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s390/module: enable generic CPU feature modalias using s390 ELF hwcaps 

Add support for the generic CPU feature modalias implementation that wires
up optional CPU features to udev-based module autoprobing.

The <asm/cpufeature.h> file provides definitions to map CPU features to
s390 ELF hardware capabilities.

Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
hifive-unleashed-5.1
Hendrik Brueckner 2015-02-19 12:22:02 +01:00 committed by Martin Schwidefsky
parent 7d0c502040
commit 8f00b3e28f
4 changed files with 40 additions and 1 deletions
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1
arch/s390/Kconfig
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@ -105,6 +105,7 @@ config S390
select CLONE_BACKWARDS2
select DYNAMIC_FTRACE if FUNCTION_TRACER
select GENERIC_CLOCKEVENTS
select GENERIC_CPU_AUTOPROBE
select GENERIC_CPU_DEVICES if !SMP
select GENERIC_FIND_FIRST_BIT
select GENERIC_SMP_IDLE_THREAD

29
arch/s390/include/asm/cpufeature.h 100644
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@ -0,0 +1,29 @@
/*
* Module interface for CPU features
*
* Copyright IBM Corp. 2015
* Author(s): Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
*/
#ifndef __ASM_S390_CPUFEATURE_H
#define __ASM_S390_CPUFEATURE_H
#include <asm/elf.h>
/* Hardware features on Linux on z Systems are indicated by facility bits that
* are mapped to the so-called machine flags. Particular machine flags are
* then used to define ELF hardware capabilities; most notably hardware flags
* that are essential for user space / glibc.
*
* Restrict the set of exposed CPU features to ELF hardware capabilities for
* now. Additional machine flags can be indicated by values larger than
* MAX_ELF_HWCAP_FEATURES.
*/
#define MAX_ELF_HWCAP_FEATURES (8 * sizeof(elf_hwcap))
#define MAX_CPU_FEATURES MAX_ELF_HWCAP_FEATURES
#define cpu_feature(feat) ilog2(HWCAP_S390_ ## feat)
int cpu_have_feature(unsigned int nr);
#endif /* __ASM_S390_CPUFEATURE_H */

9
arch/s390/kernel/processor.c
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@ -40,6 +40,15 @@ void cpu_init(void)
enter_lazy_tlb(&init_mm, current);
}
/*
* cpu_have_feature - Test CPU features on module initialization
*/
int cpu_have_feature(unsigned int num)
{
return elf_hwcap & (1UL << num);
}
EXPORT_SYMBOL(cpu_have_feature);
/*
* show_cpuinfo - Get information on one CPU for use by procfs.
*/

2
arch/s390/kernel/setup.c
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@ -76,7 +76,7 @@ EXPORT_SYMBOL(console_devno);
unsigned int console_irq = -1;
EXPORT_SYMBOL(console_irq);
unsigned long elf_hwcap = 0;
unsigned long elf_hwcap __read_mostly = 0;
char elf_platform[ELF_PLATFORM_SIZE];
int __initdata memory_end_set;