From patchwork Tue Jul 11 09:19:51 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Petr Pavlu X-Patchwork-Id: 13308323 X-Patchwork-Delegate: mhiramat@kernel.org 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 76D21EB64DC for ; Tue, 11 Jul 2023 09:25:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231782AbjGKJZO (ORCPT ); Tue, 11 Jul 2023 05:25:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48850 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229591AbjGKJYt (ORCPT ); Tue, 11 Jul 2023 05:24:49 -0400 Received: from smtp-out2.suse.de (smtp-out2.suse.de [IPv6:2001:67c:2178:6::1d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A41361700; Tue, 11 Jul 2023 02:20:17 -0700 (PDT) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id 06E28204C9; Tue, 11 Jul 2023 09:20:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1689067216; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=iI7nJcUhT/ujZHR+Nu6KvZN0K988m1KlGbGdgYPc0ZA=; b=gII+4A1SQ9F3e8Un+jXswik76i6nU2M4zNhLLHxtwt2f4AwpMtpr05kTdAY5zN/15XRXMi PHriPhZPz95uGpnixVpCNsbdkLaJnDDg92kOG6g+JPaz2ZtbHIFa/FgWWwTaRwQU7OEiNM VC5MFn4ylEhcbxxlL6w3KGN7DhwrSdU= Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id BCCB11390F; Tue, 11 Jul 2023 09:20:15 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id CJpdLc8erWSiVwAAMHmgww (envelope-from ); Tue, 11 Jul 2023 09:20:15 +0000 From: Petr Pavlu To: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com, mhiramat@kernel.org, peterz@infradead.org Cc: samitolvanen@google.com, x86@kernel.org, linux-trace-kernel@vger.kernel.org, linux-kernel@vger.kernel.org, Petr Pavlu Subject: [PATCH v2 1/2] x86/retpoline,kprobes: Fix position of thunk sections with CONFIG_LTO_CLANG Date: Tue, 11 Jul 2023 11:19:51 +0200 Message-Id: <20230711091952.27944-2-petr.pavlu@suse.com> X-Mailer: git-send-email 2.35.3 In-Reply-To: <20230711091952.27944-1-petr.pavlu@suse.com> References: <20230711091952.27944-1-petr.pavlu@suse.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-trace-kernel@vger.kernel.org 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 = .; *(.text.__x86.*) __indirect_thunk_end = .; [...] } 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. Fixes: dc5723b02e52 ("kbuild: add support for Clang LTO") Signed-off-by: Petr Pavlu Acked-by: Peter Zijlstra (Intel) --- arch/x86/kernel/vmlinux.lds.S | 2 +- arch/x86/lib/retpoline.S | 4 ++-- 2 files changed, 3 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S index 03c885d3640f..a4cd04c458df 100644 --- a/arch/x86/kernel/vmlinux.lds.S +++ b/arch/x86/kernel/vmlinux.lds.S @@ -134,7 +134,7 @@ SECTIONS SOFTIRQENTRY_TEXT #ifdef CONFIG_RETPOLINE __indirect_thunk_start = .; - *(.text.__x86.*) + *(.text..__x86.*) __indirect_thunk_end = .; #endif STATIC_CALL_TEXT diff --git a/arch/x86/lib/retpoline.S b/arch/x86/lib/retpoline.S index 3fd066d42ec0..3bea96341d00 100644 --- a/arch/x86/lib/retpoline.S +++ b/arch/x86/lib/retpoline.S @@ -12,7 +12,7 @@ #include #include - .section .text.__x86.indirect_thunk + .section .text..__x86.indirect_thunk .macro POLINE reg @@ -131,7 +131,7 @@ SYM_CODE_END(__x86_indirect_jump_thunk_array) */ #ifdef CONFIG_RETHUNK - .section .text.__x86.return_thunk + .section .text..__x86.return_thunk /* * Safety details here pertain to the AMD Zen{1,2} microarchitecture: