From nobody Tue Apr 7 18:01:51 2026 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 E6DF9C32796 for ; Wed, 24 Aug 2022 16:43:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239337AbiHXQnb (ORCPT ); Wed, 24 Aug 2022 12:43:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38806 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239087AbiHXQn1 (ORCPT ); Wed, 24 Aug 2022 12:43:27 -0400 Received: from mail.skyhub.de (mail.skyhub.de [IPv6:2a01:4f8:190:11c2::b:1457]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 549271AF36; Wed, 24 Aug 2022 09:43:24 -0700 (PDT) Received: from zn.tnic (p200300ea971b9859329c23fffea6a903.dip0.t-ipconnect.de [IPv6:2003:ea:971b:9859:329c:23ff:fea6:a903]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id ED6861EC06C1; Wed, 24 Aug 2022 18:43:18 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1661359399; h=from:from: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:in-reply-to:in-reply-to: references:references; bh=gGxXDwbKEJ0yko3Vb9vrS3rjtdtk6tHV0mhI9adXULo=; b=CcbQXShNX9wumDLPtpetSXFC5InAy7LlherUDUSrIX8ak3G4pCbWEu0HcOShG2J2PNMb0i b6uHXUhxY7laybG3Iojr6qyRdqYgVtvV3JIODBqsqdR/D1d+fgTeSGEo5Gp+uaJPwDAt58 Q0ewBx6MuAYN0GAK4cGByjk5G2SF1yM= Date: Wed, 24 Aug 2022 18:43:14 +0200 From: Borislav Petkov To: Peter Zijlstra Cc: X86 ML , Michael Matz , linux-toolchains@vger.kernel.org, LKML , Josh Poimboeuf Subject: [PATCH v2] x86/sev: Mark snp_abort() noreturn Message-ID: References: <20220824152420.20547-1-bp@alien8.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" On Wed, Aug 24, 2022 at 06:16:34PM +0200, Peter Zijlstra wrote: > If only there would be a trace of it left in the ELF file... Ah, there's that. --- From: Borislav Petkov Mark both the function prototype and definition as noreturn in order to prevent the compiler from doing transformations which confuse objtool like so: vmlinux.o: warning: objtool: sme_enable+0x71: unreachable instruction This triggers with gcc-12. Add it and sev_es_terminate() to the objtool noreturn tracking array too. Sort it while at it. Signed-off-by: Borislav Petkov --- arch/x86/include/asm/sev.h | 2 +- arch/x86/kernel/sev.c | 2 +- tools/objtool/check.c | 34 ++++++++++++++++++---------------- 3 files changed, 20 insertions(+), 18 deletions(-) diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h index 4a23e52fe0ee..ebc271bb6d8e 100644 --- a/arch/x86/include/asm/sev.h +++ b/arch/x86/include/asm/sev.h @@ -195,7 +195,7 @@ void snp_set_memory_shared(unsigned long vaddr, unsigne= d int npages); void snp_set_memory_private(unsigned long vaddr, unsigned int npages); void snp_set_wakeup_secondary_cpu(void); bool snp_init(struct boot_params *bp); -void snp_abort(void); +void __init __noreturn snp_abort(void); int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, uns= igned long *fw_err); #else static inline void sev_es_ist_enter(struct pt_regs *regs) { } diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c index 4f84c3f11af5..a428c62330d3 100644 --- a/arch/x86/kernel/sev.c +++ b/arch/x86/kernel/sev.c @@ -2112,7 +2112,7 @@ bool __init snp_init(struct boot_params *bp) return true; } =20 -void __init snp_abort(void) +void __init __noreturn snp_abort(void) { sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SNP_UNSUPPORTED); } diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 0cec74da7ffe..ad51689dfb41 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -162,32 +162,34 @@ static bool __dead_end_function(struct objtool_file *= file, struct symbol *func, =20 /* * Unfortunately these have to be hard coded because the noreturn - * attribute isn't provided in ELF data. + * attribute isn't provided in ELF data. Keep 'em sorted. */ static const char * const global_noreturns[] =3D { + "__invalid_creds", + "__module_put_and_kthread_exit", + "__reiserfs_panic", "__stack_chk_fail", - "panic", + "__ubsan_handle_builtin_unreachable", + "cpu_bringup_and_idle", + "cpu_startup_entry", "do_exit", + "do_group_exit", "do_task_dead", - "kthread_exit", - "make_task_dead", - "__module_put_and_kthread_exit", + "ex_handler_msr_mce", + "fortify_panic", "kthread_complete_and_exit", - "__reiserfs_panic", + "kthread_exit", + "kunit_try_catch_throw", "lbug_with_loc", - "fortify_panic", - "usercopy_abort", "machine_real_restart", + "make_task_dead", + "panic", "rewind_stack_and_make_dead", - "kunit_try_catch_throw", - "xen_start_kernel", - "cpu_bringup_and_idle", - "do_group_exit", + "sev_es_terminate", + "snp_abort", "stop_this_cpu", - "__invalid_creds", - "cpu_startup_entry", - "__ubsan_handle_builtin_unreachable", - "ex_handler_msr_mce", + "usercopy_abort", + "xen_start_kernel", }; =20 if (!func) --=20 2.35.1 --=20 Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette