Re: [PATCH] riscv, bpf: Optimize zextw insn with Zba extension

[Ben Dooks]

On 07/05/2024 13:47, Pu Lehui wrote:
> On 2024/5/7 18:45, Xiao Wang wrote:
> > The Zba extension provides add.uw insn which can be used to implement
> > zext.w with rs2 set as ZERO.
> >
> > Signed-off-by: Xiao Wang <xiao.w.wang@xxxxxxxxx>
> > ---
> >   arch/riscv/Kconfig       | 19 +++++++++++++++++++
> >   arch/riscv/net/bpf_jit.h | 18 ++++++++++++++++++
> >   2 files changed, 37 insertions(+)
> >
> > diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> > index 6bec1bce6586..0679127cc0ea 100644
> > --- a/arch/riscv/Kconfig
> > +++ b/arch/riscv/Kconfig
> > @@ -586,6 +586,14 @@ config RISCV_ISA_V_PREEMPTIVE
> >         preemption. Enabling this config will result in higher memory
> >         consumption due to the allocation of per-task's kernel Vector 
> > context.
> > +config TOOLCHAIN_HAS_ZBA
> > +    bool
> > +    default y
> > +    depends on !64BIT || $(cc-option,-mabi=lp64 -march=rv64ima_zba)
> > +    depends on !32BIT || $(cc-option,-mabi=ilp32 -march=rv32ima_zba)
> > +    depends on LLD_VERSION >= 150000 || LD_VERSION >= 23900
> > +    depends on AS_HAS_OPTION_ARCH
> > +
> >   config TOOLCHAIN_HAS_ZBB

At this point would it be easier to ask the toolchain what's enabled
and put into kconfig via some sort of script?

--
Ben Dooks				http://www.codethink.co.uk/
Senior Engineer				Codethink - Providing Genius

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