From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id E181ACFC52C for ; Mon, 14 Oct 2024 10:08:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=NrilqX9I0/mXNvp4xDJtkTprlVVw46zascPCdyF0ul0=; b=AvwYfXyIKoPMhKy54d7hWxn5W/ 1mAuL+Sjv20xK3cgYFtrEoWiz4nKaUMMYPAMonTJDz68wdFwzjmdZW+8+TsHEipIR1TjDdldn5w8F HSucRUIIGE201BdcJO1fr0Bk3FgjxI1zddwtoRt7wzMn8bIr+jdoEuWFEw5FLAWhSwFZaASUCT1Wg FI1V5qXopSGYcbOkQv6iN0FErng5+fAjFhKeoNwvIboFUYmh9x8y0VFwg35QqtSK3wnlsyi7bnJi/ jk/jwUKqllKSnsa0Fuib6jRJ/UV/FuYsqi+0P6NPPXYw+7C4N5Da/jsDmFa23dObhsvT/ESU33W6E /LTBc5rg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1t0I0L-00000004eD5-3bS7; Mon, 14 Oct 2024 10:08:45 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1t0Hm1-00000004bnH-0rdh for linux-arm-kernel@lists.infradead.org; Mon, 14 Oct 2024 09:53:58 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 090851424; Mon, 14 Oct 2024 02:54:26 -0700 (PDT) Received: from [10.57.78.229] (unknown [10.57.78.229]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 4A29B3F51B; Mon, 14 Oct 2024 02:53:54 -0700 (PDT) Message-ID: <87ba9595-6229-4a79-aa65-d76567ef708e@arm.com> Date: Mon, 14 Oct 2024 10:54:00 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] ARM: NOMMU: Fix exc_ret for stack frame type To: Jisheng Zhang , Russell King Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <20241013132520.2848-1-jszhang@kernel.org> Content-Language: en-GB From: Vladimir Murzin In-Reply-To: <20241013132520.2848-1-jszhang@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20241014_025357_324879_54A53776 X-CRM114-Status: UNSURE ( 7.28 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 10/13/24 14:25, Jisheng Zhang wrote: > commit 72cd4064fcca ("ARM: 8830/1: NOMMU: Toggle only bits in > EXC_RETURN we are really care of") only sets BIT[3] for Thread mode > and BIT[2] for PSP, it leaves BIT[4] untouched. But there's such a > case: the pre-linux env makes use of FPU then the BIT[4] in 'lr' is > cleared, this brings an umatch issue since the NOMMU kernel doesn't Can pre-linux env disable FPU before passing control to kernel (which is, as correctly pointed, doesn't know how to use FPU)? Cheers Vladimir