Add a simple infrastructure for setting, resetting and querying platform feature flags. Flags can be either global or architecture specific. Signed-off-by: Juergen Gross <jgross at suse.com> --- MAINTAINERS | 8 +++++++ include/asm-generic/Kbuild | 1 + include/asm-generic/platform-feature.h | 8 +++++++ include/linux/platform-feature.h | 29 ++++++++++++++++++++++++++ kernel/Makefile | 2 +- kernel/platform-feature.c | 7 +++++++ 6 files changed, 54 insertions(+), 1 deletion(-) create mode 100644 include/asm-generic/platform-feature.h create mode 100644 include/linux/platform-feature.h create mode 100644 kernel/platform-feature.c diff --git a/MAINTAINERS b/MAINTAINERS index 5e8c2f611766..eb943f089eda 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -15650,6 +15650,14 @@ S: Maintained F: Documentation/devicetree/bindings/iio/chemical/plantower,pms7003.yaml F: drivers/iio/chemical/pms7003.c +PLATFORM FEATURE INFRASTRUCTURE +M: Juergen Gross <jgross at suse.com> +S: Maintained +F: arch/*/include/asm/platform-feature.h +F: include/asm-generic/platform-feature.h +F: include/linux/platform-feature.h +F: kernel/platform-feature.c + PLDMFW LIBRARY M: Jacob Keller <jacob.e.keller at intel.com> S: Maintained diff --git a/include/asm-generic/Kbuild b/include/asm-generic/Kbuild index 302506bbc2a4..8e47d483b524 100644 --- a/include/asm-generic/Kbuild +++ b/include/asm-generic/Kbuild @@ -44,6 +44,7 @@ mandatory-y += msi.h mandatory-y += pci.h mandatory-y += percpu.h mandatory-y += pgalloc.h +mandatory-y += platform-feature.h mandatory-y += preempt.h mandatory-y += rwonce.h mandatory-y += sections.h diff --git a/include/asm-generic/platform-feature.h b/include/asm-generic/platform-feature.h new file mode 100644 index 000000000000..4b0af3d51588 --- /dev/null +++ b/include/asm-generic/platform-feature.h @@ -0,0 +1,8 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_GENERIC_PLATFORM_FEATURE_H +#define _ASM_GENERIC_PLATFORM_FEATURE_H + +/* Number of arch specific feature flags. */ +#define PLATFORM_ARCH_FEAT_N 0 + +#endif /* _ASM_GENERIC_PLATFORM_FEATURE_H */ diff --git a/include/linux/platform-feature.h b/include/linux/platform-feature.h new file mode 100644 index 000000000000..df393d502a4f --- /dev/null +++ b/include/linux/platform-feature.h @@ -0,0 +1,29 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _PLATFORM_FEATURE_H +#define _PLATFORM_FEATURE_H + +#include <linux/bitops.h> +#include <asm/platform-feature.h> + +/* The platform features are starting with the architecture specific ones. */ +#define PLATFORM_FEAT_N (0 + PLATFORM_ARCH_FEAT_N) + +#define PLATFORM_FEAT_ARRAY_SZ BITS_TO_LONGS(PLATFORM_FEAT_N) +extern unsigned long platform_features[PLATFORM_FEAT_ARRAY_SZ]; + +static inline void platform_set_feature(unsigned int feature) +{ + set_bit(feature, platform_features); +} + +static inline void platform_reset_feature(unsigned int feature) +{ + clear_bit(feature, platform_features); +} + +static inline bool platform_has(unsigned int feature) +{ + return test_bit(feature, platform_features); +} + +#endif /* _PLATFORM_FEATURE_H */ diff --git a/kernel/Makefile b/kernel/Makefile index 847a82bfe0e3..2f412f80110d 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -7,7 +7,7 @@ obj-y = fork.o exec_domain.o panic.o \ cpu.o exit.o softirq.o resource.o \ sysctl.o capability.o ptrace.o user.o \ signal.o sys.o umh.o workqueue.o pid.o task_work.o \ - extable.o params.o \ + extable.o params.o platform-feature.o \ kthread.o sys_ni.o nsproxy.o \ notifier.o ksysfs.o cred.o reboot.o \ async.o range.o smpboot.o ucount.o regset.o diff --git a/kernel/platform-feature.c b/kernel/platform-feature.c new file mode 100644 index 000000000000..2d52f8442cd5 --- /dev/null +++ b/kernel/platform-feature.c @@ -0,0 +1,7 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include <linux/cache.h> +#include <linux/platform-feature.h> + +unsigned long __read_mostly platform_features[PLATFORM_FEAT_ARRAY_SZ]; +EXPORT_SYMBOL_GPL(platform_features); -- 2.34.1
Borislav Petkov
2022-Apr-26 17:31 UTC
[PATCH 1/2] kernel: add platform_has() infrastructure
On Tue, Apr 26, 2022 at 03:40:20PM +0200, Juergen Gross wrote:> diff --git a/kernel/platform-feature.c b/kernel/platform-feature.c > new file mode 100644 > index 000000000000..2d52f8442cd5 > --- /dev/null > +++ b/kernel/platform-feature.c > @@ -0,0 +1,7 @@ > +// SPDX-License-Identifier: GPL-2.0 > + > +#include <linux/cache.h> > +#include <linux/platform-feature.h> > + > +unsigned long __read_mostly platform_features[PLATFORM_FEAT_ARRAY_SZ];Probably __ro_after_init.> +EXPORT_SYMBOL_GPL(platform_features);You probably should make that thing static and use only accessors to modify it in case you wanna change the underlying data structure in the future. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette