xref: /openbmc/linux/arch/sh/include/asm/futex.h (revision feac8c8b)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef __ASM_SH_FUTEX_H
3 #define __ASM_SH_FUTEX_H
4 
5 #ifdef __KERNEL__
6 
7 #include <linux/futex.h>
8 #include <linux/uaccess.h>
9 #include <asm/errno.h>
10 
11 #if !defined(CONFIG_SMP)
12 #include <asm/futex-irq.h>
13 #elif defined(CONFIG_CPU_J2)
14 #include <asm/futex-cas.h>
15 #elif defined(CONFIG_CPU_SH4A)
16 #include <asm/futex-llsc.h>
17 #else
18 #error SMP not supported on this configuration.
19 #endif
20 
21 static inline int
22 futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
23 			      u32 oldval, u32 newval)
24 {
25 	if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
26 		return -EFAULT;
27 
28 	return atomic_futex_op_cmpxchg_inatomic(uval, uaddr, oldval, newval);
29 }
30 
31 static inline int arch_futex_atomic_op_inuser(int op, u32 oparg, int *oval,
32 		u32 __user *uaddr)
33 {
34 	u32 oldval, newval, prev;
35 	int ret;
36 
37 	pagefault_disable();
38 
39 	do {
40 		if (op == FUTEX_OP_SET)
41 			ret = oldval = 0;
42 		else
43 			ret = get_user(oldval, uaddr);
44 
45 		if (ret) break;
46 
47 		switch (op) {
48 		case FUTEX_OP_SET:
49 			newval = oparg;
50 			break;
51 		case FUTEX_OP_ADD:
52 			newval = oldval + oparg;
53 			break;
54 		case FUTEX_OP_OR:
55 			newval = oldval | oparg;
56 			break;
57 		case FUTEX_OP_ANDN:
58 			newval = oldval & ~oparg;
59 			break;
60 		case FUTEX_OP_XOR:
61 			newval = oldval ^ oparg;
62 			break;
63 		default:
64 			ret = -ENOSYS;
65 			break;
66 		}
67 
68 		if (ret) break;
69 
70 		ret = futex_atomic_cmpxchg_inatomic(&prev, uaddr, oldval, newval);
71 	} while (!ret && prev != oldval);
72 
73 	pagefault_enable();
74 
75 	if (!ret)
76 		*oval = oldval;
77 
78 	return ret;
79 }
80 
81 #endif /* __KERNEL__ */
82 #endif /* __ASM_SH_FUTEX_H */
83