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
   9 #include <asm/percpu.h>
  10
  11 #ifndef PER_CPU_BASE_SECTION
  12 #ifdef CONFIG_SMP
  13 #define PER_CPU_BASE_SECTION ".data.percpu"
  14 #else
  15 #define PER_CPU_BASE_SECTION ".data"
  16 #endif
  17 #endif
  18
  19 #ifdef CONFIG_SMP
  20
  21 #ifdef MODULE
  22 #define PER_CPU_SHARED_ALIGNED_SECTION ""
  23 #else
  24 #define PER_CPU_SHARED_ALIGNED_SECTION ".shared_aligned"
  25 #endif
  26 #define PER_CPU_FIRST_SECTION ".first"
  27
  28 #else
  29
  30 #define PER_CPU_SHARED_ALIGNED_SECTION ""
  31 #define PER_CPU_FIRST_SECTION ""
  32
  33 #endif
  34
  35 #define DEFINE_PER_CPU_SECTION(type, name, section)                     \
  36         __attribute__((__section__(PER_CPU_BASE_SECTION section)))      \
  37         PER_CPU_ATTRIBUTES __typeof__(type) per_cpu__##name
  38
  39 #define DEFINE_PER_CPU(type, name)                                      \
  40         DEFINE_PER_CPU_SECTION(type, name, "")
  41
  42 #define DEFINE_PER_CPU_SHARED_ALIGNED(type, name)                       \
  43         DEFINE_PER_CPU_SECTION(type, name, PER_CPU_SHARED_ALIGNED_SECTION) \
  44         ____cacheline_aligned_in_smp
  45
  46 #define DEFINE_PER_CPU_PAGE_ALIGNED(type, name)                         \
  47         DEFINE_PER_CPU_SECTION(type, name, ".page_aligned")
  48
  49 #define DEFINE_PER_CPU_FIRST(type, name)                                \
  50         DEFINE_PER_CPU_SECTION(type, name, PER_CPU_FIRST_SECTION)
  51
  52 #define EXPORT_PER_CPU_SYMBOL(var) EXPORT_SYMBOL(per_cpu__##var)
  53 #define EXPORT_PER_CPU_SYMBOL_GPL(var) EXPORT_SYMBOL_GPL(per_cpu__##var)
  54
  55 /* Enough to cover all DEFINE_PER_CPUs in kernel, including modules. */
  56 #ifndef PERCPU_ENOUGH_ROOM
  57 #ifdef CONFIG_MODULES
  58 #define PERCPU_MODULE_RESERVE   8192
  59 #else
  60 #define PERCPU_MODULE_RESERVE   0
  61 #endif
  62
  63 #define PERCPU_ENOUGH_ROOM                                              \
  64         (__per_cpu_end - __per_cpu_start + PERCPU_MODULE_RESERVE)
  65 #endif  /* PERCPU_ENOUGH_ROOM */
  66
  67 /*
  68  * Must be an lvalue. Since @var must be a simple identifier,
  69  * we force a syntax error here if it isn't.
  70  */
  71 #define get_cpu_var(var) (*({                           \
  72         extern int simple_identifier_##var(void);       \
  73         preempt_disable();                              \
  74         &__get_cpu_var(var); }))
  75 #define put_cpu_var(var) preempt_enable()
  76
  77 #ifdef CONFIG_SMP
  78
  79 struct percpu_data {
  80         void *ptrs[1];
  81 };
  82
  83 #define __percpu_disguise(pdata) (struct percpu_data *)~(unsigned long)(pdata)
  84 /*
  85  * Use this to get to a cpu's version of the per-cpu object dynamically
  86  * allocated. Non-atomic access to the current CPU's version should
  87  * probably be combined with get_cpu()/put_cpu().
  88  */
  89 #define percpu_ptr(ptr, cpu)                              \
  90 ({                                                        \
  91         struct percpu_data *__p = __percpu_disguise(ptr); \
  92         (__typeof__(ptr))__p->ptrs[(cpu)];                \
  93 })
  94
  95 extern void *__percpu_alloc_mask(size_t size, gfp_t gfp, cpumask_t *mask);
  96 extern void percpu_free(void *__pdata);
  97
  98 #else /* CONFIG_SMP */
  99
 100 #define percpu_ptr(ptr, cpu) ({ (void)(cpu); (ptr); })
 101
 102 static __always_inline void *__percpu_alloc_mask(size_t size, gfp_t gfp, cpumask_t *mask)
 103 {
 104         return kzalloc(size, gfp);
 105 }
 106
 107 static inline void percpu_free(void *__pdata)
 108 {
 109         kfree(__pdata);
 110 }
 111
 112 #endif /* CONFIG_SMP */
 113
 114 #define percpu_alloc_mask(size, gfp, mask) \
 115         __percpu_alloc_mask((size), (gfp), &(mask))
 116
 117 #define percpu_alloc(size, gfp) percpu_alloc_mask((size), (gfp), cpu_online_map)
 118
 119 /* (legacy) interface for use without CPU hotplug handling */
 120
 121 #define __alloc_percpu(size)    percpu_alloc_mask((size), GFP_KERNEL, \
 122                                                   cpu_possible_map)
 123 #define alloc_percpu(type)      (type *)__alloc_percpu(sizeof(type))
 124 #define free_percpu(ptr)        percpu_free((ptr))
 125 #define per_cpu_ptr(ptr, cpu)   percpu_ptr((ptr), (cpu))
 126
 127 #endif /* __LINUX_PERCPU_H */