RE: [PATCH] riscv, bpf: Introduce shift add helper with Zba optimization

[Wang, Xiao W]

> -----Original Message-----
> From: Björn Töpel <bjorn@xxxxxxxxxx>
> Sent: Wednesday, May 22, 2024 12:40 AM
> To: Wang, Xiao W <xiao.w.wang@xxxxxxxxx>; paul.walmsley@xxxxxxxxxx;
> palmer@xxxxxxxxxxx; aou@xxxxxxxxxxxxxxxxx; luke.r.nels@xxxxxxxxx;
> xi.wang@xxxxxxxxx
> Cc: ast@xxxxxxxxxx; daniel@xxxxxxxxxxxxx; andrii@xxxxxxxxxx;
> martin.lau@xxxxxxxxx; eddyz87@xxxxxxxxx; song@xxxxxxxxxx;
> yonghong.song@xxxxxxxxx; john.fastabend@xxxxxxxxx; kpsingh@xxxxxxxxxx;
> sdf@xxxxxxxxxx; haoluo@xxxxxxxxxx; jolsa@xxxxxxxxxx; linux-
> riscv@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; bpf@xxxxxxxxxxxxxxx;
> pulehui@xxxxxxxxxx; Li, Haicheng <haicheng.li@xxxxxxxxx>; Wang, Xiao W
> <xiao.w.wang@xxxxxxxxx>
> Subject: Re: [PATCH] riscv, bpf: Introduce shift add helper with Zba
> optimization
> 
> Xiao Wang <xiao.w.wang@xxxxxxxxx> writes:
> 
> > Zba extension is very useful for generating addresses that index into array
> > of basic data types. This patch introduces sh2add and sh3add helpers for
> > RV32 and RV64 respectively, to accelerate pointer array addressing.
> >
> > Signed-off-by: Xiao Wang <xiao.w.wang@xxxxxxxxx>
> 
> This is dependent on [1], and given it hasn't been accepted yet, I'd
> make this patch part of that series.

I would make a new version, combining them as a series. Meanwhile
this patch needs rebase on top of bpf-next and enable one more sh3add
use cases.

BRs,
Xiao

> 
> 
> Björn
> 
> [1] https://lore.kernel.org/linux-riscv/20240516090430.493122-1-
> xiao.w.wang@xxxxxxxxx/