xref: /openbmc/linux/arch/ia64/include/asm/futex.h (revision 4f3db074)
1 #ifndef _ASM_FUTEX_H
2 #define _ASM_FUTEX_H
3 
4 #include <linux/futex.h>
5 #include <linux/uaccess.h>
6 #include <asm/errno.h>
7 
8 #define __futex_atomic_op1(insn, ret, oldval, uaddr, oparg) \
9 do {									\
10 	register unsigned long r8 __asm ("r8") = 0;			\
11 	__asm__ __volatile__(						\
12 		"	mf;;					\n"	\
13 		"[1:] "	insn ";;				\n"	\
14 		"	.xdata4 \"__ex_table\", 1b-., 2f-.	\n"	\
15 		"[2:]"							\
16 		: "+r" (r8), "=r" (oldval)				\
17 		: "r" (uaddr), "r" (oparg)				\
18 		: "memory");						\
19 	ret = r8;							\
20 } while (0)
21 
22 #define __futex_atomic_op2(insn, ret, oldval, uaddr, oparg) \
23 do {									\
24 	register unsigned long r8 __asm ("r8") = 0;			\
25 	int val, newval;						\
26 	do {								\
27 		__asm__ __volatile__(					\
28 			"	mf;;				  \n"	\
29 			"[1:]	ld4 %3=[%4];;			  \n"	\
30 			"	mov %2=%3			  \n"	\
31 				insn	";;			  \n"	\
32 			"	mov ar.ccv=%2;;			  \n"	\
33 			"[2:]	cmpxchg4.acq %1=[%4],%3,ar.ccv;;  \n"	\
34 			"	.xdata4 \"__ex_table\", 1b-., 3f-.\n"	\
35 			"	.xdata4 \"__ex_table\", 2b-., 3f-.\n"	\
36 			"[3:]"						\
37 			: "+r" (r8), "=r" (val), "=&r" (oldval),	\
38 			   "=&r" (newval)				\
39 			: "r" (uaddr), "r" (oparg)			\
40 			: "memory");					\
41 		if (unlikely (r8))					\
42 			break;						\
43 	} while (unlikely (val != oldval));				\
44 	ret = r8;							\
45 } while (0)
46 
47 static inline int
48 futex_atomic_op_inuser (int encoded_op, u32 __user *uaddr)
49 {
50 	int op = (encoded_op >> 28) & 7;
51 	int cmp = (encoded_op >> 24) & 15;
52 	int oparg = (encoded_op << 8) >> 20;
53 	int cmparg = (encoded_op << 20) >> 20;
54 	int oldval = 0, ret;
55 	if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
56 		oparg = 1 << oparg;
57 
58 	if (! access_ok (VERIFY_WRITE, uaddr, sizeof(u32)))
59 		return -EFAULT;
60 
61 	pagefault_disable();
62 
63 	switch (op) {
64 	case FUTEX_OP_SET:
65 		__futex_atomic_op1("xchg4 %1=[%2],%3", ret, oldval, uaddr,
66 				   oparg);
67 		break;
68 	case FUTEX_OP_ADD:
69 		__futex_atomic_op2("add %3=%3,%5", ret, oldval, uaddr, oparg);
70 		break;
71 	case FUTEX_OP_OR:
72 		__futex_atomic_op2("or %3=%3,%5", ret, oldval, uaddr, oparg);
73 		break;
74 	case FUTEX_OP_ANDN:
75 		__futex_atomic_op2("and %3=%3,%5", ret, oldval, uaddr,
76 				   ~oparg);
77 		break;
78 	case FUTEX_OP_XOR:
79 		__futex_atomic_op2("xor %3=%3,%5", ret, oldval, uaddr, oparg);
80 		break;
81 	default:
82 		ret = -ENOSYS;
83 	}
84 
85 	pagefault_enable();
86 
87 	if (!ret) {
88 		switch (cmp) {
89 		case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break;
90 		case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break;
91 		case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break;
92 		case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break;
93 		case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break;
94 		case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break;
95 		default: ret = -ENOSYS;
96 		}
97 	}
98 	return ret;
99 }
100 
101 static inline int
102 futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
103 			      u32 oldval, u32 newval)
104 {
105 	if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
106 		return -EFAULT;
107 
108 	{
109 		register unsigned long r8 __asm ("r8") = 0;
110 		unsigned long prev;
111 		__asm__ __volatile__(
112 			"	mf;;					\n"
113 			"	mov ar.ccv=%4;;				\n"
114 			"[1:]	cmpxchg4.acq %1=[%2],%3,ar.ccv		\n"
115 			"	.xdata4 \"__ex_table\", 1b-., 2f-.	\n"
116 			"[2:]"
117 			: "+r" (r8), "=&r" (prev)
118 			: "r" (uaddr), "r" (newval),
119 			  "rO" ((long) (unsigned) oldval)
120 			: "memory");
121 		*uval = prev;
122 		return r8;
123 	}
124 }
125 
126 #endif /* _ASM_FUTEX_H */
127