/* * vmm.h - virtual memory management related operations * * Authors Ghassan Almaless (2008,2009,2010,2011, 2012) * Mohamed Lamine Karaoui (2015) * Alain Greiner (2016,2017) * * Copyright (c) UPMC Sorbonne Universites * * This file is part of ALMOS-MKH. * * ALMOS-MKH is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License as published by * the Free Software Foundation; version 2.0 of the License. * * ALMOS-MKH is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public License * along with ALMOS-MKH; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */ #ifndef _VMM_H_ #define _VMM_H_ #include #include #include #include #include #include #include /**** Forward declarations ****/ struct process_s; /********************************************************************************************* * This structure defines the STACK allocator used by the VMM to dynamically handle * a STACK vseg requested or released by an user process. * This allocator handles a fixed size array of fixed size slots in the STACK zone. * The stack size and the number of slots are defined by the CONFIG_VMM_STACK_SIZE, and * CONFIG_VMM_STACK_BASE parameters. * Each slot can contain one user stack vseg. The first page in the slot is not allocated * to detect stack overflow. * The slot index can be computed form the slot base address, and reversely. * All allocation / release operations are registered in the stack_bitmap, that completely * define the STACK zone state. ********************************************************************************************/ typedef struct stack_mgr_s { spinlock_t lock; /*! lock protecting STACK allocator */ vpn_t vpn_base; /*! first page of STACK zone */ bitmap_t bitmap; /*! bit bector of allocated stacks */ } stack_mgr_t; /********************************************************************************************* * This structure defines the MMAP allocator used by the VMM to dynamically handle * MMAP vsegs requested or released by an user process. * This allocator should be only used in the reference cluster. * - allocation policy : all allocated vsegs occupy an integer number of pages that is * power of 2, and are aligned on a page boundary. The requested number of pages is * rounded if required. The first_free_vpn variable defines completely the MMAP zone state. * It is never decremented, as the released vsegs are simply registered in a zombi_list. * The relevant zombi_list is checked first for each allocation request. * - release policy : a released MMAP vseg is registered in an array of zombi_lists. * This array is indexed by ln(number of pages), and each entry contains the root of * a local list of zombi vsegs that have the same size. The physical memory allocated * for a zombi vseg descriptor is not released, to use the "list" field. * This physical memory allocated for MMAP vseg descriptors is actually released * when the VMM is destroyed. ********************************************************************************************/ typedef struct mmap_mgr_s { spinlock_t lock; /*! lock protecting MMAP allocator */ vpn_t vpn_base; /*! first page of MMAP zone */ vpn_t vpn_size; /*! number of pages in MMAP zone */ vpn_t first_free_vpn; /*! first free page in MMAP zone */ list_entry_t zombi_list[32]; /*! array of roots of released vsegs lists */ } mmap_mgr_t; /********************************************************************************************* * This structure defines the Virtual Memory Manager for a given process in a given cluster. * This local VMM provides four main services: * 1) It registers all vsegs in the local copy of the vseg list (VSL). * 2) It contains the local copy of the generic page table (GPT). * 3) The stack manager dynamically allocates virtual memory space for the STACK vsegs. * 4) The mmap manager dynamically allocates virtual memory for the (FILE/ANON/REMOTE) vsegs. ******************************************************a************************************** * Implementation notes: * 1. The VSL contains only local vsegs, but it is implemented as an xlist, and protected by * a remote_rwlock, because it can be accessed by a thread running in a remote cluster. * An exemple is the vmm_fork_copy() function. * 2. In most custers, the VSL and GPT are only partial copies of the reference VSL and GPT * structures, stored in the reference cluster. ********************************************************************************************/ typedef struct vmm_s { remote_rwlock_t vsegs_lock; /*! lock protecting the vsegs list */ xlist_entry_t vsegs_root; /*! VSL root (VSL only complete in reference) */ uint32_t vsegs_nr; /*! total number of local vsegs */ gpt_t gpt; /*! Generic Page Table (complete in reference) */ stack_mgr_t stack_mgr; /*! embedded STACK vsegs allocator */ mmap_mgr_t mmap_mgr; /*! embedded MMAP vsegs allocator */ uint32_t pgfault_nr; /*! page fault counter (instrumentation) */ vpn_t kent_vpn_base; /*! kentry vseg first page */ vpn_t args_vpn_base; /*! args vseg first page */ vpn_t envs_vpn_base; /*! envs zone first page */ vpn_t heap_vpn_base; /*! envs zone first page */ vpn_t code_vpn_base; /*! code zone first page */ vpn_t data_vpn_base; /*! data zone first page */ intptr_t entry_point; /*! main thread entry point */ } vmm_t; /********************************************************************************************* * This function initialises the virtual memory manager attached to an user process. * - It initializes the STACK and MMAP allocators. * - It registers the "kentry", "args", "envs" vsegs in the VSL. * - It initializes the generic page table, calling the HAL specific hal_gpt_init() function. * - For TSAR it map all pages for the "kentry" vseg, that must be identity mapping. * Note: * - The "code" and "data" vsegs are registered by the elf_load_process() function. * - The "stack" vsegs are dynamically created by the thread_user_create() function. * - The "file", "anon", "remote" vsegs are dynamically created by the mmap() syscall. * TODO : Any error in this function gives a kernel panic => improve error handling. ********************************************************************************************* * @ process : pointer on process descriptor ********************************************************************************************/ void vmm_init( struct process_s * process ); /********************************************************************************************* * This function displays on TXY0 the list or registered vsegs for a given . * If the argument is true, it displays for each vesg all mapped PTEs in GPT. ********************************************************************************************* * @ process : pointer on process descriptor. * @ mapping : detailed mapping if true. ********************************************************************************************/ void vmm_display( struct process_s * process, bool_t mapping ); /********************************************************************************************* * This function is called by the process_fork_create() function. It partially copies * the content of a remote parent process VMM to the local child process VMM: * - all DATA, MMAP, REMOTE vsegs registered in the parent VSL are registered in the child * VSL, and all valid GPT entries in parent GPT are copied to the child GPT. * The WRITABLE flag is reset and the COW flag is set in child GPT. * - all CODE vsegs registered in the parent VSL are registered in the child VSL, but the * GPT entries are not copied in the chilf GPT, that will be dynamically updated from * the .elf file when a page fault is reported. * - all FILE vsegs registered in the parent VSL are registered in the child VSL, and all * valid GPT entries in parent GPT are copied to the child GPT. The COW flag is not set. * - no STACK vseg is copied from parent VMM to child VMM, because the child STACK vseg * must be copied from the cluster containing the user thread requesting the fork(). ********************************************************************************************* * @ child_process : local pointer on local child process descriptor. * @ parent_process_xp : extended pointer on remote parent process descriptor. * @ return 0 if success / return ENOMEM if failure. ********************************************************************************************/ error_t vmm_fork_copy( struct process_s * child_process, xptr_t parent_process_xp ); /********************************************************************************************* * This function is called by the process_make_fork() function to handle the fork syscall. * It set the COW flag, and reset the WRITABLE flag of all GPT entries of the DATA, MMAP, * and REMOTE vsegs of a process identified by the argument. * It must be called by a thread running in the reference cluster, that contains the complete * list of vsegs. Use the rpc_vmm_set_cow_client() when the calling thread client is remote. * It updates all copies of the process in all clusters, to maintain coherence in GPT copies, * using the list of copies stored in the owner process, and using remote_write accesses to * update the remote GPTs. It cannot fail, as only mapped entries in GPT copies are updated. ********************************************************************************************* * @ process : local pointer on local reference process descriptor. ********************************************************************************************/ void vmm_set_cow( struct process_s * process ); /********************************************************************************************* * This function is called by the vmm_get_pte() function in case of COW exception. * It modifies both the PPN an the attributes for a GPT entry identified by the * and arguments. * It updates all copies of the process in all clusters, to maintain coherence in GPT copies, * using the list of copies stored in the owner process, and using remote_write accesses to * update the remote GPTs. It cannot fail, as only mapped entries in GPT copies are updated. ********************************************************************************************* * @ process : local pointer on local process descriptor. * @ vpn : PTE index. * @ attr : PTE / attributes. * @ ppn : PTE / physical page index. ********************************************************************************************/ void vmm_update_pte( struct process_s * process, vpn_t vpn, uint32_t attr, ppn_t ppn ); /********************************************************************************************* * This function scan the list of vsegs registered in the VSL of the process * identified by the argument, and for each vseg: * - it unmap from the GPT and releases all mapped pages in vseg. * - it removes the vseg from the process VSL. * - It releases the memory allocated to the vseg descriptor. * Finally, it releases the memory allocated to the GPT itself. ********************************************************************************************* * @ process : pointer on process descriptor. ********************************************************************************************/ void vmm_destroy( struct process_s * process ); /********************************************************************************************* * This function scans the list of vsegs registered in the VMM of a given process descriptor * to check if a given virtual region (defined by a base and size) overlap an existing vseg. ********************************************************************************************* * @ process : pointer on process descriptor. * @ base : region virtual base address. * @ size : region size (bytes). * @ returns NULL if no conflict / return conflicting vseg pointer if conflict. ********************************************************************************************/ vseg_t * vmm_check_conflict( struct process_s * process, vpn_t base, vpn_t size ); /********************************************************************************************* * This function allocates memory for a vseg descriptor, initialises it, and register it * in the VMM of the local process descriptor, that should be the reference process. * For the 'stack", "file", "anon", & "remote" types, it does not use the argument, * but uses the STACK and MMAP virtual memory allocators. * It checks collision with all pre-existing vsegs. * To comply with the "on-demand" paging policy, this function does NOT modify the page table, * and does not allocate physical memory for vseg data. * It should be called by a local thread (could be a RPC thread if the client thread is not * running in the regerence cluster). ********************************************************************************************* * @ process : pointer on local processor descriptor. * @ type : vseg type. * @ base : vseg base address (not used for dynamically allocated vsegs). * @ size : vseg size (bytes). * @ file_offset : offset in file for CODE, DATA, FILE types. * @ file_size : can be smaller than "size" for DATA type. * @ mapper_xp : extended pointer on mapper for CODE, DATA, FILE types. * @ cxy : physical mapping cluster (for non distributed vsegs). * @ returns pointer on vseg if success / returns NULL if no memory, or conflict. ********************************************************************************************/ vseg_t * vmm_create_vseg( struct process_s * process, vseg_type_t type, intptr_t base, uint32_t size, uint32_t file_offset, uint32_t file_size, xptr_t mapper_xp, cxy_t cxy ); /********************************************************************************************* * This function removes a vseg identified by it's pointer from the VMM of the calling process. * - If the vseg has not the STACK or MMAP type, it is removed from the vsegs list, * and the physical memory allocated to vseg descriptor is released to KMEM. * - If the vseg has the STACK type, it is removed from the vsegs list, the physical memory * allocated to vseg descriptor is released to KMEM, and the stack slot is returned to the * VMM STACK allocator. * - If the vseg has the MMAP type, it is removed from the vsegs list and is registered * in the zombi_list of the VMM MMAP allocator for future reuse. The physical memory * allocated to vseg descriptor is NOT released to KMEM. ********************************************************************************************* * @ vseg : pointer on vseg to be removed. ********************************************************************************************/ void vmm_remove_vseg( vseg_t * vseg ); /********************************************************************************************* * This function allocates physical memory from the local cluster to map all PTEs * of a "kernel" vseg (type KCODE , KDATA, or KDEV) in the page table of process_zero. * WARNING : It should not be used for "user" vsegs, that must be mapped using the * "on-demand-paging" policy. ********************************************************************************************* * @ vseg : pointer on the vseg to be mapped. * @ attr : GPT attributes to be set for all vseg pages. * @ returns 0 if success / returns ENOMEM if no memory ********************************************************************************************/ error_t vmm_map_kernel_vseg( vseg_t * vseg, uint32_t attr ); /********************************************************************************************* * This function unmaps all mapped PTEs of a given vseg, from the generic page table * associated to a given process descriptor, and releases the physical memory allocated * to all mapped GPT entries. It can be used for any type of vseg. ********************************************************************************************* * @ process : pointer on process descriptor. * @ vseg : pointer on the vseg to be unmapped. ********************************************************************************************/ void vmm_unmap_vseg( struct process_s * process, vseg_t * vseg ); /********************************************************************************************* * This function removes a given region (defined by a base address and a size) from * the VMM of a given process descriptor. This can modify the number of vsegs: * (a) if the region is not entirely mapped in an existing vseg, it's an error. * (b) if the region has same base and size as an existing vseg, the vseg is removed. * (c) if the removed region cut the vseg in two parts, it is modified. * (d) if the removed region cut the vseg in three parts, it is modified, and a new * vseg is created with same type. * FIXME [AG] this function must be called by a thread running in the reference cluster, * and the VMM must be updated in all process descriptors copies. ********************************************************************************************* * @ process : pointer on process descriptor * @ base : vseg base address * @ size : vseg size (bytes) ********************************************************************************************/ error_t vmm_resize_vseg( struct process_s * process, intptr_t base, intptr_t size ); /********************************************************************************************* * This function checks that a given virtual address is contained in a registered vseg. * It can be called by any thread running in any cluster: * - if the vseg is registered in the local process VMM, it returns the local vseg pointer. * - if the vseg is missing in local VMM, it uses a RPC to get it from the reference cluster, * register it in local VMM and returns the local vseg pointer, if success. * - it returns an user error if the vseg is missing in the reference VMM, or if there is * not enough memory for a new vseg descriptor in cluster containing the calling thread. ********************************************************************************************* * @ process : [in] pointer on process descriptor * @ vaddr : [in] virtual address * @ vseg : [out] pointer on found vseg * @ returns 0 if success / returns -1 if user error. *********************************************************************************************/ error_t vmm_get_vseg( struct process_s * process, intptr_t vaddr, vseg_t ** vseg ); /********************************************************************************************* * This function is called by the generic exception handler when a page-fault event * has been detected in a given cluster. * - If the local cluster is the reference, it call directly the vmm_get_pte() function. * - If the local cluster is not the reference cluster, it send a RPC_VMM_GET_PTE * to the reference cluster to get the missing PTE attributes and PPN, * and update the local page table. ********************************************************************************************* * @ process : pointer on process descriptor. * @ vpn : VPN of the missing PTE. * @ returns 0 if success / returns ENOMEM if no memory. ********************************************************************************************/ error_t vmm_handle_page_fault( struct process_s * process, vpn_t vpn ); /********************************************************************************************* * This function is called by the generic exception handler when a copy-on-write event * has been detected in a given cluster. * - If the local cluster is the reference, it call directly the vmm_get_pte() function. * - If the local cluster is not the reference cluster, it send a RPC_VMM_GET_PTE * to the reference cluster to get the missing PTE attributes and PPN, * and update the local page table. ********************************************************************************************* * @ process : pointer on process descriptor. * @ vpn : VPN of the missing PTE. * @ returns 0 if success / returns ENOMEM if no memory. ********************************************************************************************/ error_t vmm_handle_cow( struct process_s * process, vpn_t vpn ); /********************************************************************************************* * This function is called when a new PTE (GPT entry) is required because a "page-fault", * or "copy-on_write" event has been detected for a given in a given . * The argument defines the type of event to be handled. * This function must be called by a thread running in reference cluster, and the vseg * containing the searched VPN should be registered in the reference VMM. * - for an actual page-fault, it allocates the missing physical page from the target cluster * defined by the vseg type, initialize it, and update the reference page table. * - for a copy-on-write, it allocates a new physical page from the target cluster, * initialise it from the old physical page, and update the reference page table. * In both cases, it calls the RPC_PMEM_GET_PAGES to get the new physical page if the * target cluster is not the reference cluster. * It returns in the and arguments the accessed or modified PTE. ********************************************************************************************* * @ process : [in] pointer on process descriptor. * @ vpn : [in] VPN defining the missing PTE. * @ cow : [in] "copy_on_write" if true / "page_fault" if false. * @ attr : [out] PTE attributes. * @ ppn : [out] PTE ppn. * @ returns 0 if success / returns ENOMEM if error. ********************************************************************************************/ error_t vmm_get_pte( struct process_s * process, vpn_t vpn, bool_t cow, uint32_t * attr, ppn_t * ppn ); /********************************************************************************************* * This function is called by the vmm_get_pte() function when a page is unmapped. * Depending on the vseg type, defined by the argument, it returns the PPN * (Physical Page Number) associated to a missing page defined by the argument. * - For the FILE type, it returns directly the physical page from the file mapper. * - For the CODE and DATA types, it allocates a new phsical page from the cluster defined * by the cxy> field, or by the MSB bits for a distributed vseg, * and initialize this page from the .elf file mapper. * - For all other types, it allocates a new physical page from the cluster defined * by the cxy> field, or by the MSB bits for a distributed vseg, * but the new page is not initialized. ********************************************************************************************* * @ vseg : local pointer on vseg containing the mising page. * @ vpn : Virtual Page Number identifying the missing page. * @ ppn : [out] returned Physical Page Number. * return 0 if success / return EINVAL or ENOMEM if error. ********************************************************************************************/ error_t vmm_get_one_ppn( vseg_t * vseg, vpn_t vpn, ppn_t * ppn ); /********************************************************************************************* * This function makes the virtual to physical address translation, using the calling * process page table. It uses identity mapping if required by the argument. * This address translation is required to configure the peripherals having a DMA * capability, or to implement the software L2/L3 cache cohérence, using the MMC device * synchronisation primitives. * WARNING : the value must be defined by the CONFIG_KERNEL_IDENTITY_MAP parameter. ********************************************************************************************* * @ ident : [in] uses identity mapping if true. * @ ptr : [in] virtual address. * @ paddr : [out] pointer on buffer for physical address. * @ returns 0 if success / returns ENOMEM if error. ********************************************************************************************/ error_t vmm_v2p_translate( bool_t ident, void * ptr, paddr_t * paddr ); #endif /* _VMM_H_ */