arch/s390/include/asm/cpufeature.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * Module interface for CPU features
   4  *
   5  * Copyright IBM Corp. 2015
   6  * Author(s): Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
   7  */
   8
   9 #ifndef __ASM_S390_CPUFEATURE_H
  10 #define __ASM_S390_CPUFEATURE_H
  11
  12 #include <asm/elf.h>
  13
  14 /* Hardware features on Linux on z Systems are indicated by facility bits that
  15  * are mapped to the so-called machine flags.  Particular machine flags are
  16  * then used to define ELF hardware capabilities; most notably hardware flags
  17  * that are essential for user space / glibc.
  18  *
  19  * Restrict the set of exposed CPU features to ELF hardware capabilities for
  20  * now.  Additional machine flags can be indicated by values larger than
  21  * MAX_ELF_HWCAP_FEATURES.
  22  */
  23 #define MAX_ELF_HWCAP_FEATURES  (8 * sizeof(elf_hwcap))
  24 #define MAX_CPU_FEATURES        MAX_ELF_HWCAP_FEATURES
  25
  26 #define cpu_feature(feat)       ilog2(HWCAP_S390_ ## feat)
  27
  28 int cpu_have_feature(unsigned int nr);
  29
  30 #endif /* __ASM_S390_CPUFEATURE_H */