void Thread_base::_deinit_platform_thread()
 {
 	using namespace Fiasco;
 
-	if (_context->utcb && _thread_cap.valid()) {
-		Cap_index *i = (Cap_index*)l4_utcb_tcr_u(_context->utcb)->user[UTCB_TCR_BADGE];
+	if (_tid.kcap && _thread_cap.valid()) {
+		Cap_index *i = (Cap_index*)l4_utcb_tcr_u(utcb()->foc_utcb)->user[UTCB_TCR_BADGE];
 		cap_map()->remove(i);
 		_cpu_session->kill_thread(_thread_cap);
 		env()->rm_session()->remove_client(_pager_cap);
@@ -59,7 +62,7 @@ void Thread_base::_init_platform_thread(size_t weight, Type type)
 		return;
 	}
 	/* adjust values whose computation differs for a main thread */
-	_tid = Fiasco::MAIN_THREAD_CAP;
+	_tid.kcap = Fiasco::MAIN_THREAD_CAP;
 	_thread_cap = env()->parent()->main_thread_cap();
 
 	if (!_thread_cap.valid())
@@ -83,15 +86,19 @@ void Thread_base::start()
 	Thread_state state;
 	try { state = _cpu_session->state(_thread_cap); }
 	catch (...) { throw Cpu_session::Thread_creation_failed(); }
-	_tid = state.kcap;
-	_context->utcb = state.utcb;
+
+	/* remember UTCB of the new thread */
+	Fiasco::l4_utcb_t * const foc_utcb = (Fiasco::l4_utcb_t *)state.utcb;
+	utcb()->foc_utcb = foc_utcb;
+
+	_tid = Native_thread(state.kcap);
 
 	Cap_index *i = cap_map()->insert(state.id, state.kcap);
-	l4_utcb_tcr_u(state.utcb)->user[UTCB_TCR_BADGE]      = (unsigned long) i;
-	l4_utcb_tcr_u(state.utcb)->user[UTCB_TCR_THREAD_OBJ] = (addr_t)this;
+	l4_utcb_tcr_u(foc_utcb)->user[UTCB_TCR_BADGE]      = (unsigned long) i;
+	l4_utcb_tcr_u(foc_utcb)->user[UTCB_TCR_THREAD_OBJ] = (addr_t)this;
 
 	/* register initial IP and SP at core */
-	_cpu_session->start(_thread_cap, (addr_t)_thread_start, _context->stack_top());
+	_cpu_session->start(_thread_cap, (addr_t)_thread_start, _stack->top());
 }
 
 

diff --git a/repos/base-foc/src/core/cpu_session_extension.cc b/repos/base-foc/src/core/cpu_session_extension.cc
@@ -43,7 +43,7 @@ void Genode::Cpu_session_component::enable_vcpu(Genode::Thread_capability thread
 	auto lambda = [&] (Cpu_thread_component *thread) {
 		if (!thread) return;
 
-		Native_thread tid = thread->platform_thread()->thread().local.dst();
+		l4_cap_idx_t tid = thread->platform_thread()->thread().local.dst();
 
 		l4_msgtag_t tag = l4_thread_vcpu_control(tid, vcpu_state);
 		if (l4_msgtag_has_error(tag))
@@ -103,7 +103,7 @@ void Genode::Cpu_session_component::single_step(Genode::Thread_capability thread
 	auto lambda = [&] (Cpu_thread_component *thread) {
 		if (!thread) return;
 
-		Native_thread tid = thread->platform_thread()->thread().local.dst();
+		Fiasco::l4_cap_idx_t tid = thread->platform_thread()->thread().local.dst();
 
 		enum { THREAD_SINGLE_STEP = 0x40000 };
 		int flags = enable ? THREAD_SINGLE_STEP : 0;

diff --git a/repos/base-foc/src/core/include/irq_object.h b/repos/base-foc/src/core/include/irq_object.h
@@ -38,7 +38,7 @@ class Genode::Irq_object
 
 		Signal_context_capability _sig_cap;
 
-		Native_thread _capability() const { return _cap->kcap(); }
+		Fiasco::l4_cap_idx_t _capability() const { return _cap->kcap(); }
 
 	public:
 

diff --git a/repos/base-foc/src/core/include/platform_pd.h b/repos/base-foc/src/core/include/platform_pd.h
@@ -48,8 +48,8 @@ namespace Genode {
 
 			addr_t utcb_area_start()
 			{
-				return (Native_config::context_area_virtual_base() +
-				       THREAD_MAX * Native_config::context_virtual_size());
+				return (Native_config::stack_area_virtual_base() +
+				       THREAD_MAX * Native_config::stack_virtual_size());
 			}
 
 			Cap_mapping       _task;

diff --git a/repos/base-foc/src/core/include/platform_thread.h b/repos/base-foc/src/core/include/platform_thread.h
@@ -42,7 +42,7 @@ namespace Genode {
 			Cap_mapping        _gate;
 			Cap_mapping        _pager;
 			Cap_mapping        _irq;
-			Native_utcb        _utcb;
+			addr_t             _utcb;
 			char               _name[32];       /* thread name that will be
 			                                      registered at the kernel
 			                                      debugger */
@@ -185,7 +185,7 @@ namespace Genode {
 			Cap_mapping& gate()              { return _gate;        }
 			const char  *name()        const { return _name;        }
 			bool         core_thread() const { return _core_thread; }
-			Native_utcb  utcb()        const { return _utcb;        }
+			addr_t       utcb()        const { return _utcb;        }
 	};
 }
 

diff --git a/repos/base-foc/src/core/ipc_pager.cc b/repos/base-foc/src/core/ipc_pager.cc
@@ -106,7 +106,7 @@ void Ipc_pager::reply_and_wait_for_fault()
 	}
 	l4_utcb_mr()->mr[1] = _reply_mapping.fpage().raw;
 
-	_tag = l4_ipc_send_and_wait(_last, l4_utcb(), snd_tag,
+	_tag = l4_ipc_send_and_wait(_last.kcap, l4_utcb(), snd_tag,
 	                            &label, L4_IPC_SEND_TIMEOUT_0);
 	int err = l4_ipc_error(_tag, l4_utcb());
 	if (err) {
@@ -119,7 +119,7 @@ void Ipc_pager::reply_and_wait_for_fault()
 
 void Ipc_pager::acknowledge_wakeup()
 {
-	l4_cap_idx_t dst = Fiasco::Capability::valid(_last) ? _last : L4_SYSF_REPLY;
+	l4_cap_idx_t dst = Fiasco::Capability::valid(_last.kcap) ? _last.kcap : L4_SYSF_REPLY;
 
 	/* answer wakeup call from one of core's region-manager sessions */
 	l4_ipc_send(dst, l4_utcb(), l4_msgtag(0, 0, 0, 0), L4_IPC_SEND_TIMEOUT_0);
@@ -129,7 +129,7 @@ void Ipc_pager::acknowledge_wakeup()
 void Ipc_pager::acknowledge_exception()
 {
 	memcpy(l4_utcb_exc(), &_regs, sizeof(l4_exc_regs_t));
-	l4_cap_idx_t dst = Fiasco::Capability::valid(_last) ? _last : L4_SYSF_REPLY;
+	l4_cap_idx_t dst = Fiasco::Capability::valid(_last.kcap) ? _last.kcap : L4_SYSF_REPLY;
 	l4_ipc_send(dst, l4_utcb(), l4_msgtag(0, L4_UTCB_EXCEPTION_REGS_SIZE, 0, 0), L4_IPC_SEND_TIMEOUT_0);
 }
 

diff --git a/repos/base-foc/src/core/irq_session_component.cc b/repos/base-foc/src/core/irq_session_component.cc
@@ -53,7 +53,7 @@ class Genode::Interrupt_handler : public Thread<2048*sizeof(long)>
 
 		void entry();
 
-		static Native_thread handler_cap()
+		static Fiasco::l4_cap_idx_t handler_cap()
 		{
 			static Interrupt_handler handler;
 			return handler._thread_cap.dst();