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Linux kernel mirror (for testing)
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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#ifdef CONFIG_X86_64_SMP
38#define INIT_PER_CPU_VAR(var) init_per_cpu__##var
39#else
40#define INIT_PER_CPU_VAR(var) per_cpu__##var
41#endif
42
43#else /* ...!ASSEMBLY */
44
45#include <linux/kernel.h>
46#include <linux/stringify.h>
47
48#ifdef CONFIG_SMP
49#define __percpu_arg(x) "%%"__stringify(__percpu_seg)":%P" #x
50#define __my_cpu_offset percpu_read(this_cpu_off)
51#else
52#define __percpu_arg(x) "%P" #x
53#endif
54
55/*
56 * Initialized pointers to per-cpu variables needed for the boot
57 * processor need to use these macros to get the proper address
58 * offset from __per_cpu_load on SMP.
59 *
60 * There also must be an entry in vmlinux_64.lds.S
61 */
62#define DECLARE_INIT_PER_CPU(var) \
63 extern typeof(per_cpu_var(var)) init_per_cpu_var(var)
64
65#ifdef CONFIG_X86_64_SMP
66#define init_per_cpu_var(var) init_per_cpu__##var
67#else
68#define init_per_cpu_var(var) per_cpu_var(var)
69#endif
70
71/* For arch-specific code, we can use direct single-insn ops (they
72 * don't give an lvalue though). */
73extern void __bad_percpu_size(void);
74
75#define percpu_to_op(op, var, val) \
76do { \
77 typedef typeof(var) T__; \
78 if (0) { \
79 T__ tmp__; \
80 tmp__ = (val); \
81 } \
82 switch (sizeof(var)) { \
83 case 1: \
84 asm(op "b %1,"__percpu_arg(0) \
85 : "+m" (var) \
86 : "qi" ((T__)(val))); \
87 break; \
88 case 2: \
89 asm(op "w %1,"__percpu_arg(0) \
90 : "+m" (var) \
91 : "ri" ((T__)(val))); \
92 break; \
93 case 4: \
94 asm(op "l %1,"__percpu_arg(0) \
95 : "+m" (var) \
96 : "ri" ((T__)(val))); \
97 break; \
98 case 8: \
99 asm(op "q %1,"__percpu_arg(0) \
100 : "+m" (var) \
101 : "re" ((T__)(val))); \
102 break; \
103 default: __bad_percpu_size(); \
104 } \
105} while (0)
106
107#define percpu_from_op(op, var, constraint) \
108({ \
109 typeof(var) ret__; \
110 switch (sizeof(var)) { \
111 case 1: \
112 asm(op "b "__percpu_arg(1)",%0" \
113 : "=q" (ret__) \
114 : constraint); \
115 break; \
116 case 2: \
117 asm(op "w "__percpu_arg(1)",%0" \
118 : "=r" (ret__) \
119 : constraint); \
120 break; \
121 case 4: \
122 asm(op "l "__percpu_arg(1)",%0" \
123 : "=r" (ret__) \
124 : constraint); \
125 break; \
126 case 8: \
127 asm(op "q "__percpu_arg(1)",%0" \
128 : "=r" (ret__) \
129 : constraint); \
130 break; \
131 default: __bad_percpu_size(); \
132 } \
133 ret__; \
134})
135
136/*
137 * percpu_read() makes gcc load the percpu variable every time it is
138 * accessed while percpu_read_stable() allows the value to be cached.
139 * percpu_read_stable() is more efficient and can be used if its value
140 * is guaranteed to be valid across cpus. The current users include
141 * get_current() and get_thread_info() both of which are actually
142 * per-thread variables implemented as per-cpu variables and thus
143 * stable for the duration of the respective task.
144 */
145#define percpu_read(var) percpu_from_op("mov", per_cpu__##var, \
146 "m" (per_cpu__##var))
147#define percpu_read_stable(var) percpu_from_op("mov", per_cpu__##var, \
148 "p" (&per_cpu__##var))
149#define percpu_write(var, val) percpu_to_op("mov", per_cpu__##var, val)
150#define percpu_add(var, val) percpu_to_op("add", per_cpu__##var, val)
151#define percpu_sub(var, val) percpu_to_op("sub", per_cpu__##var, val)
152#define percpu_and(var, val) percpu_to_op("and", per_cpu__##var, val)
153#define percpu_or(var, val) percpu_to_op("or", per_cpu__##var, val)
154#define percpu_xor(var, val) percpu_to_op("xor", per_cpu__##var, val)
155
156/* This is not atomic against other CPUs -- CPU preemption needs to be off */
157#define x86_test_and_clear_bit_percpu(bit, var) \
158({ \
159 int old__; \
160 asm volatile("btr %2,"__percpu_arg(1)"\n\tsbbl %0,%0" \
161 : "=r" (old__), "+m" (per_cpu__##var) \
162 : "dIr" (bit)); \
163 old__; \
164})
165
166#include <asm-generic/percpu.h>
167
168/* We can use this directly for local CPU (faster). */
169DECLARE_PER_CPU(unsigned long, this_cpu_off);
170
171#endif /* !__ASSEMBLY__ */
172
173#ifdef CONFIG_SMP
174
175/*
176 * Define the "EARLY_PER_CPU" macros. These are used for some per_cpu
177 * variables that are initialized and accessed before there are per_cpu
178 * areas allocated.
179 */
180
181#define DEFINE_EARLY_PER_CPU(_type, _name, _initvalue) \
182 DEFINE_PER_CPU(_type, _name) = _initvalue; \
183 __typeof__(_type) _name##_early_map[NR_CPUS] __initdata = \
184 { [0 ... NR_CPUS-1] = _initvalue }; \
185 __typeof__(_type) *_name##_early_ptr __refdata = _name##_early_map
186
187#define EXPORT_EARLY_PER_CPU_SYMBOL(_name) \
188 EXPORT_PER_CPU_SYMBOL(_name)
189
190#define DECLARE_EARLY_PER_CPU(_type, _name) \
191 DECLARE_PER_CPU(_type, _name); \
192 extern __typeof__(_type) *_name##_early_ptr; \
193 extern __typeof__(_type) _name##_early_map[]
194
195#define early_per_cpu_ptr(_name) (_name##_early_ptr)
196#define early_per_cpu_map(_name, _idx) (_name##_early_map[_idx])
197#define early_per_cpu(_name, _cpu) \
198 *(early_per_cpu_ptr(_name) ? \
199 &early_per_cpu_ptr(_name)[_cpu] : \
200 &per_cpu(_name, _cpu))
201
202#else /* !CONFIG_SMP */
203#define DEFINE_EARLY_PER_CPU(_type, _name, _initvalue) \
204 DEFINE_PER_CPU(_type, _name) = _initvalue
205
206#define EXPORT_EARLY_PER_CPU_SYMBOL(_name) \
207 EXPORT_PER_CPU_SYMBOL(_name)
208
209#define DECLARE_EARLY_PER_CPU(_type, _name) \
210 DECLARE_PER_CPU(_type, _name)
211
212#define early_per_cpu(_name, _cpu) per_cpu(_name, _cpu)
213#define early_per_cpu_ptr(_name) NULL
214/* no early_per_cpu_map() */
215
216#endif /* !CONFIG_SMP */
217
218#endif /* _ASM_X86_PERCPU_H */