/* * \brief Virtual-memory space * \author Norman Feske * \date 2015-05-04 */ /* * Copyright (C) 2015 Genode Labs GmbH * * This file is part of the Genode OS framework, which is distributed * under the terms of the GNU General Public License version 2. */ #ifndef _CORE__INCLUDE__VM_SPACE_H_ #define _CORE__INCLUDE__VM_SPACE_H_ /* Genode includes */ #include /* core includes */ #include #include namespace Genode { class Vm_space; } class Genode::Vm_space { private: Page_table_registry &_page_table_registry; unsigned const _id; unsigned const _pd_sel; Range_allocator &_phys_alloc; /** * Maximum number of page tables and page frames for the VM space */ enum { NUM_VM_SEL_LOG2 = 13 }; Cnode &_top_level_cnode; Cnode &_phys_cnode; /** * 2nd-level CNode for aligning '_vm_cnode' with the LSB of the CSpace */ Cnode _vm_pad_cnode; /** * 3rd-level CNode for storing page-table and page-frame capabilities */ Cnode _vm_cnode; /** * Allocator for the selectors within '_vm_cnode' */ Bit_allocator<1UL << NUM_VM_SEL_LOG2> _sel_alloc; Lock _lock; /** * Return selector for a capability slot within '_vm_cnode' */ unsigned _idx_to_sel(unsigned idx) const { return (_id << 20) | idx; } void _map_page(addr_t from_phys, addr_t to_virt) { /* allocate page-table entry selector */ unsigned pte_idx = _sel_alloc.alloc(); /* * Copy page-frame selector to pte_sel * * This is needed because each page-frame selector can be * inserted into only a single page table. */ _vm_cnode.copy(_phys_cnode, from_phys >> get_page_size_log2(), pte_idx); /* remember relationship between pte_sel and the virtual address */ _page_table_registry.insert_page_table_entry(to_virt, pte_idx); /* * Insert copy of page-frame selector into page table */ { seL4_IA32_Page const service = _idx_to_sel(pte_idx); seL4_IA32_PageDirectory const pd = _pd_sel; seL4_Word const vaddr = to_virt; seL4_CapRights const rights = seL4_AllRights; seL4_IA32_VMAttributes const attr = seL4_IA32_Default_VMAttributes; int const ret = seL4_IA32_Page_Map(service, pd, vaddr, rights, attr); if (ret != 0) PERR("seL4_IA32_Page_Map to 0x%lx returned %d", (unsigned long)vaddr, ret); } } void _unmap_page(addr_t virt) { /* delete copy of the mapping's page-frame selector */ _page_table_registry.apply(virt, [&] (unsigned idx) { _vm_cnode.remove(idx); }); /* release meta data about the mapping */ _page_table_registry.forget_page_table_entry(virt); } void _map_page_table(unsigned pt_sel, addr_t to_virt) { seL4_IA32_PageTable const service = pt_sel; seL4_IA32_PageDirectory const pd = _pd_sel; seL4_Word const vaddr = to_virt; seL4_IA32_VMAttributes const attr = seL4_IA32_Default_VMAttributes; int const ret = seL4_IA32_PageTable_Map(service, pd, vaddr, attr); if (ret != 0) PDBG("seL4_IA32_PageTable_Map returned %d", ret); } class Alloc_page_table_failed : Exception { }; /** * Allocate and install page table at given virtual address * * \throw Alloc_page_table_failed */ void _alloc_and_map_page_table(addr_t to_virt) { /* allocate page-table selector */ unsigned const pt_idx = _sel_alloc.alloc(); /* XXX account the consumed backing store */ try { Kernel_object::create(_phys_alloc, _vm_cnode.sel(), pt_idx); } catch (...) { throw Alloc_page_table_failed(); } unsigned const pt_sel = _idx_to_sel(pt_idx); _page_table_registry.insert_page_table(to_virt, pt_sel); _map_page_table(pt_sel, to_virt); } public: /** * Constructor * * \param pd_sel selector for page directory * \param vm_pad_cnode_sel selector for the (2nd-level) VM pad CNode * \param vm_cnode_sel selector for the (3rd-level) VM CNode * \param phys_alloc backing store for the CNodes * \param top_level_cnode top-level CNode to insert 'vm_pad_cnode_sel' * \param id ID used as index in 'top_level_cnode' * \param page_table_registry association of VM CNode selectors with * with virtual addresses */ Vm_space(unsigned pd_sel, unsigned vm_pad_cnode_sel, unsigned vm_cnode_sel, Range_allocator &phys_alloc, Cnode &top_level_cnode, Cnode &core_cnode, Cnode &phys_cnode, unsigned id, Page_table_registry &page_table_registry) : _page_table_registry(page_table_registry), _id(id), _pd_sel(pd_sel), _phys_alloc(phys_alloc), _top_level_cnode(top_level_cnode), _phys_cnode(phys_cnode), _vm_pad_cnode(core_cnode.sel(), vm_pad_cnode_sel, 32 - 12 - NUM_VM_SEL_LOG2, phys_alloc), _vm_cnode(core_cnode.sel(), vm_cnode_sel, NUM_VM_SEL_LOG2, phys_alloc) { Cnode_base const cspace(seL4_CapInitThreadCNode, 32); /* insert 3rd-level VM CNode into 2nd-level VM-pad CNode */ _vm_pad_cnode.copy(cspace, vm_cnode_sel, 0); /* insert 2nd-level VM-pad CNode into 1st-level CNode */ _top_level_cnode.copy(cspace, vm_pad_cnode_sel, id); } void map(addr_t from_phys, addr_t to_virt, size_t num_pages) { Lock::Guard guard(_lock); /* check if we need to add a page table to core's VM space */ if (!_page_table_registry.has_page_table_at(to_virt)) _alloc_and_map_page_table(to_virt); for (size_t i = 0; i < num_pages; i++) { off_t const offset = i << get_page_size_log2(); _map_page(from_phys + offset, to_virt + offset); } } void unmap(addr_t virt, size_t num_pages) { Lock::Guard guard(_lock); for (size_t i = 0; i < num_pages; i++) { off_t const offset = i << get_page_size_log2(); _unmap_page(virt + offset); } } }; #endif /* _CORE__INCLUDE__VM_SPACE_H_ */