/* * Copyright 2010 Stefan Lankes, Chair for Operating Systems, * RWTH Aachen University * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. * * This file is part of MetalSVM. */ /** * @file arch/x86/include/asm/page.h * @brief Definitions and functions related to paging * @author Stefan Lankes * * This file defines the interface for paging as like structures related to paging. */ #ifndef __ARCH_PAGE_H__ #define __ARCH_PAGE_H__ #include #include #define _PAGE_BIT_PRESENT 0 /* is present */ #define _PAGE_BIT_RW 1 /* writeable */ #define _PAGE_BIT_USER 2 /* userspace addressable */ #define _PAGE_BIT_PWT 3 /* page write through */ #define _PAGE_BIT_PCD 4 /* page cache disabled */ #define _PAGE_BIT_ACCESSED 5 /* was accessed (raised by CPU) */ #define _PAGE_BIT_DIRTY 6 /* was written to (raised by CPU) */ #define _PAGE_BIT_PSE 7 /* 4 MB (or 2MB) page */ #define _PAGE_BIT_PAT 7 /* on 4KB pages */ #define _PAGE_BIT_GLOBAL 8 /* Global TLB entry PPro+ */ #define _PAGE_BIT_SVM_STRONG 9 /* mark a virtual address range as used by the SVM system */ #define _PAGE_BIT_SVM_LAZYRELEASE 10 /* mark a virtual address range as used by the SVM system */ #define _PAGE_BIT_SVM_INIT 11 /* mark if the MBP proxy is used */ /// Page is present #define PG_PRESENT (1 << _PAGE_BIT_PRESENT) /// Page is read- and writable #define PG_RW (1 << _PAGE_BIT_RW) /// Page is addressable from userspace #define PG_USER (1 << _PAGE_BIT_USER) /// Page write through is activated #define PG_PWT (1 << _PAGE_BIT_PWT) /// Page cache is disabled #define PG_PCD (1 << _PAGE_BIT_PCD) /// Page was recently accessed (set by CPU) #define PG_ACCESSED (1 << _PAGE_BIT_ACCESSED) /// Page is dirty due to recentwrite-access (set by CPU) #define PG_DIRTY (1 << _PAGE_BIT_DIRTY) /// Big page: 4MB (or 2MB) #define PG_PSE (1 << _PAGE_BIT_PSE) /// Page is part of the MPB (SCC specific entry) #define PG_MPE PG_PSE /// Global TLB entry (Pentium Pro and later) #define PG_GLOBAL (1 << _PAGE_BIT_GLOBAL) /// Pattern flag #define PG_PAT (1 << _PAGE_BIT_PAT) /// This virtual address range is used by SVM system as marked #define PG_SVM PG_SVM_STRONG #define PG_SVM_STRONG (1 << _PAGE_BIT_SVM_STRONG) /// This virtual address range is used by SVM system as marked #define PG_SVM_LAZYRELEASE (1 << _PAGE_BIT_SVM_LAZYRELEASE) /// Currently, no page frame is behind this page (only the MBP proxy) #define PG_SVM_INIT (1 << _PAGE_BIT_SVM_INIT) /// This is a whole set of flags (PRESENT,RW,ACCESSED,DIRTY) for kernelspace tables #define KERN_TABLE (PG_PRESENT|PG_RW|PG_ACCESSED|PG_DIRTY) /// This is a whole set of flags (PRESENT,RW,ACCESSED,DIRTY,USER) for userspace tables #define USER_TABLE (PG_PRESENT|PG_RW|PG_ACCESSED|PG_DIRTY|PG_USER) /// This is a whole set of flags (PRESENT,RW,GLOBAL) for kernelspace pages #define KERN_PAGE (PG_PRESENT|PG_RW|PG_GLOBAL) /// This is a whole set of flags (PRESENT,RW,USER) for userspace pages #define USER_PAGE (PG_PRESENT|PG_RW|PG_USER) #if __SIZEOF_POINTER__ == 4 #define PGT_ENTRIES 1024 #elif __SIZEOF_POINTER__ == 8 #define PGT_ENTRIES 512 #endif /** @brief Page table structure * * This structure keeps page table entries.\n * On a 32bit system, a page table consists normally of 1024 entries. */ typedef struct page_table { /// Page table entries are unsigned 32bit integers. size_t entries[PGT_ENTRIES]; } page_table_t __attribute__ ((aligned (4096))); /** @brief Page directory structure * * This structure keeps page directory entries.\ * On a 32bit system, a page directory consists normally of 1024 entries. */ typedef struct page_dir { /// Page dir entries are unsigned 32bit integers. size_t entries[PGT_ENTRIES]; } page_dir_t __attribute__ ((aligned (4096))); /** @brief Converts a virtual address to a physical * * @param viraddr Virtual address to convert * @return physical address */ size_t virt_to_phys(size_t viraddr); /** @brief Allocates a virtual address space range of npages * * The address range with special flags (if given) will have the size of n pages. * * @param npages The range in page-granularity * @param flags further page flags * * @return The new range's address */ size_t vm_alloc(uint32_t npages, uint32_t flags); /** @brief Frees a range in the virtual address space * * @param addr Address of the range * @param npages Size of the range in pages * * @return * - 0 on success * - -EINVAL (-22) on failure. */ int vm_free(size_t addr, uint32_t npages); /** @brief Unmap the physical memory at a specific virtual address * * All Page table entries within this range will be marked as not present * and (in the case of userspace memory) the page usage of the task will be decremented. * * @param viraddr The range's virtual address * @param npages The range's size in pages * * @return * - 0 on success * - -EINVAL (-22) on failure. */ int unmap_region(size_t viraddr, uint32_t npages); /** @brief Mapping a physical mem-region to a virtual address * * Maps a physical memory region to a specific virtual address. * If the virtual address is zero, this functions allocates a valid virtual address on demand. * * @param viraddr Desired virtual address * @param phyaddr Physical address to map from * @param npages The region's size in number of pages * @param flags Further page flags * * @return * - A virtual address on success * - 0 on failure. */ size_t map_region(size_t viraddr, size_t phyaddr, uint32_t npages, uint32_t flags); /** @brief Sets up the environment and enables paging. * * - Installs the page handler IRQ * - sets up the whole page directory and page tables for the kernel space (virt adr = phys adr) * - maps VGA, multi boot info and initrd into kernel space * - writes to cr0 and cr3 register * - marks 'paging_enabled' var = 1 * - Registers kernel thread for task state switching * * @return returns * - 0 on success * - -ENOMEM (-12) on failure */ int arch_paging_init(void); /** @brief Returns the page directory of the boot task * * The boot task's page directory is a static array of page_dir_t type vars. * * @return Returns the address of the boot task's page dir array. */ page_dir_t* get_boot_pgd(void); /** @brief Setup a new page directory for a new user-level task * * @param task Pointer to the task-specific task_t structure * @param copy If true: PGD will be a copy of the kernel's address space PGD * * @return * - counter of allocated page tables * - -ENOMEM (-12) on failure */ int create_pgd(task_t* task, int copy); /** @brief Delete page directory and its page tables * * Puts page tables and page directory back to buffer and * sets the task's page directory pointer to NULL * * @return * - 0 on success * - -EINVAL (-22) on failure (in case PGD is still the boot-pgd). */ int drop_pgd(void); /** @brief Change the page permission in the page tables of the current task * * Applies given flags noted in the 'flags' parameter to * the range denoted by virtual start and end addresses. * * @param start Range's virtual start address * @param end Range's virtual end address * @param flags flags to apply * * @return * - 0 on success * - -EINVAL (-22) on failure. */ int change_page_permissions(size_t start, size_t end, uint32_t flags); #endif