From patchwork Wed Dec 5 01:34:05 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nadav Amit X-Patchwork-Id: 10713339 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 115291932 for ; Wed, 5 Dec 2018 08:52:43 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0515F2CCB2 for ; Wed, 5 Dec 2018 08:52:43 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 035032CCDA; Wed, 5 Dec 2018 08:52:42 +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=-5.4 required=2.0 tests=BAYES_00,DATE_IN_PAST_06_12, RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 937D42CCB8 for ; Wed, 5 Dec 2018 08:52:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727461AbeLEIwN (ORCPT ); Wed, 5 Dec 2018 03:52:13 -0500 Received: from ex13-edg-ou-002.vmware.com ([208.91.0.190]:46460 "EHLO EX13-EDG-OU-002.vmware.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727437AbeLEIwM (ORCPT ); Wed, 5 Dec 2018 03:52:12 -0500 Received: from sc9-mailhost3.vmware.com (10.113.161.73) by EX13-EDG-OU-002.vmware.com (10.113.208.156) with Microsoft SMTP Server id 15.0.1156.6; Wed, 5 Dec 2018 00:52:03 -0800 Received: from sc2-haas01-esx0118.eng.vmware.com (sc2-haas01-esx0118.eng.vmware.com [10.172.44.118]) by sc9-mailhost3.vmware.com (Postfix) with ESMTP id 2F837412B7; Wed, 5 Dec 2018 00:52:05 -0800 (PST) From: Nadav Amit To: Ingo Molnar CC: , , "H. Peter Anvin" , Thomas Gleixner , Borislav Petkov , Andy Lutomirski , Nadav Amit , Dave Hansen , Peter Zijlstra , , , , Nadav Amit , Kees Cook , Dave Hansen , Masami Hiramatsu Subject: [PATCH v7 11/14] x86/jump-label: remove support for custom poker Date: Tue, 4 Dec 2018 17:34:05 -0800 Message-ID: <20181205013408.47725-12-namit@vmware.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20181205013408.47725-1-namit@vmware.com> References: <20181205013408.47725-1-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) Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: X-Virus-Scanned: ClamAV using ClamSMTP There are only two types of poking: early and breakpoint based. The use of a function pointer to perform poking complicates the code and is probably inefficient due to the use of indirect branches. Cc: Andy Lutomirski Cc: Kees Cook Cc: Peter Zijlstra Cc: Dave Hansen Cc: Masami Hiramatsu Signed-off-by: Nadav Amit --- arch/x86/kernel/jump_label.c | 24 ++++++++---------------- 1 file changed, 8 insertions(+), 16 deletions(-) diff --git a/arch/x86/kernel/jump_label.c b/arch/x86/kernel/jump_label.c index ed5fe274a7d8..994c13e2867d 100644 --- a/arch/x86/kernel/jump_label.c +++ b/arch/x86/kernel/jump_label.c @@ -39,7 +39,6 @@ static void bug_at(unsigned char *ip, int line) static void __ref __jump_label_transform(struct jump_entry *entry, enum jump_label_type type, - void *(*poker)(void *, const void *, size_t), int init) { union jump_code_union jmp; @@ -52,14 +51,6 @@ static void __ref __jump_label_transform(struct jump_entry *entry, jmp.offset = jump_entry_target(entry) - (jump_entry_code(entry) + JUMP_LABEL_NOP_SIZE); - /* - * As long as we're UP and not yet marked RO, we can use - * text_poke_early; SYSTEM_BOOTING guarantees both, as we switch to - * SYSTEM_SCHEDULING before going either. - */ - if (system_state == SYSTEM_BOOTING) - poker = text_poke_early; - if (type == JUMP_LABEL_JMP) { if (init) { expect = default_nop; line = __LINE__; @@ -82,16 +73,17 @@ static void __ref __jump_label_transform(struct jump_entry *entry, bug_at((void *)jump_entry_code(entry), line); /* - * Make text_poke_bp() a default fallback poker. + * As long as we're UP and not yet marked RO, we can use + * text_poke_early; SYSTEM_BOOTING guarantees both, as we switch to + * SYSTEM_SCHEDULING before going either. * * At the time the change is being done, just ignore whether we * are doing nop -> jump or jump -> nop transition, and assume * always nop being the 'currently valid' instruction - * */ - if (poker) { - (*poker)((void *)jump_entry_code(entry), code, - JUMP_LABEL_NOP_SIZE); + if (init || system_state == SYSTEM_BOOTING) { + text_poke_early((void *)jump_entry_code(entry), code, + JUMP_LABEL_NOP_SIZE); return; } @@ -103,7 +95,7 @@ void arch_jump_label_transform(struct jump_entry *entry, enum jump_label_type type) { mutex_lock(&text_mutex); - __jump_label_transform(entry, type, NULL, 0); + __jump_label_transform(entry, type, 0); mutex_unlock(&text_mutex); } @@ -133,7 +125,7 @@ __init_or_module void arch_jump_label_transform_static(struct jump_entry *entry, jlstate = JL_STATE_NO_UPDATE; } if (jlstate == JL_STATE_UPDATE) - __jump_label_transform(entry, type, text_poke_early, 1); + __jump_label_transform(entry, type, 1); } #endif