120 lines
2.7 KiB
C++
120 lines
2.7 KiB
C++
/*
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* \brief Interface for allocating RAM dataspaces
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* \author Norman Feske
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* \date 2017-05-02
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*/
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/*
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* Copyright (C) 2017 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 Affero General Public License version 3.
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*/
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#ifndef _INCLUDE__BASE__RAM_ALLOCATOR_H_
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#define _INCLUDE__BASE__RAM_ALLOCATOR_H_
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#include <base/capability.h>
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#include <base/quota_guard.h>
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#include <base/cache.h>
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#include <dataspace/dataspace.h>
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namespace Genode {
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struct Ram_dataspace : Dataspace { };
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typedef Capability<Ram_dataspace> Ram_dataspace_capability;
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struct Ram_allocator;
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class Constrained_ram_allocator;
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}
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struct Genode::Ram_allocator : Interface
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{
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/**
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* Allocate RAM dataspace
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*
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* \param size size of RAM dataspace
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* \param cached selects cacheability attributes of the memory,
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* uncached memory, i.e., for DMA buffers
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*
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* \throw Out_of_ram
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* \throw Out_of_caps
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*
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* \return capability to new RAM dataspace
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*/
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virtual Ram_dataspace_capability alloc(size_t size,
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Cache_attribute cached = CACHED) = 0;
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/**
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* Free RAM dataspace
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*
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* \param ds dataspace capability as returned by alloc
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*/
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virtual void free(Ram_dataspace_capability ds) = 0;
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/**
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* Return size of dataspace in bytes
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*/
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virtual size_t dataspace_size(Ram_dataspace_capability ds) const = 0;
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};
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/**
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* Quota-bounds-checking wrapper of the 'Ram_allocator' interface
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*/
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class Genode::Constrained_ram_allocator : public Ram_allocator
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{
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private:
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Ram_allocator &_ram_alloc;
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Ram_quota_guard &_ram_guard;
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Cap_quota_guard &_cap_guard;
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public:
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Constrained_ram_allocator(Ram_allocator &ram_alloc,
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Ram_quota_guard &ram_guard,
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Cap_quota_guard &cap_guard)
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:
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_ram_alloc(ram_alloc), _ram_guard(ram_guard), _cap_guard(cap_guard)
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{ }
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Ram_dataspace_capability alloc(size_t size, Cache_attribute cached = CACHED) override
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{
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size_t page_aligned_size = align_addr(size, 12);
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Ram_quota_guard::Reservation ram (_ram_guard, Ram_quota{page_aligned_size});
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Cap_quota_guard::Reservation caps(_cap_guard, Cap_quota{1});
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/*
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* \throw Out_of_caps, Out_of_ram
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*/
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Ram_dataspace_capability ds = _ram_alloc.alloc(page_aligned_size, cached);
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ram. acknowledge();
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caps.acknowledge();
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return ds;
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}
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void free(Ram_dataspace_capability ds) override
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{
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size_t const size = _ram_alloc.dataspace_size(ds);
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_ram_alloc.free(ds);
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_ram_guard.replenish(Ram_quota{size});
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_cap_guard.replenish(Cap_quota{1});
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}
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size_t dataspace_size(Ram_dataspace_capability ds) const override
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{
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return _ram_alloc.dataspace_size(ds);
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}
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};
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#endif /* _INCLUDE__BASE__RAM_ALLOCATOR_H_ */
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