67 lines
1.5 KiB
C++
67 lines
1.5 KiB
C++
/*
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* \brief Guard to save a UTCB and restore it during guard destruction
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* \author Alexander Boettcher
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* \date 2013-07-05
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*/
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/*
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* Copyright (C) 2013 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__VMM__UTCB_GUARD_H_
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#define _INCLUDE__VMM__UTCB_GUARD_H_
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/* Genode includes */
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#include <base/printf.h>
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#include <util/string.h>
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/* NOVA syscalls */
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#include <nova/syscalls.h>
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namespace Vmm {
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using namespace Genode;
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class Utcb_guard;
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}
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class Vmm::Utcb_guard
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{
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public:
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struct Utcb_backup { char buf[Nova::Utcb::size()]; };
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private:
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Utcb_backup &_backup_utcb;
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public:
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Utcb_guard(Utcb_backup &backup_utcb) : _backup_utcb(backup_utcb)
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{
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Nova::Utcb *utcb =
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reinterpret_cast<Nova::Utcb *>(Thread_base::myself()->utcb());
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unsigned header_len = (char *)utcb->msg - (char *)utcb;
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unsigned len = header_len + utcb->msg_words() * sizeof(Nova::mword_t);
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Genode::memcpy(&_backup_utcb, utcb, len);
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if (utcb->msg_items())
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PWRN("Error: msg items on UTCB are not saved and restored!");
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}
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~Utcb_guard()
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{
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Nova::Utcb *utcb = reinterpret_cast<Nova::Utcb *>(&_backup_utcb);
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unsigned header_len = (char *)utcb->msg - (char *)utcb;
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unsigned len = header_len + utcb->msg_words() * sizeof(Nova::mword_t);
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Genode::memcpy(Thread_base::myself()->utcb(), utcb, len);
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}
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};
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#endif /* _INCLUDE__VMM__UTCB_GUARD_H_ */
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