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41eaff2cc6
This is an interim fix for issue #112. This patch extends the 'Capability_allocator' class with the ability to register the global ID of a Genode capability so that the ID gets associated with a process-local kernel capability. Whenever a Genode capability gets unmarshalled from an IPC message, the capability-allocator is asked, with the global ID as key, whether the kernel-cap already exists. This significantly reduces the waste of kernel-capability slots. To circumvent problems of having one and the same ID for different kernel objects, the following problems had to be solved: * Replace pseudo IDs with unique ones from core's badge allocator * When freeing a session object, free the global ID _after_ unmapping the kernel object, otherwise the global ID might get re-used in some process and the registry will find a valid but wrong capability for the ID Because core aggregates all capabilities of all different processes, its capability registry needs much more memory compared to a regular process. By parametrizing capability allocators differently for core and non-core processes, the global memory overhead for capability registries is kept at a reasonable level.
153 lines
3.0 KiB
C++
153 lines
3.0 KiB
C++
/*
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* \brief IPC message buffer layout for Fiasco.OC
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* \author Stefan Kalkowski
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* \date 2010-11-30
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*
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* On Fiasco.OC, IPC is used to transmit plain data and capabilities.
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* Therefore the message buffer contains both categories of payload.
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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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#ifndef _INCLUDE__BASE__IPC_MSGBUF_H_
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#define _INCLUDE__BASE__IPC_MSGBUF_H_
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/* Genode includes */
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#include <base/cap_sel_alloc.h>
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/* Fiasco.OC includes */
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namespace Fiasco {
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#include <l4/sys/types.h>
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#include <l4/sys/utcb.h>
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}
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namespace Genode {
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class Msgbuf_base
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{
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public:
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enum { MAX_CAP_ARGS_LOG2 = 2, MAX_CAP_ARGS = 1 << MAX_CAP_ARGS_LOG2 };
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protected:
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size_t _size;
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/**
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* Number of capability selectors to send.
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*/
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size_t _snd_cap_sel_cnt;
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/**
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* Capability selectors to delegate.
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*/
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addr_t _snd_cap_sel[MAX_CAP_ARGS];
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/**
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* Base of capability receive window.
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*/
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addr_t _rcv_cap_sel_base;
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/**
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* Read counter for unmarshalling portal capability selectors
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*/
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addr_t _rcv_cap_sel_cnt;
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char _msg_start[]; /* symbol marks start of message */
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public:
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/**
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* Constructor
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*/
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Msgbuf_base()
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: _rcv_cap_sel_base(cap_alloc()->alloc(MAX_CAP_ARGS))
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{
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rcv_reset();
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snd_reset();
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}
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/*
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* Begin of actual message buffer
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*/
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char buf[];
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/**
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* Return size of message buffer
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*/
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inline size_t size() const { return _size; };
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/**
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* Return address of message buffer
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*/
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inline void *addr() { return &_msg_start[0]; };
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/**
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* Reset portal capability selector payload
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*/
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inline void snd_reset() { _snd_cap_sel_cnt = 0; }
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/**
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* Append capability selector to message buffer
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*/
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inline bool snd_append_cap_sel(addr_t cap_sel)
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{
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if (_snd_cap_sel_cnt >= MAX_CAP_ARGS)
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return false;
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_snd_cap_sel[_snd_cap_sel_cnt++] = cap_sel;
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return true;
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}
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/**
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* Return number of marshalled capability selectors
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*/
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inline size_t snd_cap_sel_cnt() { return _snd_cap_sel_cnt; }
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/**
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* Return capability selector to send.
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*
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* \param i index (0 ... 'snd_cap_sel_cnt()' - 1)
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* \return capability selector, or 0 if index is invalid
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*/
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addr_t snd_cap_sel(unsigned i) {
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return i < _snd_cap_sel_cnt ? _snd_cap_sel[i] : 0; }
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/**
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* Return address of capability receive window.
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*/
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addr_t rcv_cap_sel_base() { return _rcv_cap_sel_base; }
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/**
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* Reset capability receive window
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*/
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void rcv_reset() { _rcv_cap_sel_cnt = 0; }
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/**
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* Return next received capability selector.
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*
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* \return capability selector, or 0 if index is invalid
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*/
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addr_t rcv_cap_sel() {
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return _rcv_cap_sel_base + _rcv_cap_sel_cnt++ * Fiasco::L4_CAP_SIZE; }
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};
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template <unsigned BUF_SIZE>
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class Msgbuf : public Msgbuf_base
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{
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public:
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char buf[BUF_SIZE];
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Msgbuf() { _size = BUF_SIZE; }
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};
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}
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#endif /* _INCLUDE__BASE__IPC_MSGBUF_H_ */
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