From nobody Thu Dec 18 18:51:19 2025 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 8B18BEB64DD for ; Mon, 14 Aug 2023 10:01:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233700AbjHNKAn (ORCPT ); Mon, 14 Aug 2023 06:00:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52436 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234554AbjHNKA1 (ORCPT ); Mon, 14 Aug 2023 06:00:27 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BCC58E65; Mon, 14 Aug 2023 03:00:26 -0700 (PDT) Date: Mon, 14 Aug 2023 10:00:24 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1692007225; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=7sNSLYyhA4qV7EEKt3GZvB5O3YA2jlDM3bozLIDUGkU=; b=qMVDkV6QNPtPMVlTFtOldtNHq4ZMMy66F5G4oqyMQvZqClRi1DCOvxkgLyWwv4tT51cgQ1 ntX1Wh6kH5T9DTM5Et0A5+tCUTykOe5GNORcXvNGErMng7Bk8V2XcxB9LyzEehwDcTNJhf Kod7sxqEod4CvM0JNMOJIynPmdR0tXxfr/lUgg7/duhRTmCwUOLPt5uaiWukwGlNNtn54J QmGaTJG+SU3dl88lnqj807Yum/Uxlqfs4pQf95Xik5syIXCuACtUXxFxSTDk+5kabSo09r ud9wTRu3lqUqqu96lK42gs4JhDLx8De97SXDJcWKD0tDiiCGtBEY+AhpnkOVew== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1692007225; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=7sNSLYyhA4qV7EEKt3GZvB5O3YA2jlDM3bozLIDUGkU=; b=AlAeZz5zpYlXbgXzULu3S4I4bJrdwvL+UY1IH3/pJtYQWkNc70zhAiTtyYNpSq2ARQygCZ Q3wdA7CZQe4Ud8Dw== From: "tip-bot2 for Petr Pavlu" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: x86/urgent] x86/retpoline,kprobes: Fix position of thunk sections with CONFIG_LTO_CLANG Cc: Petr Pavlu , "Peter Zijlstra (Intel)" , Nathan Chancellor , "Borislav Petkov (AMD)" , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20230711091952.27944-2-petr.pavlu@suse.com> References: <20230711091952.27944-2-petr.pavlu@suse.com> MIME-Version: 1.0 Message-ID: <169200722469.27769.3677814215325694646.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the x86/urgent branch of tip: Commit-ID: 79cd2a11224eab86d6673fe8a11d2046ae9d2757 Gitweb: https://git.kernel.org/tip/79cd2a11224eab86d6673fe8a11d2046a= e9d2757 Author: Petr Pavlu AuthorDate: Tue, 11 Jul 2023 11:19:51 +02:00 Committer: Borislav Petkov (AMD) CommitterDate: Mon, 14 Aug 2023 11:44:19 +02:00 x86/retpoline,kprobes: Fix position of thunk sections with CONFIG_LTO_CLANG The linker script arch/x86/kernel/vmlinux.lds.S matches the thunk sections ".text.__x86.*" from arch/x86/lib/retpoline.S as follows: .text { [...] TEXT_TEXT [...] __indirect_thunk_start =3D .; *(.text.__x86.*) __indirect_thunk_end =3D .; [...] } Macro TEXT_TEXT references TEXT_MAIN which normally expands to only ".text". However, with CONFIG_LTO_CLANG, TEXT_MAIN becomes ".text .text.[0-9a-zA-Z_]*" which wrongly matches also the thunk sections. The output layout is then different than expected. For instance, the currently defined range [__indirect_thunk_start, __indirect_thunk_end] becomes empty. Prevent the problem by using ".." as the first separator, for example, ".text..__x86.indirect_thunk". This pattern is utilized by other explicit section names which start with one of the standard prefixes, such as ".text" or ".data", and that need to be individually selected in the linker script. [ nathan: Fix conflicts with SRSO and fold in fix issue brought up by Andrew Cooper in post-review: https://lore.kernel.org/20230803230323.1478869-1-andrew.cooper3@citrix.= com ] Fixes: dc5723b02e52 ("kbuild: add support for Clang LTO") Signed-off-by: Petr Pavlu Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Nathan Chancellor Signed-off-by: Borislav Petkov (AMD) Link: https://lore.kernel.org/r/20230711091952.27944-2-petr.pavlu@suse.com --- arch/x86/kernel/vmlinux.lds.S | 8 ++++---- arch/x86/lib/retpoline.S | 8 ++++---- tools/objtool/check.c | 2 +- 3 files changed, 9 insertions(+), 9 deletions(-) diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S index ef06211..dfb8783 100644 --- a/arch/x86/kernel/vmlinux.lds.S +++ b/arch/x86/kernel/vmlinux.lds.S @@ -134,15 +134,15 @@ SECTIONS SOFTIRQENTRY_TEXT #ifdef CONFIG_RETPOLINE __indirect_thunk_start =3D .; - *(.text.__x86.indirect_thunk) - *(.text.__x86.return_thunk) + *(.text..__x86.indirect_thunk) + *(.text..__x86.return_thunk) __indirect_thunk_end =3D .; #endif STATIC_CALL_TEXT =20 ALIGN_ENTRY_TEXT_BEGIN #ifdef CONFIG_CPU_SRSO - *(.text.__x86.rethunk_untrain) + *(.text..__x86.rethunk_untrain) #endif =20 ENTRY_TEXT @@ -153,7 +153,7 @@ SECTIONS * definition. */ . =3D srso_untrain_ret_alias | (1 << 2) | (1 << 8) | (1 << 14) | (1 << 2= 0); - *(.text.__x86.rethunk_safe) + *(.text..__x86.rethunk_safe) #endif ALIGN_ENTRY_TEXT_END *(.gnu.warning) diff --git a/arch/x86/lib/retpoline.S b/arch/x86/lib/retpoline.S index 132cedb..8db74d8 100644 --- a/arch/x86/lib/retpoline.S +++ b/arch/x86/lib/retpoline.S @@ -13,7 +13,7 @@ #include #include =20 - .section .text.__x86.indirect_thunk + .section .text..__x86.indirect_thunk =20 =20 .macro POLINE reg @@ -148,7 +148,7 @@ SYM_CODE_END(__x86_indirect_jump_thunk_array) * As a result, srso_safe_ret_alias() becomes a safe return. */ #ifdef CONFIG_CPU_SRSO - .section .text.__x86.rethunk_untrain + .section .text..__x86.rethunk_untrain =20 SYM_START(srso_untrain_ret_alias, SYM_L_GLOBAL, SYM_A_NONE) ANNOTATE_NOENDBR @@ -158,7 +158,7 @@ SYM_START(srso_untrain_ret_alias, SYM_L_GLOBAL, SYM_A_N= ONE) SYM_FUNC_END(srso_untrain_ret_alias) __EXPORT_THUNK(srso_untrain_ret_alias) =20 - .section .text.__x86.rethunk_safe + .section .text..__x86.rethunk_safe #endif =20 /* Needs a definition for the __x86_return_thunk alternative below. */ @@ -172,7 +172,7 @@ SYM_START(srso_safe_ret_alias, SYM_L_GLOBAL, SYM_A_NONE) int3 SYM_FUNC_END(srso_safe_ret_alias) =20 - .section .text.__x86.return_thunk + .section .text..__x86.return_thunk =20 /* * Safety details here pertain to the AMD Zen{1,2} microarchitecture: diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 8936a05..e2ee10c 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -389,7 +389,7 @@ static int decode_instructions(struct objtool_file *fil= e) if (!strcmp(sec->name, ".noinstr.text") || !strcmp(sec->name, ".entry.text") || !strcmp(sec->name, ".cpuidle.text") || - !strncmp(sec->name, ".text.__x86.", 12)) + !strncmp(sec->name, ".text..__x86.", 13)) sec->noinstr =3D true; =20 /*