0,0 → 1,391 |
/* |
* Copyright (C) 2001-2006 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. |
*/ |
|
/* |
* This file contains address space manipulation functions. |
* Roughly speaking, this is a higher-level client of |
* Virtual Address Translation (VAT) subsystem. |
*/ |
|
#include <mm/as.h> |
#include <arch/mm/as.h> |
#include <mm/page.h> |
#include <mm/frame.h> |
#include <mm/slab.h> |
#include <mm/tlb.h> |
#include <arch/mm/page.h> |
#include <genarch/mm/page_pt.h> |
#include <mm/asid.h> |
#include <arch/mm/asid.h> |
#include <arch/types.h> |
#include <typedefs.h> |
#include <synch/spinlock.h> |
#include <config.h> |
#include <adt/list.h> |
#include <panic.h> |
#include <arch/asm.h> |
#include <debug.h> |
#include <memstr.h> |
#include <arch.h> |
#include <print.h> |
|
as_operations_t *as_operations = NULL; |
|
/** Address space lock. It protects inactive_as_with_asid_head. */ |
SPINLOCK_INITIALIZE(as_lock); |
|
/** |
* This list contains address spaces that are not active on any |
* processor and that have valid ASID. |
*/ |
LIST_INITIALIZE(inactive_as_with_asid_head); |
|
/** Kernel address space. */ |
as_t *AS_KERNEL = NULL; |
|
static int get_area_flags(as_area_t *a); |
|
/** Initialize address space subsystem. */ |
void as_init(void) |
{ |
as_arch_init(); |
AS_KERNEL = as_create(FLAG_AS_KERNEL); |
if (!AS_KERNEL) |
panic("can't create kernel address space\n"); |
} |
|
/** Create address space. |
* |
* @param flags Flags that influence way in wich the address space is created. |
*/ |
as_t *as_create(int flags) |
{ |
as_t *as; |
|
as = (as_t *) malloc(sizeof(as_t), 0); |
link_initialize(&as->inactive_as_with_asid_link); |
spinlock_initialize(&as->lock, "as_lock"); |
list_initialize(&as->as_area_head); |
|
if (flags & FLAG_AS_KERNEL) |
as->asid = ASID_KERNEL; |
else |
as->asid = ASID_INVALID; |
|
as->refcount = 0; |
as->page_table = page_table_create(flags); |
|
return as; |
} |
|
/** Create address space area of common attributes. |
* |
* The created address space area is added to the target address space. |
* |
* @param as Target address space. |
* @param type Type of area. |
* @param size Size of area in multiples of PAGE_SIZE. |
* @param base Base address of area. |
* |
* @return Address space area on success or NULL on failure. |
*/ |
as_area_t *as_area_create(as_t *as, as_area_type_t type, size_t size, __address base) |
{ |
ipl_t ipl; |
as_area_t *a; |
|
if (base % PAGE_SIZE) |
panic("addr not aligned to a page boundary"); |
|
ipl = interrupts_disable(); |
spinlock_lock(&as->lock); |
|
/* |
* TODO: test as_area which is to be created doesn't overlap with an existing one. |
*/ |
|
a = (as_area_t *) malloc(sizeof(as_area_t), 0); |
|
spinlock_initialize(&a->lock, "as_area_lock"); |
|
link_initialize(&a->link); |
a->type = type; |
a->size = size; |
a->base = base; |
|
list_append(&a->link, &as->as_area_head); |
|
spinlock_unlock(&as->lock); |
interrupts_restore(ipl); |
|
return a; |
} |
|
/** Initialize mapping for one page of address space. |
* |
* This functions maps 'page' to 'frame' according |
* to attributes of the address space area to |
* wich 'page' belongs. |
* |
* @param a Target address space. |
* @param page Virtual page within the area. |
* @param frame Physical frame to which page will be mapped. |
*/ |
void as_set_mapping(as_t *as, __address page, __address frame) |
{ |
as_area_t *a, *area = NULL; |
link_t *cur; |
ipl_t ipl; |
|
ipl = interrupts_disable(); |
spinlock_lock(&as->lock); |
|
/* |
* First, try locate an area. |
*/ |
for (cur = as->as_area_head.next; cur != &as->as_area_head; cur = cur->next) { |
a = list_get_instance(cur, as_area_t, link); |
spinlock_lock(&a->lock); |
|
if ((page >= a->base) && (page < a->base + a->size * PAGE_SIZE)) { |
area = a; |
break; |
} |
|
spinlock_unlock(&a->lock); |
} |
|
if (!area) { |
panic("page not part of any as_area\n"); |
} |
|
/* |
* Note: area->lock is held. |
*/ |
|
page_mapping_insert(as, page, frame, get_area_flags(area)); |
|
spinlock_unlock(&area->lock); |
spinlock_unlock(&as->lock); |
interrupts_restore(ipl); |
} |
|
/** Handle page fault within the current address space. |
* |
* This is the high-level page fault handler. |
* Interrupts are assumed disabled. |
* |
* @param page Faulting page. |
* |
* @return 0 on page fault, 1 on success. |
*/ |
int as_page_fault(__address page) |
{ |
link_t *cur; |
as_area_t *a, *area = NULL; |
__address frame; |
|
ASSERT(AS); |
spinlock_lock(&AS->lock); |
|
/* |
* Search this areas of this address space for presence of 'page'. |
*/ |
for (cur = AS->as_area_head.next; cur != &AS->as_area_head; cur = cur->next) { |
a = list_get_instance(cur, as_area_t, link); |
spinlock_lock(&a->lock); |
|
if ((page >= a->base) && (page < a->base + a->size * PAGE_SIZE)) { |
|
/* |
* We found the area containing 'page'. |
* TODO: access checking |
*/ |
area = a; |
break; |
} |
|
spinlock_unlock(&a->lock); |
} |
|
if (!area) { |
/* |
* No area contained mapping for 'page'. |
* Signal page fault to low-level handler. |
*/ |
spinlock_unlock(&AS->lock); |
return 0; |
} |
|
/* |
* Note: area->lock is held. |
*/ |
|
/* |
* In general, there can be several reasons that |
* can have caused this fault. |
* |
* - non-existent mapping: the area is a scratch |
* area (e.g. 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 = PFN2ADDR(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, page, frame, get_area_flags(area)); |
|
spinlock_unlock(&area->lock); |
spinlock_unlock(&AS->lock); |
|
return 1; |
} |
|
/** Switch address spaces. |
* |
* @param old Old address space or NULL. |
* @param new New address space. |
*/ |
void as_switch(as_t *old, as_t *new) |
{ |
ipl_t ipl; |
bool needs_asid = false; |
|
ipl = interrupts_disable(); |
spinlock_lock(&as_lock); |
|
/* |
* First, take care of the old address space. |
*/ |
if (old) { |
spinlock_lock(&old->lock); |
ASSERT(old->refcount); |
if((--old->refcount == 0) && (old != AS_KERNEL)) { |
/* |
* The old address space is no longer active on |
* any processor. It can be appended to the |
* list of inactive address spaces with assigned |
* ASID. |
*/ |
ASSERT(old->asid != ASID_INVALID); |
list_append(&old->inactive_as_with_asid_link, &inactive_as_with_asid_head); |
} |
spinlock_unlock(&old->lock); |
} |
|
/* |
* Second, prepare the new address space. |
*/ |
spinlock_lock(&new->lock); |
if ((new->refcount++ == 0) && (new != AS_KERNEL)) { |
if (new->asid != ASID_INVALID) |
list_remove(&new->inactive_as_with_asid_link); |
else |
needs_asid = true; /* defer call to asid_get() until new->lock is released */ |
} |
SET_PTL0_ADDRESS(new->page_table); |
spinlock_unlock(&new->lock); |
|
if (needs_asid) { |
/* |
* Allocation of new ASID was deferred |
* until now in order to avoid deadlock. |
*/ |
asid_t asid; |
|
asid = asid_get(); |
spinlock_lock(&new->lock); |
new->asid = asid; |
spinlock_unlock(&new->lock); |
} |
spinlock_unlock(&as_lock); |
interrupts_restore(ipl); |
|
/* |
* Perform architecture-specific steps. |
* (e.g. write ASID to hardware register etc.) |
*/ |
as_install_arch(new); |
|
AS = new; |
} |
|
/** Compute flags for virtual address translation subsytem. |
* |
* The address space area must be locked. |
* Interrupts must be disabled. |
* |
* @param a Address space area. |
* |
* @return Flags to be used in page_mapping_insert(). |
*/ |
int get_area_flags(as_area_t *a) |
{ |
int flags; |
|
switch (a->type) { |
case AS_AREA_TEXT: |
flags = PAGE_EXEC | PAGE_READ | PAGE_USER | PAGE_PRESENT | PAGE_CACHEABLE; |
break; |
case AS_AREA_DATA: |
case AS_AREA_STACK: |
flags = PAGE_READ | PAGE_WRITE | PAGE_USER | PAGE_PRESENT | PAGE_CACHEABLE; |
break; |
default: |
panic("unexpected as_area_type_t %d", a->type); |
} |
|
return flags; |
} |
|
/** Create page table. |
* |
* Depending on architecture, create either address space |
* private or global page table. |
* |
* @param flags Flags saying whether the page table is for kernel address space. |
* |
* @return First entry of the page table. |
*/ |
pte_t *page_table_create(int flags) |
{ |
ASSERT(as_operations); |
ASSERT(as_operations->page_table_create); |
|
return as_operations->page_table_create(flags); |
} |