#include <linux/vs_cvirt.h>
#define pid_hashfn(nr) hash_long((unsigned long)nr, pidhash_shift)
-static struct hlist_head *pid_hash;
+static struct hlist_head *pid_hash[PIDTYPE_MAX];
static int pidhash_shift;
-static kmem_cache_t *pid_cachep;
int pid_max = PID_MAX_DEFAULT;
int last_pid;
static pidmap_t pidmap_array[PIDMAP_ENTRIES] =
{ [ 0 ... PIDMAP_ENTRIES-1 ] = { ATOMIC_INIT(BITS_PER_PAGE), NULL } };
-/*
- * Note: disable interrupts while the pidmap_lock is held as an
- * interrupt might come in and do read_lock(&tasklist_lock).
- *
- * If we don't disable interrupts there is a nasty deadlock between
- * detach_pid()->free_pid() and another cpu that does
- * spin_lock(&pidmap_lock) followed by an interrupt routine that does
- * read_lock(&tasklist_lock);
- *
- * After we clean up the tasklist_lock and know there are no
- * irq handlers that take it we can leave the interrupts enabled.
- * For now it is easier to be safe than to prove it can't happen.
- */
static __cacheline_aligned_in_smp DEFINE_SPINLOCK(pidmap_lock);
-static fastcall void free_pidmap(int pid)
+fastcall void free_pidmap(int pid)
{
pidmap_t *map = pidmap_array + pid / BITS_PER_PAGE;
int offset = pid & BITS_PER_PAGE_MASK;
atomic_inc(&map->nr_free);
}
-static int alloc_pidmap(void)
+int alloc_pidmap(void)
{
int i, offset, max_scan, pid, last = last_pid;
pidmap_t *map;
* Free the page if someone raced with us
* installing it:
*/
- spin_lock_irq(&pidmap_lock);
+ spin_lock(&pidmap_lock);
if (map->page)
free_page(page);
else
map->page = (void *)page;
- spin_unlock_irq(&pidmap_lock);
+ spin_unlock(&pidmap_lock);
if (unlikely(!map->page))
break;
}
return -1;
}
-fastcall void put_pid(struct pid *pid)
-{
- if (!pid)
- return;
- if ((atomic_read(&pid->count) == 1) ||
- atomic_dec_and_test(&pid->count))
- kmem_cache_free(pid_cachep, pid);
-}
-
-static void delayed_put_pid(struct rcu_head *rhp)
-{
- struct pid *pid = container_of(rhp, struct pid, rcu);
- put_pid(pid);
-}
-
-fastcall void free_pid(struct pid *pid)
-{
- /* We can be called with write_lock_irq(&tasklist_lock) held */
- unsigned long flags;
-
- spin_lock_irqsave(&pidmap_lock, flags);
- hlist_del_rcu(&pid->pid_chain);
- spin_unlock_irqrestore(&pidmap_lock, flags);
-
- free_pidmap(pid->nr);
- call_rcu(&pid->rcu, delayed_put_pid);
-}
-
-struct pid *alloc_pid(void)
-{
- struct pid *pid;
- enum pid_type type;
- int nr = -1;
-
- pid = kmem_cache_alloc(pid_cachep, GFP_KERNEL);
- if (!pid)
- goto out;
-
- nr = alloc_pidmap();
- if (nr < 0)
- goto out_free;
-
- atomic_set(&pid->count, 1);
- pid->nr = nr;
- for (type = 0; type < PIDTYPE_MAX; ++type)
- INIT_HLIST_HEAD(&pid->tasks[type]);
-
- spin_lock_irq(&pidmap_lock);
- hlist_add_head_rcu(&pid->pid_chain, &pid_hash[pid_hashfn(pid->nr)]);
- spin_unlock_irq(&pidmap_lock);
-
-out:
- return pid;
-
-out_free:
- kmem_cache_free(pid_cachep, pid);
- pid = NULL;
- goto out;
-}
-
-struct pid * fastcall find_pid(int nr)
+struct pid * fastcall find_pid(enum pid_type type, int nr)
{
struct hlist_node *elem;
struct pid *pid;
hlist_for_each_entry_rcu(pid, elem,
- &pid_hash[pid_hashfn(nr)], pid_chain) {
+ &pid_hash[type][pid_hashfn(nr)], pid_chain) {
if (pid->nr == nr)
return pid;
}
return NULL;
}
-int fastcall attach_pid(struct task_struct *task, enum pid_type type, int nr)
+int fastcall attach_pid(task_t *task, enum pid_type type, int nr)
{
- struct pid_link *link;
- struct pid *pid;
-
- WARN_ON(!task->pid); /* to be removed soon */
- WARN_ON(!nr); /* to be removed soon */
-
- link = &task->pids[type];
- link->pid = pid = find_pid(nr);
- hlist_add_head_rcu(&link->node, &pid->tasks[type]);
+ struct pid *pid, *task_pid;
+
+ task_pid = &task->pids[type];
+ pid = find_pid(type, nr);
+ task_pid->nr = nr;
+ if (pid == NULL) {
+ INIT_LIST_HEAD(&task_pid->pid_list);
+ hlist_add_head_rcu(&task_pid->pid_chain,
+ &pid_hash[type][pid_hashfn(nr)]);
+ } else {
+ INIT_HLIST_NODE(&task_pid->pid_chain);
+ list_add_tail_rcu(&task_pid->pid_list, &pid->pid_list);
+ }
return 0;
}
-void fastcall detach_pid(struct task_struct *task, enum pid_type type)
+static fastcall int __detach_pid(task_t *task, enum pid_type type)
{
- struct pid_link *link;
- struct pid *pid;
- int tmp;
+ struct pid *pid, *pid_next;
+ int nr = 0;
- link = &task->pids[type];
- pid = link->pid;
+ pid = &task->pids[type];
+ if (!hlist_unhashed(&pid->pid_chain)) {
- hlist_del_rcu(&link->node);
- link->pid = NULL;
+ if (list_empty(&pid->pid_list)) {
+ nr = pid->nr;
+ hlist_del_rcu(&pid->pid_chain);
+ } else {
+ pid_next = list_entry(pid->pid_list.next,
+ struct pid, pid_list);
+ /* insert next pid from pid_list to hash */
+ hlist_replace_rcu(&pid->pid_chain,
+ &pid_next->pid_chain);
+ }
+ }
- for (tmp = PIDTYPE_MAX; --tmp >= 0; )
- if (!hlist_empty(&pid->tasks[tmp]))
- return;
+ list_del_rcu(&pid->pid_list);
+ pid->nr = 0;
- free_pid(pid);
+ return nr;
}
-struct task_struct * fastcall pid_task(struct pid *pid, enum pid_type type)
+void fastcall detach_pid(task_t *task, enum pid_type type)
{
- struct task_struct *result = NULL;
- if (pid) {
- struct hlist_node *first;
- first = rcu_dereference(pid->tasks[type].first);
- if (first)
- result = hlist_entry(first, struct task_struct, pids[(type)].node);
- if (result && (pid->nr != 1) &&
- !vx_check(vx_task_xid(result), VX_WATCH|VX_ADMIN|VX_IDENT)) {
- vxwprintk((type == PIDTYPE_PID) && (current->xid),
- "pid_task(%d,%d): task %p[#%u,%u] did lookup %p[#%u,%u]",
- pid->nr, type, current, vx_current_xid(), current->pid,
- result, vx_task_xid(result), result->pid);
- result = NULL;
- }
- }
- return result;
-}
+ int tmp, nr;
-/*
- * Must be called under rcu_read_lock() or with tasklist_lock read-held.
- */
-struct task_struct *find_task_by_pid_type(int type, int nr)
-{
- if (type == PIDTYPE_PID)
- nr = vx_rmap_pid(nr);
- else if (type == PIDTYPE_REALPID)
- type = PIDTYPE_PID;
- return pid_task(find_pid(nr), type);
-}
+ nr = __detach_pid(task, type);
+ if (!nr)
+ return;
-EXPORT_SYMBOL(find_task_by_pid_type);
+ for (tmp = PIDTYPE_MAX; --tmp >= 0; )
+ if (tmp != type && find_pid(tmp, nr))
+ return;
-struct task_struct *fastcall get_pid_task(struct pid *pid, enum pid_type type)
-{
- struct task_struct *result;
- rcu_read_lock();
- result = pid_task(pid, type);
- if (result)
- get_task_struct(result);
- rcu_read_unlock();
- return result;
+ free_pidmap(nr);
}
-struct pid *find_get_pid(pid_t nr)
+task_t *find_task_by_pid_type(int type, int nr)
{
struct pid *pid;
- rcu_read_lock();
- pid = get_pid(find_pid(nr));
- rcu_read_unlock();
+ if (type == PIDTYPE_REALPID)
+ type = PIDTYPE_PID;
+ else if (type == PIDTYPE_PID)
+ nr = vx_rmap_pid(nr);
+
+ pid = find_pid(type, nr);
+ if (!pid)
+ return NULL;
+
+ return pid_task(&pid->pid_list, type);
+}
+
+EXPORT_SYMBOL(find_task_by_pid_type);
- return pid;
+/*
+ * This function switches the PIDs if a non-leader thread calls
+ * sys_execve() - this must be done without releasing the PID.
+ * (which a detach_pid() would eventually do.)
+ */
+void switch_exec_pids(task_t *leader, task_t *thread)
+{
+ __detach_pid(leader, PIDTYPE_PID);
+ __detach_pid(leader, PIDTYPE_TGID);
+ __detach_pid(leader, PIDTYPE_PGID);
+ __detach_pid(leader, PIDTYPE_SID);
+
+ __detach_pid(thread, PIDTYPE_PID);
+ __detach_pid(thread, PIDTYPE_TGID);
+
+ leader->pid = leader->tgid = thread->pid;
+ thread->pid = thread->tgid;
+
+ attach_pid(thread, PIDTYPE_PID, thread->pid);
+ attach_pid(thread, PIDTYPE_TGID, thread->tgid);
+ attach_pid(thread, PIDTYPE_PGID, thread->signal->pgrp);
+ attach_pid(thread, PIDTYPE_SID, thread->signal->session);
+ list_add_tail(&thread->tasks, &init_task.tasks);
+
+ attach_pid(leader, PIDTYPE_PID, leader->pid);
+ attach_pid(leader, PIDTYPE_TGID, leader->tgid);
+ attach_pid(leader, PIDTYPE_PGID, leader->signal->pgrp);
+ attach_pid(leader, PIDTYPE_SID, leader->signal->session);
}
/*
*/
void __init pidhash_init(void)
{
- int i, pidhash_size;
+ int i, j, pidhash_size;
unsigned long megabytes = nr_kernel_pages >> (20 - PAGE_SHIFT);
pidhash_shift = max(4, fls(megabytes * 4));
printk("PID hash table entries: %d (order: %d, %Zd bytes)\n",
pidhash_size, pidhash_shift,
- pidhash_size * sizeof(struct hlist_head));
-
- pid_hash = alloc_bootmem(pidhash_size * sizeof(*(pid_hash)));
- if (!pid_hash)
- panic("Could not alloc pidhash!\n");
- for (i = 0; i < pidhash_size; i++)
- INIT_HLIST_HEAD(&pid_hash[i]);
+ PIDTYPE_MAX * pidhash_size * sizeof(struct hlist_head));
+
+ for (i = 0; i < PIDTYPE_MAX; i++) {
+ pid_hash[i] = alloc_bootmem(pidhash_size *
+ sizeof(*(pid_hash[i])));
+ if (!pid_hash[i])
+ panic("Could not alloc pidhash!\n");
+ for (j = 0; j < pidhash_size; j++)
+ INIT_HLIST_HEAD(&pid_hash[i][j]);
+ }
}
void __init pidmap_init(void)
{
+ int i;
+
pidmap_array->page = (void *)get_zeroed_page(GFP_KERNEL);
- /* Reserve PID 0. We never call free_pidmap(0) */
set_bit(0, pidmap_array->page);
atomic_dec(&pidmap_array->nr_free);
- pid_cachep = kmem_cache_create("pid", sizeof(struct pid),
- __alignof__(struct pid),
- SLAB_PANIC, NULL, NULL);
+ /*
+ * Allocate PID 0, and hash it via all PID types:
+ */
+
+ for (i = 0; i < PIDTYPE_MAX; i++)
+ attach_pid(current, i, 0);
}