xref: /openbmc/linux/arch/sh/include/asm/futex.h (revision 80483c3a)
1 #ifndef __ASM_SH_FUTEX_H
2 #define __ASM_SH_FUTEX_H
3 
4 #ifdef __KERNEL__
5 
6 #include <linux/futex.h>
7 #include <linux/uaccess.h>
8 #include <asm/errno.h>
9 
10 #if !defined(CONFIG_SMP)
11 #include <asm/futex-irq.h>
12 #elif defined(CONFIG_CPU_J2)
13 #include <asm/futex-cas.h>
14 #elif defined(CONFIG_CPU_SH4A)
15 #include <asm/futex-llsc.h>
16 #else
17 #error SMP not supported on this configuration.
18 #endif
19 
20 static inline int
21 futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
22 			      u32 oldval, u32 newval)
23 {
24 	if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
25 		return -EFAULT;
26 
27 	return atomic_futex_op_cmpxchg_inatomic(uval, uaddr, oldval, newval);
28 }
29 
30 static inline int futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr)
31 {
32 	int op = (encoded_op >> 28) & 7;
33 	int cmp = (encoded_op >> 24) & 15;
34 	u32 oparg = (encoded_op << 8) >> 20;
35 	u32 cmparg = (encoded_op << 20) >> 20;
36 	u32 oldval, newval, prev;
37 	int ret;
38 
39 	if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
40 		oparg = 1 << oparg;
41 
42 	if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
43 		return -EFAULT;
44 
45 	pagefault_disable();
46 
47 	do {
48 		if (op == FUTEX_OP_SET)
49 			ret = oldval = 0;
50 		else
51 			ret = get_user(oldval, uaddr);
52 
53 		if (ret) break;
54 
55 		switch (op) {
56 		case FUTEX_OP_SET:
57 			newval = oparg;
58 			break;
59 		case FUTEX_OP_ADD:
60 			newval = oldval + oparg;
61 			break;
62 		case FUTEX_OP_OR:
63 			newval = oldval | oparg;
64 			break;
65 		case FUTEX_OP_ANDN:
66 			newval = oldval & ~oparg;
67 			break;
68 		case FUTEX_OP_XOR:
69 			newval = oldval ^ oparg;
70 			break;
71 		default:
72 			ret = -ENOSYS;
73 			break;
74 		}
75 
76 		if (ret) break;
77 
78 		ret = futex_atomic_cmpxchg_inatomic(&prev, uaddr, oldval, newval);
79 	} while (!ret && prev != oldval);
80 
81 	pagefault_enable();
82 
83 	if (!ret) {
84 		switch (cmp) {
85 		case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break;
86 		case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break;
87 		case FUTEX_OP_CMP_LT: ret = ((int)oldval < (int)cmparg); break;
88 		case FUTEX_OP_CMP_GE: ret = ((int)oldval >= (int)cmparg); break;
89 		case FUTEX_OP_CMP_LE: ret = ((int)oldval <= (int)cmparg); break;
90 		case FUTEX_OP_CMP_GT: ret = ((int)oldval > (int)cmparg); break;
91 		default: ret = -ENOSYS;
92 		}
93 	}
94 
95 	return ret;
96 }
97 
98 #endif /* __KERNEL__ */
99 #endif /* __ASM_SH_FUTEX_H */
100