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Date:   Tue, 9 May 2023 06:37:44 -0700
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Subject: Re: [PATCH bpf-next] arm64,bpf: Support struct arguments in the BPF
 trampoline
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To:     Florent Revest <revest@chromium.org>, bpf@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Cc:     ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org,
        kpsingh@kernel.org, mark.rutland@arm.com, xukuohai@huaweicloud.com,
        zlim.lnx@gmail.com
References: <20230508164650.3217164-1-revest@chromium.org>
From:   Yonghong Song <yhs@meta.com>
In-Reply-To: <20230508164650.3217164-1-revest@chromium.org>
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On 5/8/23 9:46 AM, Florent Revest wrote:
> This extends the BPF trampoline JIT to support attachment to functions
> that take small structures (up to 128bit) as argument. This is trivially
> achieved by saving/restoring a number of "argument registers" rather
> than a number of arguments.
> 
> The AAPCS64 section 6.8.2 describes the parameter passing ABI.
> "Composite types" (like C structs) below 16 bytes (as enforced by the
> BPF verifier) are provided as part of the 8 argument registers as
> explained in the section C.12.
> 
> Signed-off-by: Florent Revest <revest@chromium.org>
LGTM. Thanks for adding support for arm64!

Acked-by: Yonghong Song <yhs@fb.com>