From mboxrd@z Thu Jan 1 00:00:00 1970 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 1CA93C433FE for ; Thu, 24 Feb 2022 15:19:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235952AbiBXPT7 (ORCPT ); Thu, 24 Feb 2022 10:19:59 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42682 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235982AbiBXPSb (ORCPT ); Thu, 24 Feb 2022 10:18:31 -0500 Received: from desiato.infradead.org (desiato.infradead.org [IPv6:2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CD48E145635 for ; Thu, 24 Feb 2022 07:17:58 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=Content-Type:MIME-Version:References: Subject:Cc:To:From:Date:Message-ID:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:In-Reply-To; bh=H5LNHgQS5iWSlIuTH5rZQRQTCvMu0SJcXk4UJIZt4Bw=; b=RjGdQcieKz4ShRAObRAP3xActB 7CJ850yButF61KVKD91NzYueBbqzlQ1o2Zr4JC3AVvkBehoTjf1QrpOBQT9SqrkV0DktCBI3SXrlE cGcO0qREbLlzsD634fMlQo3IETdXzScvc2vnLi1z3cFRnrfQIPwaGvVAVonvLhAU0fIQ6B/0p/Mx4 JaNDPpNH0/wxo2RC7wfSi8bJZC3gXJdhFDAjmpDhKMCy6u0lk9ty9nfSVq4EzkcfazpIsnjyiVxz8 +NrXoXx88PJmhYV3SvQwZLYAzN6deHmywrrWjYZH4zdidvbg+/2cX0rHEwsQxXd4uKJCIwXqXggk+ lKXlRIUQ==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1nNFs3-00CeLx-Sz; Thu, 24 Feb 2022 15:17:32 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 48545302D41; Thu, 24 Feb 2022 16:17:29 +0100 (CET) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id 817852B354799; Thu, 24 Feb 2022 16:17:28 +0100 (CET) Message-ID: <20220224151323.481837663@infradead.org> User-Agent: quilt/0.66 Date: Thu, 24 Feb 2022 15:52:03 +0100 From: Peter Zijlstra To: x86@kernel.org, joao@overdrivepizza.com, hjl.tools@gmail.com, jpoimboe@redhat.com, andrew.cooper3@citrix.com Cc: linux-kernel@vger.kernel.org, peterz@infradead.org, ndesaulniers@google.com, keescook@chromium.org, samitolvanen@google.com, mark.rutland@arm.com, alyssa.milburn@intel.com, mbenes@suse.cz, rostedt@goodmis.org, mhiramat@kernel.org, alexei.starovoitov@gmail.com Subject: [PATCH v2 25/39] x86/ibt,paravirt: Use text_gen_insn() for paravirt_patch() References: <20220224145138.952963315@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Now that writing direct JMP/CALL instructions is non-trivial, ensure we only have a single copy of all the relevant magic. Signed-off-by: Peter Zijlstra (Intel) --- arch/x86/include/asm/text-patching.h | 20 ++++++++++++++------ arch/x86/kernel/paravirt.c | 23 +++-------------------- 2 files changed, 17 insertions(+), 26 deletions(-) --- a/arch/x86/include/asm/text-patching.h +++ b/arch/x86/include/asm/text-patching.h @@ -97,16 +97,18 @@ union text_poke_insn { }; static __always_inline -void *text_gen_insn(u8 opcode, const void *addr, const void *dest) +void __text_gen_insn(void *buf, u8 opcode, const void *addr, const void *dest, int size) { - static union text_poke_insn insn; /* per instance */ - int size = text_opcode_size(opcode); + union text_poke_insn *insn = buf; + + BUG_ON(size < text_opcode_size(opcode)); /* * Hide the addresses to avoid the compiler folding in constants when * referencing code, these can mess up annotations like * ANNOTATE_NOENDBR. */ + OPTIMIZER_HIDE_VAR(insn); OPTIMIZER_HIDE_VAR(addr); OPTIMIZER_HIDE_VAR(dest); @@ -115,19 +117,25 @@ void *text_gen_insn(u8 opcode, const voi dest += 4; #endif - insn.opcode = opcode; + insn->opcode = opcode; if (size > 1) { - insn.disp = (long)dest - (long)(addr + size); + insn->disp = (long)dest - (long)(addr + size); if (size == 2) { /* * Ensure that for JMP8 the displacement * actually fits the signed byte. */ - BUG_ON((insn.disp >> 31) != (insn.disp >> 7)); + BUG_ON((insn->disp >> 31) != (insn->disp >> 7)); } } +} +static __always_inline +void *text_gen_insn(u8 opcode, const void *addr, const void *dest) +{ + static union text_poke_insn insn; /* per instance */ + __text_gen_insn(&insn, opcode, addr, dest, text_opcode_size(opcode)); return &insn.text; } --- a/arch/x86/kernel/paravirt.c +++ b/arch/x86/kernel/paravirt.c @@ -71,29 +71,12 @@ noinstr void paravirt_BUG(void) BUG(); } -struct branch { - unsigned char opcode; - u32 delta; -} __attribute__((packed)); - static unsigned paravirt_patch_call(void *insn_buff, const void *target, unsigned long addr, unsigned len) { - const int call_len = 5; - struct branch *b = insn_buff; - unsigned long delta = (unsigned long)target - (addr+call_len); - - if (len < call_len) { - pr_warn("paravirt: Failed to patch indirect CALL at %ps\n", (void *)addr); - /* Kernel might not be viable if patching fails, bail out: */ - BUG_ON(1); - } - - b->opcode = 0xe8; /* call */ - b->delta = delta; - BUILD_BUG_ON(sizeof(*b) != call_len); - - return call_len; + __text_gen_insn(insn_buff, CALL_INSN_OPCODE, + (void *)addr, target, CALL_INSN_SIZE); + return CALL_INSN_SIZE; } #ifdef CONFIG_PARAVIRT_XXL