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=-9.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 0D6A7C43466 for ; Mon, 21 Sep 2020 15:45:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9A27020C09 for ; Mon, 21 Sep 2020 15:45:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="TcmqrnJh" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727219AbgIUPpj (ORCPT ); Mon, 21 Sep 2020 11:45:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53244 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726749AbgIUPpj (ORCPT ); Mon, 21 Sep 2020 11:45:39 -0400 Received: from mail-pj1-x1041.google.com (mail-pj1-x1041.google.com [IPv6:2607:f8b0:4864:20::1041]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E73DBC061755; Mon, 21 Sep 2020 08:45:38 -0700 (PDT) Received: by mail-pj1-x1041.google.com with SMTP id fa1so7578pjb.0; Mon, 21 Sep 2020 08:45:38 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:message-id:in-reply-to:references:subject :mime-version:content-transfer-encoding; bh=ir04M09cwY3BUoPMN1Wi06xEKFUOseBSBQoS6jEdlnA=; b=TcmqrnJhPO2sEjXg/1jAmooXdo3FyGLVogLfrv++YKM73CyraNJgq0K7Y/7I+YeCXN rih+tyTUfK6RXt+TC12jPqYnTFkNuSBn86NYlMbOL4kwbK1UTi7PNlRV4BRJqI6hMot7 18LG0P73Mser8HQTzQmH5Yd3UKgpJojaGjJwXTzoV4W7zOqumXqtR8vb+NRO9GakEtha 3r+rzYpfG2HfolLKLwSIFEINA/vXp94MwLf9x+tnUIl2lUcHMpXW4nmvlKiFW0LCWXkz d58L4RW9W8jczqgmsGl8UWhmfavQarXANBg8VOxd3fE7ucn/IUeWku0WHMRcMvSwRnOL Hp3g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:message-id:in-reply-to :references:subject:mime-version:content-transfer-encoding; bh=ir04M09cwY3BUoPMN1Wi06xEKFUOseBSBQoS6jEdlnA=; b=KL2/3bFZr9s1vCeTbeO8o+Q0Vi/BMu+DOqeQ1HNFaE1HJJltNM5FIf7ZeJGq3kTVjm qwGWfg0Z41HeDgTEw3nT1XALBHWBahK1Sd2T/OcqErersxTyKDJRCACmK8+6E7ub/Zup T8IiVOuoIHNObO8gDjXtdBGh0O2pHXoYXlymnmJxTx8dyPFfSruFS/8NLiDQK6O9eLDY Irsy2IhsUDqCTzRg3242/vhHSVk5IXSDQ5577J/nV9G5KZbj18RDHB6RegXiN9xsXKHm QXLaknb3LXs0VcSFNyG5ZmiH+xdYk8CQwStjlauDbKMXawz76a7orhBPuZJb6paTQsWZ odQw== X-Gm-Message-State: AOAM530EMCcgerQdlA8nxYHLm1H7hATyYp2y0S9b/OwWa8TQqd6VFyxB bxGhJdCYEcUjO7hwk7fCK9o= X-Google-Smtp-Source: ABdhPJx4kAjMmOp7LGnoaJfadMncLeVnldwL3ZHVVAu2D7sXvcsT8LiCZGqwqxZiRNBxcjlNFQwNCg== X-Received: by 2002:a17:90a:71c7:: with SMTP id m7mr23756pjs.190.1600703138516; Mon, 21 Sep 2020 08:45:38 -0700 (PDT) Received: from localhost ([184.63.162.180]) by smtp.gmail.com with ESMTPSA id y6sm6646pji.1.2020.09.21.08.45.37 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 21 Sep 2020 08:45:37 -0700 (PDT) Date: Mon, 21 Sep 2020 08:45:32 -0700 From: John Fastabend To: Tony Ambardar , Alexei Starovoitov , Daniel Borkmann Cc: Tony Ambardar , netdev@vger.kernel.org, bpf@vger.kernel.org, linux-arch@vger.kernel.org, Arnd Bergmann Message-ID: <5f68ca9c9302a_17370208f9@john-XPS-13-9370.notmuch> In-Reply-To: References: Subject: RE: [PATCH bpf v1 2/3] bpf: prevent .BTF section elimination Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org Tony Ambardar wrote: > Systems with memory or disk constraints often reduce the kernel footprint > by configuring LD_DEAD_CODE_DATA_ELIMINATION. However, this can result in > removal of any BTF information. > > Use the KEEP() macro to preserve the BTF data as done with other important > sections, while still allowing for smaller kernels. > > Fixes: 90ceddcb4950 ("bpf: Support llvm-objcopy for vmlinux BTF") > > Signed-off-by: Tony Ambardar > --- > include/asm-generic/vmlinux.lds.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h > index 5430febd34be..7636bc71c71f 100644 > --- a/include/asm-generic/vmlinux.lds.h > +++ b/include/asm-generic/vmlinux.lds.h > @@ -661,7 +661,7 @@ > #define BTF \ > .BTF : AT(ADDR(.BTF) - LOAD_OFFSET) { \ > __start_BTF = .; \ > - *(.BTF) \ > + KEEP(*(.BTF)) \ > __stop_BTF = .; \ > } \ > . = ALIGN(4); \ > -- > 2.25.1 > Acked-by: John Fastabend