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| /* |
| * Copyright (c) 2006 Jakub Jermar |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * |
| * - Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * - Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * - The name of the author may not be used to endorse or promote products |
| * derived from this software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| /** @addtogroup genericmm |
| * @{ |
| */ |
| |
| /** |
| * @file |
| * @brief Backend for anonymous memory address space areas. |
| * |
| */ |
| |
| #include <mm/as.h> |
| #include <mm/page.h> |
| #include <genarch/mm/page_pt.h> |
| #include <genarch/mm/page_ht.h> |
| #include <mm/frame.h> |
| #include <mm/slab.h> |
| #include <synch/mutex.h> |
| #include <adt/list.h> |
| #include <adt/btree.h> |
| #include <errno.h> |
| #include <arch/types.h> |
| #include <align.h> |
| #include <arch.h> |
| |
| #ifdef CONFIG_VIRT_IDX_DCACHE |
| #include <arch/mm/cache.h> |
| #endif |
| |
| static int anon_page_fault(as_area_t *area, uintptr_t addr, pf_access_t access); |
| static void anon_frame_free(as_area_t *area, uintptr_t page, uintptr_t frame); |
| static void anon_share(as_area_t *area); |
| |
| mem_backend_t anon_backend = { |
| .page_fault = anon_page_fault, |
| .frame_free = anon_frame_free, |
| .share = anon_share |
| }; |
| |
| /** Service a page fault in the anonymous memory address space area. |
| * |
| * The address space area and page tables must be already locked. |
| * |
| * @param area Pointer to the address space area. |
| * @param addr Faulting virtual address. |
| * @param access Access mode that caused the fault (i.e. read/write/exec). |
| * |
| * @return AS_PF_FAULT on failure (i.e. page fault) or AS_PF_OK on success (i.e. |
| * serviced). |
| */ |
| int anon_page_fault(as_area_t *area, uintptr_t addr, pf_access_t access) |
| { |
| uintptr_t frame; |
| bool dirty = false; |
| |
| if (!as_area_check_access(area, access)) |
| return AS_PF_FAULT; |
| |
| if (area->sh_info) { |
| btree_node_t *leaf; |
| |
| /* |
| * The area is shared, chances are that the mapping can be found |
| * in the pagemap of the address space area share info |
| * structure. |
| * In the case that the pagemap does not contain the respective |
| * mapping, a new frame is allocated and the mapping is created. |
| */ |
| mutex_lock(&area->sh_info->lock); |
| frame = (uintptr_t) btree_search(&area->sh_info->pagemap, |
| ALIGN_DOWN(addr, PAGE_SIZE) - area->base, &leaf); |
| if (!frame) { |
| bool allocate = true; |
| unsigned int i; |
| |
| /* |
| * Zero can be returned as a valid frame address. |
| * Just a small workaround. |
| */ |
| for (i = 0; i < leaf->keys; i++) { |
| if (leaf->key[i] == |
| ALIGN_DOWN(addr, PAGE_SIZE)) { |
| allocate = false; |
| break; |
| } |
| } |
| if (allocate) { |
| frame = (uintptr_t) frame_alloc(ONE_FRAME, 0); |
| memsetb((void *) PA2KA(frame), FRAME_SIZE, 0); |
| dirty = true; |
| |
| /* |
| * Insert the address of the newly allocated |
| * frame to the pagemap. |
| */ |
| btree_insert(&area->sh_info->pagemap, |
| ALIGN_DOWN(addr, PAGE_SIZE) - area->base, |
| (void *) frame, leaf); |
| } |
| } |
| frame_reference_add(ADDR2PFN(frame)); |
| mutex_unlock(&area->sh_info->lock); |
| } else { |
| |
| /* |
| * In general, there can be several reasons that |
| * can have caused this fault. |
| * |
| * - non-existent mapping: the area is an anonymous |
| * area (e.g. heap or stack) and so far has not been |
| * allocated a frame for the faulting page |
| * |
| * - non-present mapping: another possibility, |
| * currently not implemented, would be frame |
| * reuse; when this becomes a possibility, |
| * do not forget to distinguish between |
| * the different causes |
| */ |
| frame = (uintptr_t) frame_alloc(ONE_FRAME, 0); |
| memsetb((void *) PA2KA(frame), FRAME_SIZE, 0); |
| dirty = true; |
| } |
| |
| /* |
| * Map 'page' to 'frame'. |
| * Note that TLB shootdown is not attempted as only new information is |
| * being inserted into page tables. |
| */ |
| page_mapping_insert(AS, addr, frame, as_area_get_flags(area)); |
| if (!used_space_insert(area, ALIGN_DOWN(addr, PAGE_SIZE), 1)) |
| panic("Could not insert used space.\n"); |
| |
| return AS_PF_OK; |
| } |
| |
| /** Free a frame that is backed by the anonymous memory backend. |
| * |
| * The address space area and page tables must be already locked. |
| * |
| * @param area Ignored. |
| * @param page Virtual address of the page corresponding to the frame. |
| * @param frame Frame to be released. |
| */ |
| void anon_frame_free(as_area_t *area, uintptr_t page, uintptr_t frame) |
| { |
| frame_free(frame); |
| } |
| |
| /** Share the anonymous address space area. |
| * |
| * Sharing of anonymous area is done by duplicating its entire mapping |
| * to the pagemap. Page faults will primarily search for frames there. |
| * |
| * The address space and address space area must be already locked. |
| * |
| * @param area Address space area to be shared. |
| */ |
| void anon_share(as_area_t *area) |
| { |
| link_t *cur; |
| |
| /* |
| * Copy used portions of the area to sh_info's page map. |
| */ |
| mutex_lock(&area->sh_info->lock); |
| for (cur = area->used_space.leaf_head.next; |
| cur != &area->used_space.leaf_head; cur = cur->next) { |
| btree_node_t *node; |
| unsigned int i; |
| |
| node = list_get_instance(cur, btree_node_t, leaf_link); |
| for (i = 0; i < node->keys; i++) { |
| uintptr_t base = node->key[i]; |
| count_t count = (count_t) node->value[i]; |
| unsigned int j; |
| |
| for (j = 0; j < count; j++) { |
| pte_t *pte; |
| |
| page_table_lock(area->as, false); |
| pte = page_mapping_find(area->as, |
| base + j * PAGE_SIZE); |
| ASSERT(pte && PTE_VALID(pte) && |
| PTE_PRESENT(pte)); |
| btree_insert(&area->sh_info->pagemap, |
| (base + j * PAGE_SIZE) - area->base, |
| (void *) PTE_GET_FRAME(pte), NULL); |
| page_table_unlock(area->as, false); |
| |
| pfn_t pfn = ADDR2PFN(PTE_GET_FRAME(pte)); |
| frame_reference_add(pfn); |
| } |
| |
| } |
| } |
| mutex_unlock(&area->sh_info->lock); |
| } |
| |
| /** @} |
| */ |