1 #ifndef _ASM_GENERIC_FUTEX_H
2 #define _ASM_GENERIC_FUTEX_H
4 #include <linux/futex.h>
5 #include <linux/uaccess.h>
10 * The following implementation only for uniprocessor machines.
11 * It relies on preempt_disable() ensuring mutual exclusion.
16 * futex_atomic_op_inuser() - Atomic arithmetic operation with constant
17 * argument and comparison of the previous
18 * futex value with another constant.
20 * @encoded_op: encoded operation to execute
21 * @uaddr: pointer to user space address
28 futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr)
30 int op = (encoded_op >> 28) & 7;
31 int cmp = (encoded_op >> 24) & 15;
32 int oparg = (encoded_op << 8) >> 20;
33 int cmparg = (encoded_op << 20) >> 20;
37 if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
44 if (unlikely(get_user(oldval, uaddr) != 0))
45 goto out_pagefault_enable;
70 if (ret == 0 && unlikely(put_user(tmp, uaddr) != 0))
79 case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break;
80 case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break;
81 case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break;
82 case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break;
83 case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break;
84 case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break;
85 default: ret = -ENOSYS;
92 * futex_atomic_cmpxchg_inatomic() - Compare and exchange the content of the
93 * uaddr with newval if the current value is
95 * @uval: pointer to store content of @uaddr
96 * @uaddr: pointer to user space address
98 * @newval: new value to store to @uaddr
105 futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
106 u32 oldval, u32 newval)
111 if (unlikely(get_user(val, uaddr) != 0))
114 if (val == oldval && unlikely(put_user(newval, uaddr) != 0))
125 futex_atomic_op_inuser (int encoded_op, u32 __user *uaddr)
127 int op = (encoded_op >> 28) & 7;
128 int cmp = (encoded_op >> 24) & 15;
129 int oparg = (encoded_op << 8) >> 20;
130 int cmparg = (encoded_op << 20) >> 20;
132 if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
135 if (! access_ok (VERIFY_WRITE, uaddr, sizeof(u32)))
154 case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break;
155 case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break;
156 case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break;
157 case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break;
158 case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break;
159 case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break;
160 default: ret = -ENOSYS;
167 futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
168 u32 oldval, u32 newval)
173 #endif /* CONFIG_SMP */