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.
59 lines
1.4 KiB
C++
59 lines
1.4 KiB
C++
/*
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* \brief Fiasco.OC-specific supplements to the IPC framework
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* \author Norman Feske
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* \author Stefan Kalkowski
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* \date 2010-01-27
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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_H_
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#define _INCLUDE__BASE__IPC_H_
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#include <base/ipc_generic.h>
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namespace Fiasco {
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#include <l4/sys/consts.h>
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#include <l4/sys/task.h>
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}
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inline void Genode::Ipc_ostream::_marshal_capability(Genode::Native_capability const &cap)
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{
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long unique_id = cap.local_name();
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_write_to_buf(unique_id);
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if (unique_id)
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_snd_msg->snd_append_cap_sel(cap.dst());
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}
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inline void Genode::Ipc_istream::_unmarshal_capability(Genode::Native_capability &cap)
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{
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using namespace Fiasco;
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/* extract Genode internal capability label from message buffer */
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long unique_id = 0;
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_read_from_buf(unique_id);
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if (!unique_id) {
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cap = Native_capability();
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return;
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}
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/* allocate new cap slot and grant cap to it out of receive window */
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Genode::addr_t cap_sel = cap_alloc()->alloc_id(unique_id);
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l4_msgtag_t tag = l4_task_cap_valid(L4_BASE_TASK_CAP, cap_sel);
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if (!tag.label()) {
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l4_task_map(L4_BASE_TASK_CAP, L4_BASE_TASK_CAP,
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l4_obj_fpage(_rcv_msg->rcv_cap_sel(), 0, L4_FPAGE_RWX),
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cap_sel | L4_ITEM_MAP | L4_MAP_ITEM_GRANT);
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}
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cap = Native_capability(cap_sel, unique_id);
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}
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#endif /* _INCLUDE__BASE__IPC_H_ */
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