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 CB15CC433FE for ; Tue, 18 Oct 2022 13:50:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231208AbiJRNux (ORCPT ); Tue, 18 Oct 2022 09:50:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58406 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230521AbiJRNuv (ORCPT ); Tue, 18 Oct 2022 09:50:51 -0400 Received: from mail-qt1-f178.google.com (mail-qt1-f178.google.com [209.85.160.178]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7A17FBC61C for ; Tue, 18 Oct 2022 06:50:45 -0700 (PDT) Received: by mail-qt1-f178.google.com with SMTP id g11so9646676qts.1 for ; Tue, 18 Oct 2022 06:50:45 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=LKYnNweZgxwgNxf4yalBU36d5h/7Dl8cIFGnGJ7yPZM=; b=olvjzpejiAfeQgTLEvYRqg+mo24C7GjdH/StZDGcFIXCTFdsKIRXxVDclDT4XS658I dGmuodgSc8cUXq/2GgxSuUsaVSKoA5jCTFoPsUcS1EfKjTfARmrJEe7QI6tJwITkTrB8 RvZb3dKzSWZyrbYf8PGDsnG+sGNbiC1zmSxlJYXsRW2Plt1ybdqOIBtodR2Ihfy0Ba+O Z/0D8dQEcQJoClkJWeOFVO1nsCUfMnWXjW6o93NzqRy5qvYfd/TybxpmPU7ppKCXiH/T l/OxwDNhq02571PVTM776St6MMrajaaYnzaoV/1EnLA4eImNkx3SciCzS5YeFQaDWlPm B08A== X-Gm-Message-State: ACrzQf27KGGX7OA+xYMqwIBal6t0Wx0TduErnTnUvqWVu5gcge/QM9VT TUH1TWLb6uDledHBrhbuscocFIiRgCCg4j8C X-Google-Smtp-Source: AMsMyM43Emcrb7acUwrv7edBwF5gEbisgJ1X4NoYUNyYXAHyPStc9gSPOzGHNtBa962YDSMY8Mjnxg== X-Received: by 2002:a05:622a:490:b0:39c:c82d:557c with SMTP id p16-20020a05622a049000b0039cc82d557cmr2146018qtx.463.1666101044380; Tue, 18 Oct 2022 06:50:44 -0700 (PDT) Received: from mail-yb1-f180.google.com (mail-yb1-f180.google.com. [209.85.219.180]) by smtp.gmail.com with ESMTPSA id p7-20020a05620a132700b006b61b2cb1d2sm2396778qkj.46.2022.10.18.06.50.43 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 18 Oct 2022 06:50:43 -0700 (PDT) Received: by mail-yb1-f180.google.com with SMTP id 203so17014111ybc.10 for ; Tue, 18 Oct 2022 06:50:43 -0700 (PDT) X-Received: by 2002:a5b:104:0:b0:6b0:429:3fe9 with SMTP id 4-20020a5b0104000000b006b004293fe9mr2419104ybx.543.1666101042984; Tue, 18 Oct 2022 06:50:42 -0700 (PDT) MIME-Version: 1.0 References: <20220905230820.3295223-1-yury.norov@gmail.com> <20220905230820.3295223-6-yury.norov@gmail.com> In-Reply-To: From: Geert Uytterhoeven Date: Tue, 18 Oct 2022 15:50:31 +0200 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v2 5/5] lib/cpumask: add FORCE_NR_CPUS config option To: Andreas Schwab Cc: Yury Norov , linux-kernel@vger.kernel.org, Andy Shevchenko , Rasmus Villemoes , Andrew Morton , Stephen Rothwell , Peter Zijlstra , Thomas Gleixner , "Paul E . McKenney" , Vlastimil Babka , Dmitry Vyukov , Valentin Schneider , Sander Vanheule , Alexey Klimov , Eric Biggers , linux-riscv Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Andreas, On Tue, Oct 18, 2022 at 3:41 PM Andreas Schwab wrote: > On Okt 18 2022, Geert Uytterhoeven wrote: > > Moreover, this cannot be used on all systems. E.g. on Icicle Kit with > > Microchip PolarFire SoC, CONFIG_NR_CPUS needs to be larger than 4, > > as the system has actually 5 CPU cores (1xE51 and 4xU54), but Linux > > runs only on 4 of them. So you cannot use FORCE_NR_CPUS=y. > > But does Linux acually see the E51 core? On the Hifive boards it is > disabled in the device tree, and the cpu probing just skips it, > effectively resulting in only four cpus. The E51 is indeed disabled in DT. The CPU parts of arch/riscv/boot/dts/sifive/fu540-c000.dtsi and arch/riscv/boot/dts/microchip/mpfs.dtsi arre very similar. Do you get 4 CPUs on Hifive with CONFIG_NR_CPUS=4? Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds