[PATCH V4 0/2] uapi: Add support for GENMASK_U128()

[Anshuman Khandual]

This adds support for GENMASK_U128() and some corresponding tests as well.
GENMASK_U128() generated 128 bit masks will be required later on the arm64
platform for enabling FEAT_SYSREG128 and FEAT_D128 features.

Because GENMAKS_U128() depends on __int128 data type being supported in the
compiler, its usage needs to be protected with CONFIG_ARCH_SUPPORTS_INT128.

This series is being used for an work in progress on arm64 platform.

https://lore.kernel.org/all/20240801054436.612024-1-anshuman.khandual@xxxxxxx/

Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Yury Norov <yury.norov@xxxxxxxxx>
Cc: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: linux-arch@xxxxxxxxxxxxxxx

Changes in V4:

- Folded in the below patch which guards against assembly code
- Fixed __GENMASK_U128() for the corner case (128 bit left shift)
- Improved genmask_u128_test() and genmask_input_check_test()

https://lore.kernel.org/lkml/20240803133753.1598137-1-yury.norov@xxxxxxxxx/

Changes in V3:

https://lore.kernel.org/lkml/20240801071646.682731-1-anshuman.khandual@xxxxxxx/

- Dropped unused __BITS_PER_U128
- Moved #ifdef CONFIG_ARCH_SUPPORTS_INT128 inside genmask_u128_test()
- Added asm unsupported comments for GENMASK_U128() and __BIT128()
- Added reviewed tag from Arnd

Changes in V2:

https://lore.kernel.org/all/20240725054808.286708-1-anshuman.khandual@xxxxxxx/

- Wrapped genmask_u128_test() with CONFIG_ARCH_SUPPORTS_INT128
- Defined __BITS_PER_U128 unconditionally as 128
- Defined __GENMASK_U128() via new _BIT128()
- Dropped _U128() and _AC128()

Changes in V1:

https://lore.kernel.org/lkml/20240724103142.165693-1-anshuman.khandual@xxxxxxx/

Anshuman Khandual (2):
  uapi: Define GENMASK_U128
  lib/test_bits.c: Add tests for GENMASK_U128()

 include/linux/bits.h       | 15 +++++++++++++++
 include/uapi/linux/bits.h  |  3 +++
 include/uapi/linux/const.h | 17 +++++++++++++++++
 lib/test_bits.c            | 34 ++++++++++++++++++++++++++++++++++
 4 files changed, 69 insertions(+)

-- 
2.30.2