| 0,0 → 1,160 |
|---|
| /* |
| * 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. |
| */ |
| |
| /** |
| * @file backend_elf.c |
| * @brief Backend for address space areas backed by an ELF image. |
| */ |
| |
| #include <elf.h> |
| #include <debug.h> |
| #include <arch/types.h> |
| #include <typedefs.h> |
| #include <mm/as.h> |
| #include <mm/frame.h> |
| #include <mm/slab.h> |
| #include <align.h> |
| #include <memstr.h> |
| #include <macros.h> |
| #include <arch.h> |
| |
| static int elf_page_fault(as_area_t *area, __address addr, pf_access_t access); |
| static void elf_frame_free(as_area_t *area, __address page, __address frame); |
| |
| mem_backend_t elf_backend = { |
| .page_fault = elf_page_fault, |
| .frame_free = elf_frame_free, |
| .share = NULL |
| }; |
| |
| /** Service a page fault in the ELF backend 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 elf_page_fault(as_area_t *area, __address addr, pf_access_t access) |
| { |
| elf_header_t *elf = (elf_header_t *) area->backend_data.d1; |
| elf_segment_header_t *entry = (elf_segment_header_t *) area->backend_data.d2; |
| __address base, frame; |
| index_t i; |
| |
| if (!as_area_check_access(area, access)) |
| return AS_PF_FAULT; |
| |
| ASSERT((addr >= entry->p_vaddr) && (addr < entry->p_vaddr + entry->p_memsz)); |
| i = (addr - entry->p_vaddr) >> PAGE_WIDTH; |
| base = (__address) (((void *) elf) + entry->p_offset); |
| ASSERT(ALIGN_UP(base, FRAME_SIZE) == base); |
| |
| if (ALIGN_DOWN(addr, PAGE_SIZE) + PAGE_SIZE < entry->p_vaddr + entry->p_filesz) { |
| /* |
| * Initialized portion of the segment. The memory is backed |
| * directly by the content of the ELF image. Pages are |
| * only copied if the segment is writable so that there |
| * can be more instantions of the same memory ELF image |
| * used at a time. Note that this could be later done |
| * as COW. |
| */ |
| if (entry->p_flags & PF_W) { |
| frame = PFN2ADDR(frame_alloc(ONE_FRAME, 0)); |
| memcpy((void *) PA2KA(frame), (void *) (base + i*FRAME_SIZE), FRAME_SIZE); |
| } else { |
| frame = KA2PA(base + i*FRAME_SIZE); |
| } |
| } else if (ALIGN_DOWN(addr, PAGE_SIZE) >= ALIGN_UP(entry->p_vaddr + entry->p_filesz, PAGE_SIZE)) { |
| /* |
| * This is the uninitialized portion of the segment. |
| * It is not physically present in the ELF image. |
| * To resolve the situation, a frame must be allocated |
| * and cleared. |
| */ |
| frame = PFN2ADDR(frame_alloc(ONE_FRAME, 0)); |
| memsetb(PA2KA(frame), FRAME_SIZE, 0); |
| } else { |
| size_t size; |
| /* |
| * The mixed case. |
| * The lower part is backed by the ELF image and |
| * the upper part is anonymous memory. |
| */ |
| size = entry->p_filesz - (i<<PAGE_WIDTH); |
| frame = PFN2ADDR(frame_alloc(ONE_FRAME, 0)); |
| memsetb(PA2KA(frame) + size, FRAME_SIZE - size, 0); |
| memcpy((void *) PA2KA(frame), (void *) (base + i*FRAME_SIZE), size); |
| } |
| |
| 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 ELF backend. |
| * |
| * The address space area and page tables must be already locked. |
| * |
| * @param area Pointer to the address space area. |
| * @param page Page that is mapped to frame. Must be aligned to PAGE_SIZE. |
| * @param frame Frame to be released. |
| * |
| */ |
| void elf_frame_free(as_area_t *area, __address page, __address frame) |
| { |
| elf_header_t *elf = (elf_header_t *) area->backend_data.d1; |
| elf_segment_header_t *entry = (elf_segment_header_t *) area->backend_data.d2; |
| __address base; |
| index_t i; |
| |
| ASSERT((page >= entry->p_vaddr) && (page < entry->p_vaddr + entry->p_memsz)); |
| i = (page - entry->p_vaddr) >> PAGE_WIDTH; |
| base = (__address) (((void *) elf) + entry->p_offset); |
| ASSERT(ALIGN_UP(base, FRAME_SIZE) == base); |
| |
| if (page + PAGE_SIZE < ALIGN_UP(entry->p_vaddr + entry->p_filesz, PAGE_SIZE)) { |
| if (entry->p_flags & PF_W) { |
| /* |
| * Free the frame with the copy of writable segment data. |
| */ |
| frame_free(ADDR2PFN(frame)); |
| } |
| } else { |
| /* |
| * The frame is either anonymous memory or the mixed case (i.e. lower |
| * part is backed by the ELF image and the upper is anonymous). |
| * In any case, a frame needs to be freed. |
| */ |
| frame_free(ADDR2PFN(frame)); |
| } |
| } |