ARCH_P4_CNTRVAL_BITS   24 arch/x86/include/asm/perf_event_p4.h #define ARCH_P4_CNTRVAL_MASK	((1ULL << ARCH_P4_CNTRVAL_BITS) - 1)
ARCH_P4_CNTRVAL_BITS   25 arch/x86/include/asm/perf_event_p4.h #define ARCH_P4_UNFLAGGED_BIT	((1ULL) << (ARCH_P4_CNTRVAL_BITS - 1))