From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-184.mta0.migadu.com (out-184.mta0.migadu.com [91.218.175.184]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AB5B03932DC for ; Sat, 9 May 2026 13:44:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.184 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778334253; cv=none; b=mFjuEcVkd2lkDYeEIo/ASp1ibD6BjzKwOgw8mDxnVIPqXYUDTtNMN6A/1m/+iKgNkne1q/tPQ025hY5Gpc8GppHtDKww+dO1LD6fd3e4O/s28v+uUuV2jr9/HhC7nZrwLqf2ZV+T3RkblxiximZyW/NxmyRrFCU2gyy2wni2VN0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778334253; c=relaxed/simple; bh=EItFukBZHihPAqnSKcifQSaMA/6ak7SU3XLqj2mJSfk=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=R5fLA/mmZO0QO1hCJ4aZySyLOk130u230rFckqURy0cCHBiM4JzI69MnGJinx2qyZ6eIiXa8Dd68iidJSt19TciEkoMCCbMnbrdrdi3MCt4lrTLgUrmBrMlcFb3xodIIM6xl/FT5hMjuKeAWlZGJkJY8W/sfMleUj/H8I2SlXVs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=Tl5cdJuA; arc=none smtp.client-ip=91.218.175.184 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="Tl5cdJuA" Message-ID: <4230ccc8-e8dc-4596-ac4b-c86b20adecd0@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1778334249; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=EItFukBZHihPAqnSKcifQSaMA/6ak7SU3XLqj2mJSfk=; b=Tl5cdJuApT3oqPLp31RMlPB5RTHIAeXtnJCQxot/+mcVSEZSCHvsTFxtMh51uOUt3lQ7+5 hSaHwAv+GpvZ3Ta589olLQdrM2iE9p2y2MxE4NpzKKdZ0HZk3ADPOo7pD45/PWmrA+ln7N 26CRuaXQCSKGhBHvauX4QP7lqinoa10= Date: Sat, 9 May 2026 14:44:07 +0100 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH bpf-next v2 21/23] bpf, arm64: Map BPF_REG_0 to x8 instead of x7 Content-Language: en-GB To: Alexei Starovoitov , bpf@vger.kernel.org Cc: Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , "Jose E . Marchesi" , kernel-team@fb.com, Martin KaFai Lau , Puranjay Mohan References: <20260507212942.1122000-1-yonghong.song@linux.dev> <20260507213156.1139442-1-yonghong.song@linux.dev> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Yonghong Song In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT On 5/8/26 8:01 PM, Alexei Starovoitov wrote: > On Thu May 7, 2026 at 2:31 PM PDT, Yonghong Song wrote: >> From: Puranjay Mohan >> >> Move the BPF return value register from x7 to x8, freeing x7 for use >> as an argument register. AAPCS64 designates x8 as the indirect result >> location register; it is caller-saved and not used for argument >> passing, making it a suitable home for BPF_REG_0. >> >> This is a prerequisite for stack argument support, which needs x5-x7 >> to pass arguments 6-8 to native kfuncs following the AAPCS64 calling >> convention. >> >> Signed-off-by: Yonghong Song >> Signed-off-by: Yonghong Song > That's not right. > It should probably be: > Signed-off-by: Puranjay Mohan > Signed-off-by: Yonghong Song My mistake. Will fix.