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 X-Spam-Level: X-Spam-Status: No, score=-12.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C6D6FC43461 for ; Mon, 14 Sep 2020 15:14:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 91A4F20829 for ; Mon, 14 Sep 2020 15:14:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726421AbgINPOY (ORCPT ); Mon, 14 Sep 2020 11:14:24 -0400 Received: from foss.arm.com ([217.140.110.172]:39640 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726341AbgINPKw (ORCPT ); Mon, 14 Sep 2020 11:10:52 -0400 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 D710F1570; Mon, 14 Sep 2020 08:10:46 -0700 (PDT) Received: from seattle-bionic.arm.com.Home (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id E03623F718; Mon, 14 Sep 2020 08:10:45 -0700 (PDT) From: Oliver Swede To: catalin.marinas@arm.com, will@kernel.org Cc: robin.murphy@arm.com, linux-arm-kernel@lists.indradead.org, linux-kernel@vger.kernel.org Subject: [PATCH v5 10/14] arm64: usercopy: Store the arguments on stack Date: Mon, 14 Sep 2020 15:09:54 +0000 Message-Id: <20200914150958.2200-11-oli.swede@arm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200914150958.2200-1-oli.swede@arm.com> References: <20200914150958.2200-1-oli.swede@arm.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Use the stack to preserve the initial arguments to the usercopy functions before the copy routine modifies the relevant registers. The values in x0 (dst), x1 (src) and x2 (count) may be modified in the code paths for large copy sizes, and saving them before the copy begins enables restoration by the fixup routines to ensure they have the required information to backtrack effectively. The stack is used instead of other general-purpose registers due to resource constraints as all scratch registers x0-x17 defined by the PCS in the ABI are utilized by the imported copy routine. The stack pointer is restored to its initial position either from the fixup code in the case of a fault, or at the end of the copy algorithm otherwise. The .Luaccess_finish directive is also moved to copy_template_user.S as the code is common to all usercopy functions. Signed-off-by: Oliver Swede --- arch/arm64/lib/copy_from_user.S | 3 --- arch/arm64/lib/copy_in_user.S | 3 --- arch/arm64/lib/copy_template_user.S | 6 ++++++ arch/arm64/lib/copy_to_user.S | 3 --- arch/arm64/lib/copy_user_fixup.S | 1 + 5 files changed, 7 insertions(+), 9 deletions(-) diff --git a/arch/arm64/lib/copy_from_user.S b/arch/arm64/lib/copy_from_user.S index fa319f27a42b..cd3042e98394 100644 --- a/arch/arm64/lib/copy_from_user.S +++ b/arch/arm64/lib/copy_from_user.S @@ -110,9 +110,6 @@ SYM_FUNC_START(__arch_copy_from_user) #include "copy_template_user.S" -.Luaccess_finish: - mov x0, #0 - ret SYM_FUNC_END(__arch_copy_from_user) EXPORT_SYMBOL(__arch_copy_from_user) #include "copy_user_fixup.S" diff --git a/arch/arm64/lib/copy_in_user.S b/arch/arm64/lib/copy_in_user.S index 6b9bb6091dd8..fe035e513b34 100644 --- a/arch/arm64/lib/copy_in_user.S +++ b/arch/arm64/lib/copy_in_user.S @@ -117,9 +117,6 @@ SYM_FUNC_START(__arch_copy_in_user) #include "copy_template_user.S" -.Luaccess_finish: - mov x0, #0 - ret SYM_FUNC_END(__arch_copy_in_user) EXPORT_SYMBOL(__arch_copy_in_user) #include "copy_user_fixup.S" diff --git a/arch/arm64/lib/copy_template_user.S b/arch/arm64/lib/copy_template_user.S index 3db24dcdab05..1d13daf314b0 100644 --- a/arch/arm64/lib/copy_template_user.S +++ b/arch/arm64/lib/copy_template_user.S @@ -21,4 +21,10 @@ L(copy_non_uao): #undef L #define L(l) .Lnuao ## l + str x2, [sp, #-16]! // count + stp x0, x1, [sp, #-16]! // dstin, src #include "copy_template.S" +.Luaccess_finish: + add sp, sp, 32 + mov x0, #0 + ret diff --git a/arch/arm64/lib/copy_to_user.S b/arch/arm64/lib/copy_to_user.S index 23af6af254da..de0af211b3ba 100644 --- a/arch/arm64/lib/copy_to_user.S +++ b/arch/arm64/lib/copy_to_user.S @@ -110,9 +110,6 @@ SYM_FUNC_START(__arch_copy_to_user) #include "copy_template_user.S" -.Luaccess_finish: - mov x0, #0 - ret SYM_FUNC_END(__arch_copy_to_user) EXPORT_SYMBOL(__arch_copy_to_user) #include "copy_user_fixup.S" diff --git a/arch/arm64/lib/copy_user_fixup.S b/arch/arm64/lib/copy_user_fixup.S index 32fae9e2e799..a528b7d7d1bd 100644 --- a/arch/arm64/lib/copy_user_fixup.S +++ b/arch/arm64/lib/copy_user_fixup.S @@ -10,5 +10,6 @@ addr .req x15 ccmp addr, srcend, #0x0, ge csel x0, srcend, dstend, lt sub x0, x0, addr + add sp, sp, 32 ret -- 2.17.1