2 * linux/kernel/futex_compat.c
4 * Futex compatibililty routines.
6 * Copyright 2006, Red Hat, Inc., Ingo Molnar
9 #include <linux/linkage.h>
10 #include <linux/compat.h>
11 #include <linux/nsproxy.h>
12 #include <linux/futex.h>
13 #include <linux/ptrace.h>
15 #include <asm/uaccess.h>
19 * Fetch a robust-list pointer. Bit 0 signals PI futexes:
22 fetch_robust_entry(compat_uptr_t *uentry, struct robust_list __user **entry,
23 compat_uptr_t __user *head, unsigned int *pi)
25 if (get_user(*uentry, head))
28 *entry = compat_ptr((*uentry) & ~1);
29 *pi = (unsigned int)(*uentry) & 1;
34 static void __user *futex_uaddr(struct robust_list __user *entry,
35 compat_long_t futex_offset)
37 compat_uptr_t base = ptr_to_compat(entry);
38 void __user *uaddr = compat_ptr(base + futex_offset);
44 * Walk curr->robust_list (very carefully, it's a userspace list!)
45 * and mark any locks found there dead, and notify any waiters.
47 * We silently return on any sign of list-walking problem.
49 void compat_exit_robust_list(struct task_struct *curr)
51 struct compat_robust_list_head __user *head = curr->compat_robust_list;
52 struct robust_list __user *entry, *next_entry, *pending;
53 unsigned int limit = ROBUST_LIST_LIMIT, pi, pip;
54 unsigned int uninitialized_var(next_pi);
55 compat_uptr_t uentry, next_uentry, upending;
56 compat_long_t futex_offset;
59 if (!futex_cmpxchg_enabled)
63 * Fetch the list head (which was registered earlier, via
64 * sys_set_robust_list()):
66 if (fetch_robust_entry(&uentry, &entry, &head->list.next, &pi))
69 * Fetch the relative futex offset:
71 if (get_user(futex_offset, &head->futex_offset))
74 * Fetch any possibly pending lock-add first, and handle it
77 if (fetch_robust_entry(&upending, &pending,
78 &head->list_op_pending, &pip))
81 next_entry = NULL; /* avoid warning with gcc */
82 while (entry != (struct robust_list __user *) &head->list) {
84 * Fetch the next entry in the list before calling
87 rc = fetch_robust_entry(&next_uentry, &next_entry,
88 (compat_uptr_t __user *)&entry->next, &next_pi);
90 * A pending lock might already be on the list, so
91 * dont process it twice:
93 if (entry != pending) {
94 void __user *uaddr = futex_uaddr(entry, futex_offset);
96 if (handle_futex_death(uaddr, curr, pi))
101 uentry = next_uentry;
105 * Avoid excessively long or circular lists:
113 void __user *uaddr = futex_uaddr(pending, futex_offset);
115 handle_futex_death(uaddr, curr, pip);
120 compat_sys_set_robust_list(struct compat_robust_list_head __user *head,
123 if (!futex_cmpxchg_enabled)
126 if (unlikely(len != sizeof(*head)))
129 current->compat_robust_list = head;
135 compat_sys_get_robust_list(int pid, compat_uptr_t __user *head_ptr,
136 compat_size_t __user *len_ptr)
138 struct compat_robust_list_head __user *head;
140 struct task_struct *p;
142 if (!futex_cmpxchg_enabled)
145 WARN_ONCE(1, "deprecated: get_robust_list will be deleted in 2013.\n");
153 p = find_task_by_vpid(pid);
159 if (!ptrace_may_access(p, PTRACE_MODE_READ))
162 head = p->compat_robust_list;
165 if (put_user(sizeof(*head), len_ptr))
167 return put_user(ptr_to_compat(head), head_ptr);
175 asmlinkage long compat_sys_futex(u32 __user *uaddr, int op, u32 val,
176 struct compat_timespec __user *utime, u32 __user *uaddr2,
180 ktime_t t, *tp = NULL;
182 int cmd = op & FUTEX_CMD_MASK;
184 if (utime && (cmd == FUTEX_WAIT || cmd == FUTEX_LOCK_PI ||
185 cmd == FUTEX_WAIT_BITSET ||
186 cmd == FUTEX_WAIT_REQUEUE_PI)) {
187 if (get_compat_timespec(&ts, utime))
189 if (!timespec_valid(&ts))
192 t = timespec_to_ktime(ts);
193 if (cmd == FUTEX_WAIT)
194 t = ktime_add_safe(ktime_get(), t);
197 if (cmd == FUTEX_REQUEUE || cmd == FUTEX_CMP_REQUEUE ||
198 cmd == FUTEX_CMP_REQUEUE_PI || cmd == FUTEX_WAKE_OP)
199 val2 = (int) (unsigned long) utime;
201 return do_futex(uaddr, op, val, tp, uaddr2, val2, val3);