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• This comparison shows the changes necessary to convert path

  → /branches/fs/kernel/generic/src/mm/as.c @ 2421

  → /branches/fs/kernel/generic/src/mm/as.c @ 2422

  ↔ Reverse comparison

• Compare Path:	Rev

  With Path:	Rev

Ignore whitespace Rev 2421 → Rev 2422

/branches/fs/kernel/generic/src/mm/as.c
57,6 → 57,7
#include <genarch/mm/page_ht.h>
#include <mm/asid.h>
#include <arch/mm/asid.h>
#include <preemption.h>
#include <synch/spinlock.h>
#include <synch/mutex.h>
#include <adt/list.h>
95,10 → 96,13
#endif
/**
* This lock protects inactive_as_with_asid_head list. It must be acquired
* before as_t mutex.
* This lock serializes access to the ASID subsystem.
* It protects:
* - inactive_as_with_asid_head list
* - as->asid for each as of the as_t type
* - asids_allocated counter
*/
SPINLOCK_INITIALIZE(inactive_as_with_asid_lock);
SPINLOCK_INITIALIZE(asidlock);
/**
* This list contains address spaces that are not active on any
178,7 → 182,7
else
as->asid = ASID_INVALID;
as->refcount = 0;
atomic_set(&as->refcount, 0);
as->cpu_refcount = 0;
#ifdef AS_PAGE_TABLE
as->genarch.page_table = page_table_create(flags);
193,26 → 197,45
*
* When there are no tasks referencing this address space (i.e. its refcount is
* zero), the address space can be destroyed.
*
* We know that we don't hold any spinlock.
*/
void as_destroy(as_t *as)
{
ipl_t ipl;
bool cond;
DEADLOCK_PROBE_INIT(p_asidlock);
ASSERT(as->refcount == 0);
ASSERT(atomic_get(&as->refcount) == 0);
/*
* Since there is no reference to this area,
* it is safe not to lock its mutex.
*/
ipl = interrupts_disable();
spinlock_lock(&inactive_as_with_asid_lock);
/*
* We need to avoid deadlock between TLB shootdown and asidlock.
* We therefore try to take asid conditionally and if we don't succeed,
* we enable interrupts and try again. This is done while preemption is
* disabled to prevent nested context switches. We also depend on the
* fact that so far no spinlocks are held.
*/
preemption_disable();
ipl = interrupts_read();
retry:
interrupts_disable();
if (!spinlock_trylock(&asidlock)) {
interrupts_enable();
DEADLOCK_PROBE(p_asidlock, DEADLOCK_THRESHOLD);
goto retry;
}
preemption_enable(); /* Interrupts disabled, enable preemption */
if (as->asid != ASID_INVALID && as != AS_KERNEL) {
if (as != AS && as->cpu_refcount == 0)
list_remove(&as->inactive_as_with_asid_link);
asid_put(as->asid);
}
spinlock_unlock(&inactive_as_with_asid_lock);
spinlock_unlock(&asidlock);
/*
* Destroy address space areas of the address space.
411,7 → 434,7
int i = 0;
if (overlaps(b, c * PAGE_SIZE, area->base,
pages*PAGE_SIZE)) {
pages * PAGE_SIZE)) {
if (b + c * PAGE_SIZE <= start_free) {
/*
468,15 → 491,16
/*
* Finish TLB shootdown sequence.
*/
tlb_invalidate_pages(as->asid, area->base + pages * PAGE_SIZE,
area->pages - pages);
tlb_shootdown_finalize();
/*
* Invalidate software translation caches (e.g. TSB on sparc64).
*/
as_invalidate_translation_cache(as, area->base +
pages * PAGE_SIZE, area->pages - pages);
tlb_shootdown_finalize();
} else {
/*
* Growing the area.
553,7 → 577,7
if (area->backend &&
area->backend->frame_free) {
area->backend->frame_free(area, b +
j * PAGE_SIZE, PTE_GET_FRAME(pte));
j * PAGE_SIZE, PTE_GET_FRAME(pte));
}
page_mapping_remove(as, b + j * PAGE_SIZE);
page_table_unlock(as, false);
564,14 → 588,14
/*
* Finish TLB shootdown sequence.
*/
tlb_invalidate_pages(as->asid, area->base, area->pages);
tlb_shootdown_finalize();
/*
* Invalidate potential software translation caches (e.g. TSB on
* sparc64).
*/
as_invalidate_translation_cache(as, area->base, area->pages);
tlb_shootdown_finalize();
btree_destroy(&area->used_space);
613,8 → 637,7
* 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. ENOTSUP is returned if the address space area backend does not support
* sharing or if the kernel detects an attempt to create an illegal address
* alias.
* sharing.
*/
int as_area_share(as_t *src_as, uintptr_t src_base, size_t acc_size,
as_t *dst_as, uintptr_t dst_base, int dst_flags_mask)
667,20 → 690,6
return EPERM;
}
#ifdef CONFIG_VIRT_IDX_DCACHE
if (!(dst_flags_mask & AS_AREA_EXEC)) {
if (PAGE_COLOR(src_area->base) != PAGE_COLOR(dst_base)) {
/*
* Refuse to create an illegal address alias.
*/
mutex_unlock(&src_area->lock);
mutex_unlock(&src_as->lock);
interrupts_restore(ipl);
return ENOTSUP;
}
}
#endif /* CONFIG_VIRT_IDX_DCACHE */
/*
* Now we are committed to sharing the area.
* First, prepare the area for sharing.
875,24 → 884,37
/** Switch address spaces.
*
* Note that this function cannot sleep as it is essentially a part of
* scheduling. Sleeping here would lead to deadlock on wakeup.
* scheduling. Sleeping here would lead to deadlock on wakeup. Another
* thing which is forbidden in this context is locking the address space.
*
* When this function is enetered, no spinlocks may be held.
*
* @param old Old address space or NULL.
* @param new New address space.
*/
void as_switch(as_t *old_as, as_t *new_as)
{
ipl_t ipl;
bool needs_asid = false;
ipl = interrupts_disable();
spinlock_lock(&inactive_as_with_asid_lock);
DEADLOCK_PROBE_INIT(p_asidlock);
preemption_disable();
retry:
(void) interrupts_disable();
if (!spinlock_trylock(&asidlock)) {
/*
* Avoid deadlock with TLB shootdown.
* We can enable interrupts here because
* preemption is disabled. We should not be
* holding any other lock.
*/
(void) interrupts_enable();
DEADLOCK_PROBE(p_asidlock, DEADLOCK_THRESHOLD);
goto retry;
}
preemption_enable();
/*
* First, take care of the old address space.
*/
if (old_as) {
mutex_lock_active(&old_as->lock);
ASSERT(old_as->cpu_refcount);
if((--old_as->cpu_refcount == 0) && (old_as != AS_KERNEL)) {
/*
901,11 → 923,10
* list of inactive address spaces with assigned
* ASID.
*/
ASSERT(old_as->asid != ASID_INVALID);
list_append(&old_as->inactive_as_with_asid_link,
&inactive_as_with_asid_head);
ASSERT(old_as->asid != ASID_INVALID);
list_append(&old_as->inactive_as_with_asid_link,
&inactive_as_with_asid_head);
}
mutex_unlock(&old_as->lock);
/*
* Perform architecture-specific tasks when the address space
917,36 → 938,15
/*
* Second, prepare the new address space.
*/
mutex_lock_active(&new_as->lock);
if ((new_as->cpu_refcount++ == 0) && (new_as != AS_KERNEL)) {
if (new_as->asid != ASID_INVALID) {
if (new_as->asid != ASID_INVALID)
list_remove(&new_as->inactive_as_with_asid_link);
} else {
/*
* Defer call to asid_get() until new_as->lock is released.
*/
needs_asid = true;
}
else
new_as->asid = asid_get();
}
#ifdef AS_PAGE_TABLE
SET_PTL0_ADDRESS(new_as->genarch.page_table);
#endif
mutex_unlock(&new_as->lock);
if (needs_asid) {
/*
* Allocation of new ASID was deferred
* until now in order to avoid deadlock.
*/
asid_t asid;
asid = asid_get();
mutex_lock_active(&new_as->lock);
new_as->asid = asid;
mutex_unlock(&new_as->lock);
}
spinlock_unlock(&inactive_as_with_asid_lock);
interrupts_restore(ipl);
/*
* Perform architecture-specific steps.
953,6 → 953,8
* (e.g. write ASID to hardware register etc.)
*/
as_install_arch(new_as);
spinlock_unlock(&asidlock);
AS = new_as;
}