6b289a1423
This patch replaces the former prominent use of pointers by references wherever feasible. This has the following benefits: * The contract between caller and callee becomes more obvious. When passing a reference, the contract says that the argument cannot be a null pointer. The caller is responsible to ensure that. Therefore, the use of reference eliminates the need to add defensive null-pointer checks at the callee site, which sometimes merely exist to be on the safe side. The bottom line is that the code becomes easier to follow. * Reference members must be initialized via an object initializer, which promotes a programming style that avoids intermediate object- construction states. Within core, there are still a few pointers as member variables left though. E.g., caused by the late association of 'Platform_thread' objects with their 'Platform_pd' objects. * If no pointers are present as member variables, we don't need to manually provide declarations of a private copy constructor and an assignment operator to avoid -Weffc++ errors "class ... has pointer data members [-Werror=effc++]". This patch also changes a few system bindings on NOVA and Fiasco.OC, e.g., the return value of the global 'cap_map' accessor has become a reference. Hence, the patch touches a few places outside of core. Fixes #3135
147 lines
3.0 KiB
C++
147 lines
3.0 KiB
C++
/*
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* \brief Low-level page-fault handling
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* \author Norman Feske
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* \date 2009-10-02
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*/
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/*
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* Copyright (C) 2009-2017 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 _CORE__INCLUDE__IPC_PAGER_H_
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#define _CORE__INCLUDE__IPC_PAGER_H_
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/* Genode includes */
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#include <base/cache.h>
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#include <base/ipc.h>
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#include <base/stdint.h>
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/* NOVA includes */
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#include <nova/syscalls.h>
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namespace Genode {
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class Mapping;
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class Ipc_pager;
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}
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class Genode::Mapping
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{
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private:
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addr_t const _dst_addr;
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Cache_attribute const _attr;
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Nova::Mem_crd const _mem_crd;
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enum { PAGE_SIZE_LOG2 = 12 };
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public:
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/**
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* Constructor
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*/
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Mapping(addr_t dst_addr, addr_t source_addr,
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Cache_attribute c, bool /* io_mem */,
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unsigned size_log2,
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bool writeable, bool executable)
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:
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_dst_addr(dst_addr),
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_attr(c),
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_mem_crd(source_addr >> PAGE_SIZE_LOG2,
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size_log2 - PAGE_SIZE_LOG2,
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Nova::Rights(true, writeable, executable))
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{ }
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void prepare_map_operation() { }
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Nova::Mem_crd mem_crd() const { return _mem_crd; }
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bool dma() { return _attr != CACHED; };
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bool write_combined() { return _attr == WRITE_COMBINED; };
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addr_t dst_addr() { return _dst_addr; }
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};
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class Genode::Ipc_pager
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{
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private:
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addr_t _pd_dst;
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addr_t _pd_core;
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addr_t _fault_ip;
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addr_t _fault_addr;
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addr_t _sp;
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uint8_t _fault_type;
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uint8_t _syscall_res;
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uint8_t _normal_ipc;
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public:
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Ipc_pager (Nova::Utcb &, addr_t pd_dst, addr_t pd_core);
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/*
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* Intel manual: 6.15 EXCEPTION AND INTERRUPT REFERENCE
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* Interrupt 14—Page-Fault Exception (#PF)
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*/
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enum {
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ERR_I = 1 << 4,
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ERR_R = 1 << 3,
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ERR_U = 1 << 2,
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ERR_W = 1 << 1,
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ERR_P = 1 << 0,
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};
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/**
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* Answer current page fault
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*/
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void reply_and_wait_for_fault(addr_t sm = 0UL);
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/**
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* Request instruction pointer of current fault
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*/
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addr_t fault_ip() { return _fault_ip; }
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/**
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* Request page-fault address of current fault
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*/
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addr_t fault_addr() { return _fault_addr; }
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/**
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* Set page-fault reply parameters
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*/
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void set_reply_mapping(Mapping m);
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/**
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* Return true if fault was a write fault
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*/
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bool write_fault() const { return _fault_type & ERR_W; }
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/**
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* Return true if fault was a non-executable fault
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*/
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bool exec_fault() const {
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return _fault_type & ERR_P && _fault_type & ERR_I; }
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/**
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* Return result of delegate syscall
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*/
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uint8_t syscall_result() const { return _syscall_res; }
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/**
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* Return low level fault type info
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* Intel manual: 6.15 EXCEPTION AND INTERRUPT REFERENCE
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* Interrupt 14—Page-Fault Exception (#PF)
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*/
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addr_t fault_type() { return _fault_type; }
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/**
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* Return stack pointer address valid during page-fault
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*/
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addr_t sp() { return _sp; }
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};
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#endif /* _CORE__INCLUDE__IPC_PAGER_H_ */
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