94 lines
2.2 KiB
C++
94 lines
2.2 KiB
C++
/*
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* \brief Virtual Machine Monitor MMU definition
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* \author Stefan Kalkowski
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* \date 2012-06-25
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*/
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/*
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* Copyright (C) 2012-2017 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 _SRC__SERVER__VMM__INCLUDE__MMU_H_
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#define _SRC__SERVER__VMM__INCLUDE__MMU_H_
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/* base includes */
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#include <cpu/vm_state.h>
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/* local includes */
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#include <ram.h>
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class Mmu
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{
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private:
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Genode::Vm_state &_state;
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Ram const &_ram;
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unsigned _n_bits() { return _state.ttbrc & 0x7; }
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bool _ttbr0(Genode::addr_t mva) {
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return (!_n_bits() || !(mva >> (32 - _n_bits()))); }
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Genode::addr_t _first_level(Genode::addr_t va)
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{
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if (!_ttbr0(va))
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return ((_state.ttbr[1] & 0xffffc000) |
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((va >> 18) & 0xffffc));
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unsigned shift = 14 - _n_bits();
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return (((_state.ttbr[0] >> shift) << shift) |
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(((va << _n_bits()) >> (18 + _n_bits())) & 0x3ffc));
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}
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Genode::addr_t _page(Genode::addr_t fe, Genode::addr_t va)
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{
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enum Type { FAULT, LARGE, SMALL };
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Genode::addr_t se = *((Genode::addr_t*)_ram.va(((fe & (~0UL << 10)) |
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((va >> 10) & 0x3fc))));
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switch (se & 0x3) {
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case FAULT:
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return 0;
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case LARGE:
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return ((se & (~0UL << 16)) | (va & (~0UL >> 16)));
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default:
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return ((se & (~0UL << 12)) | (va & (~0UL >> 20)));
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}
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return 0;
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}
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Genode::addr_t _section(Genode::addr_t fe, Genode::addr_t va) {
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return ((fe & 0xfff00000) | (va & 0xfffff)); }
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Genode::addr_t _supersection(Genode::addr_t fe, Genode::addr_t va)
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{
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Genode::warning(__func__, " not implemented yet!");
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return 0;
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}
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public:
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Mmu(Genode::Vm_state &state, Ram const &ram)
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: _state(state), _ram(ram) {}
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Genode::addr_t phys_addr(Genode::addr_t va)
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{
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enum Type { FAULT, PAGETABLE, SECTION };
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Genode::addr_t fe = *((Genode::addr_t*)_ram.va(_first_level(va)));
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switch (fe & 0x3) {
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case PAGETABLE:
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return _page(fe, va);
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case SECTION:
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return (fe & 0x40000) ? _supersection(fe, va)
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: _section(fe, va);
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}
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return 0;
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}
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};
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#endif /* _SRC__SERVER__VMM__INCLUDE__MMU_H_ */
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