0,0 → 1,963 |
/* |
* 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. |
*/ |
|
/** |
* @file as.c |
* @brief Address space related functions. |
* |
* This file contains address space manipulation functions. |
* Roughly speaking, this is a higher-level client of |
* Virtual Address Translation (VAT) subsystem. |
* |
* Functionality provided by this file allows one to |
* create address space and create, resize and share |
* address space areas. |
* |
* @see page.c |
* |
*/ |
|
#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 <genarch/mm/page_ht.h> |
#include <mm/asid.h> |
#include <arch/mm/asid.h> |
#include <synch/spinlock.h> |
#include <adt/list.h> |
#include <adt/btree.h> |
#include <proc/task.h> |
#include <proc/thread.h> |
#include <arch/asm.h> |
#include <panic.h> |
#include <debug.h> |
#include <print.h> |
#include <memstr.h> |
#include <macros.h> |
#include <arch.h> |
#include <errno.h> |
#include <config.h> |
#include <arch/types.h> |
#include <typedefs.h> |
#include <syscall/copy.h> |
#include <arch/interrupt.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 area_flags_to_page_flags(int aflags); |
static int get_area_flags(as_area_t *a); |
static as_area_t *find_area_and_lock(as_t *as, __address va); |
static bool check_area_conflicts(as_t *as, __address va, size_t size, as_area_t *avoid_area); |
|
/** 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"); |
btree_create(&as->as_area_btree); |
|
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; |
} |
|
/** Free Adress space */ |
void as_free(as_t *as) |
{ |
ASSERT(as->refcount == 0); |
|
/* TODO: free as_areas and other resources held by as */ |
/* TODO: free page table */ |
free(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 flags Flags of the area memory. |
* @param size Size of area. |
* @param base Base address of area. |
* @param attrs Attributes of the area. |
* |
* @return Address space area on success or NULL on failure. |
*/ |
as_area_t *as_area_create(as_t *as, int flags, size_t size, __address base, int attrs) |
{ |
ipl_t ipl; |
as_area_t *a; |
|
if (base % PAGE_SIZE) |
return NULL; |
|
if (!size) |
return NULL; |
|
/* Writeable executable areas are not supported. */ |
if ((flags & AS_AREA_EXEC) && (flags & AS_AREA_WRITE)) |
return NULL; |
|
ipl = interrupts_disable(); |
spinlock_lock(&as->lock); |
|
if (!check_area_conflicts(as, base, size, NULL)) { |
spinlock_unlock(&as->lock); |
interrupts_restore(ipl); |
return NULL; |
} |
|
a = (as_area_t *) malloc(sizeof(as_area_t), 0); |
|
spinlock_initialize(&a->lock, "as_area_lock"); |
|
a->flags = flags; |
a->attributes = attrs; |
a->pages = SIZE2FRAMES(size); |
a->base = base; |
|
btree_insert(&as->as_area_btree, base, (void *) a, NULL); |
|
spinlock_unlock(&as->lock); |
interrupts_restore(ipl); |
|
return a; |
} |
|
/** Find address space area and change it. |
* |
* @param as Address space. |
* @param address Virtual address belonging to the area to be changed. Must be page-aligned. |
* @param size New size of the virtual memory block starting at address. |
* @param flags Flags influencing the remap operation. Currently unused. |
* |
* @return Zero on success or a value from @ref errno.h otherwise. |
*/ |
int as_area_resize(as_t *as, __address address, size_t size, int flags) |
{ |
as_area_t *area; |
ipl_t ipl; |
size_t pages; |
|
ipl = interrupts_disable(); |
spinlock_lock(&as->lock); |
|
/* |
* Locate the area. |
*/ |
area = find_area_and_lock(as, address); |
if (!area) { |
spinlock_unlock(&as->lock); |
interrupts_restore(ipl); |
return ENOENT; |
} |
|
if (area->flags & AS_AREA_DEVICE) { |
/* |
* Remapping of address space areas associated |
* with memory mapped devices is not supported. |
*/ |
spinlock_unlock(&area->lock); |
spinlock_unlock(&as->lock); |
interrupts_restore(ipl); |
return ENOTSUP; |
} |
|
pages = SIZE2FRAMES((address - area->base) + size); |
if (!pages) { |
/* |
* Zero size address space areas are not allowed. |
*/ |
spinlock_unlock(&area->lock); |
spinlock_unlock(&as->lock); |
interrupts_restore(ipl); |
return EPERM; |
} |
|
if (pages < area->pages) { |
int i; |
|
/* |
* Shrinking the area. |
* No need to check for overlaps. |
*/ |
for (i = pages; i < area->pages; i++) { |
pte_t *pte; |
|
/* |
* Releasing physical memory. |
* This depends on the fact that the memory was allocated using frame_alloc(). |
*/ |
page_table_lock(as, false); |
pte = page_mapping_find(as, area->base + i*PAGE_SIZE); |
if (pte && PTE_VALID(pte)) { |
__address frame; |
|
ASSERT(PTE_PRESENT(pte)); |
frame = PTE_GET_FRAME(pte); |
page_mapping_remove(as, area->base + i*PAGE_SIZE); |
page_table_unlock(as, false); |
|
frame_free(ADDR2PFN(frame)); |
} else { |
page_table_unlock(as, false); |
} |
} |
/* |
* Invalidate TLB's. |
*/ |
tlb_shootdown_start(TLB_INVL_PAGES, AS->asid, area->base + pages*PAGE_SIZE, area->pages - pages); |
tlb_invalidate_pages(AS->asid, area->base + pages*PAGE_SIZE, area->pages - pages); |
tlb_shootdown_finalize(); |
} else { |
/* |
* Growing the area. |
* Check for overlaps with other address space areas. |
*/ |
if (!check_area_conflicts(as, address, pages * PAGE_SIZE, area)) { |
spinlock_unlock(&area->lock); |
spinlock_unlock(&as->lock); |
interrupts_restore(ipl); |
return EADDRNOTAVAIL; |
} |
} |
|
area->pages = pages; |
|
spinlock_unlock(&area->lock); |
spinlock_unlock(&as->lock); |
interrupts_restore(ipl); |
|
return 0; |
} |
|
/** Destroy address space area. |
* |
* @param as Address space. |
* @param address Address withing the area to be deleted. |
* |
* @return Zero on success or a value from @ref errno.h on failure. |
*/ |
int as_area_destroy(as_t *as, __address address) |
{ |
as_area_t *area; |
__address base; |
ipl_t ipl; |
int i; |
|
ipl = interrupts_disable(); |
spinlock_lock(&as->lock); |
|
area = find_area_and_lock(as, address); |
if (!area) { |
spinlock_unlock(&as->lock); |
interrupts_restore(ipl); |
return ENOENT; |
} |
|
base = area->base; |
for (i = 0; i < area->pages; i++) { |
pte_t *pte; |
|
/* |
* Releasing physical memory. |
* Areas mapping memory-mapped devices are treated differently than |
* areas backing frame_alloc()'ed memory. |
*/ |
page_table_lock(as, false); |
pte = page_mapping_find(as, area->base + i*PAGE_SIZE); |
if (pte && PTE_VALID(pte)) { |
ASSERT(PTE_PRESENT(pte)); |
page_mapping_remove(as, area->base + i*PAGE_SIZE); |
if (area->flags & AS_AREA_DEVICE) { |
__address frame; |
frame = PTE_GET_FRAME(pte); |
frame_free(ADDR2PFN(frame)); |
} |
page_table_unlock(as, false); |
} else { |
page_table_unlock(as, false); |
} |
} |
/* |
* Invalidate TLB's. |
*/ |
tlb_shootdown_start(TLB_INVL_PAGES, AS->asid, area->base, area->pages); |
tlb_invalidate_pages(AS->asid, area->base, area->pages); |
tlb_shootdown_finalize(); |
|
area->attributes |= AS_AREA_ATTR_PARTIAL; |
spinlock_unlock(&area->lock); |
|
/* |
* Remove the empty area from address space. |
*/ |
btree_remove(&AS->as_area_btree, base, NULL); |
|
free(area); |
|
spinlock_unlock(&AS->lock); |
interrupts_restore(ipl); |
return 0; |
} |
|
/** Steal address space area from another task. |
* |
* Address space area is stolen from another task |
* Moreover, any existing mapping |
* is copied as well, providing thus a mechanism |
* for sharing group of pages. The source address |
* space area and any associated mapping is preserved. |
* |
* @param src_task Pointer of source task |
* @param src_base Base address of the source address space area. |
* @param acc_size Expected size of the source area |
* @param dst_base Target base address |
* |
* @return Zero on success or ENOENT if there is no such task or |
* if there is no such address space area, |
* EPERM if there was a problem in accepting the area or |
* ENOMEM if there was a problem in allocating destination |
* address space area. |
*/ |
int as_area_steal(task_t *src_task, __address src_base, size_t acc_size, |
__address dst_base) |
{ |
ipl_t ipl; |
count_t i; |
as_t *src_as; |
int src_flags; |
size_t src_size; |
as_area_t *src_area, *dst_area; |
|
ipl = interrupts_disable(); |
spinlock_lock(&src_task->lock); |
src_as = src_task->as; |
|
spinlock_lock(&src_as->lock); |
src_area = find_area_and_lock(src_as, src_base); |
if (!src_area) { |
/* |
* Could not find the source address space area. |
*/ |
spinlock_unlock(&src_task->lock); |
spinlock_unlock(&src_as->lock); |
interrupts_restore(ipl); |
return ENOENT; |
} |
src_size = src_area->pages * PAGE_SIZE; |
src_flags = src_area->flags; |
spinlock_unlock(&src_area->lock); |
spinlock_unlock(&src_as->lock); |
|
|
if (src_size != acc_size) { |
spinlock_unlock(&src_task->lock); |
interrupts_restore(ipl); |
return EPERM; |
} |
/* |
* Create copy of the source address space area. |
* The destination area is created with AS_AREA_ATTR_PARTIAL |
* attribute set which prevents race condition with |
* preliminary as_page_fault() calls. |
*/ |
dst_area = as_area_create(AS, src_flags, src_size, dst_base, AS_AREA_ATTR_PARTIAL); |
if (!dst_area) { |
/* |
* Destination address space area could not be created. |
*/ |
spinlock_unlock(&src_task->lock); |
interrupts_restore(ipl); |
return ENOMEM; |
} |
|
spinlock_unlock(&src_task->lock); |
|
/* |
* Avoid deadlock by first locking the address space with lower address. |
*/ |
if (AS < src_as) { |
spinlock_lock(&AS->lock); |
spinlock_lock(&src_as->lock); |
} else { |
spinlock_lock(&AS->lock); |
spinlock_lock(&src_as->lock); |
} |
|
for (i = 0; i < SIZE2FRAMES(src_size); i++) { |
pte_t *pte; |
__address frame; |
|
page_table_lock(src_as, false); |
pte = page_mapping_find(src_as, src_base + i*PAGE_SIZE); |
if (pte && PTE_VALID(pte)) { |
ASSERT(PTE_PRESENT(pte)); |
frame = PTE_GET_FRAME(pte); |
if (!(src_flags & AS_AREA_DEVICE)) |
frame_reference_add(ADDR2PFN(frame)); |
page_table_unlock(src_as, false); |
} else { |
page_table_unlock(src_as, false); |
continue; |
} |
|
page_table_lock(AS, false); |
page_mapping_insert(AS, dst_base + i*PAGE_SIZE, frame, area_flags_to_page_flags(src_flags)); |
page_table_unlock(AS, false); |
} |
|
/* |
* Now the destination address space area has been |
* fully initialized. Clear the AS_AREA_ATTR_PARTIAL |
* attribute. |
*/ |
spinlock_lock(&dst_area->lock); |
dst_area->attributes &= ~AS_AREA_ATTR_PARTIAL; |
spinlock_unlock(&dst_area->lock); |
|
spinlock_unlock(&AS->lock); |
spinlock_unlock(&src_as->lock); |
interrupts_restore(ipl); |
|
return 0; |
} |
|
/** 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 as 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 *area; |
ipl_t ipl; |
|
ipl = interrupts_disable(); |
page_table_lock(as, true); |
|
area = find_area_and_lock(as, page); |
if (!area) { |
panic("page not part of any as_area\n"); |
} |
|
page_mapping_insert(as, page, frame, get_area_flags(area)); |
|
spinlock_unlock(&area->lock); |
page_table_unlock(as, true); |
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. |
* @param istate Pointer to interrupted state. |
* |
* @return 0 on page fault, 1 on success or 2 if the fault was caused by copy_to_uspace() or copy_from_uspace(). |
*/ |
int as_page_fault(__address page, istate_t *istate) |
{ |
pte_t *pte; |
as_area_t *area; |
__address frame; |
|
ASSERT(AS); |
|
spinlock_lock(&AS->lock); |
area = find_area_and_lock(AS, page); |
if (!area) { |
/* |
* No area contained mapping for 'page'. |
* Signal page fault to low-level handler. |
*/ |
spinlock_unlock(&AS->lock); |
goto page_fault; |
} |
|
if (area->attributes & AS_AREA_ATTR_PARTIAL) { |
/* |
* The address space area is not fully initialized. |
* Avoid possible race by returning error. |
*/ |
spinlock_unlock(&area->lock); |
spinlock_unlock(&AS->lock); |
goto page_fault; |
} |
|
ASSERT(!(area->flags & AS_AREA_DEVICE)); |
|
page_table_lock(AS, false); |
|
/* |
* To avoid race condition between two page faults |
* on the same address, we need to make sure |
* the mapping has not been already inserted. |
*/ |
if ((pte = page_mapping_find(AS, page))) { |
if (PTE_PRESENT(pte)) { |
page_table_unlock(AS, false); |
spinlock_unlock(&area->lock); |
spinlock_unlock(&AS->lock); |
return 1; |
} |
} |
|
/* |
* 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)); |
page_table_unlock(AS, false); |
|
spinlock_unlock(&area->lock); |
spinlock_unlock(&AS->lock); |
return AS_PF_OK; |
|
page_fault: |
if (!THREAD) |
return AS_PF_FAULT; |
|
if (THREAD->in_copy_from_uspace) { |
THREAD->in_copy_from_uspace = false; |
istate_set_retaddr(istate, (__address) &memcpy_from_uspace_failover_address); |
} else if (THREAD->in_copy_to_uspace) { |
THREAD->in_copy_to_uspace = false; |
istate_set_retaddr(istate, (__address) &memcpy_to_uspace_failover_address); |
} else { |
return AS_PF_FAULT; |
} |
|
return AS_PF_DEFER; |
} |
|
/** 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; |
} |
|
/** Convert address space area flags to page flags. |
* |
* @param aflags Flags of some address space area. |
* |
* @return Flags to be passed to page_mapping_insert(). |
*/ |
int area_flags_to_page_flags(int aflags) |
{ |
int flags; |
|
flags = PAGE_USER | PAGE_PRESENT; |
|
if (aflags & AS_AREA_READ) |
flags |= PAGE_READ; |
|
if (aflags & AS_AREA_WRITE) |
flags |= PAGE_WRITE; |
|
if (aflags & AS_AREA_EXEC) |
flags |= PAGE_EXEC; |
|
if (!(aflags & AS_AREA_DEVICE)) |
flags |= PAGE_CACHEABLE; |
|
return flags; |
} |
|
/** 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) |
{ |
return area_flags_to_page_flags(a->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); |
} |
|
/** Lock page table. |
* |
* This function should be called before any page_mapping_insert(), |
* page_mapping_remove() and page_mapping_find(). |
* |
* Locking order is such that address space areas must be locked |
* prior to this call. Address space can be locked prior to this |
* call in which case the lock argument is false. |
* |
* @param as Address space. |
* @param lock If false, do not attempt to lock as->lock. |
*/ |
void page_table_lock(as_t *as, bool lock) |
{ |
ASSERT(as_operations); |
ASSERT(as_operations->page_table_lock); |
|
as_operations->page_table_lock(as, lock); |
} |
|
/** Unlock page table. |
* |
* @param as Address space. |
* @param unlock If false, do not attempt to unlock as->lock. |
*/ |
void page_table_unlock(as_t *as, bool unlock) |
{ |
ASSERT(as_operations); |
ASSERT(as_operations->page_table_unlock); |
|
as_operations->page_table_unlock(as, unlock); |
} |
|
|
/** Find address space area and lock it. |
* |
* The address space must be locked and interrupts must be disabled. |
* |
* @param as Address space. |
* @param va Virtual address. |
* |
* @return Locked address space area containing va on success or NULL on failure. |
*/ |
as_area_t *find_area_and_lock(as_t *as, __address va) |
{ |
as_area_t *a; |
btree_node_t *leaf, *lnode; |
int i; |
|
a = (as_area_t *) btree_search(&as->as_area_btree, va, &leaf); |
if (a) { |
/* va is the base address of an address space area */ |
spinlock_lock(&a->lock); |
return a; |
} |
|
/* |
* Search the leaf node and the righmost record of its left neighbour |
* to find out whether this is a miss or va belongs to an address |
* space area found there. |
*/ |
|
/* First, search the leaf node itself. */ |
for (i = 0; i < leaf->keys; i++) { |
a = (as_area_t *) leaf->value[i]; |
spinlock_lock(&a->lock); |
if ((a->base <= va) && (va < a->base + a->pages * PAGE_SIZE)) { |
return a; |
} |
spinlock_unlock(&a->lock); |
} |
|
/* |
* Second, locate the left neighbour and test its last record. |
* Because of its position in the B+tree, it must have base < va. |
*/ |
if ((lnode = btree_leaf_node_left_neighbour(&as->as_area_btree, leaf))) { |
a = (as_area_t *) lnode->value[lnode->keys - 1]; |
spinlock_lock(&a->lock); |
if (va < a->base + a->pages * PAGE_SIZE) { |
return a; |
} |
spinlock_unlock(&a->lock); |
} |
|
return NULL; |
} |
|
/** Check area conflicts with other areas. |
* |
* The address space must be locked and interrupts must be disabled. |
* |
* @param as Address space. |
* @param va Starting virtual address of the area being tested. |
* @param size Size of the area being tested. |
* @param avoid_area Do not touch this area. |
* |
* @return True if there is no conflict, false otherwise. |
*/ |
bool check_area_conflicts(as_t *as, __address va, size_t size, as_area_t *avoid_area) |
{ |
as_area_t *a; |
btree_node_t *leaf, *node; |
int i; |
|
/* |
* We don't want any area to have conflicts with NULL page. |
*/ |
if (overlaps(va, size, NULL, PAGE_SIZE)) |
return false; |
|
/* |
* The leaf node is found in O(log n), where n is proportional to |
* the number of address space areas belonging to as. |
* The check for conflicts is then attempted on the rightmost |
* record in the left neighbour, the leftmost record in the right |
* neighbour and all records in the leaf node itself. |
*/ |
|
if ((a = (as_area_t *) btree_search(&as->as_area_btree, va, &leaf))) { |
if (a != avoid_area) |
return false; |
} |
|
/* First, check the two border cases. */ |
if ((node = btree_leaf_node_left_neighbour(&as->as_area_btree, leaf))) { |
a = (as_area_t *) node->value[node->keys - 1]; |
spinlock_lock(&a->lock); |
if (overlaps(va, size, a->base, a->pages * PAGE_SIZE)) { |
spinlock_unlock(&a->lock); |
return false; |
} |
spinlock_unlock(&a->lock); |
} |
if ((node = btree_leaf_node_right_neighbour(&as->as_area_btree, leaf))) { |
a = (as_area_t *) node->value[0]; |
spinlock_lock(&a->lock); |
if (overlaps(va, size, a->base, a->pages * PAGE_SIZE)) { |
spinlock_unlock(&a->lock); |
return false; |
} |
spinlock_unlock(&a->lock); |
} |
|
/* Second, check the leaf node. */ |
for (i = 0; i < leaf->keys; i++) { |
a = (as_area_t *) leaf->value[i]; |
|
if (a == avoid_area) |
continue; |
|
spinlock_lock(&a->lock); |
if (overlaps(va, size, a->base, a->pages * PAGE_SIZE)) { |
spinlock_unlock(&a->lock); |
return false; |
} |
spinlock_unlock(&a->lock); |
} |
|
/* |
* So far, the area does not conflict with other areas. |
* Check if it doesn't conflict with kernel address space. |
*/ |
if (!KERNEL_ADDRESS_SPACE_SHADOWED) { |
return !overlaps(va, size, |
KERNEL_ADDRESS_SPACE_START, KERNEL_ADDRESS_SPACE_END-KERNEL_ADDRESS_SPACE_START); |
} |
|
return true; |
} |
|
/** Return size of address space of current task pointed to by base */ |
size_t as_get_size(__address base) |
{ |
ipl_t ipl; |
as_area_t *src_area; |
size_t size; |
|
ipl = interrupts_disable(); |
src_area = find_area_and_lock(AS, base); |
if (src_area){ |
size = src_area->pages * PAGE_SIZE; |
spinlock_unlock(&src_area->lock); |
} else { |
size = 0; |
} |
interrupts_restore(ipl); |
return size; |
} |
|
/* |
* Address space related syscalls. |
*/ |
|
/** Wrapper for as_area_create(). */ |
__native sys_as_area_create(__address address, size_t size, int flags) |
{ |
if (as_area_create(AS, flags, size, address, AS_AREA_ATTR_NONE)) |
return (__native) address; |
else |
return (__native) -1; |
} |
|
/** Wrapper for as_area_resize. */ |
__native sys_as_area_resize(__address address, size_t size, int flags) |
{ |
return (__native) as_area_resize(AS, address, size, 0); |
} |
|
/** Wrapper for as_area_destroy. */ |
__native sys_as_area_destroy(__address address) |
{ |
return (__native) as_area_destroy(AS, address); |
} |
|