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/futex.h>
13 #include <asm/uaccess.h>
17 * Fetch a robust-list pointer. Bit 0 signals PI futexes:
20 fetch_robust_entry(compat_uptr_t
*uentry
, struct robust_list __user
**entry
,
21 compat_uptr_t __user
*head
, int *pi
)
23 if (get_user(*uentry
, head
))
26 *entry
= compat_ptr((*uentry
) & ~1);
27 *pi
= (unsigned int)(*uentry
) & 1;
33 * Walk curr->robust_list (very carefully, it's a userspace list!)
34 * and mark any locks found there dead, and notify any waiters.
36 * We silently return on any sign of list-walking problem.
38 void compat_exit_robust_list(struct task_struct
*curr
)
40 struct compat_robust_list_head __user
*head
= curr
->compat_robust_list
;
41 struct robust_list __user
*entry
, *next_entry
, *pending
;
42 unsigned int limit
= ROBUST_LIST_LIMIT
, pi
, next_pi
, pip
;
43 compat_uptr_t uentry
, next_uentry
, upending
;
44 compat_long_t futex_offset
;
48 * Fetch the list head (which was registered earlier, via
49 * sys_set_robust_list()):
51 if (fetch_robust_entry(&uentry
, &entry
, &head
->list
.next
, &pi
))
54 * Fetch the relative futex offset:
56 if (get_user(futex_offset
, &head
->futex_offset
))
59 * Fetch any possibly pending lock-add first, and handle it
62 if (fetch_robust_entry(&upending
, &pending
,
63 &head
->list_op_pending
, &pip
))
66 next_entry
= NULL
; /* avoid warning with gcc */
67 while (entry
!= (struct robust_list __user
*) &head
->list
) {
69 * Fetch the next entry in the list before calling
72 rc
= fetch_robust_entry(&next_uentry
, &next_entry
,
73 (compat_uptr_t __user
*)&entry
->next
, &next_pi
);
75 * A pending lock might already be on the list, so
76 * dont process it twice:
79 if (handle_futex_death((void __user
*)entry
+ futex_offset
,
89 * Avoid excessively long or circular lists:
97 handle_futex_death((void __user
*)pending
+ futex_offset
,
102 compat_sys_set_robust_list(struct compat_robust_list_head __user
*head
,
105 if (unlikely(len
!= sizeof(*head
)))
108 current
->compat_robust_list
= head
;
114 compat_sys_get_robust_list(int pid
, compat_uptr_t __user
*head_ptr
,
115 compat_size_t __user
*len_ptr
)
117 struct compat_robust_list_head __user
*head
;
121 head
= current
->compat_robust_list
;
123 struct task_struct
*p
;
126 read_lock(&tasklist_lock
);
127 p
= find_task_by_pid(pid
);
131 if ((current
->euid
!= p
->euid
) && (current
->euid
!= p
->uid
) &&
132 !capable(CAP_SYS_PTRACE
))
134 head
= p
->compat_robust_list
;
135 read_unlock(&tasklist_lock
);
138 if (put_user(sizeof(*head
), len_ptr
))
140 return put_user(ptr_to_compat(head
), head_ptr
);
143 read_unlock(&tasklist_lock
);
148 asmlinkage
long compat_sys_futex(u32 __user
*uaddr
, int op
, u32 val
,
149 struct compat_timespec __user
*utime
, u32 __user
*uaddr2
,
153 ktime_t t
, *tp
= NULL
;
155 int cmd
= op
& FUTEX_CMD_MASK
;
157 if (utime
&& (cmd
== FUTEX_WAIT
|| cmd
== FUTEX_LOCK_PI
)) {
158 if (get_compat_timespec(&ts
, utime
))
160 if (!timespec_valid(&ts
))
163 t
= timespec_to_ktime(ts
);
164 if (cmd
== FUTEX_WAIT
)
165 t
= ktime_add(ktime_get(), t
);
168 if (cmd
== FUTEX_REQUEUE
|| cmd
== FUTEX_CMP_REQUEUE
)
169 val2
= (int) (unsigned long) utime
;
171 return do_futex(uaddr
, op
, val
, tp
, uaddr2
, val2
, val3
);