genode/base-foc/include/base/cap_alloc.h
2013-01-10 21:44:47 +01:00

131 lines
3.2 KiB
C++

/*
* \brief Capability index allocator for Fiasco.OC.
* \author Stefan Kalkowski
* \date 2012-02-16
*/
/*
* Copyright (C) 2012-2013 Genode Labs GmbH
*
* This file is part of the Genode OS framework, which is distributed
* under the terms of the GNU General Public License version 2.
*/
#ifndef _INCLUDE__BASE__CAP_ALLOC_H_
#define _INCLUDE__BASE__CAP_ALLOC_H_
#include <base/cap_map.h>
#include <base/native_types.h>
#include <util/assert.h>
namespace Genode {
/**
* Cap_index_allocator_tpl implements the Cap_index_allocator for Fiasco.OC.
*
* It's designed as a template because we need two distinguished versions
* for core and non-core processes with respect to dimensioning. Moreover,
* core needs more information within a Cap_index object, than the base
* class provides.
*
* \param T Cap_index specialization to use
* \param SZ size of Cap_index array used by the allocator
*/
template <typename T, unsigned SZ>
class Cap_index_allocator_tpl : public Cap_index_allocator
{
private:
Spin_lock _lock; /* used very early in initialization,
where normal lock isn't feasible */
enum {
/* everything above START_IDX is managed by core */
START_IDX = Fiasco::USER_BASE_CAP >> Fiasco::L4_CAP_SHIFT
};
protected:
unsigned char _data[SZ*sizeof(T)];
T* _indices;
public:
Cap_index_allocator_tpl() : _indices(reinterpret_cast<T*>(&_data)) {
memset(&_data, 0, sizeof(_data)); }
/***********************************
** Cap_index_allocator interface **
***********************************/
Cap_index* alloc_range(size_t cnt)
{
Lock_guard<Spin_lock> guard(_lock);
/*
* iterate through array and find unused, consecutive entries
*/
for (unsigned i = START_IDX, j = 0; (i+cnt) < SZ; i+=j+1, j=0) {
for (; j < cnt; j++)
if (_indices[i+j].used())
break;
/* if we found a fitting hole, initialize the objects */
if (j == cnt) {
for (j = 0; j < cnt; j++)
new (&_indices[i+j]) T();
return &_indices[i];
}
}
ASSERT(0, "cap index allocation failed");
return 0;
}
Cap_index* alloc(addr_t addr)
{
Lock_guard<Spin_lock> guard(_lock);
/*
* construct the Cap_index pointer from the given
* address in capability space
*/
T* obj = reinterpret_cast<T*>(kcap_to_idx(addr));
if (obj < &_indices[0] || obj >= &_indices[SZ]) {
ASSERT(0, "cap index out of bounds");
throw Index_out_of_bounds();
}
return new (obj) T();
}
void free(Cap_index* idx, size_t cnt)
{
Lock_guard<Spin_lock> guard(_lock);
T* obj = static_cast<T*>(idx);
for (size_t i = 0; i < cnt; obj++, i++) {
/* range check given pointer address */
if (obj < &_indices[0] || obj >= &_indices[SZ]) {
ASSERT(0, "cap index out of bounds");
throw Index_out_of_bounds();
}
delete obj;
}
}
addr_t idx_to_kcap(Cap_index *idx) {
return ((T*)idx - &_indices[0]) << Fiasco::L4_CAP_SHIFT;
}
Cap_index* kcap_to_idx(addr_t kcap) {
return &_indices[kcap >> Fiasco::L4_CAP_SHIFT]; }
bool static_idx(Cap_index *idx) {
return ((T*)idx) < &_indices[START_IDX]; }
};
}
#endif /* _INCLUDE__BASE__CAP_ALLOC_H_ */