Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752120AbdGIJF6 (ORCPT ); Sun, 9 Jul 2017 05:05:58 -0400 Received: from mail-wr0-f195.google.com ([209.85.128.195]:36570 "EHLO mail-wr0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751946AbdGIJF4 (ORCPT ); Sun, 9 Jul 2017 05:05:56 -0400 Date: Sun, 9 Jul 2017 11:05:51 +0200 From: Ingo Molnar To: Nicholas Piggin Cc: linux-arch@vger.kernel.org, linux-kbuild@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org, Nicolas Pitre , Arnd Bergmann , Paul Burton , Linus Torvalds , Thomas Gleixner , "H. Peter Anvin" , Peter Zijlstra , Andrew Morton Subject: Re: [RFC PATCH] x86: enable dead code and data elimination (LTO) Message-ID: <20170709090551.bm2c55ctt3togim7@gmail.com> References: <20170709031333.29443-1-npiggin@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170709031333.29443-1-npiggin@gmail.com> User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 522 Lines: 19 * Nicholas Piggin wrote: > FYI, easiest way to check if you forgot to KEEP a linker table is > to look at `readelf -S vmlinux` differences, and to see what is > being trimmed, look at nm differences or use --print-gc-sections > LD option to see what symbols you're trimming. Linker tables, > boot entry, and exception entry tends to require anchoring. Could you please add a debug build target to display all discarded symbols/sections? Something like: make lto-check ... or so? Thanks, Ingo