[0/2] introduce unified static key mechanism for ISA ext

Message

Jisheng Zhang May 17, 2022, 6:44 p.m. UTC

Currently, riscv has several extensions which may not be supported on all
riscv platforms, for example, FPU and so on. To support unified kernel
Image style, we need to check whether the feature is suportted or not.
If the check sits at hot code path, the performance will be impacted a
lot. static key can be used to solve the issue. In the past, FPU
support has been converted to use static key mechanism. I believe we
will have similar cases in the future.

Jisheng Zhang (2):
  riscv: introduce unified static key mechanism for ISA extensions
  riscv: switch has_fpu() to the unified static key mechanism

 arch/riscv/include/asm/hwcap.h     | 40 ++++++++++++++++++++++++++++++
 arch/riscv/include/asm/switch_to.h |  5 ++--
 arch/riscv/kernel/cpufeature.c     | 14 +++++------
 3 files changed, 50 insertions(+), 9 deletions(-)