From patchwork Fri Apr 26 00:11:22 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nadav Amit X-Patchwork-Id: 10918609 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id B589492A for ; Fri, 26 Apr 2019 07:32:50 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A5B8428DA2 for ; Fri, 26 Apr 2019 07:32:50 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 99EAE28DA4; Fri, 26 Apr 2019 07:32:50 +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=-3.7 required=2.0 tests=BAYES_00,DATE_IN_PAST_06_12, MAILING_LIST_MULTI,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 B83CE28DA3 for ; Fri, 26 Apr 2019 07:32:49 +0000 (UTC) Received: (qmail 19505 invoked by uid 550); 26 Apr 2019 07:32:01 -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: Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 18262 invoked from network); 26 Apr 2019 07:31:59 -0000 From: Nadav Amit To: Peter Zijlstra , Borislav Petkov , Andy Lutomirski , Ingo Molnar CC: , , , Thomas Gleixner , Nadav Amit , Dave Hansen , , , , , , , , , , , Rick Edgecombe , Nadav Amit , Kees Cook , Dave Hansen , Masami Hiramatsu Subject: [PATCH v5 02/23] x86/jump_label: Use text_poke_early() during early init Date: Thu, 25 Apr 2019 17:11:22 -0700 Message-ID: <20190426001143.4983-3-namit@vmware.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190426001143.4983-1-namit@vmware.com> References: <20190426001143.4983-1-namit@vmware.com> MIME-Version: 1.0 Received-SPF: None (EX13-EDG-OU-002.vmware.com: namit@vmware.com does not designate permitted sender hosts) X-Virus-Scanned: ClamAV using ClamSMTP There is no apparent reason not to use text_poke_early() during early-init, since no patching of code that might be on the stack is done and only a single core is running. This is required for the next patches that would set a temporary mm for text poking, and this mm is only initialized after some static-keys are enabled/disabled. Cc: Andy Lutomirski Cc: Kees Cook Cc: Dave Hansen Cc: Masami Hiramatsu Acked-by: Peter Zijlstra (Intel) Signed-off-by: Nadav Amit Signed-off-by: Rick Edgecombe --- arch/x86/kernel/jump_label.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/jump_label.c b/arch/x86/kernel/jump_label.c index f99bd26bd3f1..e7d8c636b228 100644 --- a/arch/x86/kernel/jump_label.c +++ b/arch/x86/kernel/jump_label.c @@ -50,7 +50,12 @@ static void __ref __jump_label_transform(struct jump_entry *entry, jmp.offset = jump_entry_target(entry) - (jump_entry_code(entry) + JUMP_LABEL_NOP_SIZE); - if (early_boot_irqs_disabled) + /* + * As long as only a single processor is running and the code is still + * not marked as RO, text_poke_early() can be used; Checking that + * system_state is SYSTEM_BOOTING guarantees it. + */ + if (system_state == SYSTEM_BOOTING) poker = text_poke_early; if (type == JUMP_LABEL_JMP) {