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[v2,0/2] riscv: Optimize bitops with Zbb extension

Message ID 20230920074653.2509631-1-xiao.w.wang@intel.com
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Series riscv: Optimize bitops with Zbb extension | expand

Message

Wang, Xiao W Sept. 20, 2023, 7:46 a.m. UTC 
Bitops optimization with specialized instructions is common practice in
popular ISAs, this patch set uses RISC-V Zbb extension to optimize four
bitops: __ffs, __fls, ffs and fls.

The first patch rearranges the content in hwcap.h cpufeature.h, it helps
to avoid a cyclic header including issue for patch 2.

The second patch leverages the alternative mechanism to dynamically apply
this optimization.

The series has following dependency:
https://lore.kernel.org/linux-riscv/20230918131518.56803-8-ajones@ventanamicro.com/

Thanks,
Xiao

v2:
- Remove the "EFI_" prefix from macro name "EFI_NO_ALTERNATIVE" to make it
  generic. (Ard)
- patch-1 is added, it's based on "RISC-V: Enable cbo.zero in usermode". (Andrew)

Xiao Wang (2):
  riscv: Rearrange hwcap.h and cpufeature.h
  riscv: Optimize bitops with Zbb extension

 arch/riscv/include/asm/bitops.h       | 266 +++++++++++++++++++++++++-
 arch/riscv/include/asm/cpufeature.h   |  83 ++++++++
 arch/riscv/include/asm/hwcap.h        |  91 ---------
 arch/riscv/include/asm/pgtable.h      |   1 +
 arch/riscv/include/asm/switch_to.h    |   2 +-
 arch/riscv/include/asm/vector.h       |   2 +-
 drivers/firmware/efi/libstub/Makefile |   2 +-
 7 files changed, 350 insertions(+), 97 deletions(-)