xref: /openbmc/linux/arch/alpha/include/asm/futex.h (revision f3539c12)
1 #ifndef _ASM_ALPHA_FUTEX_H
2 #define _ASM_ALPHA_FUTEX_H
3 
4 #ifdef __KERNEL__
5 
6 #include <linux/futex.h>
7 #include <linux/uaccess.h>
8 #include <asm/errno.h>
9 #include <asm/barrier.h>
10 
11 #define __futex_atomic_op(insn, ret, oldval, uaddr, oparg)	\
12 	__asm__ __volatile__(					\
13 		__ASM_SMP_MB					\
14 	"1:	ldl_l	%0,0(%2)\n"				\
15 		insn						\
16 	"2:	stl_c	%1,0(%2)\n"				\
17 	"	beq	%1,4f\n"				\
18 	"	mov	$31,%1\n"				\
19 	"3:	.subsection 2\n"				\
20 	"4:	br	1b\n"					\
21 	"	.previous\n"					\
22 	"	.section __ex_table,\"a\"\n"			\
23 	"	.long	1b-.\n"					\
24 	"	lda	$31,3b-1b(%1)\n"			\
25 	"	.long	2b-.\n"					\
26 	"	lda	$31,3b-2b(%1)\n"			\
27 	"	.previous\n"					\
28 	:	"=&r" (oldval), "=&r"(ret)			\
29 	:	"r" (uaddr), "r"(oparg)				\
30 	:	"memory")
31 
32 static inline int futex_atomic_op_inuser (int encoded_op, u32 __user *uaddr)
33 {
34 	int op = (encoded_op >> 28) & 7;
35 	int cmp = (encoded_op >> 24) & 15;
36 	int oparg = (encoded_op << 8) >> 20;
37 	int cmparg = (encoded_op << 20) >> 20;
38 	int oldval = 0, ret;
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 	switch (op) {
48 	case FUTEX_OP_SET:
49 		__futex_atomic_op("mov %3,%1\n", ret, oldval, uaddr, oparg);
50 		break;
51 	case FUTEX_OP_ADD:
52 		__futex_atomic_op("addl %0,%3,%1\n", ret, oldval, uaddr, oparg);
53 		break;
54 	case FUTEX_OP_OR:
55 		__futex_atomic_op("or %0,%3,%1\n", ret, oldval, uaddr, oparg);
56 		break;
57 	case FUTEX_OP_ANDN:
58 		__futex_atomic_op("andnot %0,%3,%1\n", ret, oldval, uaddr, oparg);
59 		break;
60 	case FUTEX_OP_XOR:
61 		__futex_atomic_op("xor %0,%3,%1\n", ret, oldval, uaddr, oparg);
62 		break;
63 	default:
64 		ret = -ENOSYS;
65 	}
66 
67 	pagefault_enable();
68 
69 	if (!ret) {
70 		switch (cmp) {
71 		case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break;
72 		case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break;
73 		case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break;
74 		case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break;
75 		case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break;
76 		case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break;
77 		default: ret = -ENOSYS;
78 		}
79 	}
80 	return ret;
81 }
82 
83 static inline int
84 futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
85 			      u32 oldval, u32 newval)
86 {
87 	int ret = 0, cmp;
88 	u32 prev;
89 
90 	if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
91 		return -EFAULT;
92 
93 	__asm__ __volatile__ (
94 		__ASM_SMP_MB
95 	"1:	ldl_l	%1,0(%3)\n"
96 	"	cmpeq	%1,%4,%2\n"
97 	"	beq	%2,3f\n"
98 	"	mov	%5,%2\n"
99 	"2:	stl_c	%2,0(%3)\n"
100 	"	beq	%2,4f\n"
101 	"3:	.subsection 2\n"
102 	"4:	br	1b\n"
103 	"	.previous\n"
104 	"	.section __ex_table,\"a\"\n"
105 	"	.long	1b-.\n"
106 	"	lda	$31,3b-1b(%0)\n"
107 	"	.long	2b-.\n"
108 	"	lda	$31,3b-2b(%0)\n"
109 	"	.previous\n"
110 	:	"+r"(ret), "=&r"(prev), "=&r"(cmp)
111 	:	"r"(uaddr), "r"((long)(int)oldval), "r"(newval)
112 	:	"memory");
113 
114 	*uval = prev;
115 	return ret;
116 }
117 
118 #endif /* __KERNEL__ */
119 #endif /* _ASM_ALPHA_FUTEX_H */
120