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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 54ADFC43217 for ; Thu, 10 Mar 2022 14:31:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243829AbiCJOcL (ORCPT ); Thu, 10 Mar 2022 09:32:11 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49800 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244733AbiCJO30 (ORCPT ); Thu, 10 Mar 2022 09:29:26 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 628D9DCE00; Thu, 10 Mar 2022 06:24:34 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 81F7BB82544; Thu, 10 Mar 2022 14:24:32 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B31A4C340E8; Thu, 10 Mar 2022 14:24:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1646922271; bh=PD8YDBuRBOII3aVAAcFtCX2cx+HFLHuZPpAQYmq1x+Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=TtiwXKaqZ+uZBDt91hUaHlJDDA90eMjUYS2e7KJpX5D7py3Hn675r0Y4F4N2WYuZK Hr3fkM7qg6lCDcW4RBiFFVlkq5f4mIqBowekXE0d+uBpBK74h5QNwWCsEszZg7t/Dk bn2qT9mxzZjb1gkx10I+k/mQtVT72NCqzKCgpf5c= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Russell King (Oracle)" , Catalin Marinas , James Morse Subject: [PATCH 5.10 25/58] arm64: entry: Make the trampoline cleanup optional Date: Thu, 10 Mar 2022 15:18:45 +0100 Message-Id: <20220310140813.593477273@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220310140812.869208747@linuxfoundation.org> References: <20220310140812.869208747@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: James Morse commit d739da1694a0eaef0358a42b76904b611539b77b upstream. Subsequent patches will add additional sets of vectors that use the same tricks as the kpti vectors to reach the full-fat vectors. The full-fat vectors contain some cleanup for kpti that is patched in by alternatives when kpti is in use. Once there are additional vectors, the cleanup will be needed in more cases. But on big/little systems, the cleanup would be harmful if no trampoline vector were in use. Instead of forcing CPUs that don't need a trampoline vector to use one, make the trampoline cleanup optional. Entry at the top of the vectors will skip the cleanup. The trampoline vectors can then skip the first instruction, triggering the cleanup to run. Reviewed-by: Russell King (Oracle) Reviewed-by: Catalin Marinas Signed-off-by: James Morse Signed-off-by: Greg Kroah-Hartman --- arch/arm64/kernel/entry.S | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -65,14 +65,18 @@ .Lventry_start\@: #ifdef CONFIG_UNMAP_KERNEL_AT_EL0 .if \el == 0 -alternative_if ARM64_UNMAP_KERNEL_AT_EL0 + /* + * This must be the first instruction of the EL0 vector entries. It is + * skipped by the trampoline vectors, to trigger the cleanup. + */ + b .Lskip_tramp_vectors_cleanup\@ .if \regsize == 64 mrs x30, tpidrro_el0 msr tpidrro_el0, xzr .else mov x30, xzr .endif -alternative_else_nop_endif +.Lskip_tramp_vectors_cleanup\@: .endif #endif @@ -831,7 +835,7 @@ alternative_if_not ARM64_WORKAROUND_CAVI prfm plil1strm, [x30, #(1b - tramp_vectors)] alternative_else_nop_endif msr vbar_el1, x30 - add x30, x30, #(1b - tramp_vectors) + add x30, x30, #(1b - tramp_vectors + 4) isb ret .org 1b + 128 // Did we overflow the ventry slot?