Re: [PATCH v3 0/2] Add Zawrs support and use it for spinlocks

[Andrea Parri]

On Sun, May 21, 2023 at 01:47:13PM +0200, Heiko Stuebner wrote:
> From: Heiko Stuebner <heiko.stuebner@xxxxxxxx>
> 
> Zawrs [0] was ratified in november 2022 [1], so I've resurrect the patch
> adding Zawrs support for spinlocks and adapted it to recent kernel
> changes.
> 
> Also incorporated are the nice comments David Laight provided on v2.
> 
> 
> Changes since v2:
> - Rebase on top of 6.4-rc1
> - Adapt to changed alternatives Kconfig handling
> - Adapt to changed cpufeature extension handling
> - Address review comments from David Laight
>   - better handling for 32/64bit cases (less ifdefery)
>   - less macros calling macros
>   - don't duplicate __smp_load_reserved_relaxed in
>     __smp_load_reserved_aquire
> 
> Changes since v1:
> - Fixing type checking code for 32/64-bit values
> - Adjustments according to the specification change
> - Adding "depends on !XIP_KERNEL" to RISCV_ISA_ZAWRS
> 
> 
> [0] https://github.com/riscv/riscv-zawrs/blob/main/zawrs.adoc
> [1] https://github.com/riscv/riscv-zawrs/commit/9ff54f7e7fcd95cf1b111d2e54276ff1183bcd37
> 
> Christoph Müllner (1):
>   riscv: Add Zawrs support for spinlocks
> 
> Heiko Stuebner (1):
>   riscv: don't include kernel.h into alternative.h
> 
>  arch/riscv/Kconfig                   | 10 +++++
>  arch/riscv/include/asm/alternative.h |  1 -
>  arch/riscv/include/asm/barrier.h     | 64 ++++++++++++++++++++++++++++
>  arch/riscv/include/asm/errata_list.h | 14 ++++++
>  arch/riscv/include/asm/hwcap.h       |  1 +
>  arch/riscv/kernel/cpu.c              |  1 +
>  arch/riscv/kernel/cpufeature.c       |  1 +
>  7 files changed, 91 insertions(+), 1 deletion(-)


Hi Heiko and Christoph,

I was wondering about the plan for this series: am I missing some update to
this discussion? do we have a new version to review?

I actually went ahead (as Palmer suggested in private  :-) ) and spent some
time trying to integrate feedback provided in this thread into your changes,
obtaining the diff below (on 6.6-rc6, the #include removal fixes some nommu
builds and should/can be splitted into a separate patch); thoughts?

  Andrea