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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id D7698C433F5 for ; Thu, 2 Dec 2021 15:05:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:Message-ID:Subject:Cc:To: From:Date:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References: List-Owner; bh=DXqLYlzMdzOhSimu9A136TBspqTc2LN6GAMLtxcHI9o=; b=YFiUCvHnsTCMti XRfruVMTlYHK1qtFf8cPCT+n4O13GzLKmWM4Q6j0hoveKF6SqQrlGk++srSZ4B+RYFCo9Rqtj/Nbo LePKtytB8XrEqiIe5Vv3QbzwSW9QkHmZ9Cu2PMDI5zJuUapAk4T3F3czAQFdFAzik6NceHwm1vzFe VHPRqkUFiUp3jrckaN0lSFL8G4tjswmjxks1tD/NrFiWqeHYfMuLI4sCy/iSx26WdbCUmEgNcuJ5w i0tprnCua6fM9rMds1tr5JerxqXI2+oIe9caPGywo5VqH4Ie8yv4HK8Kj15pS1NhaA65T0Obq0ynL KEkXKFyTu+DuCRKxBujg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1msneK-00Chl2-6V; Thu, 02 Dec 2021 15:05:28 +0000 Received: from mail-pf1-x42a.google.com ([2607:f8b0:4864:20::42a]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1msneF-00Chjs-CB for linux-riscv@lists.infradead.org; Thu, 02 Dec 2021 15:05:26 +0000 Received: by mail-pf1-x42a.google.com with SMTP id z6so28175010pfe.7 for ; Thu, 02 Dec 2021 07:05:22 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ventanamicro.com; s=google; h=date:from:to:cc:subject:message-id:mime-version:content-disposition; bh=FMccx88RykZoULvAHDtbX2BYTCQploTSiNhL4A6PbxU=; b=EDTMsPiCmkjPgfbdmz86xCC6o4S7u2/XRInDSbc11lWN3Z1WypUbfrDCWiynOY53mh J9SFPTrcvaBJ80rcJh80EBBTM467lfQXI2kANFj92fX5LipR8hvM1HEbqLBtAD0BLYhk +EW3mocr/Lah7OxumEfkLiBgL685nPieJmHwhxnfkrbYewQvfKjpQBX5kram4sCxufEu RUe0Tika5iCRfUGaW3W5Umdp6JTeb/wSvHprg0rqPg+qnDoTIbfMTFDCBppbOBUx0iqW 9alEI6nZBa02tSuMwAJAS5oBDG3R8sqoYrBHe4KbVjjiBGsfGm3NJIaXpWp+Tfj7cUY9 acIw== 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:mime-version :content-disposition; bh=FMccx88RykZoULvAHDtbX2BYTCQploTSiNhL4A6PbxU=; b=1SqseCeHTBzYpJ2MfmqMubMlEBW7irYSC0oVHOouWAyGfJ/h0i1fZ46XNWvxzEsu0A 1Mdhi+wWZGtVNb/c1jIZcDdQ293EOppfpuR8wQpAr2vl2P1aFo4+yNMCMM60XCUdJmWR JbdzsrVCRW6Tt/EcAs65WuJ+ZI6Za6qyQF/FsOR7ALdQ5a/zCvtYoUT/ydviuPYNZW4O BAmIqHLXRXBIgZRaVpUw+nPE6652LIkTcApaqwnWRIMDJJ6mHDEzdQ7ohhMSis0fI0Tt O6l36q+E5eonMNiUEBuMIIW60oMxoLYEaiOc1J/FJiv+bcplSe/PqNH4z/QhJWP4VeOw Q0sw== X-Gm-Message-State: AOAM531kORjznYx3SF58dbNFwFajc9/w6EfJtRv2yxhRt+i4rLPj0DmI ER8niCWX2E8i4yEtyDlUQ+C0ZQ== X-Google-Smtp-Source: ABdhPJxLJDpQ5vtfJyQ+xGg3yxHSkk9cKkitsvZUSN5t/lMXlXt+fRuZ8EkF2prkJ5Id7T58mTCA9w== X-Received: by 2002:a62:1c58:0:b0:49f:d674:e506 with SMTP id c85-20020a621c58000000b0049fd674e506mr12793593pfc.66.1638457521629; Thu, 02 Dec 2021 07:05:21 -0800 (PST) Received: from sunil-ThinkPad-T490 ([49.206.3.187]) by smtp.gmail.com with ESMTPSA id c35sm2886930pgm.67.2021.12.02.07.05.18 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 02 Dec 2021 07:05:21 -0800 (PST) Date: Thu, 2 Dec 2021 20:35:15 +0530 From: Sunil V L To: Heinrich Schuchardt , Ard Biesheuvel , Atish Patra , Abner Chang , Jessica Clarke , Anup Patel , Palmer Dabbelt Cc: sunil.vl@gmail.com, linux-riscv@lists.infradead.org Subject: Question regarding "boot-hartid" DT node Message-ID: <20211202150515.GA97518@sunil-ThinkPad-T490> MIME-Version: 1.0 Content-Disposition: inline X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20211202_070525_199284_322F6D26 X-CRM114-Status: GOOD ( 11.09 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org Hi All, I am starting this thread to discuss about the "boot-hartid" DT node that is being used in RISC-V Linux EFI stub. As you know, the boot Hart ID is passed in a0 register to the kernel and hence there is actually no need to pass it via DT. However, since EFI stub follows EFI application calling conventions, it needs to know the boot Hart ID so that it can pass it to the proper kernel via a0. For this issue, the solution was to add "/chosen/boot-hartid" in DT. Both EDK2 and u-boot append this node in DT. But above approach causes issue for ACPI since ACPI initialization happens late in the proper kernel. Same is true even if we pass this information via SMBIOS. Do you have any suggestions what can be done in ACPI case? Can we use a UEFI variable with RVI specific GUID to pass this information? This will have the advantage that it can work with either DT or ACPI. Also, we may not need any UEFI spec update. Do you see any issue with this approach? Your inputs will be very helpful. Thanks! Sunil _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv