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 CECE9C433EF for ; Wed, 9 Mar 2022 07:55:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230390AbiCIHz4 (ORCPT ); Wed, 9 Mar 2022 02:55:56 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49310 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230054AbiCIHzp (ORCPT ); Wed, 9 Mar 2022 02:55:45 -0500 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3ABC715E6D7; Tue, 8 Mar 2022 23:54:47 -0800 (PST) Date: Wed, 09 Mar 2022 07:54:44 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1646812485; 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=2BprdItZ3kmJ5P67amXImIPKk9q58q2OOtLSEsUh47Y=; b=fPr4tN7uTh0Z/XAoUnAhcA1kY5dP5LAdCrmaZyvKdfuLSROi9PQsVv8fFelMv0QmSPJXOv uMmCu/wRC+ynLed2XRWdhQAyY3oG39pag7ZJFunTh4eiY9oVv/EoelT9Mf8SyxtL+o6AE7 5MBnQzAPo5UAFy5Y3/d6oBO3YU66RgyhiJmzQgupTHakZMPibmKa/Riq/ut3gqyegDf5XT B1dzd2ytGkgrW0AA1F4t3sHxroz3V3v9e3q8sCAT2Ju/aNlMnkWxKD/HmgRVG1n4bgdNIJ US25xyPVxdkvAhN6sP6fTEdafAWrp2/P3eayZtOBFYBQcW/YhF6ccQthhu6ftA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1646812485; 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=2BprdItZ3kmJ5P67amXImIPKk9q58q2OOtLSEsUh47Y=; b=k4Q1sFGs6L7kFSTZ5oLgMUVFfhTiiOiqvkj42Eyud7Ry0MD76mm1kas46zIClCEQQulGvx nk7OZzJGADhPiWAw== From: "tip-bot2 for Peter Zijlstra" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: x86/core] x86: Annotate call_on_stack() Cc: "Peter Zijlstra (Intel)" , Josh Poimboeuf , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20220308154319.468805622@infradead.org> References: <20220308154319.468805622@infradead.org> MIME-Version: 1.0 Message-ID: <164681248483.16921.9605178775958046023.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: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the x86/core branch of tip: Commit-ID: 2170221418e44b3c3d0171194915156db31aebc1 Gitweb: https://git.kernel.org/tip/2170221418e44b3c3d0171194915156db31aebc1 Author: Peter Zijlstra AuthorDate: Tue, 08 Mar 2022 16:30:50 +01:00 Committer: Peter Zijlstra CommitterDate: Tue, 08 Mar 2022 23:53:37 +01:00 x86: Annotate call_on_stack() vmlinux.o: warning: objtool: page_fault_oops()+0x13c: unreachable instruction 0000 000000000005b460 : ... 0128 5b588: 49 89 23 mov %rsp,(%r11) 012b 5b58b: 4c 89 dc mov %r11,%rsp 012e 5b58e: 4c 89 f2 mov %r14,%rdx 0131 5b591: 48 89 ee mov %rbp,%rsi 0134 5b594: 4c 89 e7 mov %r12,%rdi 0137 5b597: e8 00 00 00 00 call 5b59c 5b598: R_X86_64_PLT32 handle_stack_overflow-0x4 013c 5b59c: 5c pop %rsp vmlinux.o: warning: objtool: sysvec_reboot()+0x6d: unreachable instruction 0000 00000000000033f0 : ... 005d 344d: 4c 89 dc mov %r11,%rsp 0060 3450: e8 00 00 00 00 call 3455 3451: R_X86_64_PLT32 irq_enter_rcu-0x4 0065 3455: 48 89 ef mov %rbp,%rdi 0068 3458: e8 00 00 00 00 call 345d 3459: R_X86_64_PC32 .text+0x47d0c 006d 345d: e8 00 00 00 00 call 3462 345e: R_X86_64_PLT32 irq_exit_rcu-0x4 0072 3462: 5c pop %rsp Both cases are due to a call_on_stack() calling a __noreturn function. Since that's an inline asm, GCC can't do anything about the instructions after the CALL. Therefore put in an explicit ASM_REACHABLE annotation to make sure objtool and gcc are consistently confused about control flow. Signed-off-by: Peter Zijlstra (Intel) Acked-by: Josh Poimboeuf Link: https://lore.kernel.org/r/20220308154319.468805622@infradead.org --- arch/x86/include/asm/irq_stack.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/x86/include/asm/irq_stack.h b/arch/x86/include/asm/irq_stack.h index ae9d40f..05af249 100644 --- a/arch/x86/include/asm/irq_stack.h +++ b/arch/x86/include/asm/irq_stack.h @@ -99,7 +99,8 @@ } #define ASM_CALL_ARG0 \ - "call %P[__func] \n" + "call %P[__func] \n" \ + ASM_REACHABLE #define ASM_CALL_ARG1 \ "movq %[arg1], %%rdi \n" \