52 lines
1.0 KiB
C++
52 lines
1.0 KiB
C++
/*
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* \brief Global Descriptor Table (GDT)
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* \author Reto Buerki
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* \date 2015-02-27
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*/
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/*
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* Copyright (C) 2015 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 _GDT_H_
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#define _GDT_H_
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/* core includes */
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#include <pseudo_descriptor.h>
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#include <mtc_util.h>
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extern int _mt_gdt_start;
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extern int _mt_gdt_end;
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namespace Genode
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{
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/**
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* Global Descriptor Table (GDT)
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* See Intel SDM Vol. 3A, section 3.5.1
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*/
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class Gdt;
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}
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class Genode::Gdt
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{
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public:
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/**
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* Load GDT from mtc region into GDTR.
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*
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* \param virt_base virtual base address of mode transition pages
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*/
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static void load(addr_t const virt_base)
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{
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addr_t const start = (addr_t)&_mt_gdt_start;
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uint16_t const limit = _mt_gdt_end - _mt_gdt_start - 1;
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uint64_t const base = _virt_mtc_addr(virt_base, start);
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asm volatile ("lgdt %0" :: "m" (Pseudo_descriptor(limit, base)));
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}
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};
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#endif /* _GDT_H_ */
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