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 2C6F2F9EDF3 for ; Wed, 22 Apr 2026 14:55:21 +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=7x8NcCz4D4k8BoARMFXUaAiQFS57TSC8jfPtJn+E3P4=; b=SZBM8ACDDu4OdToaGDxoWWbZwn TLYMfbJwUjR3lvFcjmN0+GaBJorqybVJA+RezFyWDPdU0dV6sGkZWB/teVSeas5XGznrmgJhHxxWx NSy3RlUZrm4aJDNdcYD+t98LPxlpIAent9kxRiPIqBJ4EWWB4x+QyaF3sn9Npaj4WfQzFWdedB4G6 opG4J14ULFR7jEtcsk//OA232UZSELO9Ia3uILvvxmLRn7JtrSrCYSUil56GgKQFiASsuuDf9mhtR D6YVUV0gheNA+20hL0xCIlInyWPKkjYaWBkia5xEjftLkzlxfsJLf52P3cD2PhX+0eji9DFF5httc X/8B6cDg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1wFYyy-0000000AON9-0iQA; Wed, 22 Apr 2026 14:55:16 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1wFYyw-0000000AOLh-1CeY for linux-arm-kernel@lists.infradead.org; Wed, 22 Apr 2026 14:55:15 +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 6BBC21FC4; Wed, 22 Apr 2026 07:55:04 -0700 (PDT) Received: from [10.57.63.98] (unknown [10.57.63.98]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 11BF33FE87; Wed, 22 Apr 2026 07:55:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1776869709; bh=wJB1LFrB+6P6GUuEZG1cJk09ntt3ZtX4VBvKoiziV80=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=JBVyTXlyA0MOQUTKYlz3n9cWumPLYHdJa0eN95ySt03/esN0IUlkcZNndcqtI2ku+ awm6imBU+4GxwbUdan20Skrc47sQU8i80ATkV+PddD32eQXbbScdBWgf93zO7McgMl o4+GqLtTo3xcIMglkkN6+XCpFmpAdQcsimhtCsgA= Message-ID: <693f4d7c-46f4-409b-8944-a8c9e4b5e073@arm.com> Date: Wed, 22 Apr 2026 16:55:05 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/4] arm64: signal: Preserve POR_EL0 if poe_context is missing To: Will Deacon Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Catalin Marinas , Joey Gouly , Mark Brown , Shuah Khan , linux-kselftest@vger.kernel.org References: <20260421144252.1440365-1-kevin.brodsky@arm.com> <20260421144252.1440365-2-kevin.brodsky@arm.com> From: Kevin Brodsky Content-Language: en-GB In-Reply-To: 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-20260422_075514_375683_51FCCCE1 X-CRM114-Status: GOOD ( 16.34 ) 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 22/04/2026 14:19, Will Deacon wrote: >> @@ -74,8 +76,12 @@ struct rt_sigframe_user_layout { >> * This state needs to be carefully managed to ensure that it doesn't cause >> * uaccess to fail when setting up the signal frame, and the signal handler >> * itself also expects a well-defined state when entered. >> + * >> + * The valid_fields member is a bitfield (see UA_STATE_HAS_*), specifying which >> + * of the remaining fields is valid (has been set to a value). >> */ >> struct user_access_state { >> + unsigned int valid_fields; >> u64 por_el0; >> }; > Do you think it would be worth adding some accessors to make it easier > to keep the flags in sync? For example: > > /* Stores por_el0 into uas->por_el0 and sets UA_STATE_HAS_POR_EL0 */ > void set_ua_state_por_el0(struct user_access_state *uas, u64 por_el0); > > /* > * If UA_STATE_HAS_POR_EL0, *por_el0 = uas->por_el0 and return 0. > * Otherwise, return -ENOENT. > */ > int get_ua_state_por_el0(struct user_access_state *uas, u64 *por_el0); > > WDYT? I did get a feeling having helpers would be a good idea. I wonder if getters/setters aren't a bit overkill though, as they make accesses to the struct more cumbersome and we'd need a pair for every member (unless we use some macro magic). Maybe it would be sufficient to have say ua_state_has_field(POR_EL0) to check if the bit is set, and ua_state_set_field_valid(POR_EL0) to set the bit? >> @@ -1095,7 +1104,7 @@ SYSCALL_DEFINE0(rt_sigreturn) >> { >> struct pt_regs *regs = current_pt_regs(); >> struct rt_sigframe __user *frame; >> - struct user_access_state ua_state; >> + struct user_access_state ua_state = {0}; > nit: {} should do (no need for the '0'). Same in setup_rt_frame(). Will change it, I have some vague recollection that GCC and Clang disagreed about the meaning of {}... but that's probably fixed nowadays. Thanks for the review! - Kevin