From patchwork Mon Jul 11 20:53:52 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andy Lutomirski X-Patchwork-Id: 9224195 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 3DE8560572 for ; Mon, 11 Jul 2016 20:58:06 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 2F2ED27D76 for ; Mon, 11 Jul 2016 20:58:06 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 235BD27E33; Mon, 11 Jul 2016 20:58:06 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.wl.linuxfoundation.org (Postfix) with SMTP id 52B7027D76 for ; Mon, 11 Jul 2016 20:58:05 +0000 (UTC) Received: (qmail 26189 invoked by uid 550); 11 Jul 2016 20:54:57 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Reply-To: kernel-hardening@lists.openwall.com Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 25866 invoked from network); 11 Jul 2016 20:54:52 -0000 From: Andy Lutomirski To: x86@kernel.org, linux-kernel@vger.kernel.org Cc: linux-arch@vger.kernel.org, Borislav Petkov , Nadav Amit , Kees Cook , Brian Gerst , "kernel-hardening@lists.openwall.com" , Linus Torvalds , Josh Poimboeuf , Jann Horn , Heiko Carstens , Andy Lutomirski Date: Mon, 11 Jul 2016 13:53:52 -0700 Message-Id: X-Mailer: git-send-email 2.7.4 In-Reply-To: References: In-Reply-To: References: X-Virus-Scanned: ClamAV using ClamSMTP Subject: [kernel-hardening] [PATCH v5 19/32] x86/smp: Remove stack_smp_processor_id() X-Virus-Scanned: ClamAV using ClamSMTP It serves no purpose -- raw_smp_processor_id() works fine. This change will be needed to move thread_info off the stack. Signed-off-by: Andy Lutomirski --- arch/x86/include/asm/cpu.h | 1 - arch/x86/include/asm/smp.h | 6 ------ arch/x86/kernel/cpu/common.c | 2 +- 3 files changed, 1 insertion(+), 8 deletions(-) diff --git a/arch/x86/include/asm/cpu.h b/arch/x86/include/asm/cpu.h index 678637ad7476..59d34c521d96 100644 --- a/arch/x86/include/asm/cpu.h +++ b/arch/x86/include/asm/cpu.h @@ -17,7 +17,6 @@ static inline void prefill_possible_map(void) {} #define cpu_physical_id(cpu) boot_cpu_physical_apicid #define safe_smp_processor_id() 0 -#define stack_smp_processor_id() 0 #endif /* CONFIG_SMP */ diff --git a/arch/x86/include/asm/smp.h b/arch/x86/include/asm/smp.h index 66b057306f40..0576b6157f3a 100644 --- a/arch/x86/include/asm/smp.h +++ b/arch/x86/include/asm/smp.h @@ -172,12 +172,6 @@ extern int safe_smp_processor_id(void); #elif defined(CONFIG_X86_64_SMP) #define raw_smp_processor_id() (this_cpu_read(cpu_number)) -#define stack_smp_processor_id() \ -({ \ - struct thread_info *ti; \ - __asm__("andq %%rsp,%0; ":"=r" (ti) : "0" (CURRENT_MASK)); \ - ti->cpu; \ -}) #define safe_smp_processor_id() smp_processor_id() #endif diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 0fe6953f421c..d22a7b9c4f0e 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -1452,7 +1452,7 @@ void cpu_init(void) struct task_struct *me; struct tss_struct *t; unsigned long v; - int cpu = stack_smp_processor_id(); + int cpu = raw_smp_processor_id(); int i; wait_for_master_cpu(cpu);