1#ifndef _ASM_X86_FUTEX_H
2#define _ASM_X86_FUTEX_H
3
4#ifdef __KERNEL__
5
6#include <linux/futex.h>
7#include <linux/uaccess.h>
8
9#include <asm/asm.h>
10#include <asm/errno.h>
11#include <asm/processor.h>
12
13#define __futex_atomic_op1(insn, ret, oldval, uaddr, oparg)	\
14	asm volatile("1:\t" insn "\n"				\
15		     "2:\t.section .fixup,\"ax\"\n"		\
16		     "3:\tmov\t%3, %1\n"			\
17		     "\tjmp\t2b\n"				\
18		     "\t.previous\n"				\
19		     _ASM_EXTABLE(1b, 3b)			\
20		     : "=r" (oldval), "=r" (ret), "+m" (*uaddr)	\
21		     : "i" (-EFAULT), "0" (oparg), "1" (0))
22
23#define __futex_atomic_op2(insn, ret, oldval, uaddr, oparg)	\
24	asm volatile("1:\tmovl	%2, %0\n"			\
25		     "\tmovl\t%0, %3\n"				\
26		     "\t" insn "\n"				\
27		     "2:\t" LOCK_PREFIX "cmpxchgl %3, %2\n"	\
28		     "\tjnz\t1b\n"				\
29		     "3:\t.section .fixup,\"ax\"\n"		\
30		     "4:\tmov\t%5, %1\n"			\
31		     "\tjmp\t3b\n"				\
32		     "\t.previous\n"				\
33		     _ASM_EXTABLE(1b, 4b)			\
34		     _ASM_EXTABLE(2b, 4b)			\
35		     : "=&a" (oldval), "=&r" (ret),		\
36		       "+m" (*uaddr), "=&r" (tem)		\
37		     : "r" (oparg), "i" (-EFAULT), "1" (0))
38
39static inline int futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr)
40{
41	int op = (encoded_op >> 28) & 7;
42	int cmp = (encoded_op >> 24) & 15;
43	int oparg = (encoded_op << 8) >> 20;
44	int cmparg = (encoded_op << 20) >> 20;
45	int oldval = 0, ret, tem;
46
47	if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
48		oparg = 1 << oparg;
49
50	if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
51		return -EFAULT;
52
53#if defined(CONFIG_X86_32) && !defined(CONFIG_X86_BSWAP)
54	/* Real i386 machines can only support FUTEX_OP_SET */
55	if (op != FUTEX_OP_SET && boot_cpu_data.x86 == 3)
56		return -ENOSYS;
57#endif
58
59	pagefault_disable();
60
61	switch (op) {
62	case FUTEX_OP_SET:
63		__futex_atomic_op1("xchgl %0, %2", ret, oldval, uaddr, oparg);
64		break;
65	case FUTEX_OP_ADD:
66		__futex_atomic_op1(LOCK_PREFIX "xaddl %0, %2", ret, oldval,
67				   uaddr, oparg);
68		break;
69	case FUTEX_OP_OR:
70		__futex_atomic_op2("orl %4, %3", ret, oldval, uaddr, oparg);
71		break;
72	case FUTEX_OP_ANDN:
73		__futex_atomic_op2("andl %4, %3", ret, oldval, uaddr, ~oparg);
74		break;
75	case FUTEX_OP_XOR:
76		__futex_atomic_op2("xorl %4, %3", ret, oldval, uaddr, oparg);
77		break;
78	default:
79		ret = -ENOSYS;
80	}
81
82	pagefault_enable();
83
84	if (!ret) {
85		switch (cmp) {
86		case FUTEX_OP_CMP_EQ:
87			ret = (oldval == cmparg);
88			break;
89		case FUTEX_OP_CMP_NE:
90			ret = (oldval != cmparg);
91			break;
92		case FUTEX_OP_CMP_LT:
93			ret = (oldval < cmparg);
94			break;
95		case FUTEX_OP_CMP_GE:
96			ret = (oldval >= cmparg);
97			break;
98		case FUTEX_OP_CMP_LE:
99			ret = (oldval <= cmparg);
100			break;
101		case FUTEX_OP_CMP_GT:
102			ret = (oldval > cmparg);
103			break;
104		default:
105			ret = -ENOSYS;
106		}
107	}
108	return ret;
109}
110
111static inline int futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
112						u32 oldval, u32 newval)
113{
114	int ret = 0;
115
116#if defined(CONFIG_X86_32) && !defined(CONFIG_X86_BSWAP)
117	/* Real i386 machines have no cmpxchg instruction */
118	if (boot_cpu_data.x86 == 3)
119		return -ENOSYS;
120#endif
121
122	if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
123		return -EFAULT;
124
125	asm volatile("1:\t" LOCK_PREFIX "cmpxchgl %4, %2\n"
126		     "2:\t.section .fixup, \"ax\"\n"
127		     "3:\tmov     %3, %0\n"
128		     "\tjmp     2b\n"
129		     "\t.previous\n"
130		     _ASM_EXTABLE(1b, 3b)
131		     : "+r" (ret), "=a" (oldval), "+m" (*uaddr)
132		     : "i" (-EFAULT), "r" (newval), "1" (oldval)
133		     : "memory"
134	);
135
136	*uval = oldval;
137	return ret;
138}
139
140#endif
141#endif /* _ASM_X86_FUTEX_H */
142