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Commit 8f00b3e2 authored by Hendrik Brueckner's avatar Hendrik Brueckner Committed by Martin Schwidefsky
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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: default avatarHendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 7d0c5020
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+1 −0
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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 −0
Original line number Diff line number Diff line
/*
 * 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 −0
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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.
 */
+1 −1
Original line number Diff line number Diff line
@@ -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;