arch/powerpc/include/asm/cputhreads.h

   1 #ifndef _ASM_POWERPC_CPUTHREADS_H
   2 #define _ASM_POWERPC_CPUTHREADS_H
   3
   4 #include <linux/cpumask.h>
   5
   6 /*
   7  * Mapping of threads to cores
   8  *
   9  * Note: This implementation is limited to a power of 2 number of
  10  * threads per core and the same number for each core in the system
  11  * (though it would work if some processors had less threads as long
  12  * as the CPU numbers are still allocated, just not brought offline).
  13  *
  14  * However, the API allows for a different implementation in the future
  15  * if needed, as long as you only use the functions and not the variables
  16  * directly.
  17  */
  18
  19 #ifdef CONFIG_SMP
  20 extern int threads_per_core;
  21 extern int threads_shift;
  22 extern cpumask_t threads_core_mask;
  23 #else
  24 #define threads_per_core        1
  25 #define threads_shift           0
  26 #define threads_core_mask       (CPU_MASK_CPU0)
  27 #endif
  28
  29 /* cpu_thread_mask_to_cores - Return a cpumask of one per cores
  30  *                            hit by the argument
  31  *
  32  * @threads:    a cpumask of threads
  33  *
  34  * This function returns a cpumask which will have one "cpu" (or thread)
  35  * bit set for each core that has at least one thread set in the argument.
  36  *
  37  * This can typically be used for things like IPI for tlb invalidations
  38  * since those need to be done only once per core/TLB
  39  */
  40 static inline cpumask_t cpu_thread_mask_to_cores(cpumask_t threads)
  41 {
  42         cpumask_t       tmp, res;
  43         int             i;
  44
  45         res = CPU_MASK_NONE;
  46         for (i = 0; i < NR_CPUS; i += threads_per_core) {
  47                 cpus_shift_left(tmp, threads_core_mask, i);
  48                 if (cpus_intersects(threads, tmp))
  49                         cpu_set(i, res);
  50         }
  51         return res;
  52 }
  53
  54 static inline int cpu_nr_cores(void)
  55 {
  56         return NR_CPUS >> threads_shift;
  57 }
  58
  59 static inline cpumask_t cpu_online_cores_map(void)
  60 {
  61         return cpu_thread_mask_to_cores(cpu_online_map);
  62 }
  63
  64 static inline int cpu_thread_to_core(int cpu)
  65 {
  66         return cpu >> threads_shift;
  67 }
  68
  69 static inline int cpu_thread_in_core(int cpu)
  70 {
  71         return cpu & (threads_per_core - 1);
  72 }
  73
  74 static inline int cpu_first_thread_in_core(int cpu)
  75 {
  76         return cpu & ~(threads_per_core - 1);
  77 }
  78
  79 static inline int cpu_last_thread_in_core(int cpu)
  80 {
  81         return cpu | (threads_per_core - 1);
  82 }
  83
  84
  85
  86 #endif /* _ASM_POWERPC_CPUTHREADS_H */
  87