In another patch series [1] the need has come up to have support for a generic feature flag infrastructure. This patch series is introducing that infrastructure and adds the first use case. I have decided to use a similar interface as the already known x86 cpu_has() function. As the new infrastructure is meant to be usable for general and arch-specific feature flags, the flags are being spread between a general bitmap and an arch specific one. The bitmaps start all being zero, single features can be set or reset at any time by using the related platform_[re]set_feature() functions. The platform_has() function is using a simple test_bit() call for now, further optimization might be added when needed. [1]: https://lore.kernel.org/lkml/1650646263-22047-1-git-send-email-olekstysh@xxxxxxxxx/T/#t Juergen Gross (2): kernel: add platform_has() infrastructure virtio: replace arch_has_restricted_virtio_memory_access() MAINTAINERS | 8 ++++++++ arch/s390/Kconfig | 1 - arch/s390/mm/init.c | 13 +++---------- arch/x86/Kconfig | 1 - arch/x86/kernel/cpu/mshyperv.c | 5 ++++- arch/x86/mm/mem_encrypt.c | 6 ------ arch/x86/mm/mem_encrypt_amd.c | 4 ++++ drivers/virtio/Kconfig | 6 ------ drivers/virtio/virtio.c | 5 ++--- include/asm-generic/Kbuild | 1 + include/asm-generic/platform-feature.h | 8 ++++++++ include/linux/platform-feature.h | 16 +++++++++++++++ include/linux/virtio_config.h | 9 --------- kernel/Makefile | 2 +- kernel/platform-feature.c | 27 ++++++++++++++++++++++++++ 15 files changed, 74 insertions(+), 38 deletions(-) create mode 100644 include/asm-generic/platform-feature.h create mode 100644 include/linux/platform-feature.h create mode 100644 kernel/platform-feature.c -- 2.34.1
