Fiasco.OC: introduce Cap_index (fixes #149, #112)
This commit introduces a Cap_index class for Fiasco.OC's capabilities.
A Cap_index is a combination of the global capability id, that is used by Genode
to correctly identify a kernel-object, and a corresponding entry in a
protection-domain's (kernel-)capability-space. The cap-indices are non-copyable,
unique objects, that are held in a Cap_map. The Cap_map is used to re-find
capabilities already present in the protection-domain, when a capability is
received via IPC. The retrieval of capabilities effectively fixes issue #112,
meaning the waste of capability-space entries.
Because Cap_index objects are non-copyable (their address indicates the position
in the capability-space of the pd), they are inappropriate to use as
Native_capability. Therefore, Native_capability is implemented as a reference
to Cap_index objects. This design seems to be a good pre-condition to implement
smart-pointers for entries in the capability-space, and thereby closing existing
leaks (please refer to issue #32).
Cap_index, Cap_map, and the allocator for Cap_index objects are designed in a way,
that it should be relatively easy to apply the same concept to NOVA also. By now,
these classes are located in the `base-foc` repository, but they intentionally
contain no Fiasco.OC specific elements.
The previously explained changes had extensive impact on the whole Fiasco.OC
platform implementation, due to various dependencies. The following things had to
be changed:
* The Thread object's startup and destruction routine is re-arranged, to
enable another thread (that calls the Thread destructor) gaining the
capability id of the thread's gate to remove it from the Cap_map, the
thread's UTCB had to be made available to the caller, because there
is the current location of that id. After having the UTCB available
in the Thread object for that reason, the whole thread bootstrapping
could be simplified.
* In the course of changing the Native_capability's semantic, a new Cap_mapping
class was introduced in core, that facilitates the establishment and
destruction of capability mappings between core and it's client's, especially
mappings related to Platform_thread and Platform_task, that are relevant to
task and thread creation and destruction. Thereby, the destruction of
threads had to be reworked, which effectively removed a bug (issue #149)
where some threads weren't destroyed properly.
* In the quick fix for issue #112, something similar to the Cap_map was
introduced available in all processes. Moreover, some kind of a capability
map already existed in core, to handle cap-session request properly. The
introduction of the Cap_map unified both structures, so that the
cap-session component code in core had to be reworked too.
* The platform initialization code had to be changed sligthly due to the
changes in Native_capability
* The vcpu initialization in the L4Linux support library had to be adapted
according to the already mentioned changes in the Thread object's bootstrap
code.
2012-03-15 12:41:24 +01:00
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/*
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* \brief Capability IDs allocation service
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* \author Stefan Kalkowski
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* \date 2012-02-22
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*/
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/*
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2017-02-20 13:23:52 +01:00
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* Copyright (C) 2012-2017 Genode Labs GmbH
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Fiasco.OC: introduce Cap_index (fixes #149, #112)
This commit introduces a Cap_index class for Fiasco.OC's capabilities.
A Cap_index is a combination of the global capability id, that is used by Genode
to correctly identify a kernel-object, and a corresponding entry in a
protection-domain's (kernel-)capability-space. The cap-indices are non-copyable,
unique objects, that are held in a Cap_map. The Cap_map is used to re-find
capabilities already present in the protection-domain, when a capability is
received via IPC. The retrieval of capabilities effectively fixes issue #112,
meaning the waste of capability-space entries.
Because Cap_index objects are non-copyable (their address indicates the position
in the capability-space of the pd), they are inappropriate to use as
Native_capability. Therefore, Native_capability is implemented as a reference
to Cap_index objects. This design seems to be a good pre-condition to implement
smart-pointers for entries in the capability-space, and thereby closing existing
leaks (please refer to issue #32).
Cap_index, Cap_map, and the allocator for Cap_index objects are designed in a way,
that it should be relatively easy to apply the same concept to NOVA also. By now,
these classes are located in the `base-foc` repository, but they intentionally
contain no Fiasco.OC specific elements.
The previously explained changes had extensive impact on the whole Fiasco.OC
platform implementation, due to various dependencies. The following things had to
be changed:
* The Thread object's startup and destruction routine is re-arranged, to
enable another thread (that calls the Thread destructor) gaining the
capability id of the thread's gate to remove it from the Cap_map, the
thread's UTCB had to be made available to the caller, because there
is the current location of that id. After having the UTCB available
in the Thread object for that reason, the whole thread bootstrapping
could be simplified.
* In the course of changing the Native_capability's semantic, a new Cap_mapping
class was introduced in core, that facilitates the establishment and
destruction of capability mappings between core and it's client's, especially
mappings related to Platform_thread and Platform_task, that are relevant to
task and thread creation and destruction. Thereby, the destruction of
threads had to be reworked, which effectively removed a bug (issue #149)
where some threads weren't destroyed properly.
* In the quick fix for issue #112, something similar to the Cap_map was
introduced available in all processes. Moreover, some kind of a capability
map already existed in core, to handle cap-session request properly. The
introduction of the Cap_map unified both structures, so that the
cap-session component code in core had to be reworked too.
* The platform initialization code had to be changed sligthly due to the
changes in Native_capability
* The vcpu initialization in the L4Linux support library had to be adapted
according to the already mentioned changes in the Thread object's bootstrap
code.
2012-03-15 12:41:24 +01:00
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*
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* This file is part of the Genode OS framework, which is distributed
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2017-02-20 13:23:52 +01:00
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* under the terms of the GNU Affero General Public License version 3.
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Fiasco.OC: introduce Cap_index (fixes #149, #112)
This commit introduces a Cap_index class for Fiasco.OC's capabilities.
A Cap_index is a combination of the global capability id, that is used by Genode
to correctly identify a kernel-object, and a corresponding entry in a
protection-domain's (kernel-)capability-space. The cap-indices are non-copyable,
unique objects, that are held in a Cap_map. The Cap_map is used to re-find
capabilities already present in the protection-domain, when a capability is
received via IPC. The retrieval of capabilities effectively fixes issue #112,
meaning the waste of capability-space entries.
Because Cap_index objects are non-copyable (their address indicates the position
in the capability-space of the pd), they are inappropriate to use as
Native_capability. Therefore, Native_capability is implemented as a reference
to Cap_index objects. This design seems to be a good pre-condition to implement
smart-pointers for entries in the capability-space, and thereby closing existing
leaks (please refer to issue #32).
Cap_index, Cap_map, and the allocator for Cap_index objects are designed in a way,
that it should be relatively easy to apply the same concept to NOVA also. By now,
these classes are located in the `base-foc` repository, but they intentionally
contain no Fiasco.OC specific elements.
The previously explained changes had extensive impact on the whole Fiasco.OC
platform implementation, due to various dependencies. The following things had to
be changed:
* The Thread object's startup and destruction routine is re-arranged, to
enable another thread (that calls the Thread destructor) gaining the
capability id of the thread's gate to remove it from the Cap_map, the
thread's UTCB had to be made available to the caller, because there
is the current location of that id. After having the UTCB available
in the Thread object for that reason, the whole thread bootstrapping
could be simplified.
* In the course of changing the Native_capability's semantic, a new Cap_mapping
class was introduced in core, that facilitates the establishment and
destruction of capability mappings between core and it's client's, especially
mappings related to Platform_thread and Platform_task, that are relevant to
task and thread creation and destruction. Thereby, the destruction of
threads had to be reworked, which effectively removed a bug (issue #149)
where some threads weren't destroyed properly.
* In the quick fix for issue #112, something similar to the Cap_map was
introduced available in all processes. Moreover, some kind of a capability
map already existed in core, to handle cap-session request properly. The
introduction of the Cap_map unified both structures, so that the
cap-session component code in core had to be reworked too.
* The platform initialization code had to be changed sligthly due to the
changes in Native_capability
* The vcpu initialization in the L4Linux support library had to be adapted
according to the already mentioned changes in the Thread object's bootstrap
code.
2012-03-15 12:41:24 +01:00
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*/
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2016-01-20 20:52:51 +01:00
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#ifndef _CORE__INCLUDE__CAP_ID_ALLOC_H_
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#define _CORE__INCLUDE__CAP_ID_ALLOC_H_
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Fiasco.OC: introduce Cap_index (fixes #149, #112)
This commit introduces a Cap_index class for Fiasco.OC's capabilities.
A Cap_index is a combination of the global capability id, that is used by Genode
to correctly identify a kernel-object, and a corresponding entry in a
protection-domain's (kernel-)capability-space. The cap-indices are non-copyable,
unique objects, that are held in a Cap_map. The Cap_map is used to re-find
capabilities already present in the protection-domain, when a capability is
received via IPC. The retrieval of capabilities effectively fixes issue #112,
meaning the waste of capability-space entries.
Because Cap_index objects are non-copyable (their address indicates the position
in the capability-space of the pd), they are inappropriate to use as
Native_capability. Therefore, Native_capability is implemented as a reference
to Cap_index objects. This design seems to be a good pre-condition to implement
smart-pointers for entries in the capability-space, and thereby closing existing
leaks (please refer to issue #32).
Cap_index, Cap_map, and the allocator for Cap_index objects are designed in a way,
that it should be relatively easy to apply the same concept to NOVA also. By now,
these classes are located in the `base-foc` repository, but they intentionally
contain no Fiasco.OC specific elements.
The previously explained changes had extensive impact on the whole Fiasco.OC
platform implementation, due to various dependencies. The following things had to
be changed:
* The Thread object's startup and destruction routine is re-arranged, to
enable another thread (that calls the Thread destructor) gaining the
capability id of the thread's gate to remove it from the Cap_map, the
thread's UTCB had to be made available to the caller, because there
is the current location of that id. After having the UTCB available
in the Thread object for that reason, the whole thread bootstrapping
could be simplified.
* In the course of changing the Native_capability's semantic, a new Cap_mapping
class was introduced in core, that facilitates the establishment and
destruction of capability mappings between core and it's client's, especially
mappings related to Platform_thread and Platform_task, that are relevant to
task and thread creation and destruction. Thereby, the destruction of
threads had to be reworked, which effectively removed a bug (issue #149)
where some threads weren't destroyed properly.
* In the quick fix for issue #112, something similar to the Cap_map was
introduced available in all processes. Moreover, some kind of a capability
map already existed in core, to handle cap-session request properly. The
introduction of the Cap_map unified both structures, so that the
cap-session component code in core had to be reworked too.
* The platform initialization code had to be changed sligthly due to the
changes in Native_capability
* The vcpu initialization in the L4Linux support library had to be adapted
according to the already mentioned changes in the Thread object's bootstrap
code.
2012-03-15 12:41:24 +01:00
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/* Genode includes */
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#include <base/allocator_avl.h>
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#include <base/exception.h>
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#include <base/lock.h>
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2015-09-17 14:16:59 +02:00
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#include <synced_range_allocator.h>
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Fiasco.OC: introduce Cap_index (fixes #149, #112)
This commit introduces a Cap_index class for Fiasco.OC's capabilities.
A Cap_index is a combination of the global capability id, that is used by Genode
to correctly identify a kernel-object, and a corresponding entry in a
protection-domain's (kernel-)capability-space. The cap-indices are non-copyable,
unique objects, that are held in a Cap_map. The Cap_map is used to re-find
capabilities already present in the protection-domain, when a capability is
received via IPC. The retrieval of capabilities effectively fixes issue #112,
meaning the waste of capability-space entries.
Because Cap_index objects are non-copyable (their address indicates the position
in the capability-space of the pd), they are inappropriate to use as
Native_capability. Therefore, Native_capability is implemented as a reference
to Cap_index objects. This design seems to be a good pre-condition to implement
smart-pointers for entries in the capability-space, and thereby closing existing
leaks (please refer to issue #32).
Cap_index, Cap_map, and the allocator for Cap_index objects are designed in a way,
that it should be relatively easy to apply the same concept to NOVA also. By now,
these classes are located in the `base-foc` repository, but they intentionally
contain no Fiasco.OC specific elements.
The previously explained changes had extensive impact on the whole Fiasco.OC
platform implementation, due to various dependencies. The following things had to
be changed:
* The Thread object's startup and destruction routine is re-arranged, to
enable another thread (that calls the Thread destructor) gaining the
capability id of the thread's gate to remove it from the Cap_map, the
thread's UTCB had to be made available to the caller, because there
is the current location of that id. After having the UTCB available
in the Thread object for that reason, the whole thread bootstrapping
could be simplified.
* In the course of changing the Native_capability's semantic, a new Cap_mapping
class was introduced in core, that facilitates the establishment and
destruction of capability mappings between core and it's client's, especially
mappings related to Platform_thread and Platform_task, that are relevant to
task and thread creation and destruction. Thereby, the destruction of
threads had to be reworked, which effectively removed a bug (issue #149)
where some threads weren't destroyed properly.
* In the quick fix for issue #112, something similar to the Cap_map was
introduced available in all processes. Moreover, some kind of a capability
map already existed in core, to handle cap-session request properly. The
introduction of the Cap_map unified both structures, so that the
cap-session component code in core had to be reworked too.
* The platform initialization code had to be changed sligthly due to the
changes in Native_capability
* The vcpu initialization in the L4Linux support library had to be adapted
according to the already mentioned changes in the Thread object's bootstrap
code.
2012-03-15 12:41:24 +01:00
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namespace Genode {
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class Cap_id_allocator
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{
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private:
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enum {
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CAP_ID_RANGE = ~0UL,
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CAP_ID_MASK = ~3UL,
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CAP_ID_NUM_MAX = CAP_ID_MASK >> 2,
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CAP_ID_OFFSET = 1 << 2
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};
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2015-09-17 14:16:59 +02:00
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Synced_range_allocator<Allocator_avl> _id_alloc;
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Follow practices suggested by "Effective C++"
The patch adjust the code of the base, base-<kernel>, and os repository.
To adapt existing components to fix violations of the best practices
suggested by "Effective C++" as reported by the -Weffc++ compiler
argument. The changes follow the patterns outlined below:
* A class with virtual functions can no longer publicly inherit base
classed without a vtable. The inherited object may either be moved
to a member variable, or inherited privately. The latter would be
used for classes that inherit 'List::Element' or 'Avl_node'. In order
to enable the 'List' and 'Avl_tree' to access the meta data, the
'List' must become a friend.
* Instead of adding a virtual destructor to abstract base classes,
we inherit the new 'Interface' class, which contains a virtual
destructor. This way, single-line abstract base classes can stay
as compact as they are now. The 'Interface' utility resides in
base/include/util/interface.h.
* With the new warnings enabled, all member variables must be explicitly
initialized. Basic types may be initialized with '='. All other types
are initialized with braces '{ ... }' or as class initializers. If
basic types and non-basic types appear in a row, it is nice to only
use the brace syntax (also for basic types) and align the braces.
* If a class contains pointers as members, it must now also provide a
copy constructor and assignment operator. In the most cases, one
would make them private, effectively disallowing the objects to be
copied. Unfortunately, this warning cannot be fixed be inheriting
our existing 'Noncopyable' class (the compiler fails to detect that
the inheriting class cannot be copied and still gives the error).
For now, we have to manually add declarations for both the copy
constructor and assignment operator as private class members. Those
declarations should be prepended with a comment like this:
/*
* Noncopyable
*/
Thread(Thread const &);
Thread &operator = (Thread const &);
In the future, we should revisit these places and try to replace
the pointers with references. In the presence of at least one
reference member, the compiler would no longer implicitly generate
a copy constructor. So we could remove the manual declaration.
Issue #465
2017-12-21 15:42:15 +01:00
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Lock _lock { };
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Fiasco.OC: introduce Cap_index (fixes #149, #112)
This commit introduces a Cap_index class for Fiasco.OC's capabilities.
A Cap_index is a combination of the global capability id, that is used by Genode
to correctly identify a kernel-object, and a corresponding entry in a
protection-domain's (kernel-)capability-space. The cap-indices are non-copyable,
unique objects, that are held in a Cap_map. The Cap_map is used to re-find
capabilities already present in the protection-domain, when a capability is
received via IPC. The retrieval of capabilities effectively fixes issue #112,
meaning the waste of capability-space entries.
Because Cap_index objects are non-copyable (their address indicates the position
in the capability-space of the pd), they are inappropriate to use as
Native_capability. Therefore, Native_capability is implemented as a reference
to Cap_index objects. This design seems to be a good pre-condition to implement
smart-pointers for entries in the capability-space, and thereby closing existing
leaks (please refer to issue #32).
Cap_index, Cap_map, and the allocator for Cap_index objects are designed in a way,
that it should be relatively easy to apply the same concept to NOVA also. By now,
these classes are located in the `base-foc` repository, but they intentionally
contain no Fiasco.OC specific elements.
The previously explained changes had extensive impact on the whole Fiasco.OC
platform implementation, due to various dependencies. The following things had to
be changed:
* The Thread object's startup and destruction routine is re-arranged, to
enable another thread (that calls the Thread destructor) gaining the
capability id of the thread's gate to remove it from the Cap_map, the
thread's UTCB had to be made available to the caller, because there
is the current location of that id. After having the UTCB available
in the Thread object for that reason, the whole thread bootstrapping
could be simplified.
* In the course of changing the Native_capability's semantic, a new Cap_mapping
class was introduced in core, that facilitates the establishment and
destruction of capability mappings between core and it's client's, especially
mappings related to Platform_thread and Platform_task, that are relevant to
task and thread creation and destruction. Thereby, the destruction of
threads had to be reworked, which effectively removed a bug (issue #149)
where some threads weren't destroyed properly.
* In the quick fix for issue #112, something similar to the Cap_map was
introduced available in all processes. Moreover, some kind of a capability
map already existed in core, to handle cap-session request properly. The
introduction of the Cap_map unified both structures, so that the
cap-session component code in core had to be reworked too.
* The platform initialization code had to be changed sligthly due to the
changes in Native_capability
* The vcpu initialization in the L4Linux support library had to be adapted
according to the already mentioned changes in the Thread object's bootstrap
code.
2012-03-15 12:41:24 +01:00
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public:
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class Out_of_ids : Exception {};
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Cap_id_allocator(Allocator*);
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unsigned long alloc();
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void free(unsigned long id);
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};
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}
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2016-01-20 20:52:51 +01:00
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#endif /* _CORE__INCLUDE__CAP_ID_ALLOC_H_ */
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