1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _ASM_HEXAGON_FUTEX_H
3 #define _ASM_HEXAGON_FUTEX_H
4 
5 #ifdef __KERNEL__
6 
7 #include <linux/futex.h>
8 #include <linux/uaccess.h>
9 #include <asm/errno.h>
10 
11 /* XXX TODO-- need to add sync barriers! */
12 
13 #define __futex_atomic_op(insn, ret, oldval, uaddr, oparg) \
14 	__asm__ __volatile( \
15 	"1: %0 = memw_locked(%3);\n" \
16 	    /* For example: %1 = %4 */ \
17 	    insn \
18 	"2: memw_locked(%3,p2) = %1;\n" \
19 	"   if (!p2) jump 1b;\n" \
20 	"   %1 = #0;\n" \
21 	"3:\n" \
22 	".section .fixup,\"ax\"\n" \
23 	"4: %1 = #%5;\n" \
24 	"   jump ##3b\n" \
25 	".previous\n" \
26 	".section __ex_table,\"a\"\n" \
27 	".long 1b,4b,2b,4b\n" \
28 	".previous\n" \
29 	: "=&r" (oldval), "=&r" (ret), "+m" (*uaddr) \
30 	: "r" (uaddr), "r" (oparg), "i" (-EFAULT) \
31 	: "p2", "memory")
32 
33 
34 static inline int
arch_futex_atomic_op_inuser(int op,int oparg,int * oval,u32 __user * uaddr)35 arch_futex_atomic_op_inuser(int op, int oparg, int *oval, u32 __user *uaddr)
36 {
37 	int oldval = 0, ret;
38 
39 	if (!access_ok(uaddr, sizeof(u32)))
40 		return -EFAULT;
41 
42 	switch (op) {
43 	case FUTEX_OP_SET:
44 		__futex_atomic_op("%1 = %4\n", ret, oldval, uaddr, oparg);
45 		break;
46 	case FUTEX_OP_ADD:
47 		__futex_atomic_op("%1 = add(%0,%4)\n", ret, oldval, uaddr,
48 				  oparg);
49 		break;
50 	case FUTEX_OP_OR:
51 		__futex_atomic_op("%1 = or(%0,%4)\n", ret, oldval, uaddr,
52 				  oparg);
53 		break;
54 	case FUTEX_OP_ANDN:
55 		__futex_atomic_op("%1 = not(%4); %1 = and(%0,%1)\n", ret,
56 				  oldval, uaddr, oparg);
57 		break;
58 	case FUTEX_OP_XOR:
59 		__futex_atomic_op("%1 = xor(%0,%4)\n", ret, oldval, uaddr,
60 				  oparg);
61 		break;
62 	default:
63 		ret = -ENOSYS;
64 	}
65 
66 	if (!ret)
67 		*oval = oldval;
68 
69 	return ret;
70 }
71 
72 static inline int
futex_atomic_cmpxchg_inatomic(u32 * uval,u32 __user * uaddr,u32 oldval,u32 newval)73 futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, u32 oldval,
74 			      u32 newval)
75 {
76 	int prev;
77 	int ret;
78 
79 	if (!access_ok(uaddr, sizeof(u32)))
80 		return -EFAULT;
81 
82 	__asm__ __volatile__ (
83 	"1: %1 = memw_locked(%3)\n"
84 	"   {\n"
85 	"      p2 = cmp.eq(%1,%4)\n"
86 	"      if (!p2.new) jump:NT 3f\n"
87 	"   }\n"
88 	"2: memw_locked(%3,p2) = %5\n"
89 	"   if (!p2) jump 1b\n"
90 	"3:\n"
91 	".section .fixup,\"ax\"\n"
92 	"4: %0 = #%6\n"
93 	"   jump ##3b\n"
94 	".previous\n"
95 	".section __ex_table,\"a\"\n"
96 	".long 1b,4b,2b,4b\n"
97 	".previous\n"
98 	: "+r" (ret), "=&r" (prev), "+m" (*uaddr)
99 	: "r" (uaddr), "r" (oldval), "r" (newval), "i"(-EFAULT)
100 	: "p2", "memory");
101 
102 	*uval = prev;
103 	return ret;
104 }
105 
106 #endif /* __KERNEL__ */
107 #endif /* _ASM_HEXAGON_FUTEX_H */
108