2 * Copyright (C) 2012 ARM Ltd.
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
13 * You should have received a copy of the GNU General Public License
14 * along with this program. If not, see <http://www.gnu.org/licenses/>.
21 #include <linux/futex.h>
22 #include <linux/uaccess.h>
23 #include <asm/errno.h>
25 #define __futex_atomic_op(insn, ret, oldval, uaddr, tmp, oparg) \
27 "1: ldaxr %w1, %2\n" \
29 "2: stlxr %w3, %w0, %2\n" \
32 " .pushsection .fixup,\"ax\"\n" \
37 " .pushsection __ex_table,\"a\"\n" \
39 " .quad 1b, 4b, 2b, 4b\n" \
41 : "=&r" (ret), "=&r" (oldval), "+Q" (*uaddr), "=&r" (tmp) \
42 : "r" (oparg), "Ir" (-EFAULT) \
46 futex_atomic_op_inuser (int encoded_op
, u32 __user
*uaddr
)
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
, tmp
;
54 if (encoded_op
& (FUTEX_OP_OPARG_SHIFT
<< 28))
57 if (!access_ok(VERIFY_WRITE
, uaddr
, sizeof(u32
)))
60 pagefault_disable(); /* implies preempt_disable() */
64 __futex_atomic_op("mov %w0, %w4",
65 ret
, oldval
, uaddr
, tmp
, oparg
);
68 __futex_atomic_op("add %w0, %w1, %w4",
69 ret
, oldval
, uaddr
, tmp
, oparg
);
72 __futex_atomic_op("orr %w0, %w1, %w4",
73 ret
, oldval
, uaddr
, tmp
, oparg
);
76 __futex_atomic_op("and %w0, %w1, %w4",
77 ret
, oldval
, uaddr
, tmp
, ~oparg
);
80 __futex_atomic_op("eor %w0, %w1, %w4",
81 ret
, oldval
, uaddr
, tmp
, oparg
);
87 pagefault_enable(); /* subsumes preempt_enable() */
91 case FUTEX_OP_CMP_EQ
: ret
= (oldval
== cmparg
); break;
92 case FUTEX_OP_CMP_NE
: ret
= (oldval
!= cmparg
); break;
93 case FUTEX_OP_CMP_LT
: ret
= (oldval
< cmparg
); break;
94 case FUTEX_OP_CMP_GE
: ret
= (oldval
>= cmparg
); break;
95 case FUTEX_OP_CMP_LE
: ret
= (oldval
<= cmparg
); break;
96 case FUTEX_OP_CMP_GT
: ret
= (oldval
> cmparg
); break;
97 default: ret
= -ENOSYS
;
104 futex_atomic_cmpxchg_inatomic(u32
*uval
, u32 __user
*uaddr
,
105 u32 oldval
, u32 newval
)
110 if (!access_ok(VERIFY_WRITE
, uaddr
, sizeof(u32
)))
113 asm volatile("// futex_atomic_cmpxchg_inatomic\n"
115 " sub %w3, %w1, %w4\n"
117 "2: stlxr %w3, %w5, %2\n"
120 " .pushsection .fixup,\"ax\"\n"
124 " .pushsection __ex_table,\"a\"\n"
126 " .quad 1b, 4b, 2b, 4b\n"
128 : "+r" (ret
), "=&r" (val
), "+Q" (*uaddr
), "=&r" (tmp
)
129 : "r" (oldval
), "r" (newval
), "Ir" (-EFAULT
)
136 #endif /* __KERNEL__ */
137 #endif /* __ASM_FUTEX_H */
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