Re: [PATCH 3/3] s390/uvdevice: autoload module based on CPU facility

Claudio Imbrenda
2022-07-12T16:50:42Z

On Tue, 12 Jul 2022 12:52:20 +0200
Steffen Eiden <seiden@linux.ibm.com> wrote:

> Make sure the uvdevice driver will be automatically loaded when
> facility 158 is available.
>
> Signed-off-by: Steffen Eiden <seiden@linux.ibm.com>
> ---
> arch/s390/include/asm/cpufeature.h | 1 +
> arch/s390/kernel/cpufeature.c | 1 +
> drivers/s390/char/uvdevice.c | 5 ++---
> 3 files changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/arch/s390/include/asm/cpufeature.h b/arch/s390/include/asm/cpufeature.h
> index aa8081dad411..4b17f876ab54 100644
> --- a/arch/s390/include/asm/cpufeature.h
> +++ b/arch/s390/include/asm/cpufeature.h
> @@ -33,6 +33,7 @@ enum {
> S390_CPU_FEATURE_NNPA,
> S390_CPU_FEATURE_PCI_MIO,
> S390_CPU_FEATURE_SIE,
> + S390_CPU_FEATURE_UV,
> MAX_CPU_FEATURES
> };
>
> diff --git a/arch/s390/kernel/cpufeature.c b/arch/s390/kernel/cpufeature.c
> index e70b29804db4..0b854d37edcb 100644
> --- a/arch/s390/kernel/cpufeature.c
> +++ b/arch/s390/kernel/cpufeature.c
> @@ -42,6 +42,7 @@ static struct s390_cpu_feature s390_cpu_features[MAX_CPU_FEATURES] = {
> [S390_CPU_FEATURE_NNPA] = {.type = TYPE_HWCAP, .num = HWCAP_NR_NNPA},
> [S390_CPU_FEATURE_PCI_MIO] = {.type = TYPE_HWCAP, .num = HWCAP_NR_PCI_MIO},
> [S390_CPU_FEATURE_SIE] = {.type = TYPE_HWCAP, .num = HWCAP_NR_SIE},
> + [S390_CPU_FEATURE_UV] = {.type = TYPE_FACILITY, .num = 158},
> };
>
> /*
> diff --git a/drivers/s390/char/uvdevice.c b/drivers/s390/char/uvdevice.c
> index 66505d7166a6..1d40457c7b10 100644
> --- a/drivers/s390/char/uvdevice.c
> +++ b/drivers/s390/char/uvdevice.c
> @@ -27,6 +27,7 @@
> #include <linux/stddef.h>
> #include <linux/vmalloc.h>
> #include <linux/slab.h>
> +#include <linux/cpufeature.h>
>
> #include <asm/uvdevice.h>
> #include <asm/uv.h>
> @@ -244,12 +245,10 @@ static void __exit uvio_dev_exit(void)
>
> static int __init uvio_dev_init(void)
> {
> - if (!test_facility(158))
> - return -ENXIO;
> return misc_register(&uvio_dev_miscdev);
> }
>
> -module_init(uvio_dev_init);
> +module_cpu_feature_match(S390_CPU_FEATURE_UV, uvio_dev_init);

does this still prevent manual loading when the feature is not present?

> module_exit(uvio_dev_exit);
>
> MODULE_AUTHOR("IBM Corporation");