1 /*
2 * Atomic futex routines
3 *
4 * Based on the PowerPC implementataion
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 * Copyright (C) 2013 TangoTec Ltd.
11 *
12 * Baruch Siach <baruch@tkos.co.il>
13 */
14
15 #ifndef _ASM_XTENSA_FUTEX_H
16 #define _ASM_XTENSA_FUTEX_H
17
18 #ifdef __KERNEL__
19
20 #include <linux/futex.h>
21 #include <linux/uaccess.h>
22 #include <linux/errno.h>
23
24 #define __futex_atomic_op(insn, ret, oldval, uaddr, oparg) \
25 __asm__ __volatile( \
26 "1: l32i %0, %2, 0\n" \
27 insn "\n" \
28 " wsr %0, scompare1\n" \
29 "2: s32c1i %1, %2, 0\n" \
30 " bne %1, %0, 1b\n" \
31 " movi %1, 0\n" \
32 "3:\n" \
33 " .section .fixup,\"ax\"\n" \
34 " .align 4\n" \
35 "4: .long 3b\n" \
36 "5: l32r %0, 4b\n" \
37 " movi %1, %3\n" \
38 " jx %0\n" \
39 " .previous\n" \
40 " .section __ex_table,\"a\"\n" \
41 " .long 1b,5b,2b,5b\n" \
42 " .previous\n" \
43 : "=&r" (oldval), "=&r" (ret) \
44 : "r" (uaddr), "I" (-EFAULT), "r" (oparg) \
45 : "memory")
46
arch_futex_atomic_op_inuser(int op,int oparg,int * oval,u32 __user * uaddr)47 static inline int arch_futex_atomic_op_inuser(int op, int oparg, int *oval,
48 u32 __user *uaddr)
49 {
50 int oldval = 0, ret;
51
52 #if !XCHAL_HAVE_S32C1I
53 return -ENOSYS;
54 #endif
55
56 pagefault_disable();
57
58 switch (op) {
59 case FUTEX_OP_SET:
60 __futex_atomic_op("mov %1, %4", ret, oldval, uaddr, oparg);
61 break;
62 case FUTEX_OP_ADD:
63 __futex_atomic_op("add %1, %0, %4", ret, oldval, uaddr,
64 oparg);
65 break;
66 case FUTEX_OP_OR:
67 __futex_atomic_op("or %1, %0, %4", ret, oldval, uaddr,
68 oparg);
69 break;
70 case FUTEX_OP_ANDN:
71 __futex_atomic_op("and %1, %0, %4", ret, oldval, uaddr,
72 ~oparg);
73 break;
74 case FUTEX_OP_XOR:
75 __futex_atomic_op("xor %1, %0, %4", ret, oldval, uaddr,
76 oparg);
77 break;
78 default:
79 ret = -ENOSYS;
80 }
81
82 pagefault_enable();
83
84 if (!ret)
85 *oval = oldval;
86
87 return ret;
88 }
89
90 static inline int
futex_atomic_cmpxchg_inatomic(u32 * uval,u32 __user * uaddr,u32 oldval,u32 newval)91 futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
92 u32 oldval, u32 newval)
93 {
94 int ret = 0;
95
96 if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
97 return -EFAULT;
98
99 #if !XCHAL_HAVE_S32C1I
100 return -ENOSYS;
101 #endif
102
103 __asm__ __volatile__ (
104 " # futex_atomic_cmpxchg_inatomic\n"
105 " wsr %5, scompare1\n"
106 "1: s32c1i %1, %4, 0\n"
107 " s32i %1, %6, 0\n"
108 "2:\n"
109 " .section .fixup,\"ax\"\n"
110 " .align 4\n"
111 "3: .long 2b\n"
112 "4: l32r %1, 3b\n"
113 " movi %0, %7\n"
114 " jx %1\n"
115 " .previous\n"
116 " .section __ex_table,\"a\"\n"
117 " .long 1b,4b\n"
118 " .previous\n"
119 : "+r" (ret), "+r" (newval), "+m" (*uaddr), "+m" (*uval)
120 : "r" (uaddr), "r" (oldval), "r" (uval), "I" (-EFAULT)
121 : "memory");
122
123 return ret;
124 }
125
126 #endif /* __KERNEL__ */
127 #endif /* _ASM_XTENSA_FUTEX_H */
128