aboutsummaryrefslogtreecommitdiff
path: root/include/asm-i386/percpu.h
blob: f54830b5d5ac299c38c496e65ed17d699c8c895f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
#ifndef __ARCH_I386_PERCPU__
#define __ARCH_I386_PERCPU__

#ifdef __ASSEMBLY__

/*
 * PER_CPU finds an address of a per-cpu variable.
 *
 * Args:
 *    var - variable name
 *    reg - 32bit register
 *
 * The resulting address is stored in the "reg" argument.
 *
 * Example:
 *    PER_CPU(cpu_gdt_descr, %ebx)
 */
#ifdef CONFIG_SMP
#define PER_CPU(var, reg)				\
	movl %fs:per_cpu__##this_cpu_off, reg;		\
	lea per_cpu__##var(reg), reg
#define PER_CPU_VAR(var)	%fs:per_cpu__##var
#else /* ! SMP */
#define PER_CPU(var, reg)			\
	movl $per_cpu__##var, reg
#define PER_CPU_VAR(var)	per_cpu__##var
#endif	/* SMP */

#else /* ...!ASSEMBLY */

/*
 * PER_CPU finds an address of a per-cpu variable.
 *
 * Args:
 *    var - variable name
 *    cpu - 32bit register containing the current CPU number
 *
 * The resulting address is stored in the "cpu" argument.
 *
 * Example:
 *    PER_CPU(cpu_gdt_descr, %ebx)
 */
#ifdef CONFIG_SMP
/* Same as generic implementation except for optimized local access. */
#define __GENERIC_PER_CPU

/* This is used for other cpus to find our section. */
extern unsigned long __per_cpu_offset[];

#define per_cpu_offset(x) (__per_cpu_offset[x])

/* Separate out the type, so (int[3], foo) works. */
#define DECLARE_PER_CPU(type, name) extern __typeof__(type) per_cpu__##name
#define DEFINE_PER_CPU(type, name) \
    __attribute__((__section__(".data.percpu"))) __typeof__(type) per_cpu__##name

/* We can use this directly for local CPU (faster). */
DECLARE_PER_CPU(unsigned long, this_cpu_off);

/* var is in discarded region: offset to particular copy we want */
#define per_cpu(var, cpu) (*({				\
	extern int simple_indentifier_##var(void);	\
	RELOC_HIDE(&per_cpu__##var, __per_cpu_offset[cpu]); }))

#define __raw_get_cpu_var(var) (*({					\
	extern int simple_indentifier_##var(void);			\
	RELOC_HIDE(&per_cpu__##var, x86_read_percpu(this_cpu_off));	\
}))

#define __get_cpu_var(var) __raw_get_cpu_var(var)

/* A macro to avoid #include hell... */
#define percpu_modcopy(pcpudst, src, size)			\
do {								\
	unsigned int __i;					\
	for_each_possible_cpu(__i)				\
		memcpy((pcpudst)+__per_cpu_offset[__i],		\
		       (src), (size));				\
} while (0)

#define EXPORT_PER_CPU_SYMBOL(var) EXPORT_SYMBOL(per_cpu__##var)
#define EXPORT_PER_CPU_SYMBOL_GPL(var) EXPORT_SYMBOL_GPL(per_cpu__##var)

/* fs segment starts at (positive) offset == __per_cpu_offset[cpu] */
#define __percpu_seg "%%fs:"
#else  /* !SMP */
#include <asm-generic/percpu.h>
#define __percpu_seg ""
#endif	/* SMP */

/* For arch-specific code, we can use direct single-insn ops (they
 * don't give an lvalue though). */
extern void __bad_percpu_size(void);

#define percpu_to_op(op,var,val)				\
	do {							\
		typedef typeof(var) T__;			\
		if (0) { T__ tmp__; tmp__ = (val); }		\
		switch (sizeof(var)) {				\
		case 1:						\
			asm(op "b %1,"__percpu_seg"%0"		\
			    : "+m" (var)			\
			    :"ri" ((T__)val));			\
			break;					\
		case 2:						\
			asm(op "w %1,"__percpu_seg"%0"		\
			    : "+m" (var)			\
			    :"ri" ((T__)val));			\
			break;					\
		case 4:						\
			asm(op "l %1,"__percpu_seg"%0"		\
			    : "+m" (var)			\
			    :"ri" ((T__)val));			\
			break;					\
		default: __bad_percpu_size();			\
		}						\
	} while (0)

#define percpu_from_op(op,var)					\
	({							\
		typeof(var) ret__;				\
		switch (sizeof(var)) {				\
		case 1:						\
			asm(op "b "__percpu_seg"%1,%0"		\
			    : "=r" (ret__)			\
			    : "m" (var));			\
			break;					\
		case 2:						\
			asm(op "w "__percpu_seg"%1,%0"		\
			    : "=r" (ret__)			\
			    : "m" (var));			\
			break;					\
		case 4:						\
			asm(op "l "__percpu_seg"%1,%0"		\
			    : "=r" (ret__)			\
			    : "m" (var));			\
			break;					\
		default: __bad_percpu_size();			\
		}						\
		ret__; })

#define x86_read_percpu(var) percpu_from_op("mov", per_cpu__##var)
#define x86_write_percpu(var,val) percpu_to_op("mov", per_cpu__##var, val)
#define x86_add_percpu(var,val) percpu_to_op("add", per_cpu__##var, val)
#define x86_sub_percpu(var,val) percpu_to_op("sub", per_cpu__##var, val)
#define x86_or_percpu(var,val) percpu_to_op("or", per_cpu__##var, val)
#endif /* !__ASSEMBLY__ */

#endif /* __ARCH_I386_PERCPU__ */