From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from canpmsgout10.his.huawei.com (canpmsgout10.his.huawei.com [113.46.200.225]) (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 427733368B5; Mon, 20 Jul 2026 11:20:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=113.46.200.225 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784546435; cv=none; b=NWpgFn7zTHEXrJUlRbA1QEhhXLqoJcRjBjVBc+jm92t7a6sVp8ezp+sMWsHUNhPsL1oMdsrsbyhKaYZ3uPq5QR1vIx05AxRWVJ34Mv25bjU5DjCWmhdBv2Afg81QB+dJ5fSaoZ+2AJVVeBivD2+196xq9WU9VUivJCyDY6jHFsQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784546435; c=relaxed/simple; bh=doRTKAltGwHpfnQUN9/thEJDZ47VpG1lL9TBGkiZ6t8=; h=Message-ID:Date:MIME-Version:Subject:To:References:From: In-Reply-To:Content-Type; b=Xtt74eANnNlz4d4Q7Zexz+OYgEtqpggoklBpgYYG9HdDs5QBgGVk8OTc6KBxOPwylqv45dNmrmzx5S308n504xpClFLEdY24mymxobVwre2GaAVnsSIetTpqI4KBDRS1+mq+txNZnQeTKWm83KAb0Fwjd2gv6z8uR5NJ0R8uk7k= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=h-partners.com; dkim=pass (1024-bit key) header.d=h-partners.com header.i=@h-partners.com header.b=kmF//nHL; arc=none smtp.client-ip=113.46.200.225 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=h-partners.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=h-partners.com header.i=@h-partners.com header.b="kmF//nHL" dkim-signature: v=1; a=rsa-sha256; d=h-partners.com; s=dkim; c=relaxed/relaxed; q=dns/txt; h=From; bh=doRTKAltGwHpfnQUN9/thEJDZ47VpG1lL9TBGkiZ6t8=; b=kmF//nHLCsu0srZBhDueR+vHa8jwnpzG8yf0nTls3r/YSQ7p2sjGXrpabAAiI44N38e5W98iv 3RRvCHNDAb/aGZolD+tHvAr7UGAIR3fTo+sw+9nH/09U/i3WlHek+h3LD6x/BxLGLXdfGRUqFSq M/2mGfPukbAnpXxCVuVLxLM= Received: from mail.maildlp.com (unknown [172.19.163.214]) by canpmsgout10.his.huawei.com (SkyGuard) with ESMTPS id 4h3d9V56Mbz1K96m; Mon, 20 Jul 2026 19:10:54 +0800 (CST) Received: from kwepemo100005.china.huawei.com (unknown [7.202.195.212]) by mail.maildlp.com (Postfix) with ESMTPS id EEAEA4056C; Mon, 20 Jul 2026 19:20:14 +0800 (CST) Received: from [10.67.121.59] (10.67.121.59) by kwepemo100005.china.huawei.com (7.202.195.212) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.36; Mon, 20 Jul 2026 19:20:14 +0800 Message-ID: <624f7f2a-4741-44c7-a127-99f47e3430bd@huawei.com> Date: Mon, 20 Jul 2026 19:20:13 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 2/3] mailbox: pcc: Check shared memory signature on request To: Sudeep Holla , Jassi Brar , , References: <20260717075649.467172-1-sudeep.holla@kernel.org> <20260717075649.467172-3-sudeep.holla@kernel.org> From: "lihuisong (C)" In-Reply-To: <20260717075649.467172-3-sudeep.holla@kernel.org> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-ClientProxiedBy: kwepems500002.china.huawei.com (7.221.188.17) To kwepemo100005.china.huawei.com (7.202.195.212) On 7/17/2026 3:56 PM, Sudeep Holla wrote: > ACPI 6.6 Tables 14.9 and 14.12 define the PCC shared memory > signature as the bitwise OR of 0x50434300 and the PCC subspace ID. > They also clarify that the signature is populated by the platform and > verified by OSPM. The signature is at byte offset 0 in the generic, > extended and reduced PCC shared memory layouts. > > Check the signature when a client requests a PCC mailbox channel, > after mapping shared memory and before binding the mailbox client. > This keeps the check in the PCC mailbox controller instead of > duplicating it in individual clients. > > Treat a signature mismatch as a warning rather than rejecting the > channel request. Making this newly added check fatal could break > existing systems whose firmware did not populate the signature > correctly even though PCC communication works. Continue to reject > shared memory that is too small to contain a signature because it > cannot be inspected safely. > > Cc: Jassi Brar > Cc: Huisong Li > Signed-off-by: Sudeep Holla > --- LGTM, Acked-by: Huisong Li