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 3E3DEC433F5 for ; Tue, 28 Dec 2021 01:07:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:List-Subscribe:List-Help: List-Post:List-Archive:List-Unsubscribe:List-Id:Message-Id:Date:Subject:Cc:To :From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References: List-Owner; bh=PAGuM3XMZyvzPcdRQy1OQkaZuJJio/hI8iZ179L82Lk=; b=MWxOwbaGTmFdHY kHyZNgOdc+ucli50h5JsOePQJxfy1XqA0c5VbYu437eFUGBtRoO0lDo36wKK4LzhN8Im2D6ZyNfqR MatXKlvBRHnhmAMNLbh7JgTbqfg8UMTBDHkFow65NO5cCgwjslJX2wS6lKpQ9ZE2gze+ssmoujGtw 7MIlEDE8zps42IemFkLdG7T1T7DkFpXbZ3Dpco2LtZlY36QDdMrbirHSPdc/l6Ap2AXzIebJZnhUL wZWeN685RdDrqrFiQcZNk5j70KGV5jizrd/cweW0AkCRnuVI11lpXHw3oCQv1zcLCa1wAxfhfrxMe xQhbPxsCHOTKdyY9u1gw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1n20wi-00038L-LK; Tue, 28 Dec 2021 01:06:32 +0000 Received: from out4436.biz.mail.alibaba.com ([47.88.44.36]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1n20we-00037s-93 for linux-arm-kernel@lists.infradead.org; Tue, 28 Dec 2021 01:06:30 +0000 X-Alimail-AntiSpam: AC=PASS; BC=-1|-1; BR=01201311R131e4; CH=green; DM=||false|; DS=||; FP=0|-1|-1|-1|0|-1|-1|-1; HT=e01e04423; MF=ashimida@linux.alibaba.com; NM=1; PH=DS; RN=11; SR=0; TI=SMTPD_---0V0.tzGd_1640653565; Received: from localhost(mailfrom:ashimida@linux.alibaba.com fp:SMTPD_---0V0.tzGd_1640653565) by smtp.aliyun-inc.com(127.0.0.1); Tue, 28 Dec 2021 09:06:11 +0800 From: Dan Li To: catalin.marinas@arm.com, will@kernel.org, mark.rutland@arm.com, samitolvanen@google.com, maz@kernel.org, joey.gouly@arm.com, pcc@google.com Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org, Dan Li Subject: [PATCH] [RFC] aarch64: scs: reload shadow call stack in user exception entry Date: Mon, 27 Dec 2021 17:06:04 -0800 Message-Id: <20211228010604.109572-1-ashimida@linux.alibaba.com> X-Mailer: git-send-email 2.17.1 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20211227_170628_512611_FE576372 X-CRM114-Status: UNSURE ( 8.08 ) 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: , MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org When el0 exception occurs, kernel_entry/exit will load/save tsk->scs_sp to ensure scs working properly. AFAIK, the SCS offset should always be 0 at this time. Is it reasonable to reload x18 to scs_base directly in kernel_entry here, or am I missing something? Signed-off-by: Dan Li --- arch/arm64/include/asm/scs.h | 7 +++++++ arch/arm64/kernel/entry.S | 3 +-- 2 files changed, 8 insertions(+), 2 deletions(-) diff --git a/arch/arm64/include/asm/scs.h b/arch/arm64/include/asm/scs.h index 8297bccf0784..2bc0d0575e75 100644 --- a/arch/arm64/include/asm/scs.h +++ b/arch/arm64/include/asm/scs.h @@ -9,6 +9,10 @@ #ifdef CONFIG_SHADOW_CALL_STACK scs_sp .req x18 + .macro scs_reload tsk + ldr scs_sp, [\tsk, #TSK_TI_SCS_BASE] + .endm + .macro scs_load tsk ldr scs_sp, [\tsk, #TSK_TI_SCS_SP] .endm @@ -17,6 +21,9 @@ str scs_sp, [\tsk, #TSK_TI_SCS_SP] .endm #else + .macro scs_reload tsk + .endm + .macro scs_load tsk .endm diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index bc6d5a970a13..57547a3e4f7c 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -265,7 +265,7 @@ alternative_if ARM64_HAS_ADDRESS_AUTH alternative_else_nop_endif 1: - scs_load tsk + scs_reload tsk .else add x21, sp, #PT_REGS_SIZE get_current_task tsk @@ -365,7 +365,6 @@ alternative_if ARM64_WORKAROUND_845719 alternative_else_nop_endif #endif 3: - scs_save tsk /* Ignore asynchronous tag check faults in the uaccess routines */ ldr x0, [tsk, THREAD_SCTLR_USER] -- 2.17.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel