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   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 #define DEFINE_PER_CPU_SECTION(type, name, section)                     \
  13         __attribute__((__section__(PER_CPU_BASE_SECTION section)))      \
  14         PER_CPU_ATTRIBUTES __typeof__(type) per_cpu__##name
  15
  16 #define DEFINE_PER_CPU(type, name)                                      \
  17         DEFINE_PER_CPU_SECTION(type, name, "")
  18
  19 #define DEFINE_PER_CPU_SHARED_ALIGNED(type, name)                       \
  20         DEFINE_PER_CPU_SECTION(type, name, PER_CPU_SHARED_ALIGNED_SECTION) \
  21         ____cacheline_aligned_in_smp
  22
  23 #define DEFINE_PER_CPU_PAGE_ALIGNED(type, name)                         \
  24         DEFINE_PER_CPU_SECTION(type, name, ".page_aligned")
  25
  26 #define DEFINE_PER_CPU_FIRST(type, name)                                \
  27         DEFINE_PER_CPU_SECTION(type, name, PER_CPU_FIRST_SECTION)
  28
  29 #define EXPORT_PER_CPU_SYMBOL(var) EXPORT_SYMBOL(per_cpu__##var)
  30 #define EXPORT_PER_CPU_SYMBOL_GPL(var) EXPORT_SYMBOL_GPL(per_cpu__##var)
  31
  32 /* enough to cover all DEFINE_PER_CPUs in modules */
  33 #ifdef CONFIG_MODULES
  34 #define PERCPU_MODULE_RESERVE           (8 << 10)
  35 #else
  36 #define PERCPU_MODULE_RESERVE           0
  37 #endif
  38
  39 #ifndef PERCPU_ENOUGH_ROOM
  40 #define PERCPU_ENOUGH_ROOM                                              \
  41         (ALIGN(__per_cpu_end - __per_cpu_start, SMP_CACHE_BYTES) +      \
  42          PERCPU_MODULE_RESERVE)
  43 #endif
  44
  45 /*
  46  * Must be an lvalue. Since @var must be a simple identifier,
  47  * we force a syntax error here if it isn't.
  48  */
  49 #define get_cpu_var(var) (*({                           \
  50         extern int simple_identifier_##var(void);       \
  51         preempt_disable();                              \
  52         &__get_cpu_var(var); }))
  53 #define put_cpu_var(var) preempt_enable()
  54
  55 #ifdef CONFIG_SMP
  56
  57 #ifdef CONFIG_HAVE_DYNAMIC_PER_CPU_AREA
  58
  59 /* minimum unit size, also is the maximum supported allocation size */
  60 #define PCPU_MIN_UNIT_SIZE              PFN_ALIGN(64 << 10)
  61
  62 /*
  63  * PERCPU_DYNAMIC_RESERVE indicates the amount of free area to piggy
  64  * back on the first chunk for dynamic percpu allocation if arch is
  65  * manually allocating and mapping it for faster access (as a part of
  66  * large page mapping for example).
  67  *
  68  * The following values give between one and two pages of free space
  69  * after typical minimal boot (2-way SMP, single disk and NIC) with
  70  * both defconfig and a distro config on x86_64 and 32.  More
  71  * intelligent way to determine this would be nice.
  72  */
  73 #if BITS_PER_LONG > 32
  74 #define PERCPU_DYNAMIC_RESERVE          (20 << 10)
  75 #else
  76 #define PERCPU_DYNAMIC_RESERVE          (12 << 10)
  77 #endif
  78
  79 extern void *pcpu_base_addr;
  80
  81 typedef struct page * (*pcpu_get_page_fn_t)(unsigned int cpu, int pageno);
  82 typedef void (*pcpu_populate_pte_fn_t)(unsigned long addr);
  83
  84 extern size_t __init pcpu_setup_first_chunk(pcpu_get_page_fn_t get_page_fn,
  85                                 size_t static_size, size_t reserved_size,
  86                                 ssize_t dyn_size, ssize_t unit_size,
  87                                 void *base_addr,
  88                                 pcpu_populate_pte_fn_t populate_pte_fn);
  89
  90 extern ssize_t __init pcpu_embed_first_chunk(
  91                                 size_t static_size, size_t reserved_size,
  92                                 ssize_t dyn_size, ssize_t unit_size);
  93
  94 /*
  95  * Use this to get to a cpu's version of the per-cpu object
  96  * dynamically allocated. Non-atomic access to the current CPU's
  97  * version should probably be combined with get_cpu()/put_cpu().
  98  */
  99 #define per_cpu_ptr(ptr, cpu)   SHIFT_PERCPU_PTR((ptr), per_cpu_offset((cpu)))
 100
 101 extern void *__alloc_reserved_percpu(size_t size, size_t align);
 102
 103 #else /* CONFIG_HAVE_DYNAMIC_PER_CPU_AREA */
 104
 105 struct percpu_data {
 106         void *ptrs[1];
 107 };
 108
 109 #define __percpu_disguise(pdata) (struct percpu_data *)~(unsigned long)(pdata)
 110
 111 #define per_cpu_ptr(ptr, cpu)                                           \
 112 ({                                                                      \
 113         struct percpu_data *__p = __percpu_disguise(ptr);               \
 114         (__typeof__(ptr))__p->ptrs[(cpu)];                              \
 115 })
 116
 117 #endif /* CONFIG_HAVE_DYNAMIC_PER_CPU_AREA */
 118
 119 extern void *__alloc_percpu(size_t size, size_t align);
 120 extern void free_percpu(void *__pdata);
 121
 122 #else /* CONFIG_SMP */
 123
 124 #define per_cpu_ptr(ptr, cpu) ({ (void)(cpu); (ptr); })
 125
 126 static inline void *__alloc_percpu(size_t size, size_t align)
 127 {
 128         /*
 129          * Can't easily make larger alignment work with kmalloc.  WARN
 130          * on it.  Larger alignment should only be used for module
 131          * percpu sections on SMP for which this path isn't used.
 132          */
 133         WARN_ON_ONCE(align > SMP_CACHE_BYTES);
 134         return kzalloc(size, GFP_KERNEL);
 135 }
 136
 137 static inline void free_percpu(void *p)
 138 {
 139         kfree(p);
 140 }
 141
 142 #endif /* CONFIG_SMP */
 143
 144 #define alloc_percpu(type)      (type *)__alloc_percpu(sizeof(type), \
 145                                                        __alignof__(type))
 146
 147 /*
 148  * Optional methods for optimized non-lvalue per-cpu variable access.
 149  *
 150  * @var can be a percpu variable or a field of it and its size should
 151  * equal char, int or long.  percpu_read() evaluates to a lvalue and
 152  * all others to void.
 153  *
 154  * These operations are guaranteed to be atomic w.r.t. preemption.
 155  * The generic versions use plain get/put_cpu_var().  Archs are
 156  * encouraged to implement single-instruction alternatives which don't
 157  * require preemption protection.
 158  */
 159 #ifndef percpu_read
 160 # define percpu_read(var)                                               \
 161   ({                                                                    \
 162         typeof(per_cpu_var(var)) __tmp_var__;                           \
 163         __tmp_var__ = get_cpu_var(var);                                 \
 164         put_cpu_var(var);                                               \
 165         __tmp_var__;                                                    \
 166   })
 167 #endif
 168
 169 #define __percpu_generic_to_op(var, val, op)                            \
 170 do {                                                                    \
 171         get_cpu_var(var) op val;                                        \
 172         put_cpu_var(var);                                               \
 173 } while (0)
 174
 175 #ifndef percpu_write
 176 # define percpu_write(var, val)         __percpu_generic_to_op(var, (val), =)
 177 #endif
 178
 179 #ifndef percpu_add
 180 # define percpu_add(var, val)           __percpu_generic_to_op(var, (val), +=)
 181 #endif
 182
 183 #ifndef percpu_sub
 184 # define percpu_sub(var, val)           __percpu_generic_to_op(var, (val), -=)
 185 #endif
 186
 187 #ifndef percpu_and
 188 # define percpu_and(var, val)           __percpu_generic_to_op(var, (val), &=)
 189 #endif
 190
 191 #ifndef percpu_or
 192 # define percpu_or(var, val)            __percpu_generic_to_op(var, (val), |=)
 193 #endif
 194
 195 #ifndef percpu_xor
 196 # define percpu_xor(var, val)           __percpu_generic_to_op(var, (val), ^=)
 197 #endif
 198
 199 #endif /* __LINUX_PERCPU_H */