From 8f00b3e28f73e712a2f82a15f66acd852f60e3ba Mon Sep 17 00:00:00 2001 From: Hendrik Brueckner Date: Thu, 19 Feb 2015 12:22:02 +0100 Subject: [PATCH] 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 file provides definitions to map CPU features to s390 ELF hardware capabilities. Signed-off-by: Hendrik Brueckner Signed-off-by: Martin Schwidefsky --- arch/s390/Kconfig | 1 + arch/s390/include/asm/cpufeature.h | 29 +++++++++++++++++++++++++++++ arch/s390/kernel/processor.c | 9 +++++++++ arch/s390/kernel/setup.c | 2 +- 4 files changed, 40 insertions(+), 1 deletion(-) create mode 100644 arch/s390/include/asm/cpufeature.h diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig index b06dc3839268..91e8954f1237 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -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 diff --git a/arch/s390/include/asm/cpufeature.h b/arch/s390/include/asm/cpufeature.h new file mode 100644 index 000000000000..fa7e69b7c299 --- /dev/null +++ b/arch/s390/include/asm/cpufeature.h @@ -0,0 +1,29 @@ +/* + * Module interface for CPU features + * + * Copyright IBM Corp. 2015 + * Author(s): Hendrik Brueckner + */ + +#ifndef __ASM_S390_CPUFEATURE_H +#define __ASM_S390_CPUFEATURE_H + +#include + +/* 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 */ diff --git a/arch/s390/kernel/processor.c b/arch/s390/kernel/processor.c index dc488e13b7e3..e6e077ae3990 100644 --- a/arch/s390/kernel/processor.c +++ b/arch/s390/kernel/processor.c @@ -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. */ diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c index ca070d260af2..85a1d4770c9c 100644 --- a/arch/s390/kernel/setup.c +++ b/arch/s390/kernel/setup.c @@ -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; -- 2.20.1