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 * For UP, it's relies on the fact that pagefault_disable() also disables
12 * preemption to ensure mutual exclusion.
17 * futex_atomic_op_inuser() - Atomic arithmetic operation with constant
18 * argument and comparison of the previous
19 * futex value with another constant.
21 * @encoded_op: encoded operation to execute
22 * @uaddr: pointer to user space address
29 futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr)
31 int op = (encoded_op >> 28) & 7;
32 int cmp = (encoded_op >> 24) & 15;
33 int oparg = (encoded_op << 8) >> 20;
34 int cmparg = (encoded_op << 20) >> 20;
38 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))
78 case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break;
79 case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break;
80 case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break;
81 case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break;
82 case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break;
83 case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break;
84 default: ret = -ENOSYS;
91 * futex_atomic_cmpxchg_inatomic() - Compare and exchange the content of the
92 * uaddr with newval if the current value is
94 * @uval: pointer to store content of @uaddr
95 * @uaddr: pointer to user space address
97 * @newval: new value to store to @uaddr
104 futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
105 u32 oldval, u32 newval)
109 if (unlikely(get_user(val, uaddr) != 0))
112 if (val == oldval && unlikely(put_user(newval, uaddr) != 0))
122 futex_atomic_op_inuser (int encoded_op, u32 __user *uaddr)
124 int op = (encoded_op >> 28) & 7;
125 int cmp = (encoded_op >> 24) & 15;
126 int oparg = (encoded_op << 8) >> 20;
127 int cmparg = (encoded_op << 20) >> 20;
129 if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
132 if (! access_ok (VERIFY_WRITE, uaddr, sizeof(u32)))
151 case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break;
152 case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break;
153 case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break;
154 case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break;
155 case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break;
156 case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break;
157 default: ret = -ENOSYS;
164 futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
165 u32 oldval, u32 newval)
170 #endif /* CONFIG_SMP */