kernel/generic/src/mm/backend_phys.c

   1 /*
   2  * Copyright (c) 2006 Jakub Jermar
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  *
   9  * - Redistributions of source code must retain the above copyright
  10  *   notice, this list of conditions and the following disclaimer.
  11  * - Redistributions in binary form must reproduce the above copyright
  12  *   notice, this list of conditions and the following disclaimer in the
  13  *   documentation and/or other materials provided with the distribution.
  14  * - The name of the author may not be used to endorse or promote products
  15  *   derived from this software without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  */
  28
  29 /** @addtogroup genericmm
  30  * @{
  31  */
  32
  33 /**
  34  * @file
  35  * @brief       Backend for address space areas backed by continuous physical memory.
  36  */
  37
  38 #include <debug.h>
  39 #include <arch/types.h>
  40 #include <typedefs.h>
  41 #include <mm/as.h>
  42 #include <mm/frame.h>
  43 #include <mm/slab.h>
  44 #include <memstr.h>
  45 #include <macros.h>
  46 #include <arch.h>
  47 #include <align.h>
  48
  49 static int phys_page_fault(as_area_t *area, uintptr_t addr, pf_access_t access);
  50 static void phys_share(as_area_t *area);
  51
  52 mem_backend_t phys_backend = {
  53         .page_fault = phys_page_fault,
  54         .frame_free = NULL,
  55         .share = phys_share
  56 };
  57
  58 /** Service a page fault in the address space area backed by physical memory.
  59  *
  60  * The address space area and page tables must be already locked.
  61  *
  62  * @param area Pointer to the address space area.
  63  * @param addr Faulting virtual address.
  64  * @param access Access mode that caused the fault (i.e. read/write/exec).
  65  *
  66  * @return AS_PF_FAULT on failure (i.e. page fault) or AS_PF_OK on success (i.e. serviced).
  67  */
  68 int phys_page_fault(as_area_t *area, uintptr_t addr, pf_access_t access)
  69 {
  70         uintptr_t base = area->backend_data.base;
  71
  72         if (!as_area_check_access(area, access))
  73                 return AS_PF_FAULT;
  74
  75         ASSERT(addr - area->base < area->backend_data.frames * FRAME_SIZE);
  76         page_mapping_insert(AS, addr, base + (addr - area->base), as_area_get_flags(area));
  77         if (!used_space_insert(area, ALIGN_DOWN(addr, PAGE_SIZE), 1))
  78                 panic("Could not insert used space.\n");
  79
  80         return AS_PF_OK;
  81 }
  82
  83 /** Share address space area backed by physical memory.
  84  *
  85  * Do actually nothing as sharing of address space areas
  86  * that are backed up by physical memory is very easy.
  87  * Note that the function must be defined so that
  88  * as_area_share() will succeed.
  89  */
  90 void phys_share(as_area_t *area)
  91 {
  92 }
  93
  94 /** @}
  95  */