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 A3CC4C433EF for ; Wed, 9 Mar 2022 16:14:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234964AbiCIQPk (ORCPT ); Wed, 9 Mar 2022 11:15:40 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38206 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236113AbiCIQJh (ORCPT ); Wed, 9 Mar 2022 11:09:37 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CEFDA344F3; Wed, 9 Mar 2022 08:07:33 -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 dfw.source.kernel.org (Postfix) with ESMTPS id 6D02D61797; Wed, 9 Mar 2022 16:07:33 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 770B4C340E8; Wed, 9 Mar 2022 16:07:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1646842052; bh=Mml45n5zWOY5XUlvrM0ABUbDBgc/vQ9ckQ54OR4R62A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=N5S/6w4Z1bmTl8EMglWEjMt8hNrcWWOfWGTSvcImK1ufoXFeBfKLlskchX4xwmd6R 6YjBT3soTFMorupWcB3mnRpaejqpqaV9QAbJMJYrQR7a8jiKwpJvkTbGnuNvncSL01 inIgG8eRw7DxGLv24QtBdtW+7tOYjJWOfxY3RtoY= 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 5.15 24/43] arm64: entry: Make the trampoline cleanup optional Date: Wed, 9 Mar 2022 17:00:08 +0100 Message-Id: <20220309155900.437614562@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220309155859.734715884@linuxfoundation.org> References: <20220309155859.734715884@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: linux-kernel@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 @@ -40,14 +40,18 @@ .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 @@ -661,7 +665,7 @@ 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?