fd401bdf53
This patch cleans up the thread API and comes with the following noteworthy changes: - Introduced Cpu_session::Weight type that replaces a formerly used plain integer value to prevent the accidental mix-up of arguments. - The enum definition of Cpu_session::DEFAULT_WEIGHT moved to Cpu_session::Weight::DEFAULT_WEIGHT - New Thread constructor that takes a 'Env &' as first argument. The original constructors are now marked as deprecated. For the common use case where the default 'Weight' and 'Affinity' are used, a shortcut is provided. In the long term, those two constructors should be the only ones to remain. - The former 'Thread<>' class template has been renamed to 'Thread_deprecated'. - The former 'Thread_base' class is now called 'Thread'. - The new 'name()' accessor returns the thread's name as 'Name' object as centrally defined via 'Cpu_session::Name'. It is meant to replace the old-fashioned 'name' method that takes a buffer and size as arguments. - Adaptation of the thread test to the new API Issue #1954
136 lines
3.7 KiB
C++
136 lines
3.7 KiB
C++
/*
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* \brief Setup the thread environment of a programs first thread
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* \author Christian Helmuth
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* \author Christian Prochaska
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* \author Martin Stein
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* \date 2013-12-04
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*/
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/*
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* Copyright (C) 2013 Genode Labs GmbH
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*
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* This file is part of the Genode OS framework, which is distributed
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* under the terms of the GNU General Public License version 2.
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*/
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/* Genode includes */
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#include <util/construct_at.h>
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#include <base/env.h>
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#include <base/printf.h>
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#include <base/thread.h>
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/* base-internal includes */
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#include <base/internal/globals.h>
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using namespace Genode;
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addr_t init_main_thread_result;
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extern void init_exception_handling();
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namespace Genode { extern Region_map * env_stack_area_region_map; }
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void prepare_init_main_thread();
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enum { MAIN_THREAD_STACK_SIZE = 16UL * 1024 * sizeof(Genode::addr_t) };
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/**
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* Satisfy crt0.s in static programs, LDSO overrides this symbol
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*/
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extern "C" void init_rtld() __attribute__((weak));
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void init_rtld() { }
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/**
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* The first thread in a program
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*/
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class Main_thread : public Thread_deprecated<MAIN_THREAD_STACK_SIZE>
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{
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public:
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/**
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* Constructor
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*
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* \param reinit wether this is called for reinitialization
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*/
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Main_thread(bool reinit)
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:
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Thread_deprecated("main", reinit ? REINITIALIZED_MAIN : MAIN)
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{ }
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/**********************
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** Thread interface **
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**********************/
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void entry() { }
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};
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Main_thread * main_thread()
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{
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static Main_thread s(false);
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return &s;
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}
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/**
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* Create a thread object for the main thread
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*
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* \return stack pointer of the new environment via init_main_thread_result
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*
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* This function must be called only once per program and before the _main
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* function. It can be called as soon as a temporary environment provides
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* some stack space and inter-process communication. At this stage, global
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* static objects are not registered for implicit destruction at program exit.
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*/
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extern "C" void init_main_thread()
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{
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/* do platform specific preparation */
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prepare_init_main_thread();
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/*
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* Explicitly setup program environment at this point to ensure that its
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* destructor won't be registered for the atexit routine.
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*/
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(void*)env();
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init_log();
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/* initialize exception handling */
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init_exception_handling();
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/*
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* Trigger first exception. This step has two purposes.
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* First, it enables us to detect problems related to exception handling as
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* early as possible. If there are problems with the C++ support library,
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* it is much easier to debug them at this early stage. Otherwise problems
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* with half-working exception handling cause subtle failures that are hard
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* to interpret.
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*
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* Second, the C++ support library allocates data structures lazily on the
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* first occurrence of an exception. This allocation traverses into
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* Genode's heap and, in some corner cases, consumes several KB of stack.
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* This is usually not a problem when the first exception is triggered from
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* the main thread but it becomes an issue when the first exception is
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* thrown from the stack of a thread with a specially tailored (and
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* otherwise sufficient) stack size. By throwing an exception here, we
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* mitigate this issue by eagerly performing those allocations.
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*/
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try { throw 1; } catch (...) { }
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/* create a thread object for the main thread */
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main_thread();
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/**
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* The new stack pointer enables the caller to switch from its current
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* environment to the those that the thread object provides.
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*/
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addr_t sp = reinterpret_cast<addr_t>(main_thread()->stack_top());
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init_main_thread_result = sp;
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}
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/**
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* Reinitialize main-thread object according to a reinitialized environment
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*/
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void reinit_main_thread() { construct_at<Main_thread>(main_thread(), true); }
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