/*
* Release an access permit for a XPMEM address segment.
*/
int
xpmem_release(xpmem_apid_t apid)
{
struct xpmem_thread_group *ap_tg;
struct xpmem_access_permit *ap;
if (apid <= 0)
return -EINVAL;
ap_tg = xpmem_tg_ref_by_apid(apid);
if (IS_ERR(ap_tg))
return PTR_ERR(ap_tg);
if (current->aspace->id != ap_tg->gid) {
xpmem_tg_deref(ap_tg);
return -EACCES;
}
ap = xpmem_ap_ref_by_apid(ap_tg, apid);
if (IS_ERR(ap)) {
xpmem_tg_deref(ap_tg);
return PTR_ERR(ap);
}
BUG_ON(ap->tg != ap_tg);
xpmem_release_ap(ap_tg, ap);
xpmem_ap_deref(ap);
xpmem_tg_deref(ap_tg);
return 0;
}
static unsigned int
signal_poll(struct file * filp,
struct poll_table_struct * poll)
{
struct xpmem_thread_group * seg_tg;
struct xpmem_segment * seg;
xpmem_segid_t segid;
unsigned long irqs;
unsigned int mask = 0;
segid = (xpmem_segid_t)filp->private_data;
seg_tg = xpmem_tg_ref_by_segid(segid);
if (IS_ERR(seg_tg))
return PTR_ERR(seg_tg);
seg = xpmem_seg_ref_by_segid(seg_tg, segid);
if (IS_ERR(seg)) {
xpmem_tg_deref(seg_tg);
return PTR_ERR(seg);
}
poll_wait(filp, &(seg->signalled_wq), poll);
irqs = atomic_read(&(seg->irq_count));
if (irqs > 0)
mask = POLLIN | POLLRDNORM;
xpmem_seg_deref(seg);
xpmem_tg_deref(seg_tg);
return mask;
}
/*
* Send a signal to segment associated with access permit
*/
int
xpmem_signal(xpmem_apid_t apid)
{
struct xpmem_thread_group * ap_tg, * seg_tg;
struct xpmem_access_permit * ap;
struct xpmem_segment * seg;
int ret;
if (apid <= 0)
return -EINVAL;
ap_tg = xpmem_tg_ref_by_apid(apid);
if (IS_ERR(ap_tg))
return PTR_ERR(ap_tg);
ap = xpmem_ap_ref_by_apid(ap_tg, apid);
if (IS_ERR(ap)) {
xpmem_tg_deref(ap_tg);
return PTR_ERR(ap);
}
seg = ap->seg;
xpmem_seg_ref(seg);
seg_tg = seg->tg;
xpmem_tg_ref(seg_tg);
xpmem_seg_down(seg);
if (!(seg->flags & XPMEM_FLAG_SIGNALLABLE)) {
ret = -EACCES;
goto out;
}
/* Send signal */
if (seg->flags & XPMEM_FLAG_SHADOW) {
/* Shadow segment */
ret = xpmem_irq_deliver(
seg->segid,
*((xpmem_sigid_t *)&(seg->sig)),
seg->domid);
}
else {
/* Local segment */
xpmem_seg_signal(seg);
}
ret = 0;
out:
xpmem_seg_up(seg);
xpmem_seg_deref(seg);
xpmem_tg_deref(seg_tg);
xpmem_ap_deref(ap);
xpmem_tg_deref(ap_tg);
return ret;
}
/*
* The following function gets called whenever a thread group that has opened
* /dev/xpmem closes it.
*/
static int
xpmem_flush(struct file *file, fl_owner_t owner)
{
struct xpmem_thread_group *tg;
int index;
tg = xpmem_tg_ref_by_tgid(current->tgid);
if (IS_ERR(tg)) {
/*
* xpmem_flush() can get called twice for thread groups
* which inherited /dev/xpmem: once for the inherited fd,
* once for the first explicit use of /dev/xpmem. If we
* don't find the tg via xpmem_tg_ref_by_tgid() we assume we
* are in this type of scenario and return silently.
*/
return 0;
}
spin_lock(&tg->lock);
if (tg->flags & XPMEM_FLAG_DESTROYING) {
spin_unlock(&tg->lock);
xpmem_tg_deref(tg);
return -EALREADY;
}
tg->flags |= XPMEM_FLAG_DESTROYING;
spin_unlock(&tg->lock);
xpmem_release_aps_of_tg(tg);
xpmem_remove_segs_of_tg(tg);
xpmem_mmu_notifier_unlink(tg);
/*
* At this point, XPMEM no longer needs to reference the thread group
* leader's task_struct or mm_struct. Decrement its 'usage' and
* 'mm->mm_users' to account for the extra increments previously done
* in xpmem_open().
*/
mmput(tg->mm);
put_task_struct(tg->group_leader);
/* Remove tg structure from its hash list */
index = xpmem_tg_hashtable_index(tg->tgid);
write_lock(&xpmem_my_part->tg_hashtable[index].lock);
list_del_init(&tg->tg_hashlist);
write_unlock(&xpmem_my_part->tg_hashtable[index].lock);
xpmem_tg_destroyable(tg);
xpmem_tg_deref(tg);
return 0;
}
/*
* Detach an attached XPMEM address segment.
*/
int
xpmem_detach(vaddr_t at_vaddr)
{
struct xpmem_thread_group *tg;
struct xpmem_access_permit *ap;
struct xpmem_attachment *att;
tg = xpmem_tg_ref_by_gid(current->aspace->id);
if (IS_ERR(tg))
return PTR_ERR(tg);
att = xpmem_att_ref_by_vaddr(tg, at_vaddr);
if (IS_ERR(att)) {
xpmem_tg_deref(tg);
return PTR_ERR(att);
}
mutex_lock(&att->mutex);
if (att->flags & XPMEM_FLAG_DESTROYING) {
mutex_unlock(&att->mutex);
xpmem_att_deref(att);
xpmem_tg_deref(tg);
return 0;
}
att->flags |= XPMEM_FLAG_DESTROYING;
ap = att->ap;
xpmem_ap_ref(ap);
if (current->aspace->id != ap->tg->gid) {
att->flags &= ~XPMEM_FLAG_DESTROYING;
xpmem_ap_deref(ap);
mutex_unlock(&att->mutex);
xpmem_att_deref(att);
return -EACCES;
}
__xpmem_detach_att(ap, att);
mutex_unlock(&att->mutex);
xpmem_att_destroyable(att);
xpmem_ap_deref(ap);
xpmem_att_deref(att);
xpmem_tg_deref(tg);
return 0;
}
static ssize_t
signal_write(struct file * filp,
const char __user * buffer,
size_t length,
loff_t * offset)
{
struct xpmem_thread_group * seg_tg;
struct xpmem_segment * seg;
xpmem_segid_t segid;
unsigned long irqs;
unsigned long acks;
int status;
if (length != sizeof(unsigned long))
return -EINVAL;
status = copy_from_user(&acks, buffer, sizeof(unsigned long));
if (status)
return status;
segid = (xpmem_segid_t)filp->private_data;
seg_tg = xpmem_tg_ref_by_segid(segid);
if (IS_ERR(seg_tg))
return PTR_ERR(seg_tg);
seg = xpmem_seg_ref_by_segid(seg_tg, segid);
if (IS_ERR(seg)) {
xpmem_tg_deref(seg_tg);
return PTR_ERR(seg);
}
irqs = atomic_read(&(seg->irq_count));
if (acks > irqs)
acks = irqs;
atomic_sub(acks, &(seg->irq_count));
xpmem_seg_deref(seg);
xpmem_tg_deref(seg_tg);
return length;
}
static ssize_t
signal_read(struct file * filp,
char __user * buffer,
size_t length,
loff_t * offset)
{
struct xpmem_thread_group * seg_tg;
struct xpmem_segment * seg;
xpmem_segid_t segid;
unsigned long irqs;
int err;
if (length != sizeof(unsigned long))
return -EINVAL;
segid = (xpmem_segid_t)filp->private_data;
seg_tg = xpmem_tg_ref_by_segid(segid);
if (IS_ERR(seg_tg))
return PTR_ERR(seg_tg);
seg = xpmem_seg_ref_by_segid(seg_tg, segid);
if (IS_ERR(seg)) {
xpmem_tg_deref(seg_tg);
return PTR_ERR(seg);
}
/* Only ack if there are pending notifications */
err = (atomic_add_unless(&(seg->irq_count), -1, 0) == 0);
irqs = atomic_read(&(seg->irq_count));
xpmem_seg_deref(seg);
xpmem_tg_deref(seg_tg);
if (err)
return -ENODEV;
if (copy_to_user(buffer, &irqs, sizeof(unsigned long)))
return -EFAULT;
return length;
}
static ssize_t
signal_read(struct file * filp,
char __user * buffer,
size_t length,
loff_t * offset)
{
struct xpmem_thread_group * seg_tg;
struct xpmem_segment * seg;
xpmem_segid_t segid;
unsigned long irqs;
if (length != sizeof(unsigned long))
return -EINVAL;
segid = (xpmem_segid_t)filp->private_data;
seg_tg = xpmem_tg_ref_by_segid(segid);
if (IS_ERR(seg_tg))
return PTR_ERR(seg_tg);
seg = xpmem_seg_ref_by_segid(seg_tg, segid);
if (IS_ERR(seg)) {
xpmem_tg_deref(seg_tg);
return PTR_ERR(seg);
}
wait_event_interruptible(seg->signalled_wq,
(atomic_read(&(seg->irq_count)) > 0)
);
irqs = atomic_read(&(seg->irq_count));
atomic_set(&(seg->irq_count), 0);
xpmem_seg_deref(seg);
xpmem_tg_deref(seg_tg);
if (copy_to_user(buffer, &irqs, sizeof(unsigned long)))
return -EFAULT;
return length;
}
int
xpmem_segid_signal(xpmem_segid_t segid)
{
struct xpmem_thread_group * seg_tg;
struct xpmem_segment * seg;
seg_tg = xpmem_tg_ref_by_segid(segid);
if (IS_ERR(seg_tg))
return PTR_ERR(seg_tg);
seg = xpmem_seg_ref_by_segid(seg_tg, segid);
if (IS_ERR(seg)) {
xpmem_tg_deref(seg_tg);
return PTR_ERR(seg);
}
xpmem_seg_signal(seg);
xpmem_seg_deref(seg);
xpmem_tg_deref(seg_tg);
return 0;
}
/*
* Attach a XPMEM address segment.
*/
int
xpmem_attach(xpmem_apid_t apid,
off_t offset,
size_t size,
int att_flags,
vaddr_t * at_vaddr_p)
{
int ret, index;
vaddr_t seg_vaddr, at_vaddr;
struct xpmem_thread_group *ap_tg, *seg_tg;
struct xpmem_access_permit *ap;
struct xpmem_segment *seg;
struct xpmem_attachment *att;
if (apid <= 0)
return -EINVAL;
/* If the size is not page aligned, fix it */
if (offset_in_page(size) != 0)
size += PAGE_SIZE - offset_in_page(size);
ap_tg = xpmem_tg_ref_by_apid(apid);
if (IS_ERR(ap_tg))
return PTR_ERR(ap_tg);
ap = xpmem_ap_ref_by_apid(ap_tg, apid);
if (IS_ERR(ap)) {
xpmem_tg_deref(ap_tg);
return PTR_ERR(ap);
}
seg = ap->seg;
xpmem_seg_ref(seg);
seg_tg = seg->tg;
xpmem_tg_ref(seg_tg);
xpmem_seg_down(seg);
ret = xpmem_validate_access(ap_tg, ap, offset, size, XPMEM_RDWR, &seg_vaddr);
if (ret != 0)
goto out_1;
/* size needs to reflect page offset to start of segment */
size += offset_in_page(seg_vaddr);
if (seg->flags & XPMEM_FLAG_SHADOW) {
BUG_ON(seg->remote_apid <= 0);
/* remote - load pfns in now */
ret = xpmem_try_attach_remote(seg->segid, seg->remote_apid, offset, size, &at_vaddr);
if (ret != 0)
goto out_1;
} else {
/* not remote - simply figure out where we are smartmapped to this process */
at_vaddr = xpmem_make_smartmap_addr(seg_tg->aspace->id, seg_vaddr);
}
/* create new attach structure */
att = kmem_alloc(sizeof(struct xpmem_attachment));
if (att == NULL) {
ret = -ENOMEM;
goto out_1;
}
mutex_init(&att->mutex);
att->vaddr = seg_vaddr;
att->at_vaddr = at_vaddr;
att->at_size = size;
att->ap = ap;
att->flags = 0;
INIT_LIST_HEAD(&att->att_node);
xpmem_att_not_destroyable(att);
xpmem_att_ref(att);
/*
* The attach point where we mapped the portion of the segment the
* user was interested in is page aligned. But the start of the portion
* of the segment may not be, so we adjust the address returned to the
* user by that page offset difference so that what they see is what
* they expected to see.
*/
*at_vaddr_p = at_vaddr + offset_in_page(att->vaddr);
/* link attach structure to its access permit's att list */
spin_lock(&ap->lock);
if (ap->flags & XPMEM_FLAG_DESTROYING) {
spin_unlock(&ap->lock);
ret = -ENOENT;
goto out_2;
}
list_add_tail(&att->att_node, &ap->att_list);
/* add att to its ap_tg's hash list */
index = xpmem_att_hashtable_index(att->at_vaddr);
write_lock(&ap_tg->att_hashtable[index].lock);
list_add_tail(&att->att_hashnode, &ap_tg->att_hashtable[index].list);
write_unlock(&ap_tg->att_hashtable[index].lock);
spin_unlock(&ap->lock);
ret = 0;
out_2:
if (ret != 0) {
att->flags |= XPMEM_FLAG_DESTROYING;
xpmem_att_destroyable(att);
}
xpmem_att_deref(att);
out_1:
xpmem_seg_up(seg);
xpmem_ap_deref(ap);
xpmem_tg_deref(ap_tg);
xpmem_seg_deref(seg);
xpmem_tg_deref(seg_tg);
return ret;
}
/*
* Release an access permit and detach all associated attaches.
*/
void
xpmem_release_ap(struct xpmem_thread_group *ap_tg,
struct xpmem_access_permit *ap)
{
int index;
struct xpmem_thread_group *seg_tg;
struct xpmem_attachment *att;
struct xpmem_segment *seg;
spin_lock(&ap->lock);
if (ap->flags & XPMEM_FLAG_DESTROYING) {
spin_unlock(&ap->lock);
return;
}
ap->flags |= XPMEM_FLAG_DESTROYING;
/* deal with all attaches first */
while (!list_empty(&ap->att_list)) {
att = list_entry((&ap->att_list)->next, struct xpmem_attachment,
att_node);
xpmem_att_ref(att);
spin_unlock(&ap->lock);
xpmem_detach_att(ap, att);
xpmem_att_deref(att);
spin_lock(&ap->lock);
}
spin_unlock(&ap->lock);
/*
* Remove access structure from its hash list.
* This is done after the xpmem_detach_att to prevent any racing
* thread from looking up access permits for the owning thread group
* and not finding anything, assuming everything is clean, and
* freeing the mm before xpmem_detach_att has a chance to
* use it.
*/
index = xpmem_ap_hashtable_index(ap->apid);
write_lock(&ap_tg->ap_hashtable[index].lock);
list_del_init(&ap->ap_hashnode);
write_unlock(&ap_tg->ap_hashtable[index].lock);
/* the ap's seg and the seg's tg were ref'd in xpmem_get() */
seg = ap->seg;
seg_tg = seg->tg;
/* remove ap from its seg's access permit list */
spin_lock(&seg->lock);
list_del_init(&ap->ap_node);
spin_unlock(&seg->lock);
/* Try to teardown a shadow segment */
if (seg->flags & XPMEM_FLAG_SHADOW)
xpmem_remove_seg(seg_tg, seg);
xpmem_seg_deref(seg); /* deref of xpmem_get()'s ref */
xpmem_tg_deref(seg_tg); /* deref of xpmem_get()'s ref */
xpmem_ap_destroyable(ap);
}
/*
* Get permission to access a specified segid.
*/
int
xpmem_get(xpmem_segid_t segid, int flags, int permit_type, void *permit_value,
xpmem_apid_t *apid_p)
{
xpmem_apid_t apid = 0;
int status = 0;
int shadow_seg = 0;
struct xpmem_segment *seg = NULL;
struct xpmem_thread_group *ap_tg, *seg_tg;
if (segid <= 0)
return -EINVAL;
if ((flags & ~(XPMEM_RDONLY | XPMEM_RDWR)) ||
(flags & (XPMEM_RDONLY | XPMEM_RDWR)) ==
(XPMEM_RDONLY | XPMEM_RDWR))
return -EINVAL;
switch (permit_type) {
case XPMEM_PERMIT_MODE:
case XPMEM_GLOBAL_MODE:
if (permit_value != NULL)
return -EINVAL;
break;
default:
return -EINVAL;
}
/* There are 2 cases that result in a remote lookup:
* (1) The thread group encoded in the segment does not exist locally.
*
* (2) The thread group exists locally, but the segment does not. The
* ids for thread groups are not globally unique, so it's possible that
* the same thread group id exists in two separate enclaves, but only
* one will own the segment
*/
seg_tg = xpmem_tg_ref_by_segid(segid);
if (IS_ERR(seg_tg)) {
seg_tg = xpmem_tg_ref_by_gid(current->aspace->id);
if (IS_ERR(seg_tg))
return PTR_ERR(seg_tg);
shadow_seg = 1;
}
if (!shadow_seg) {
seg = xpmem_seg_ref_by_segid(seg_tg, segid);
if (IS_ERR(seg))
shadow_seg = 1;
}
if (shadow_seg) {
/* No local segment found. Look for a remote one */
/* NOTE: in either case, the tg has already been ref'd. We ref the
* current process' tg if no tg is found for the segid
*/
status = xpmem_try_get_remote(seg_tg, segid, flags, permit_type,
permit_value);
if (status != 0) {
xpmem_tg_deref(seg_tg);
return status;
}
/* Now, get the shadow segment */
seg = xpmem_seg_ref_by_segid(seg_tg, segid);
if (IS_ERR(seg)) {
/* Error should be impossible here, but we'll
* check anyway. The shadow segment was created in
* xpmem_try_get_remote, so destroy it here */
xpmem_remove(segid);
xpmem_tg_deref(seg_tg);
return PTR_ERR(seg);
}
}
/* find accessor's thread group structure */
ap_tg = xpmem_tg_ref_by_gid(current->aspace->id);
if (IS_ERR(ap_tg)) {
BUG_ON(PTR_ERR(ap_tg) != -ENOENT);
status = -XPMEM_ERRNO_NOPROC;
goto err_ap_tg;
}
apid = xpmem_make_apid(ap_tg);
if (apid < 0) {
status = apid;
goto err_apid;
}
status = xpmem_get_segment(flags, permit_type, permit_value, apid,
seg, seg_tg, ap_tg);
if (status != 0)
goto err_get;
*apid_p = apid;
xpmem_tg_deref(ap_tg);
/*
* The following two derefs
*
* xpmem_seg_deref(seg);
* xpmem_tg_deref(seg_tg);
*
* aren't being done at this time in order to prevent the seg
* and seg_tg structures from being prematurely kmem_free'd as long as the
* potential for them to be referenced via this ap structure exists.
*
* These two derefs will be done by xpmem_release_ap() at the time
* this ap structure is destroyed.
*/
return status;
err_get:
err_apid:
xpmem_tg_deref(ap_tg);
err_ap_tg:
/* If we created a shadow segment, destroy it on error. Else, just
* deref it
*/
if (shadow_seg)
xpmem_remove(segid);
else
xpmem_seg_deref(seg);
xpmem_tg_deref(seg_tg);
return status;
}
/*
* User open of the XPMEM driver. Called whenever /dev/xpmem is opened.
* Create a struct xpmem_thread_group structure for the specified thread group.
* And add the structure to the tg hash table.
*/
static int
xpmem_open(struct inode *inode, struct file *file)
{
struct xpmem_thread_group *tg;
int index;
struct proc_dir_entry *unpin_entry;
char tgid_string[XPMEM_TGID_STRING_LEN];
/* if this has already been done, just return silently */
tg = xpmem_tg_ref_by_tgid(current->tgid);
if (!IS_ERR(tg)) {
xpmem_tg_deref(tg);
return 0;
}
/* create tg */
tg = kzalloc(sizeof(struct xpmem_thread_group), GFP_KERNEL);
if (tg == NULL) {
return -ENOMEM;
}
tg->lock = SPIN_LOCK_UNLOCKED;
tg->tgid = current->tgid;
tg->uid = current->cred->uid;
tg->gid = current->cred->gid;
atomic_set(&tg->uniq_segid, 0);
atomic_set(&tg->uniq_apid, 0);
atomic_set(&tg->n_pinned, 0);
tg->addr_limit = TASK_SIZE;
tg->seg_list_lock = RW_LOCK_UNLOCKED;
INIT_LIST_HEAD(&tg->seg_list);
INIT_LIST_HEAD(&tg->tg_hashlist);
atomic_set(&tg->n_recall_PFNs, 0);
mutex_init(&tg->recall_PFNs_mutex);
init_waitqueue_head(&tg->block_recall_PFNs_wq);
init_waitqueue_head(&tg->allow_recall_PFNs_wq);
tg->mmu_initialized = 0;
tg->mmu_unregister_called = 0;
tg->mm = current->mm;
/* Register MMU notifier callbacks */
if (xpmem_mmu_notifier_init(tg) != 0) {
kfree(tg);
return -EFAULT;
}
/* create and initialize struct xpmem_access_permit hashtable */
tg->ap_hashtable = kzalloc(sizeof(struct xpmem_hashlist) *
XPMEM_AP_HASHTABLE_SIZE, GFP_KERNEL);
if (tg->ap_hashtable == NULL) {
xpmem_mmu_notifier_unlink(tg);
kfree(tg);
return -ENOMEM;
}
for (index = 0; index < XPMEM_AP_HASHTABLE_SIZE; index++) {
tg->ap_hashtable[index].lock = RW_LOCK_UNLOCKED;
INIT_LIST_HEAD(&tg->ap_hashtable[index].list);
}
snprintf(tgid_string, XPMEM_TGID_STRING_LEN, "%d", current->tgid);
spin_lock(&xpmem_unpin_procfs_lock);
unpin_entry = create_proc_entry(tgid_string, 0644,
xpmem_unpin_procfs_dir);
spin_unlock(&xpmem_unpin_procfs_lock);
if (unpin_entry != NULL) {
unpin_entry->data = (void *)(unsigned long)current->tgid;
unpin_entry->write_proc = xpmem_unpin_procfs_write;
unpin_entry->read_proc = xpmem_unpin_procfs_read;
//unpin_entry->owner = THIS_MODULE;
unpin_entry->uid = current->cred->uid;
unpin_entry->gid = current->cred->gid;
}
xpmem_tg_not_destroyable(tg);
/* add tg to its hash list */
index = xpmem_tg_hashtable_index(tg->tgid);
write_lock(&xpmem_my_part->tg_hashtable[index].lock);
list_add_tail(&tg->tg_hashlist,
&xpmem_my_part->tg_hashtable[index].list);
write_unlock(&xpmem_my_part->tg_hashtable[index].lock);
/*
* Increment 'usage' and 'mm->mm_users' for the current task's thread
* group leader. This ensures that both its task_struct and mm_struct
* will still be around when our thread group exits. (The Linux kernel
* normally tears down the mm_struct prior to calling a module's
* 'flush' function.) Since all XPMEM thread groups must go through
* this path, this extra reference to mm_users also allows us to
* directly inc/dec mm_users in xpmem_ensure_valid_PFNs() and avoid
* mmput() which has a scaling issue with the mmlist_lock.
*/
get_task_struct(current->group_leader);
tg->group_leader = current->group_leader;
BUG_ON(current->mm != current->group_leader->mm);
atomic_inc(¤t->group_leader->mm->mm_users);
return 0;
}