kernel: add platform_has() infrastructure

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@suse.com>
Reviewed-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Tested-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> # Arm64 only
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Juergen Gross <jgross@suse.com>
This commit is contained in:
Juergen Gross 2022-06-02 15:05:26 +02:00
parent f2906aa863
commit 2130a790ca
6 changed files with 60 additions and 1 deletions

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@ -15824,6 +15824,14 @@ S: Maintained
F: Documentation/devicetree/bindings/iio/chemical/plantower,pms7003.yaml
F: drivers/iio/chemical/pms7003.c
PLATFORM FEATURE INFRASTRUCTURE
M: Juergen Gross <jgross@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@intel.com>
S: Maintained

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@ -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

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@ -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 */

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@ -0,0 +1,15 @@
/* 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)
void platform_set(unsigned int feature);
void platform_clear(unsigned int feature);
bool platform_has(unsigned int feature);
#endif /* _PLATFORM_FEATURE_H */

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@ -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

27
kernel/platform-feature.c Normal file
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@ -0,0 +1,27 @@
// SPDX-License-Identifier: GPL-2.0
#include <linux/bitops.h>
#include <linux/cache.h>
#include <linux/export.h>
#include <linux/platform-feature.h>
#define PLATFORM_FEAT_ARRAY_SZ BITS_TO_LONGS(PLATFORM_FEAT_N)
static unsigned long __read_mostly platform_features[PLATFORM_FEAT_ARRAY_SZ];
void platform_set(unsigned int feature)
{
set_bit(feature, platform_features);
}
EXPORT_SYMBOL_GPL(platform_set);
void platform_clear(unsigned int feature)
{
clear_bit(feature, platform_features);
}
EXPORT_SYMBOL_GPL(platform_clear);
bool platform_has(unsigned int feature)
{
return test_bit(feature, platform_features);
}
EXPORT_SYMBOL_GPL(platform_has);