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 X-Spam-Level: X-Spam-Status: No, score=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BF801C7618F for ; Mon, 15 Jul 2019 09:52:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 935FE20C01 for ; Mon, 15 Jul 2019 09:52:19 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="kr7yvRxP" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729714AbfGOJwS (ORCPT ); Mon, 15 Jul 2019 05:52:18 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:38420 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729257AbfGOJwR (ORCPT ); Mon, 15 Jul 2019 05:52:17 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding: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=gqsH7R9ZkCpew7P4VmFI5+NgnAM5dz6k+qa5c5AXO+A=; b=kr7yvRxPapRr2AO3/Xqa7aBYy 040OJXK+Jn0t+zfT3XqTzjx3sJ+5Vu1+jE3P1kFhKJphToQvIaCx2MBhrLRmXvMT0YCEZGDXCTJZF CsyG+/COuGVA7pHXwYgC+1oqGQhaWIWzlLr0d7ggaphcwqLnOQRoD7XvcX24IiP+GoX6UlqBwIS1q ouACKGXrBSUl+PYrrhZsHd+CePY8FS9pS72BKC4ROZOu/gDL6A4RZP79R0KfPVcYSwwIr0EaSi+g0 ycxw0pQo7MWMb3p2zZVL7t+rYPEQOog+kKVH1DN9ZHN6QmydMkVVXAtXPwkNd6U+Ew7vczqW85xlB wHShMbi4g==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.92 #3 (Red Hat Linux)) id 1hmxeV-0006Yr-GQ; Mon, 15 Jul 2019 09:52:11 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id E827A20B29100; Mon, 15 Jul 2019 11:52:09 +0200 (CEST) Date: Mon, 15 Jul 2019 11:52:09 +0200 From: Peter Zijlstra To: Josh Poimboeuf Cc: x86@kernel.org, linux-kernel@vger.kernel.org, Thomas Gleixner , Nick Desaulniers , Arnd Bergmann , Jann Horn , Randy Dunlap Subject: Re: [PATCH 00/22] x86, objtool: several fixes/improvements Message-ID: <20190715095209.GA3419@hirez.programming.kicks-ass.net> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Jul 14, 2019 at 07:36:55PM -0500, Josh Poimboeuf wrote: > There have been a lot of objtool bug reports lately, mainly related to > Clang and BPF. As part of fixing those bugs, I added some improvements > to objtool which uncovered yet more bugs (some kernel, some objtool). > > I've given these patches a lot of testing with both GCC and Clang. More > compile testing of objtool would be appreciated, as the kbuild test > robot doesn't seem to be paying much attention to my branches lately. > > There are still at least three outstanding issues: > > 1) With clang I see: > > drivers/gpu/drm/i915/gem/i915_gem_execbuffer.o: warning: objtool: .altinstr_replacement+0x88: redundant UACCESS disable > > I haven't dug into it yet. > > 2) There's also an issue in clang where a large switch table had a bunch > of unused (bad) entries. It's not a code correctness issue, but > hopefully it can get fixed in clang anyway. See patch 20/22 for more > details. > > 3) CONFIG_LIVEPATCH is causing some objtool "unreachable instruction" > warnings due to the new -flive-patching flag. I have some fixes > pending, but this patch set is already long enough. > > > Jann Horn (1): > objtool: Support repeated uses of the same C jump table > > Josh Poimboeuf (21): > x86/paravirt: Fix callee-saved function ELF sizes > x86/kvm: Fix fastop function ELF metadata > x86/kvm: Fix frame pointer usage in vmx_vmenter() > x86/kvm: Don't call kvm_spurious_fault() from .fixup > x86/entry: Fix thunk function ELF sizes > x86/head/64: Annotate start_cpu0() as non-callable > x86/uaccess: Remove ELF function annotation from > copy_user_handle_tail() > x86/uaccess: Don't leak AC flag into fentry from mcsafe_handle_tail() > x86/uaccess: Remove redundant CLACs in getuser/putuser error paths > bpf: Disable GCC -fgcse optimization for ___bpf_prog_run() > objtool: Add mcsafe_handle_tail() to the uaccess safe list > objtool: Track original function across branches > objtool: Refactor function alias logic > objtool: Warn on zero-length functions > objtool: Change dead_end_function() to return boolean > objtool: Do frame pointer check before dead end check > objtool: Refactor sibling call detection logic > objtool: Refactor jump table code > objtool: Fix seg fault on bad switch table entry > objtool: convert insn type to enum > objtool: Support conditional retpolines Acked-by: Peter Zijlstra (Intel)