diff options
Diffstat (limited to 'kernel/cpu.c')
| -rw-r--r-- | kernel/cpu.c | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/kernel/cpu.c b/kernel/cpu.c index 29510d68338a..e202a68d1cc1 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -455,3 +455,28 @@ out: #endif /* CONFIG_PM_SLEEP_SMP */ #endif /* CONFIG_SMP */ + +/* + * cpu_bit_bitmap[] is a special, "compressed" data structure that + * represents all NR_CPUS bits binary values of 1<<nr. + * + * It is used by cpumask_of_cpu() to get a constant address to a CPU + * mask value that has a single bit set only. + */ + +/* cpu_bit_bitmap[0] is empty - so we can back into it */ +#define MASK_DECLARE_1(x) [x+1][0] = 1UL << (x) +#define MASK_DECLARE_2(x) MASK_DECLARE_1(x), MASK_DECLARE_1(x+1) +#define MASK_DECLARE_4(x) MASK_DECLARE_2(x), MASK_DECLARE_2(x+2) +#define MASK_DECLARE_8(x) MASK_DECLARE_4(x), MASK_DECLARE_4(x+4) + +const unsigned long cpu_bit_bitmap[BITS_PER_LONG+1][BITS_TO_LONGS(NR_CPUS)] = { + + MASK_DECLARE_8(0), MASK_DECLARE_8(8), + MASK_DECLARE_8(16), MASK_DECLARE_8(24), +#if BITS_PER_LONG > 32 + MASK_DECLARE_8(32), MASK_DECLARE_8(40), + MASK_DECLARE_8(48), MASK_DECLARE_8(56), +#endif +}; +EXPORT_SYMBOL_GPL(cpu_bit_bitmap); |