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
141 lines
3.8 KiB
C++
141 lines
3.8 KiB
C++
/*
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* \brief Support code for the thread API
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* \author Norman Feske
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* \author Stefan Kalkowski
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* \date 2010-01-13
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*/
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/*
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* Copyright (C) 2010-2017 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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/* Genode includes */
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#include <region_map/region_map.h>
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#include <pd_session/pd_session.h>
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#include <base/log.h>
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#include <base/synced_allocator.h>
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#include <base/thread.h>
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/* base-internal includes */
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#include <base/internal/stack_area.h>
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/* local includes */
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#include <platform.h>
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#include <map_local.h>
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#include <dataspace_component.h>
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namespace Genode {
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Region_map *env_stack_area_region_map;
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Ram_allocator *env_stack_area_ram_allocator;
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void init_stack_area();
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}
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using namespace Genode;
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/**
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* Region-manager session for allocating stacks
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*
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* This class corresponds to the managed dataspace that is normally
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* used for organizing stacks within the stack area.
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* In contrast to the ordinary implementation, core's version does
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* not split between allocation of memory and virtual memory management.
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* Due to the missing availability of "real" dataspaces and capabilities
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* referring to it without having an entrypoint in place, the allocation
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* of a dataspace has no effect, but the attachment of the thereby "empty"
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* dataspace is doing both: allocation and attachment.
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*/
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class Stack_area_region_map : public Region_map
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{
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private:
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using Ds_slab = Synced_allocator<Tslab<Dataspace_component,
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get_page_size()> >;
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Ds_slab _ds_slab { platform().core_mem_alloc() };
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public:
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/**
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* Allocate and attach on-the-fly backing store to stack area
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*/
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Local_addr attach(Dataspace_capability, size_t size, off_t,
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bool, Local_addr local_addr, bool, bool) override
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{
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/* allocate physical memory */
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size = round_page(size);
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void *phys_base = nullptr;
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Range_allocator &ra = platform_specific().ram_alloc();
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if (ra.alloc_aligned(size, &phys_base,
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get_page_size_log2()).error()) {
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error("could not allocate backing store for new stack");
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return (addr_t)0;
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}
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Dataspace_component &ds = *new (&_ds_slab)
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Dataspace_component(size, 0, (addr_t)phys_base, CACHED, true, 0);
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addr_t const core_local_addr = stack_area_virtual_base() + (addr_t)local_addr;
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if (!map_local(ds.phys_addr(), core_local_addr,
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ds.size() >> get_page_size_log2())) {
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error("could not map phys ", Hex(ds.phys_addr()),
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" at local ", Hex(core_local_addr));
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return (addr_t)0;
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}
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ds.assign_core_local_addr((void*)core_local_addr);
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return local_addr;
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}
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void detach(Local_addr local_addr) override
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{
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using Genode::addr_t;
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if ((addr_t)local_addr >= stack_area_virtual_size())
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return;
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addr_t const detach = stack_area_virtual_base() + (addr_t)local_addr;
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addr_t const stack = stack_virtual_size();
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addr_t const pages = ((detach & ~(stack - 1)) + stack - detach)
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>> get_page_size_log2();
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unmap_local(detach, pages);
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}
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void fault_handler(Signal_context_capability) override { }
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State state() override { return State(); }
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Dataspace_capability dataspace() override { return Dataspace_capability(); }
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};
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struct Stack_area_ram_allocator : Ram_allocator
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{
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Ram_dataspace_capability alloc(size_t, Cache_attribute) override {
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return reinterpret_cap_cast<Ram_dataspace>(Native_capability()); }
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void free(Ram_dataspace_capability) override { }
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size_t dataspace_size(Ram_dataspace_capability) const override { return 0; }
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};
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void Genode::init_stack_area()
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{
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static Stack_area_region_map rm;
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env_stack_area_region_map = &rm;
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static Stack_area_ram_allocator ram;
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env_stack_area_ram_allocator = &ram;
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}
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