tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1#ifndef _ASM_FUTEX_H
2#define _ASM_FUTEX_H
3
4#ifdef __KERNEL__
5
6#include <linux/futex.h>
7#include <asm/errno.h>
8#include <asm/system.h>
9#include <asm/processor.h>
10#include <asm/uaccess.h>
11
12#define __futex_atomic_op1(insn, ret, oldval, uaddr, oparg) \
13 __asm__ __volatile ( \
14"1: " insn "\n" \
15"2: .section .fixup,\"ax\"\n\
163: mov %3, %1\n\
17 jmp 2b\n\
18 .previous\n\
19 .section __ex_table,\"a\"\n\
20 .align 8\n\
21 .long 1b,3b\n\
22 .previous" \
23 : "=r" (oldval), "=r" (ret), "+m" (*uaddr) \
24 : "i" (-EFAULT), "0" (oparg), "1" (0))
25
26#define __futex_atomic_op2(insn, ret, oldval, uaddr, oparg) \
27 __asm__ __volatile ( \
28"1: movl %2, %0\n\
29 movl %0, %3\n" \
30 insn "\n" \
31"2: " LOCK_PREFIX "cmpxchgl %3, %2\n\
32 jnz 1b\n\
333: .section .fixup,\"ax\"\n\
344: mov %5, %1\n\
35 jmp 3b\n\
36 .previous\n\
37 .section __ex_table,\"a\"\n\
38 .align 8\n\
39 .long 1b,4b,2b,4b\n\
40 .previous" \
41 : "=&a" (oldval), "=&r" (ret), "+m" (*uaddr), \
42 "=&r" (tem) \
43 : "r" (oparg), "i" (-EFAULT), "1" (0))
44
45static inline int
46futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
47{
48 int op = (encoded_op >> 28) & 7;
49 int cmp = (encoded_op >> 24) & 15;
50 int oparg = (encoded_op << 8) >> 20;
51 int cmparg = (encoded_op << 20) >> 20;
52 int oldval = 0, ret, tem;
53 if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
54 oparg = 1 << oparg;
55
56 if (! access_ok (VERIFY_WRITE, uaddr, sizeof(int)))
57 return -EFAULT;
58
59 pagefault_disable();
60
61 if (op == FUTEX_OP_SET)
62 __futex_atomic_op1("xchgl %0, %2", ret, oldval, uaddr, oparg);
63 else {
64#ifndef CONFIG_X86_BSWAP
65 if (boot_cpu_data.x86 == 3)
66 ret = -ENOSYS;
67 else
68#endif
69 switch (op) {
70 case FUTEX_OP_ADD:
71 __futex_atomic_op1(LOCK_PREFIX "xaddl %0, %2", ret,
72 oldval, uaddr, oparg);
73 break;
74 case FUTEX_OP_OR:
75 __futex_atomic_op2("orl %4, %3", ret, oldval, uaddr,
76 oparg);
77 break;
78 case FUTEX_OP_ANDN:
79 __futex_atomic_op2("andl %4, %3", ret, oldval, uaddr,
80 ~oparg);
81 break;
82 case FUTEX_OP_XOR:
83 __futex_atomic_op2("xorl %4, %3", ret, oldval, uaddr,
84 oparg);
85 break;
86 default:
87 ret = -ENOSYS;
88 }
89 }
90
91 pagefault_enable();
92
93 if (!ret) {
94 switch (cmp) {
95 case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break;
96 case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break;
97 case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break;
98 case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break;
99 case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break;
100 case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break;
101 default: ret = -ENOSYS;
102 }
103 }
104 return ret;
105}
106
107static inline int
108futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, int newval)
109{
110 if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
111 return -EFAULT;
112
113 __asm__ __volatile__(
114 "1: " LOCK_PREFIX "cmpxchgl %3, %1 \n"
115
116 "2: .section .fixup, \"ax\" \n"
117 "3: mov %2, %0 \n"
118 " jmp 2b \n"
119 " .previous \n"
120
121 " .section __ex_table, \"a\" \n"
122 " .align 8 \n"
123 " .long 1b,3b \n"
124 " .previous \n"
125
126 : "=a" (oldval), "+m" (*uaddr)
127 : "i" (-EFAULT), "r" (newval), "0" (oldval)
128 : "memory"
129 );
130
131 return oldval;
132}
133
134#endif
135#endif