0,0 → 1,209 |
/* |
* 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 <typedefs.h> |
#include <align.h> |
#include <arch.h> |
|
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; |
|
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; |
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(PA2KA(frame), FRAME_SIZE, 0); |
|
/* |
* 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(PA2KA(frame), FRAME_SIZE, 0); |
} |
|
/* |
* 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 Ignored. |
* @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; |
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]; |
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); |
frame_reference_add(ADDR2PFN(PTE_GET_FRAME(pte))); |
} |
|
} |
} |
mutex_unlock(&area->sh_info->lock); |
} |
|
/** @} |
*/ |