xref: /linux/arch/s390/include/asm/cpufeature.h (revision 9958d30f38b96fb763a10d44d18ddad39127d5f4)
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_ ## feat)
27 
28 int cpu_have_feature(unsigned int nr);
29 
30 #endif /* __ASM_S390_CPUFEATURE_H */
31