297 lines
6.9 KiB
C++
297 lines
6.9 KiB
C++
/*
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* \brief Kernel backend for protection domains
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* \author Martin Stein
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* \author Stefan Kalkowski
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* \date 2012-11-30
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*/
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/*
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* Copyright (C) 2012-2013 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 _KERNEL__PD_H_
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#define _KERNEL__PD_H_
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/* Genode includes */
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#include <cpu/atomic.h>
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#include <cpu/memory_barrier.h>
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/* core includes */
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#include <kernel/early_translations.h>
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#include <kernel/configuration.h>
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#include <kernel/object.h>
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#include <kernel/cpu.h>
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#include <translation_table.h>
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#include <assert.h>
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/* structure of the mode transition */
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extern int _mt_begin;
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extern int _mt_end;
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extern int _mt_user_entry_pic;
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extern int _mt_vm_entry_pic;
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extern Genode::addr_t _mt_client_context_ptr;
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extern Genode::addr_t _mt_master_context_begin;
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extern Genode::addr_t _mt_master_context_end;
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namespace Kernel
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{
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/**
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* Lock that enables synchronization inside the kernel
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*/
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class Lock;
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}
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class Kernel::Lock
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{
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private:
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int volatile _locked;
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public:
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Lock() : _locked(0) { }
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/**
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* Request the lock
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*/
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void lock() { while (!Genode::cmpxchg(&_locked, 0, 1)); }
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/**
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* Free the lock
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*/
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void unlock()
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{
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Genode::memory_barrier();
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_locked = 0;
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}
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/**
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* Provide guard semantic for this type of lock
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*/
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typedef Genode::Lock_guard<Kernel::Lock> Guard;
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};
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namespace Kernel
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{
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/**
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* CPU context of the kernel
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*/
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class Cpu_context;
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/**
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* Controls the mode-transition page
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*
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* The mode transition page is a small memory region that is mapped by
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* every PD to the same virtual address. It contains code that acts as a
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* link between high privileged CPU mode (often called kernel) and low
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* privileged CPU mode (often called userland). The mode transition
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* control provides a simple interface to access the code from within
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* the kernel.
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*/
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class Mode_transition_control;
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/**
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* Return the system wide mode-transition control
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*/
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Mode_transition_control * mtc();
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/**
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* Kernel backend of protection domains
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*/
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class Pd;
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class Pd_ids : public Id_allocator<MAX_PDS> { };
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typedef Object_pool<Pd> Pd_pool;
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Pd_ids * pd_ids();
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Pd_pool * pd_pool();
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Lock & data_lock();
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}
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class Kernel::Cpu_context : Cpu::Context
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{
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private:
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/**
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* Hook for environment specific initializations
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*
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* \param stack_size size of kernel stack
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* \param table base of transit translation table
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*/
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void _init(size_t const stack_size, addr_t const table);
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public:
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/**
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* Constructor
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*
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* \param table mode-transition table
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*/
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Cpu_context(Genode::Translation_table * const table);
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};
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class Kernel::Mode_transition_control
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{
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friend class Pd;
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private:
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typedef Early_translations_allocator Allocator;
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typedef Early_translations_slab Slab;
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typedef Genode::Translation_table Table;
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typedef Genode::Cpu_state_modes Cpu_state_modes;
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typedef Genode::Page_flags Page_flags;
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Allocator _allocator;
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Slab _slab;
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Table _table;
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Cpu_context _master;
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/**
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* Return size of the mode transition
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*/
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static size_t _size() { return (addr_t)&_mt_end - (addr_t)&_mt_begin; }
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/**
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* Return size of master-context space in the mode transition
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*/
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static size_t _master_context_size()
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{
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addr_t const begin = (addr_t)&_mt_master_context_begin;
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addr_t const end = (addr_t)&_mt_master_context_end;
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return end - begin;
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}
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/**
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* Return virtual address of the user entry-code
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*/
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static addr_t _virt_user_entry()
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{
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addr_t const phys = (addr_t)&_mt_user_entry_pic;
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addr_t const phys_base = (addr_t)&_mt_begin;
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return VIRT_BASE + (phys - phys_base);
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}
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/**
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* Continue execution of client context
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*
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* \param context targeted CPU context
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* \param cpu kernel name of targeted CPU
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* \param entry_raw raw pointer to assembly entry-code
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*/
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void _continue_client(void * const context, unsigned const cpu,
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addr_t const entry_raw)
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{
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/* override client-context pointer of the executing CPU */
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addr_t const context_ptr_base = (addr_t)&_mt_client_context_ptr;
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size_t const context_ptr_offset = cpu * sizeof(context);
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addr_t const context_ptr = context_ptr_base + context_ptr_offset;
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*(void * *)context_ptr = context;
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/* unlock kernel data */
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data_lock().unlock();
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/* call assembly code that applies the virtual-machine context */
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typedef void (* Entry)();
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Entry __attribute__((noreturn)) const entry = (Entry)entry_raw;
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entry();
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}
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public:
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enum {
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SIZE_LOG2 = Genode::Translation_table::MIN_PAGE_SIZE_LOG2,
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SIZE = 1 << SIZE_LOG2,
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VIRT_BASE = Cpu::exception_entry,
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ALIGN_LOG2 = Genode::Translation_table::ALIGNM_LOG2,
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ALIGN = 1 << ALIGN_LOG2,
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};
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/**
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* Constructor
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*
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* \param c CPU context for kernel mode entry
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*/
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Mode_transition_control();
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/**
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* Map the mode transition page to a virtual address space
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*
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* \param tt translation buffer of the address space
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* \param ram RAM donation for mapping (first try without)
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*/
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void map(Genode::Translation_table * tt,
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Genode::Page_slab * alloc)
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{
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try {
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addr_t const phys_base = (addr_t)&_mt_begin;
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tt->insert_translation(VIRT_BASE, phys_base, SIZE,
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Page_flags::mode_transition(), alloc);
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} catch(...) {
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PERR("Inserting exception vector in page table failed!"); }
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}
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/**
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* Continue execution of 'user' at 'cpu'
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*/
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void continue_user(Cpu::Context * const user, unsigned const cpu) {
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_continue_client(user, cpu, _virt_user_entry()); }
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/**
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* Continue execution of 'vm' at 'cpu'
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*/
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void continue_vm(Cpu_state_modes * const vm, unsigned const cpu) {
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_continue_client(vm, cpu, (addr_t)&_mt_vm_entry_pic); }
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} __attribute__((aligned(Mode_transition_control::ALIGN)));
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class Kernel::Pd : public Object<Pd, MAX_PDS, Pd_ids, pd_ids, pd_pool>
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{
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public:
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typedef Genode::Translation_table Table;
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private:
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Table * const _table;
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Platform_pd * const _platform_pd;
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/* keep ready memory for size-aligned extra costs at construction */
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enum { EXTRA_RAM_SIZE = 2 * Table::MAX_COSTS_PER_TRANSLATION };
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char _extra_ram[EXTRA_RAM_SIZE];
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public:
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/**
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* Constructor
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*
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* \param table translation table of the PD
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* \param platform_pd core object of the PD
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*/
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Pd(Table * const table, Platform_pd * const platform_pd)
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: _table(table), _platform_pd(platform_pd) { }
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/**
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* Let the CPU context 'c' join the PD
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*/
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void admit(Cpu::Context * const c)
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{
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c->protection_domain(id());
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c->translation_table((addr_t)translation_table());
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}
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/***************
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** Accessors **
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***************/
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Platform_pd * platform_pd() const { return _platform_pd; }
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Table * translation_table() const { return _table; }
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};
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#endif /* _KERNEL__PD_H_ */
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