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=-10.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,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 59CEDC433DF for ; Mon, 6 Jul 2020 15:36:42 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 1BE592070C for ; Mon, 6 Jul 2020 15:36:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="aYrHPMAW"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="liJWKnQD" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1BE592070C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:MIME-Version:Message-Id:Date:Subject: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=dVE7+5jbRh0aFJLO178xKXW7bQqLzfg8ukNP8qOvwSw=; b=aYrHPMAWfXk67LRjQumHizvOKC QAkfr6lIwxpno5VM0HXSW4KzNPj/FjcDqgvvZsgmAAVgJ1MFi+FcTkOS16Y7BBhBd0YzT9367du0P KypjdaTSJO/uS/k8PwvA4lRvjW99maqw3nhRNkM6neaTav6c3APTTXu1Oo0LDdQVlbLpG+SICcql5 WPXxTRUBi/n8WI7uRSefccytZpgFvEqX+AfZu4wfbDagV5qQ0mDE2Cid9pc//8kutHytDoxYyZ0TS QbaHBXzb7ste43fJOljpZu5Y8YPQbIkvk5WBSmb/245+wOHSVdUTTEucXaSRBOTWwqnxWESMZWE1g G5gtNnYw==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jsT9D-0006oB-1Z; Mon, 06 Jul 2020 15:35:11 +0000 Received: from mail.kernel.org ([198.145.29.99]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jsT9A-0006nY-MP for linux-arm-kernel@lists.infradead.org; Mon, 06 Jul 2020 15:35:09 +0000 Received: from localhost.localdomain (82-64-249-211.subs.proxad.net [82.64.249.211]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 4630920723; Mon, 6 Jul 2020 15:35:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1594049707; bh=R/1MQmS0jBbGzLTic06YAYYGkl2MghLc7+hj8swGzj8=; h=From:To:Cc:Subject:Date:From; b=liJWKnQD5TxK4rsbDXAVMk6tLaK14soNwql0bFeMZpkus+qz7ocT01NlTblhgVpH+ VQYXOQdfAzLPfNzJDWv0sDbckxSjmYhf5Y02OmOQEVYAYaWf8455E/xd0DjfMQ0+jQ gwXs7sdlPuLwMiWS80JLofdh7WvpDi6wOCoBdxf8= From: Ard Biesheuvel To: linux-arm-kernel@lists.infradead.org Subject: [PATCH] arm64/entry: deduplicate SW PAN entry/exit routines Date: Mon, 6 Jul 2020 17:35:02 +0200 Message-Id: <20200706153502.33686-1-ardb@kernel.org> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200706_113508_879047_CCC3C5C2 X-CRM114-Status: GOOD ( 12.56 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: mark.rutland@arm.com, catalin.marinas@arm.com, james.morse@arm.com, mark.brown@arm.com, will@kernel.org, Ard Biesheuvel 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 Factor the 12 copies of the SW PAN entry and exit code into callable subroutines, and use alternatives patching to either emit a 'bl' instruction to call them, or a NOP if h/w PAN is found to be available at runtime. Signed-off-by: Ard Biesheuvel --- arch/arm64/kernel/entry.S | 96 +++++++++++++++++++-------------------- 1 file changed, 48 insertions(+), 48 deletions(-) diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index 5304d193c79d..96a9fb2ed49f 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -209,28 +209,9 @@ alternative_cb_end add x29, sp, #S_STACKFRAME #ifdef CONFIG_ARM64_SW_TTBR0_PAN - /* - * Set the TTBR0 PAN bit in SPSR. When the exception is taken from - * EL0, there is no need to check the state of TTBR0_EL1 since - * accesses are always enabled. - * Note that the meaning of this bit differs from the ARMv8.1 PAN - * feature as all TTBR0_EL1 accesses are disabled, not just those to - * user mappings. - */ -alternative_if ARM64_HAS_PAN - b 1f // skip TTBR0 PAN +alternative_if_not ARM64_HAS_PAN + bl __swpan_entry_el\el alternative_else_nop_endif - - .if \el != 0 - mrs x21, ttbr0_el1 - tst x21, #TTBR_ASID_MASK // Check for the reserved ASID - orr x23, x23, #PSR_PAN_BIT // Set the emulated PAN in the saved SPSR - b.eq 1f // TTBR0 access already disabled - and x23, x23, #~PSR_PAN_BIT // Clear the emulated PAN in the saved SPSR - .endif - - __uaccess_ttbr0_disable x21 -1: #endif stp x22, x23, [sp, #S_PC] @@ -284,34 +265,9 @@ alternative_else_nop_endif .endif #ifdef CONFIG_ARM64_SW_TTBR0_PAN - /* - * Restore access to TTBR0_EL1. If returning to EL0, no need for SPSR - * PAN bit checking. - */ -alternative_if ARM64_HAS_PAN - b 2f // skip TTBR0 PAN +alternative_if_not ARM64_HAS_PAN + bl __swpan_exit_el\el alternative_else_nop_endif - - .if \el != 0 - tbnz x22, #22, 1f // Skip re-enabling TTBR0 access if the PSR_PAN_BIT is set - .endif - - __uaccess_ttbr0_enable x0, x1 - - .if \el == 0 - /* - * Enable errata workarounds only if returning to user. The only - * workaround currently required for TTBR0_EL1 changes are for the - * Cavium erratum 27456 (broadcast TLBI instructions may cause I-cache - * corruption). - */ - bl post_ttbr_update_workaround - .endif -1: - .if \el != 0 - and x22, x22, #~PSR_PAN_BIT // ARMv8.0 CPUs do not understand this bit - .endif -2: #endif .if \el == 0 @@ -391,6 +347,50 @@ alternative_insn eret, nop, ARM64_UNMAP_KERNEL_AT_EL0 sb .endm +#ifdef CONFIG_ARM64_SW_TTBR0_PAN + /* + * Set the TTBR0 PAN bit in SPSR. When the exception is taken from + * EL0, there is no need to check the state of TTBR0_EL1 since + * accesses are always enabled. + * Note that the meaning of this bit differs from the ARMv8.1 PAN + * feature as all TTBR0_EL1 accesses are disabled, not just those to + * user mappings. + */ +SYM_CODE_START_LOCAL(__swpan_entry_el1) + mrs x21, ttbr0_el1 + tst x21, #TTBR_ASID_MASK // Check for the reserved ASID + orr x23, x23, #PSR_PAN_BIT // Set the emulated PAN in the saved SPSR + b.eq 1f // TTBR0 access already disabled + and x23, x23, #~PSR_PAN_BIT // Clear the emulated PAN in the saved SPSR +SYM_INNER_LABEL(__swpan_entry_el0, SYM_L_LOCAL) + __uaccess_ttbr0_disable x21 +1: ret +SYM_CODE_END(__swpan_entry_el1) + + /* + * Restore access to TTBR0_EL1. If returning to EL0, no need for SPSR + * PAN bit checking. + */ +SYM_CODE_START_LOCAL(__swpan_exit_el1) + tbnz x22, #22, 1f // Skip re-enabling TTBR0 access if the PSR_PAN_BIT is set + __uaccess_ttbr0_enable x0, x1 +1: and x22, x22, #~PSR_PAN_BIT // ARMv8.0 CPUs do not understand this bit + ret +SYM_CODE_END(__swpan_exit_el1) + +SYM_CODE_START_LOCAL(__swpan_exit_el0) + __uaccess_ttbr0_enable x0, x1 + /* + * Enable errata workarounds only if returning to user. The only + * workaround currently required for TTBR0_EL1 changes are for the + * Cavium erratum 27456 (broadcast TLBI instructions may cause I-cache + * corruption). + */ + bl post_ttbr_update_workaround + ret +SYM_CODE_END(__swpan_exit_el0) +#endif + .macro irq_stack_entry mov x19, sp // preserve the original sp #ifdef CONFIG_SHADOW_CALL_STACK -- 2.20.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel