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@xxxxxxxxxxxxxxxx/ Thanks, Xiao v3: - Fix riscv32 build issue reported by kernel test robot. V3 changes "hwcap.h" to "cpufeature.h" for files where cpu feature detection APIs are used. (Yujie) 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/elf.h | 2 +- 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 +- arch/riscv/kvm/aia.c | 2 +- arch/riscv/kvm/main.c | 2 +- arch/riscv/kvm/tlb.c | 2 +- arch/riscv/kvm/vcpu_fp.c | 2 +- arch/riscv/kvm/vcpu_onereg.c | 2 +- arch/riscv/kvm/vcpu_vector.c | 2 +- drivers/clocksource/timer-riscv.c | 2 +- drivers/firmware/efi/libstub/Makefile | 2 +- drivers/perf/riscv_pmu_sbi.c | 2 +- 16 files changed, 359 insertions(+), 106 deletions(-) -- 2.25.1
