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)); |
} |
} |