1
2
3
4
5#ifndef __ASM_FUTEX_H
6#define __ASM_FUTEX_H
7
8#include <linux/futex.h>
9#include <linux/uaccess.h>
10
11#include <asm/errno.h>
12
13#define FUTEX_MAX_LOOPS 128
14
15#define __futex_atomic_op(insn, ret, oldval, uaddr, tmp, oparg) \
16do { \
17 unsigned int loops = FUTEX_MAX_LOOPS; \
18 \
19 uaccess_enable_privileged(); \
20 asm volatile( \
21" prfm pstl1strm, %2\n" \
22"1: ldxr %w1, %2\n" \
23 insn "\n" \
24"2: stlxr %w0, %w3, %2\n" \
25" cbz %w0, 3f\n" \
26" sub %w4, %w4, %w0\n" \
27" cbnz %w4, 1b\n" \
28" mov %w0, %w7\n" \
29"3:\n" \
30" dmb ish\n" \
31" .pushsection .fixup,\"ax\"\n" \
32" .align 2\n" \
33"4: mov %w0, %w6\n" \
34" b 3b\n" \
35" .popsection\n" \
36 _ASM_EXTABLE(1b, 4b) \
37 _ASM_EXTABLE(2b, 4b) \
38 : "=&r" (ret), "=&r" (oldval), "+Q" (*uaddr), "=&r" (tmp), \
39 "+r" (loops) \
40 : "r" (oparg), "Ir" (-EFAULT), "Ir" (-EAGAIN) \
41 : "memory"); \
42 uaccess_disable_privileged(); \
43} while (0)
44
45static inline int
46arch_futex_atomic_op_inuser(int op, int oparg, int *oval, u32 __user *_uaddr)
47{
48 int oldval = 0, ret, tmp;
49 u32 __user *uaddr = __uaccess_mask_ptr(_uaddr);
50
51 if (!access_ok(_uaddr, sizeof(u32)))
52 return -EFAULT;
53
54 switch (op) {
55 case FUTEX_OP_SET:
56 __futex_atomic_op("mov %w3, %w5",
57 ret, oldval, uaddr, tmp, oparg);
58 break;
59 case FUTEX_OP_ADD:
60 __futex_atomic_op("add %w3, %w1, %w5",
61 ret, oldval, uaddr, tmp, oparg);
62 break;
63 case FUTEX_OP_OR:
64 __futex_atomic_op("orr %w3, %w1, %w5",
65 ret, oldval, uaddr, tmp, oparg);
66 break;
67 case FUTEX_OP_ANDN:
68 __futex_atomic_op("and %w3, %w1, %w5",
69 ret, oldval, uaddr, tmp, ~oparg);
70 break;
71 case FUTEX_OP_XOR:
72 __futex_atomic_op("eor %w3, %w1, %w5",
73 ret, oldval, uaddr, tmp, oparg);
74 break;
75 default:
76 ret = -ENOSYS;
77 }
78
79 if (!ret)
80 *oval = oldval;
81
82 return ret;
83}
84
85static inline int
86futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *_uaddr,
87 u32 oldval, u32 newval)
88{
89 int ret = 0;
90 unsigned int loops = FUTEX_MAX_LOOPS;
91 u32 val, tmp;
92 u32 __user *uaddr;
93
94 if (!access_ok(_uaddr, sizeof(u32)))
95 return -EFAULT;
96
97 uaddr = __uaccess_mask_ptr(_uaddr);
98 uaccess_enable_privileged();
99 asm volatile("// futex_atomic_cmpxchg_inatomic\n"
100" prfm pstl1strm, %2\n"
101"1: ldxr %w1, %2\n"
102" sub %w3, %w1, %w5\n"
103" cbnz %w3, 4f\n"
104"2: stlxr %w3, %w6, %2\n"
105" cbz %w3, 3f\n"
106" sub %w4, %w4, %w3\n"
107" cbnz %w4, 1b\n"
108" mov %w0, %w8\n"
109"3:\n"
110" dmb ish\n"
111"4:\n"
112" .pushsection .fixup,\"ax\"\n"
113"5: mov %w0, %w7\n"
114" b 4b\n"
115" .popsection\n"
116 _ASM_EXTABLE(1b, 5b)
117 _ASM_EXTABLE(2b, 5b)
118 : "+r" (ret), "=&r" (val), "+Q" (*uaddr), "=&r" (tmp), "+r" (loops)
119 : "r" (oldval), "r" (newval), "Ir" (-EFAULT), "Ir" (-EAGAIN)
120 : "memory");
121 uaccess_disable_privileged();
122
123 if (!ret)
124 *uval = val;
125
126 return ret;
127}
128
129#endif
130
