> -----Original Message----- > From: Conor Dooley <conor@xxxxxxxxxx> > Sent: Saturday, May 11, 2024 4:56 AM > To: Wang, Xiao W <xiao.w.wang@xxxxxxxxx> > Cc: paul.walmsley@xxxxxxxxxx; palmer@xxxxxxxxxxx; > aou@xxxxxxxxxxxxxxxxx; luke.r.nels@xxxxxxxxx; xi.wang@xxxxxxxxx; > bjorn@xxxxxxxxxx; 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> > Subject: Re: [PATCH] riscv, bpf: Optimize zextw insn with Zba extension > > On Tue, May 07, 2024 at 06:45:28PM +0800, 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 > > bool > > default y > > @@ -601,6 +609,17 @@ config TOOLCHAIN_HAS_VECTOR_CRYPTO > > def_bool $(as-instr, .option arch$(comma) +v$(comma) +zvkb) > > depends on AS_HAS_OPTION_ARCH > > > > +config RISCV_ISA_ZBA > > + bool "Zba extension support for bit manipulation instructions" > > + depends on TOOLCHAIN_HAS_ZBA > > + depends on RISCV_ALTERNATIVE > > + default y > > + help > > + Adds support to dynamically detect the presence of the ZBA > > + extension (address generation acceleration) and enable its usage. > > Recently I sent some patches to reword other extensions' help text, > because the "add support to dynamically detect" had confused people a > bit. Dynamic detection is done regardless of config options for Zba. > The wording I went with in my patch for Zbb was: > Add support for enabling optimisations in the kernel when the > Zbb extension is detected at boot. > Could you use something similar here in the opening sentence please? Agree with you. Yes, I would reword it in next version. Thanks, Xiao > > Thanks, > Conor.
