percpu.h revision 9939ddaff52787b2a7c1adf1b2afc95421aa0884 
1#ifndef _ASM_X86_PERCPU_H
2#define _ASM_X86_PERCPU_H
3
4#ifdef CONFIG_X86_64
5#define __percpu_seg		gs
6#define __percpu_mov_op		movq
7#else
8#define __percpu_seg		fs
9#define __percpu_mov_op		movl
10#endif
11
12#ifdef __ASSEMBLY__
13
14/*
15 * PER_CPU finds an address of a per-cpu variable.
16 *
17 * Args:
18 *    var - variable name
19 *    reg - 32bit register
20 *
21 * The resulting address is stored in the "reg" argument.
22 *
23 * Example:
24 *    PER_CPU(cpu_gdt_descr, %ebx)
25 */
26#ifdef CONFIG_SMP
27#define PER_CPU(var, reg)						\
28	__percpu_mov_op %__percpu_seg:per_cpu__this_cpu_off, reg;	\
29	lea per_cpu__##var(reg), reg
30#define PER_CPU_VAR(var)	%__percpu_seg:per_cpu__##var
31#else /* ! SMP */
32#define PER_CPU(var, reg)						\
33	__percpu_mov_op $per_cpu__##var, reg
34#define PER_CPU_VAR(var)	per_cpu__##var
35#endif	/* SMP */
36
37#else /* ...!ASSEMBLY */
38
39#include <linux/stringify.h>
40
41#ifdef CONFIG_SMP
42#define __percpu_seg_str	"%%"__stringify(__percpu_seg)":"
43#define __my_cpu_offset		x86_read_percpu(this_cpu_off)
44#else
45#define __percpu_seg_str
46#endif
47
48#include <asm-generic/percpu.h>
49
50/* We can use this directly for local CPU (faster). */
51DECLARE_PER_CPU(unsigned long, this_cpu_off);
52
53/* For arch-specific code, we can use direct single-insn ops (they
54 * don't give an lvalue though). */
55extern void __bad_percpu_size(void);
56
57#define percpu_to_op(op, var, val)			\
58do {							\
59	typedef typeof(var) T__;			\
60	if (0) {					\
61		T__ tmp__;				\
62		tmp__ = (val);				\
63	}						\
64	switch (sizeof(var)) {				\
65	case 1:						\
66		asm(op "b %1,"__percpu_seg_str"%0"	\
67		    : "+m" (var)			\
68		    : "ri" ((T__)val));			\
69		break;					\
70	case 2:						\
71		asm(op "w %1,"__percpu_seg_str"%0"	\
72		    : "+m" (var)			\
73		    : "ri" ((T__)val));			\
74		break;					\
75	case 4:						\
76		asm(op "l %1,"__percpu_seg_str"%0"	\
77		    : "+m" (var)			\
78		    : "ri" ((T__)val));			\
79		break;					\
80	case 8:						\
81		asm(op "q %1,"__percpu_seg_str"%0"	\
82		    : "+m" (var)			\
83		    : "r" ((T__)val));			\
84		break;					\
85	default: __bad_percpu_size();			\
86	}						\
87} while (0)
88
89#define percpu_from_op(op, var)				\
90({							\
91	typeof(var) ret__;				\
92	switch (sizeof(var)) {				\
93	case 1:						\
94		asm(op "b "__percpu_seg_str"%1,%0"	\
95		    : "=r" (ret__)			\
96		    : "m" (var));			\
97		break;					\
98	case 2:						\
99		asm(op "w "__percpu_seg_str"%1,%0"	\
100		    : "=r" (ret__)			\
101		    : "m" (var));			\
102		break;					\
103	case 4:						\
104		asm(op "l "__percpu_seg_str"%1,%0"	\
105		    : "=r" (ret__)			\
106		    : "m" (var));			\
107		break;					\
108	case 8:						\
109		asm(op "q "__percpu_seg_str"%1,%0"	\
110		    : "=r" (ret__)			\
111		    : "m" (var));			\
112		break;					\
113	default: __bad_percpu_size();			\
114	}						\
115	ret__;						\
116})
117
118#define x86_read_percpu(var) percpu_from_op("mov", per_cpu__##var)
119#define x86_write_percpu(var, val) percpu_to_op("mov", per_cpu__##var, val)
120#define x86_add_percpu(var, val) percpu_to_op("add", per_cpu__##var, val)
121#define x86_sub_percpu(var, val) percpu_to_op("sub", per_cpu__##var, val)
122#define x86_or_percpu(var, val) percpu_to_op("or", per_cpu__##var, val)
123
124#ifdef CONFIG_X86_64
125extern void load_pda_offset(int cpu);
126#else
127static inline void load_pda_offset(int cpu) { }
128#endif
129
130#endif /* !__ASSEMBLY__ */
131
132#ifdef CONFIG_SMP
133
134/*
135 * Define the "EARLY_PER_CPU" macros.  These are used for some per_cpu
136 * variables that are initialized and accessed before there are per_cpu
137 * areas allocated.
138 */
139
140#define	DEFINE_EARLY_PER_CPU(_type, _name, _initvalue)			\
141	DEFINE_PER_CPU(_type, _name) = _initvalue;			\
142	__typeof__(_type) _name##_early_map[NR_CPUS] __initdata =	\
143				{ [0 ... NR_CPUS-1] = _initvalue };	\
144	__typeof__(_type) *_name##_early_ptr __refdata = _name##_early_map
145
146#define EXPORT_EARLY_PER_CPU_SYMBOL(_name)			\
147	EXPORT_PER_CPU_SYMBOL(_name)
148
149#define DECLARE_EARLY_PER_CPU(_type, _name)			\
150	DECLARE_PER_CPU(_type, _name);				\
151	extern __typeof__(_type) *_name##_early_ptr;		\
152	extern __typeof__(_type)  _name##_early_map[]
153
154#define	early_per_cpu_ptr(_name) (_name##_early_ptr)
155#define	early_per_cpu_map(_name, _idx) (_name##_early_map[_idx])
156#define	early_per_cpu(_name, _cpu) 				\
157	*(early_per_cpu_ptr(_name) ?				\
158		&early_per_cpu_ptr(_name)[_cpu] :		\
159		&per_cpu(_name, _cpu))
160
161#else	/* !CONFIG_SMP */
162#define	DEFINE_EARLY_PER_CPU(_type, _name, _initvalue)		\
163	DEFINE_PER_CPU(_type, _name) = _initvalue
164
165#define EXPORT_EARLY_PER_CPU_SYMBOL(_name)			\
166	EXPORT_PER_CPU_SYMBOL(_name)
167
168#define DECLARE_EARLY_PER_CPU(_type, _name)			\
169	DECLARE_PER_CPU(_type, _name)
170
171#define	early_per_cpu(_name, _cpu) per_cpu(_name, _cpu)
172#define	early_per_cpu_ptr(_name) NULL
173/* no early_per_cpu_map() */
174
175#endif	/* !CONFIG_SMP */
176
177#endif /* _ASM_X86_PERCPU_H */
178