From patchwork Mon Oct 3 13:10:19 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thadeu Lima de Souza Cascardo X-Patchwork-Id: 12997562 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 E3614C433FE for ; Mon, 3 Oct 2022 13:12:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230055AbiJCNMi (ORCPT ); Mon, 3 Oct 2022 09:12:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60104 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230138AbiJCNM0 (ORCPT ); Mon, 3 Oct 2022 09:12:26 -0400 Received: from smtp-relay-canonical-1.canonical.com (smtp-relay-canonical-1.canonical.com [185.125.188.121]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 97CFD4DB08; Mon, 3 Oct 2022 06:12:20 -0700 (PDT) Received: from quatroqueijos.. (unknown [179.93.174.77]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by smtp-relay-canonical-1.canonical.com (Postfix) with ESMTPSA id 825B442FB6; Mon, 3 Oct 2022 13:11:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=canonical.com; s=20210705; t=1664802722; bh=2v7bqh/+VXkzyq7DtBvxVkdvkf/HUwlbh79QVDR68BY=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=iU97hdOYqLCMGA73b2OK4tXtPpE7bgdDnSSpMbIQqbtVrCO8ahQmHlfzs7VULu1Ao ofLUdUP5pqa6E3XjqqAAUgR4gd7DNj0q+jEG9a6SbZlwQtQYCWAn6aekKrY+zkLv0n aS3zeqD2cKLYSHKlJ2OUv9k9hHfrxYjdMUXTan8nWo7jJLTcjVLyQXwAdqFq3k110x Jo+W205QTIjHrNN13UZp6GLnIV031F3Az0yN8bmejpVMUY0QjbmmfKEl6xiuwP0MCd hNyZzBUVqxzOq95svoAbMcSvJe6EPOg4bDR8KJhcxpiu8H1zLrOUaxaeKNebxezq53 AMAI1X13UGqAg== From: Thadeu Lima de Souza Cascardo To: stable@vger.kernel.org Cc: x86@kernel.org, kvm@vger.kernel.org, bp@alien8.de, pbonzini@redhat.com, peterz@infradead.org, jpoimboe@kernel.org Subject: [PATCH 5.4 18/37] x86/speculation: Change FILL_RETURN_BUFFER to work with objtool Date: Mon, 3 Oct 2022 10:10:19 -0300 Message-Id: <20221003131038.12645-19-cascardo@canonical.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20221003131038.12645-1-cascardo@canonical.com> References: <20221003131038.12645-1-cascardo@canonical.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Peter Zijlstra commit 089dd8e53126ebaf506e2dc0bf89d652c36bfc12 upstream. Change FILL_RETURN_BUFFER so that objtool groks it and can generate correct ORC unwind information. - Since ORC is alternative invariant; that is, all alternatives should have the same ORC entries, the __FILL_RETURN_BUFFER body can not be part of an alternative. Therefore, move it out of the alternative and keep the alternative as a sort of jump_label around it. - Use the ANNOTATE_INTRA_FUNCTION_CALL annotation to white-list these 'funny' call instructions to nowhere. - Use UNWIND_HINT_EMPTY to 'fill' the speculation traps, otherwise objtool will consider them unreachable. - Move the RSP adjustment into the loop, such that the loop has a deterministic stack layout. Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Alexandre Chartre Acked-by: Josh Poimboeuf Link: https://lkml.kernel.org/r/20200428191700.032079304@infradead.org [cascardo: fixup because of backport of ba6e31af2be96c4d0536f2152ed6f7b6c11bca47 ("x86/speculation: Add LFENCE to RSB fill sequence")] [cascardo: no intra-function call validation support] [cascardo: avoid UNWIND_HINT_EMPTY because of svm] Signed-off-by: Thadeu Lima de Souza Cascardo --- arch/x86/include/asm/nospec-branch.h | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h index 0b1630c2c46b..460360cfab5a 100644 --- a/arch/x86/include/asm/nospec-branch.h +++ b/arch/x86/include/asm/nospec-branch.h @@ -4,11 +4,13 @@ #define _ASM_X86_NOSPEC_BRANCH_H_ #include +#include #include #include #include #include +#include /* * This should be used immediately before a retpoline alternative. It tells @@ -60,9 +62,9 @@ lfence; \ jmp 775b; \ 774: \ + add $(BITS_PER_LONG/8) * 2, sp; \ dec reg; \ jnz 771b; \ - add $(BITS_PER_LONG/8) * nr, sp; \ /* barrier for jnz misprediction */ \ lfence; #else @@ -154,10 +156,8 @@ */ .macro FILL_RETURN_BUFFER reg:req nr:req ftr:req #ifdef CONFIG_RETPOLINE - ANNOTATE_NOSPEC_ALTERNATIVE - ALTERNATIVE "jmp .Lskip_rsb_\@", \ - __stringify(__FILL_RETURN_BUFFER(\reg,\nr,%_ASM_SP)) \ - \ftr + ALTERNATIVE "jmp .Lskip_rsb_\@", "", \ftr + __FILL_RETURN_BUFFER(\reg,\nr,%_ASM_SP) .Lskip_rsb_\@: #endif .endm