113 lines
2.2 KiB
C++
113 lines
2.2 KiB
C++
/*
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* \brief Capability-selector allocator
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* \author Norman Feske
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* \author Sebastian Sumpf
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* \author Alexander Boettcher
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* \date 2010-01-19
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*
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* This is a NOVA-specific addition to the process environment.
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*/
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/*
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* Copyright (C) 2010-2012 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 <base/cap_sel_alloc.h>
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/* NOVA includes */
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#include <nova/syscalls.h>
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using namespace Genode;
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/**
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* First available capability selector for custom use
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*
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* Must be initialized by the startup code
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*/
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int __first_free_cap_selector;
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int __local_pd_sel;
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/**
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* Low-level lock to protect the allocator
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*
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* We cannot use a normal Genode lock because this lock is used by code
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* executed prior the initialization of Genode.
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*/
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class Alloc_lock
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{
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private:
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addr_t _sm_cap;
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public:
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/**
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* Constructor
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*
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* \param sm_cap capability selector for the used semaphore
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*/
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Alloc_lock() : _sm_cap(Nova::PD_SEL_CAP_LOCK) { }
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void lock() { Nova::sm_ctrl(_sm_cap, Nova::SEMAPHORE_DOWN); }
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void unlock() { Nova::sm_ctrl(_sm_cap, Nova::SEMAPHORE_UP); }
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};
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/**
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* Return lock used to protect capability selector allocations
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*/
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static Alloc_lock *alloc_lock()
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{
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static Alloc_lock alloc_lock_inst;
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return &alloc_lock_inst;
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}
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addr_t Cap_selector_allocator::alloc(size_t num_caps_log2)
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{
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alloc_lock()->lock();
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addr_t ret_base = Bit_allocator::alloc(num_caps_log2);
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alloc_lock()->unlock();
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return ret_base;
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}
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void Cap_selector_allocator::free(addr_t cap, size_t num_caps_log2)
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{
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alloc_lock()->lock();
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Bit_allocator::free(cap, num_caps_log2);
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alloc_lock()->unlock();
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}
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unsigned Cap_selector_allocator::pd_sel() { return __local_pd_sel; }
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Cap_selector_allocator::Cap_selector_allocator() : Bit_allocator<4096>()
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{
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/* initialize lock */
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alloc_lock();
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/* the first free selector is used for the lock */
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Bit_allocator::_reserve(0, __first_free_cap_selector + 1);
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}
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namespace Genode {
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/**
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* This function must not be called prior the initialization of
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* '__first_free_cap_selector'.
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*/
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Cap_selector_allocator *cap_selector_allocator()
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{
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static Cap_selector_allocator inst;
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return &inst;
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}
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}
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