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[2620:137:e000::1:20]) by mx.google.com with ESMTP id k22-20020a6568d6000000b004fb435b44ddsi160592pgt.704.2023.03.10.08.36.56; Fri, 10 Mar 2023 08:37:08 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=fail header.i=@igalia.com header.s=20170329 header.b="G1uAn/ZL"; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231429AbjCJPwt (ORCPT + 99 others); Fri, 10 Mar 2023 10:52:49 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58434 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231398AbjCJPwU (ORCPT ); Fri, 10 Mar 2023 10:52:20 -0500 Received: from fanzine2.igalia.com (fanzine2.igalia.com [213.97.179.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F2EC47A95; Fri, 10 Mar 2023 07:45:02 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=EmUdI2uVUfuPNoWMJdKhp3ipY0dPgGVWuc1bZMi1Tuk=; b=G1uAn/ZLjmzB1bt6JNKoeD9mNf JxY69NNC+u5wnQIE9sg6u/lMlgPV3KcpSeN5rJQxVC0XNmjPhwBlm9aGblSAG/VY3OoXUfZW8kcho NRI7LT78KFkGsSYFmhjCOvpoONjnslM7vSpa0J08u15oWKPaYunKRsdv5TZTmy7NeYPXEZh7Rxedi EW1+Znfcrqb+DHXOdkFqiRV8UT5Vo+1sUo4hENIptH9A8Rfbks+l2xpMxEMgge+Z3aQ0/r4q/gwxp tCR6IbvO8RSb+ODkgiIHuQZ62geHJOA5vuxwdYhL/G96ISkrlnVfpns82dB3Y46rs/BZTLzDSkqud sRWScJag==; Received: from 201-68-164-191.dsl.telesp.net.br ([201.68.164.191] helo=localhost) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim) id 1paevT-002v8a-DI; Fri, 10 Mar 2023 16:45:00 +0100 From: "Guilherme G. Piccoli" To: linux-hyperv@vger.kernel.org, x86@kernel.org Cc: linux-kernel@vger.kernel.org, decui@microsoft.com, haiyangz@microsoft.com, kys@microsoft.com, wei.liu@kernel.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com, thomas.lendacky@amd.com, jpoimboe@kernel.org, peterz@infradead.org, kernel-dev@igalia.com, kernel@gpiccoli.net, "Guilherme G. Piccoli" , Arnd Bergmann Subject: [PATCH v2] x86/hyperv: Mark hv_ghcb_terminate() as noreturn Date: Fri, 10 Mar 2023 12:44:52 -0300 Message-Id: <20230310154452.1169204-1-gpiccoli@igalia.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230310152442.cbrjise6uex4ak4x@treble> References: <20230310152442.cbrjise6uex4ak4x@treble> MIME-Version: 1.0 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1759997059728087181?= X-GMAIL-MSGID: =?utf-8?q?1759999404146737469?= Annotate the function prototype 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/ Cc: Josh Poimboeuf Signed-off-by: Guilherme G. Piccoli --- V2: - Per Josh's suggestion (thanks!), added the function to the objtool global table as well. arch/x86/include/asm/mshyperv.h | 2 +- tools/objtool/check.c | 1 + 2 files changed, 2 insertions(+), 1 deletion(-) 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 f937be1afe65..4b5e03f61f1f 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -209,6 +209,7 @@ static bool __dead_end_function(struct objtool_file *file, struct symbol *func, "do_task_dead", "ex_handler_msr_mce", "fortify_panic", + "hv_ghcb_terminate", "kthread_complete_and_exit", "kthread_exit", "kunit_try_catch_throw",