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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date: Tue, 7 May 2024 15:00:04 +0100
From: Ben Dooks <ben.dooks@...ethink.co.uk>
To: Pu Lehui <pulehui@...wei.com>, Xiao Wang <xiao.w.wang@...el.com>,
 paul.walmsley@...ive.com, palmer@...belt.com, aou@...s.berkeley.edu,
 luke.r.nels@...il.com, xi.wang@...il.com, bjorn@...nel.org
Cc: ast@...nel.org, daniel@...earbox.net, andrii@...nel.org,
 martin.lau@...ux.dev, eddyz87@...il.com, song@...nel.org,
 yonghong.song@...ux.dev, john.fastabend@...il.com, kpsingh@...nel.org,
 sdf@...gle.com, haoluo@...gle.com, jolsa@...nel.org,
 linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org,
 bpf@...r.kernel.org, haicheng.li@...el.com
Subject: Re: [PATCH] riscv, bpf: Optimize zextw insn with Zba extension

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@...el.com>
>> ---
>>   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

https://www.codethink.co.uk/privacy.html