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 9481CC433EF for ; Sat, 19 Mar 2022 19:04:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234610AbiCSTFg (ORCPT ); Sat, 19 Mar 2022 15:05:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43008 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235662AbiCSTFf (ORCPT ); Sat, 19 Mar 2022 15:05:35 -0400 Received: from mail-pf1-x441.google.com (mail-pf1-x441.google.com [IPv6:2607:f8b0:4864:20::441]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8D12BFD0D for ; Sat, 19 Mar 2022 12:04:14 -0700 (PDT) Received: by mail-pf1-x441.google.com with SMTP id p8so12240939pfh.8 for ; Sat, 19 Mar 2022 12:04:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=7v3ursllm2d7zLn65JqdXT+6TgRSaq3PMvYUmltsZd0=; b=c8FYRd+NMSbbKd906Mx/bWzGN/EzUZ+NIKsFFuIr5HEOWXbwodweDeSf0Hseh0XLiw szA81gXDwL/XTefVzVJ61cbifaweunPKW9CZqcZviA7XegFq+OHpg2Zla2M7B/zodHZh pCbryCf8YrMS15uh/Il49y+Wm9gjmGrOfLC9tZo08tdATu8gADj0DyM/9TLghy/VaxHx mvn8BikoLHpRCN0R8xtB9GQUo/kSsGL7Abq6odX29bZp8bJrpSfTObbWXAnjQiq8P1Vk 0DW1D6ar7Q/6/+ymK90YIvOTagSNnA+UsDwWdwRkk6uQnWKcMg4n/893gXGHkUHTsnmh vKiA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=7v3ursllm2d7zLn65JqdXT+6TgRSaq3PMvYUmltsZd0=; b=lyjBRJNc57eC65AmUY9xdrChNuMOgXTNFlEg72fG3X/2NW0czDmvOJXd16kBD/5v6R up9efANpJj7f0EJGE8Nd0lXEzYnCqqF33wutgROx508cBbjL+cHaxVUB71AlONZvH1yq lLI5smqF3BaqhTiHItxWzHHXyfNrw2GKPx1fAogvq8MlGgFVVqAqGqiKl12BNRMky5CG 1mrOwFJnR4ce6JhBEII1sS0FITaHtkHh53I+vIE6Vy69YfpDHd0Ph1lLqIAnPl38SYhF v+UQ55lRR+VIeelUGcfqCYeSNTu/g/+Rzt+dy2SsDaeipJ99nLTNdtg9FLBfXCYwZmzQ IIZA== X-Gm-Message-State: AOAM530MxbnZwTqOsLsvrgqWBhYcygzy9+YeLqegWzkoLHRWnRId023D C3XolTNefyUrDpQp8AOZKvE= X-Google-Smtp-Source: ABdhPJwU9OlPH2UNs2rji9v2/EQswRPV1r3pCpZACoLM9QIjx4qpoZVPySCKz+R1CugivwLHLtXoJQ== X-Received: by 2002:a05:6a00:851:b0:4f7:68db:51bb with SMTP id q17-20020a056a00085100b004f768db51bbmr16347275pfk.74.1647716654100; Sat, 19 Mar 2022 12:04:14 -0700 (PDT) Received: from localhost ([14.139.187.71]) by smtp.gmail.com with ESMTPSA id g17-20020a056a0023d100b004fa8892df25sm1489149pfc.64.2022.03.19.12.04.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 19 Mar 2022 12:04:13 -0700 (PDT) Date: Sun, 20 Mar 2022 00:34:09 +0530 From: Kumar Kartikeya Dwivedi To: Alexei Starovoitov Cc: bpf@vger.kernel.org, Hao Luo , Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= , Jesper Dangaard Brouer Subject: Re: [PATCH bpf-next v2 05/15] bpf: Allow storing percpu kptr in map Message-ID: <20220319190409.7n3bkjdp67finojx@apollo> References: <20220317115957.3193097-1-memxor@gmail.com> <20220317115957.3193097-6-memxor@gmail.com> <20220319183028.pwzaoz2qogek6nwz@ast-mbp.dhcp.thefacebook.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220319183028.pwzaoz2qogek6nwz@ast-mbp.dhcp.thefacebook.com> Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Sun, Mar 20, 2022 at 12:00:28AM IST, Alexei Starovoitov wrote: > On Thu, Mar 17, 2022 at 05:29:47PM +0530, Kumar Kartikeya Dwivedi wrote: > > Make adjustments to the code to allow storing percpu PTR_TO_BTF_ID in a > > map. Similar to 'kptr_ref' tag, a new 'kptr_percpu' allows tagging types > > of pointers accepting stores of such register types. On load, verifier > > marks destination register as having type PTR_TO_BTF_ID | MEM_PERCPU | > > PTR_MAYBE_NULL. > > > > Cc: Hao Luo > > Signed-off-by: Kumar Kartikeya Dwivedi > > --- > > include/linux/bpf.h | 3 ++- > > kernel/bpf/btf.c | 13 ++++++++++--- > > kernel/bpf/verifier.c | 26 +++++++++++++++++++++----- > > 3 files changed, 33 insertions(+), 9 deletions(-) > > > > diff --git a/include/linux/bpf.h b/include/linux/bpf.h > > index 702aa882e4a3..433f5cb161cf 100644 > > --- a/include/linux/bpf.h > > +++ b/include/linux/bpf.h > > @@ -161,7 +161,8 @@ enum { > > }; > > > > enum { > > - BPF_MAP_VALUE_OFF_F_REF = (1U << 0), > > + BPF_MAP_VALUE_OFF_F_REF = (1U << 0), > > + BPF_MAP_VALUE_OFF_F_PERCPU = (1U << 1), > > What is the use case for storing __percpu pointer into a map? No specific use case for me, just thought it would be useful, especially now that __percpu tag is understood by verifier for kernel BTF, so it may also refer to dynamically allocated per-CPU memory, not just global percpu variables. But fine with dropping both this and user kptr if you don't feel like keeping them. -- Kartikeya