126,13 → 126,14 |
* The created address space area is added to the target address space. |
* |
* @param as Target address space. |
* @param flags Flags of the area. |
* @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) |
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; |
161,6 → 162,7 |
spinlock_initialize(&a->lock, "as_area_lock"); |
|
a->flags = flags; |
a->attributes = attrs; |
a->pages = SIZE2FRAMES(size); |
a->base = base; |
|
289,8 → 291,8 |
* for sharing group of pages. The source address |
* space area and any associated mapping is preserved. |
* |
* @param id Task ID of the accepting task. |
* @param base Base address of the source address space area. |
* @param dst_id Task ID of the accepting task. |
* @param src_base Base address of the source address space area. |
* |
* @return 0 on success or ENOENT if there is no such task or |
* if there is no such address space area, |
298,21 → 300,21 |
* ENOMEM if there was a problem in allocating destination |
* address space area. |
*/ |
int as_area_send(task_id_t id, __address base) |
int as_area_send(task_id_t dst_id, __address src_base) |
{ |
ipl_t ipl; |
task_t *t; |
count_t i; |
as_t *as; |
as_t *dst_as; |
__address dst_base; |
int flags; |
size_t size; |
as_area_t *area; |
int src_flags; |
size_t src_size; |
as_area_t *src_area, *dst_area; |
|
ipl = interrupts_disable(); |
spinlock_lock(&tasks_lock); |
|
t = task_find_by_id(id); |
t = task_find_by_id(dst_id); |
if (!NULL) { |
spinlock_unlock(&tasks_lock); |
interrupts_restore(ipl); |
322,10 → 324,10 |
spinlock_lock(&t->lock); |
spinlock_unlock(&tasks_lock); |
|
as = t->as; |
dst_as = t->as; |
dst_base = (__address) t->accept_arg.base; |
|
if (as == AS) { |
if (dst_as == AS) { |
/* |
* The two tasks share the entire address space. |
* Return error since there is no point in continuing. |
336,8 → 338,8 |
} |
|
spinlock_lock(&AS->lock); |
area = find_area_and_lock(AS, base); |
if (!area) { |
src_area = find_area_and_lock(AS, src_base); |
if (!src_area) { |
/* |
* Could not find the source address space area. |
*/ |
346,13 → 348,13 |
interrupts_restore(ipl); |
return ENOENT; |
} |
size = area->pages * PAGE_SIZE; |
flags = area->flags; |
spinlock_unlock(&area->lock); |
src_size = src_area->pages * PAGE_SIZE; |
src_flags = src_area->flags; |
spinlock_unlock(&src_area->lock); |
spinlock_unlock(&AS->lock); |
|
if ((t->accept_arg.task_id != TASK->taskid) || (t->accept_arg.size != size) || |
(t->accept_arg.flags != flags)) { |
if ((t->accept_arg.task_id != TASK->taskid) || (t->accept_arg.size != src_size) || |
(t->accept_arg.flags != src_flags)) { |
/* |
* Discrepancy in either task ID, size or flags. |
*/ |
362,9 → 364,13 |
} |
|
/* |
* Create copy of the address space area. |
* 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. |
*/ |
if (!as_area_create(as, flags, size, dst_base)) { |
dst_area = as_area_create(dst_as, src_flags, src_size, dst_base, AS_AREA_ATTR_PARTIAL); |
if (!dst_area) { |
/* |
* Destination address space area could not be created. |
*/ |
373,18 → 379,6 |
return ENOMEM; |
} |
|
/* |
* NOTE: we have just introduced a race condition. |
* The destination task can try to attempt the newly |
* created area before its mapping is copied from |
* the source address space area. In result, frames |
* can get lost. |
* |
* Currently, this race is not solved, but one of the |
* possible solutions would be to sleep in as_page_fault() |
* when this situation is detected. |
*/ |
|
memsetb((__address) &t->accept_arg, sizeof(as_area_acptsnd_arg_t), 0); |
spinlock_unlock(&t->lock); |
|
391,24 → 385,24 |
/* |
* Avoid deadlock by first locking the address space with lower address. |
*/ |
if (as < AS) { |
spinlock_lock(&as->lock); |
if (dst_as < AS) { |
spinlock_lock(&dst_as->lock); |
spinlock_lock(&AS->lock); |
} else { |
spinlock_lock(&AS->lock); |
spinlock_lock(&as->lock); |
spinlock_lock(&dst_as->lock); |
} |
|
for (i = 0; i < SIZE2FRAMES(size); i++) { |
for (i = 0; i < SIZE2FRAMES(src_size); i++) { |
pte_t *pte; |
__address frame; |
|
page_table_lock(AS, false); |
pte = page_mapping_find(AS, base + i*PAGE_SIZE); |
pte = page_mapping_find(AS, src_base + i*PAGE_SIZE); |
if (pte && PTE_VALID(pte)) { |
ASSERT(PTE_PRESENT(pte)); |
frame = PTE_GET_FRAME(pte); |
if (!(flags & AS_AREA_DEVICE)) |
if (!(src_flags & AS_AREA_DEVICE)) |
frame_reference_add(ADDR2PFN(frame)); |
page_table_unlock(AS, false); |
} else { |
416,13 → 410,22 |
continue; |
} |
|
page_table_lock(as, false); |
page_mapping_insert(as, dst_base + i*PAGE_SIZE, frame, area_flags_to_page_flags(flags)); |
page_table_unlock(as, false); |
page_table_lock(dst_as, false); |
page_mapping_insert(dst_as, dst_base + i*PAGE_SIZE, frame, area_flags_to_page_flags(src_flags)); |
page_table_unlock(dst_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(&as->lock); |
spinlock_unlock(&dst_as->lock); |
interrupts_restore(ipl); |
|
return 0; |
486,6 → 489,16 |
return 0; |
} |
|
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); |
return 0; |
} |
|
ASSERT(!(area->flags & AS_AREA_DEVICE)); |
|
page_table_lock(AS, false); |
839,7 → 852,7 |
/** 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)) |
if (as_area_create(AS, flags, size, address, AS_AREA_ATTR_NONE)) |
return (__native) address; |
else |
return (__native) -1; |