570fb18de2ba988f891a75ef9c421fbdc216bafb
[linux-2.6.git] / include / linux / percpu.h
1 #ifndef __LINUX_PERCPU_H
2 #define __LINUX_PERCPU_H
3
4 #include <linux/preempt.h>
5 #include <linux/slab.h> /* For kmalloc() */
6 #include <linux/smp.h>
7 #include <linux/cpumask.h>
8 #include <linux/pfn.h>
9
10 #include <asm/percpu.h>
11
12 /* enough to cover all DEFINE_PER_CPUs in modules */
13 #ifdef CONFIG_MODULES
14 #define PERCPU_MODULE_RESERVE           (8 << 10)
15 #else
16 #define PERCPU_MODULE_RESERVE           0
17 #endif
18
19 #ifndef PERCPU_ENOUGH_ROOM
20 #define PERCPU_ENOUGH_ROOM                                              \
21         (ALIGN(__per_cpu_end - __per_cpu_start, SMP_CACHE_BYTES) +      \
22          PERCPU_MODULE_RESERVE)
23 #endif
24
25 /*
26  * Must be an lvalue. Since @var must be a simple identifier,
27  * we force a syntax error here if it isn't.
28  */
29 #define get_cpu_var(var) (*({                           \
30         extern int simple_identifier_##var(void);       \
31         preempt_disable();                              \
32         &__get_cpu_var(var); }))
33 #define put_cpu_var(var) preempt_enable()
34
35 #ifdef CONFIG_SMP
36
37 #ifndef CONFIG_HAVE_LEGACY_PER_CPU_AREA
38
39 /* minimum unit size, also is the maximum supported allocation size */
40 #define PCPU_MIN_UNIT_SIZE              PFN_ALIGN(64 << 10)
41
42 /*
43  * PERCPU_DYNAMIC_RESERVE indicates the amount of free area to piggy
44  * back on the first chunk for dynamic percpu allocation if arch is
45  * manually allocating and mapping it for faster access (as a part of
46  * large page mapping for example).
47  *
48  * The following values give between one and two pages of free space
49  * after typical minimal boot (2-way SMP, single disk and NIC) with
50  * both defconfig and a distro config on x86_64 and 32.  More
51  * intelligent way to determine this would be nice.
52  */
53 #if BITS_PER_LONG > 32
54 #define PERCPU_DYNAMIC_RESERVE          (20 << 10)
55 #else
56 #define PERCPU_DYNAMIC_RESERVE          (12 << 10)
57 #endif
58
59 extern void *pcpu_base_addr;
60 extern const int *pcpu_unit_map;
61
62 enum pcpu_fc {
63         PCPU_FC_AUTO,
64         PCPU_FC_EMBED,
65         PCPU_FC_PAGE,
66         PCPU_FC_LPAGE,
67
68         PCPU_FC_NR,
69 };
70 extern const char *pcpu_fc_names[PCPU_FC_NR];
71
72 extern enum pcpu_fc pcpu_chosen_fc;
73
74 typedef void * (*pcpu_fc_alloc_fn_t)(unsigned int cpu, size_t size,
75                                      size_t align);
76 typedef void (*pcpu_fc_free_fn_t)(void *ptr, size_t size);
77 typedef void (*pcpu_fc_populate_pte_fn_t)(unsigned long addr);
78 typedef int (pcpu_fc_cpu_distance_fn_t)(unsigned int from, unsigned int to);
79 typedef void (*pcpu_fc_map_fn_t)(void *ptr, size_t size, void *addr);
80
81 #ifdef CONFIG_NEED_PER_CPU_LPAGE_FIRST_CHUNK
82 extern int __init pcpu_lpage_build_unit_map(
83                                 size_t reserved_size, ssize_t *dyn_sizep,
84                                 size_t *unit_sizep, size_t lpage_size,
85                                 int *unit_map,
86                                 pcpu_fc_cpu_distance_fn_t cpu_distance_fn);
87 #endif
88
89 extern size_t __init pcpu_setup_first_chunk(
90                                 size_t static_size, size_t reserved_size,
91                                 size_t dyn_size, size_t unit_size,
92                                 void *base_addr, const int *unit_map);
93
94 #ifdef CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK
95 extern ssize_t __init pcpu_embed_first_chunk(
96                                 size_t reserved_size, ssize_t dyn_size);
97 #endif
98
99 #ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
100 extern ssize_t __init pcpu_page_first_chunk(
101                                 size_t reserved_size,
102                                 pcpu_fc_alloc_fn_t alloc_fn,
103                                 pcpu_fc_free_fn_t free_fn,
104                                 pcpu_fc_populate_pte_fn_t populate_pte_fn);
105 #endif
106
107 #ifdef CONFIG_NEED_PER_CPU_LPAGE_FIRST_CHUNK
108 extern ssize_t __init pcpu_lpage_first_chunk(
109                                 size_t reserved_size, size_t dyn_size,
110                                 size_t unit_size, size_t lpage_size,
111                                 const int *unit_map, int nr_units,
112                                 pcpu_fc_alloc_fn_t alloc_fn,
113                                 pcpu_fc_free_fn_t free_fn,
114                                 pcpu_fc_map_fn_t map_fn);
115
116 extern void *pcpu_lpage_remapped(void *kaddr);
117 #else
118 static inline void *pcpu_lpage_remapped(void *kaddr)
119 {
120         return NULL;
121 }
122 #endif
123
124 /*
125  * Use this to get to a cpu's version of the per-cpu object
126  * dynamically allocated. Non-atomic access to the current CPU's
127  * version should probably be combined with get_cpu()/put_cpu().
128  */
129 #define per_cpu_ptr(ptr, cpu)   SHIFT_PERCPU_PTR((ptr), per_cpu_offset((cpu)))
130
131 extern void *__alloc_reserved_percpu(size_t size, size_t align);
132
133 #else /* CONFIG_HAVE_LEGACY_PER_CPU_AREA */
134
135 struct percpu_data {
136         void *ptrs[1];
137 };
138
139 /* pointer disguising messes up the kmemleak objects tracking */
140 #ifndef CONFIG_DEBUG_KMEMLEAK
141 #define __percpu_disguise(pdata) (struct percpu_data *)~(unsigned long)(pdata)
142 #else
143 #define __percpu_disguise(pdata) (struct percpu_data *)(pdata)
144 #endif
145
146 #define per_cpu_ptr(ptr, cpu)                                           \
147 ({                                                                      \
148         struct percpu_data *__p = __percpu_disguise(ptr);               \
149         (__typeof__(ptr))__p->ptrs[(cpu)];                              \
150 })
151
152 #endif /* CONFIG_HAVE_LEGACY_PER_CPU_AREA */
153
154 extern void *__alloc_percpu(size_t size, size_t align);
155 extern void free_percpu(void *__pdata);
156
157 #ifndef CONFIG_HAVE_SETUP_PER_CPU_AREA
158 extern void __init setup_per_cpu_areas(void);
159 #endif
160
161 #else /* CONFIG_SMP */
162
163 #define per_cpu_ptr(ptr, cpu) ({ (void)(cpu); (ptr); })
164
165 static inline void *__alloc_percpu(size_t size, size_t align)
166 {
167         /*
168          * Can't easily make larger alignment work with kmalloc.  WARN
169          * on it.  Larger alignment should only be used for module
170          * percpu sections on SMP for which this path isn't used.
171          */
172         WARN_ON_ONCE(align > SMP_CACHE_BYTES);
173         return kzalloc(size, GFP_KERNEL);
174 }
175
176 static inline void free_percpu(void *p)
177 {
178         kfree(p);
179 }
180
181 static inline void __init setup_per_cpu_areas(void) { }
182
183 static inline void *pcpu_lpage_remapped(void *kaddr)
184 {
185         return NULL;
186 }
187
188 #endif /* CONFIG_SMP */
189
190 #define alloc_percpu(type)      (type *)__alloc_percpu(sizeof(type), \
191                                                        __alignof__(type))
192
193 /*
194  * Optional methods for optimized non-lvalue per-cpu variable access.
195  *
196  * @var can be a percpu variable or a field of it and its size should
197  * equal char, int or long.  percpu_read() evaluates to a lvalue and
198  * all others to void.
199  *
200  * These operations are guaranteed to be atomic w.r.t. preemption.
201  * The generic versions use plain get/put_cpu_var().  Archs are
202  * encouraged to implement single-instruction alternatives which don't
203  * require preemption protection.
204  */
205 #ifndef percpu_read
206 # define percpu_read(var)                                               \
207   ({                                                                    \
208         typeof(per_cpu_var(var)) __tmp_var__;                           \
209         __tmp_var__ = get_cpu_var(var);                                 \
210         put_cpu_var(var);                                               \
211         __tmp_var__;                                                    \
212   })
213 #endif
214
215 #define __percpu_generic_to_op(var, val, op)                            \
216 do {                                                                    \
217         get_cpu_var(var) op val;                                        \
218         put_cpu_var(var);                                               \
219 } while (0)
220
221 #ifndef percpu_write
222 # define percpu_write(var, val)         __percpu_generic_to_op(var, (val), =)
223 #endif
224
225 #ifndef percpu_add
226 # define percpu_add(var, val)           __percpu_generic_to_op(var, (val), +=)
227 #endif
228
229 #ifndef percpu_sub
230 # define percpu_sub(var, val)           __percpu_generic_to_op(var, (val), -=)
231 #endif
232
233 #ifndef percpu_and
234 # define percpu_and(var, val)           __percpu_generic_to_op(var, (val), &=)
235 #endif
236
237 #ifndef percpu_or
238 # define percpu_or(var, val)            __percpu_generic_to_op(var, (val), |=)
239 #endif
240
241 #ifndef percpu_xor
242 # define percpu_xor(var, val)           __percpu_generic_to_op(var, (val), ^=)
243 #endif
244
245 #endif /* __LINUX_PERCPU_H */