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#ifndef PERCPU_H
#define PERCPU_H
#include <stddef.h>
#include "bug_on.h"
#include "preempt.h"
#define __percpu
/* Maximum size of any percpu data. */
#define PERCPU_OFFSET (4 * sizeof(long))
/* Ignore alignment, as CBMC doesn't care about false sharing. */
#define alloc_percpu(type) __alloc_percpu(sizeof(type), 1)
static inline void *__alloc_percpu(size_t size, size_t align)
{
BUG();
return NULL;
}
static inline void free_percpu(void *ptr)
{
BUG();
}
#define per_cpu_ptr(ptr, cpu) \
((typeof(ptr)) ((char *) (ptr) + PERCPU_OFFSET * cpu))
#define __this_cpu_inc(pcp) __this_cpu_add(pcp, 1)
#define __this_cpu_dec(pcp) __this_cpu_sub(pcp, 1)
#define __this_cpu_sub(pcp, n) __this_cpu_add(pcp, -(typeof(pcp)) (n))
#define this_cpu_inc(pcp) this_cpu_add(pcp, 1)
#define this_cpu_dec(pcp) this_cpu_sub(pcp, 1)
#define this_cpu_sub(pcp, n) this_cpu_add(pcp, -(typeof(pcp)) (n))
/* Make CBMC use atomics to work around bug. */
#ifdef RUN
#define THIS_CPU_ADD_HELPER(ptr, x) (*(ptr) += (x))
#else
/*
* Split the atomic into a read and a write so that it has the least
* possible ordering.
*/
#define THIS_CPU_ADD_HELPER(ptr, x) \
do { \
typeof(ptr) this_cpu_add_helper_ptr = (ptr); \
typeof(ptr) this_cpu_add_helper_x = (x); \
typeof(*ptr) this_cpu_add_helper_temp; \
__CPROVER_atomic_begin(); \
this_cpu_add_helper_temp = *(this_cpu_add_helper_ptr); \
__CPROVER_atomic_end(); \
this_cpu_add_helper_temp += this_cpu_add_helper_x; \
__CPROVER_atomic_begin(); \
*(this_cpu_add_helper_ptr) = this_cpu_add_helper_temp; \
__CPROVER_atomic_end(); \
} while (0)
#endif
/*
* For some reason CBMC needs an atomic operation even though this is percpu
* data.
*/
#define __this_cpu_add(pcp, n) \
do { \
BUG_ON(preemptible()); \
THIS_CPU_ADD_HELPER(per_cpu_ptr(&(pcp), thread_cpu_id), \
(typeof(pcp)) (n)); \
} while (0)
#define this_cpu_add(pcp, n) \
do { \
int this_cpu_add_impl_cpu = get_cpu(); \
THIS_CPU_ADD_HELPER(per_cpu_ptr(&(pcp), this_cpu_add_impl_cpu), \
(typeof(pcp)) (n)); \
put_cpu(); \
} while (0)
/*
* This will cause a compiler warning because of the cast from char[][] to
* type*. This will cause a compile time error if type is too big.
*/
#define DEFINE_PER_CPU(type, name) \
char name[NR_CPUS][PERCPU_OFFSET]; \
typedef char percpu_too_big_##name \
[sizeof(type) > PERCPU_OFFSET ? -1 : 1]
#define for_each_possible_cpu(cpu) \
for ((cpu) = 0; (cpu) < NR_CPUS; ++(cpu))
#endif
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