From patchwork Wed Apr 12 23:49:41 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Josh Poimboeuf X-Patchwork-Id: 13209661 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 D6076C77B77 for ; Wed, 12 Apr 2023 23:50:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230007AbjDLXuT (ORCPT ); Wed, 12 Apr 2023 19:50:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45674 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229910AbjDLXuG (ORCPT ); Wed, 12 Apr 2023 19:50:06 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A543C7280; Wed, 12 Apr 2023 16:50:05 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 82D026375F; Wed, 12 Apr 2023 23:50:05 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 766C0C4339C; Wed, 12 Apr 2023 23:50:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1681343404; bh=fv7dp6bnjJALXLewb9lTFvUBDPbaWCiPUy0hgG3NFLs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=YGpI28UrR5Zv3CYWpQ0VUGjdfUzVFojUtUlbbKFI5Bwyx+iXrsuGIp8s4v1k8SoJI nONptSfN0QUqyQ8t2DgvmD7tYUwACn4ZT+b7jSmj1NfXtuJ8T3FSAnKA98Hso7t2V9 ppJawnoz8YeoM/ykNlsVPlkBpo8jB/1URJXGVgpbc2KwjMzX5FAIFDvqcNM6aHI2z8 osGmvarU93OQGE9PYaYzIBCAyoH2DpmhKPNQfBlUT/XZlZPOx9y6OEpB6Y0xGjMqpG CitYIh2s2Aag3+xNbvuJ51BhWD7tsF+vSHN/8bqdL1tgYkPGAAazNtDdNH6j4Dto4e 4f/PLPj1QPGag== From: Josh Poimboeuf To: x86@kernel.org Cc: linux-kernel@vger.kernel.org, Peter Zijlstra , Miroslav Benes , linux-btrfs@vger.kernel.org, Mark Rutland , linux-scsi@vger.kernel.org, linux-hyperv@vger.kernel.org, Arnd Bergmann , "Guilherme G . Piccoli" , Michael Kelley , Nick Desaulniers , Nathan Chancellor Subject: [PATCH v2 11/11] x86/hyperv: Mark hv_ghcb_terminate() as noreturn Date: Wed, 12 Apr 2023 16:49:41 -0700 Message-Id: <32453a703dfcf0d007b473c9acbf70718222b74b.1681342859.git.jpoimboe@kernel.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: References: MIME-Version: 1.0 Content-type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org From: "Guilherme G. Piccoli" Annotate the function prototype and definition as noreturn to prevent objtool warnings like: vmlinux.o: warning: objtool: hyperv_init+0x55c: unreachable instruction Also, as per Josh's suggestion, add it to the global_noreturns list. As a comparison, an objdump output without the annotation: [...] 1b63: mov $0x1,%esi 1b68: xor %edi,%edi 1b6a: callq ffffffff8102f680 1b6f: jmpq ffffffff82f217ec # unreachable 1b74: cmpq $0xffffffffffffffff,-0x702a24(%rip) [...] Now, after adding the __noreturn to the function prototype: [...] 17df: callq ffffffff8102f6d0 17e4: test %al,%al 17e6: je ffffffff82f21bb9 [...] 1bb9: mov $0x1,%esi 1bbe: xor %edi,%edi 1bc0: callq ffffffff8102f680 1bc5: nopw %cs:0x0(%rax,%rax,1) # end of function Reported-by: Arnd Bergmann Link: https://lore.kernel.org/r/9698eff1-9680-4f0a-94de-590eaa923e94@app.fastmail.com/ Signed-off-by: Guilherme G. Piccoli Reviewed-by: Michael Kelley Signed-off-by: Josh Poimboeuf --- arch/x86/hyperv/ivm.c | 2 +- arch/x86/include/asm/mshyperv.h | 2 +- tools/objtool/check.c | 1 + 3 files changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c index 1dbcbd9da74d..4f79dc76042d 100644 --- a/arch/x86/hyperv/ivm.c +++ b/arch/x86/hyperv/ivm.c @@ -127,7 +127,7 @@ static enum es_result hv_ghcb_hv_call(struct ghcb *ghcb, u64 exit_code, return ES_OK; } -void hv_ghcb_terminate(unsigned int set, unsigned int reason) +void __noreturn hv_ghcb_terminate(unsigned int set, unsigned int reason) { u64 val = GHCB_MSR_TERM_REQ; diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h index 4c4c0ec3b62e..09c26e658bcc 100644 --- a/arch/x86/include/asm/mshyperv.h +++ b/arch/x86/include/asm/mshyperv.h @@ -212,7 +212,7 @@ int hv_set_mem_host_visibility(unsigned long addr, int numpages, bool visible); void hv_ghcb_msr_write(u64 msr, u64 value); void hv_ghcb_msr_read(u64 msr, u64 *value); bool hv_ghcb_negotiate_protocol(void); -void hv_ghcb_terminate(unsigned int set, unsigned int reason); +void __noreturn hv_ghcb_terminate(unsigned int set, unsigned int reason); #else static inline void hv_ghcb_msr_write(u64 msr, u64 value) {} static inline void hv_ghcb_msr_read(u64 msr, u64 *value) {} diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 8586d4c36600..e23d12041be0 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -213,6 +213,7 @@ static bool __dead_end_function(struct objtool_file *file, struct symbol *func, "ex_handler_msr_mce", "fortify_panic", "hlt_play_dead", + "hv_ghcb_terminate", "kthread_complete_and_exit", "kthread_exit", "kunit_try_catch_throw",