[0/3] RISC-V: Export Zba, Zbb to usermode via hwprobe

Message

Evan Green April 28, 2023, 7:06 p.m. UTC

This change detects the presence of Zba and Zbb extensions and exports
them per-hart to userspace via the hwprobe mechanism. Glibc can then use
these in setting up hwcaps-based library search paths.

There's a little bit of extra housekeeping here: the first change adds
Zba to the set of extensions the kernel recognizes, and the second
change starts tracking ISA features per-hart (in addition to the ANDed
mask of features across all harts which the kernel uses to make
decisions). Now that we track the ISA information per-hart, we could
even fix up /proc/cpuinfo to accurately report extension per-hart,
though I've left that out of this series for now.


Evan Green (3):
  RISC-V: Add Zba extension probing
  RISC-V: Track ISA extensions per hart
  RISC-V: hwprobe: Expose Zba and Zbb

 Documentation/riscv/hwprobe.rst       |  7 +++++
 arch/riscv/include/asm/cpufeature.h   | 10 +++++++
 arch/riscv/include/asm/hwcap.h        |  1 +
 arch/riscv/include/uapi/asm/hwprobe.h |  2 ++
 arch/riscv/kernel/cpu.c               |  1 +
 arch/riscv/kernel/cpufeature.c        | 19 ++++++++----
 arch/riscv/kernel/sys_riscv.c         | 43 ++++++++++++++++++++++-----
 7 files changed, 70 insertions(+), 13 deletions(-)

Comments

Andrew Jones April 29, 2023, 12:34 p.m. UTC | #1

On Fri, Apr 28, 2023 at 12:06:05PM -0700, Evan Green wrote:
> 
> This change detects the presence of Zba and Zbb extensions and exports
> them per-hart to userspace via the hwprobe mechanism. Glibc can then use
> these in setting up hwcaps-based library search paths.
> 
> There's a little bit of extra housekeeping here: the first change adds
> Zba to the set of extensions the kernel recognizes, and the second
> change starts tracking ISA features per-hart (in addition to the ANDed
> mask of features across all harts which the kernel uses to make
> decisions). Now that we track the ISA information per-hart, we could
> even fix up /proc/cpuinfo to accurately report extension per-hart,
> though I've left that out of this series for now.
> 
> 
> Evan Green (3):
>   RISC-V: Add Zba extension probing
>   RISC-V: Track ISA extensions per hart
>   RISC-V: hwprobe: Expose Zba and Zbb
> 
>  Documentation/riscv/hwprobe.rst       |  7 +++++
>  arch/riscv/include/asm/cpufeature.h   | 10 +++++++
>  arch/riscv/include/asm/hwcap.h        |  1 +
>  arch/riscv/include/uapi/asm/hwprobe.h |  2 ++
>  arch/riscv/kernel/cpu.c               |  1 +
>  arch/riscv/kernel/cpufeature.c        | 19 ++++++++----
>  arch/riscv/kernel/sys_riscv.c         | 43 ++++++++++++++++++++++-----
>  7 files changed, 70 insertions(+), 13 deletions(-)
> 
> -- 
> 2.25.1
>

For the series

Reviewed-by: Andrew Jones <[e-mail]>