From patchwork Tue Aug 15 00:48:03 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vineet Gupta X-Patchwork-Id: 1821213 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=none (no SPF record) smtp.mailfrom=lists.infradead.org (client-ip=2607:7c80:54:3::133; helo=bombadil.infradead.org; envelope-from=linux-snps-arc-bounces+incoming=patchwork.ozlabs.org@lists.infradead.org; receiver=) Authentication-Results: legolas.ozlabs.org; dkim=pass (2048-bit key; secure) header.d=lists.infradead.org header.i=@lists.infradead.org header.a=rsa-sha256 header.s=bombadil.20210309 header.b=WxtZVoFK; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=jIuvLqPb; dkim-atps=neutral Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:3::133]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-384) server-digest SHA384) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4RPt194Fswz1yfb for ; Tue, 15 Aug 2023 10:48:29 +1000 (AEST) 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:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=qhK7KBXr7/p8NcwzlOSs1NQtRU4QQgJ/j/vAnu+E87g=; b=WxtZVoFKrIQOfn RKlTSK9ZVp4jWoJr5cbqC88j/yxgfLq9wIALbIPLD7vfP0ETjHwkrL8VTjLgruukqU6jCEreb9mDG dVOLr7SWeUn/ElWcWdU9//DGfYZm96c+/fI2XItddZDFl5+4jdLE4W9IBqU/4kte3AIeyqEr5yTEP 1c000MiClIc+8jFuhP0B41BYV/Ce52IZa2SOVlrm+01iowkPKZP+QclwVo2T9J39rDXedj7KPdSfk JeCAwA7/vXhRqP5xDGtnAoFqoHckN8wTFIaXpxL0ArtUT0ijoptakjJr8cddQefr546hUhEftdP2w QJCxs7KfJoGKRLlTLBIg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qViEU-000cb3-2t; Tue, 15 Aug 2023 00:48:26 +0000 Received: from dfw.source.kernel.org ([139.178.84.217]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qViER-000cVi-0Q for linux-snps-arc@lists.infradead.org; Tue, 15 Aug 2023 00:48:24 +0000 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id A167B64BE3; Tue, 15 Aug 2023 00:48:22 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3D212C433CC; Tue, 15 Aug 2023 00:48:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1692060502; bh=yWcyUxif3dikEYknmSArzeGyfZedu8yajJX9cu4DT8o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jIuvLqPbU//pLE4JPxKRp9UCHkrq9i+/o1874YalJxOHW1DzCuOc5eTpgw+36PDDD 2aOy8LOzN/4I/Y66XzxsCN/UDZ1ZlY544oyu35GmmcdnL7yq0qCBggnlJcDCF580Rx b2xdpHvMrUc/wnQ1wJTJYlgeosSMYovaiGmHWOcPHkxLTCNCtCKV3v7sRF8bov3N6R 4KTt9Ifyn9CofxXD/PVV8Ebi4mYtym7AeLTudA5ZA+xApAxDL242HS3ZDBNETyHs/y qpHDFhaLXhhTveQNORVxZZ6zFk+UD+YbDI7/VrH5bxw/OVgzuk2z7VRZE21OhoWNSA vlDa9wN4DEArQ== From: Vineet Gupta To: linux-snps-arc@lists.infradead.org Cc: linux-kernel@vger.kernel.org, Shahab Vahedi , Alexey Brodkin , Vineet Gupta Subject: [PATCH 10/20] ARC: kernel stack: INIT_THREAD need not setup @init_stack in @ksp Date: Mon, 14 Aug 2023 17:48:03 -0700 Message-Id: <20230815004813.555115-11-vgupta@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230815004813.555115-1-vgupta@kernel.org> References: <20230815004813.555115-1-vgupta@kernel.org> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230814_174823_219207_0F4CB622 X-CRM114-Status: GOOD ( 11.89 ) X-Spam-Score: -5.4 (-----) X-Spam-Report: Spam detection software, running on the system "bombadil.infradead.org", has NOT identified this incoming email as spam. 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Content preview: There are 2 pointers to kernel mode stack of a task - task_struct.stack: base address of stack page (max possible stack top) - thread_info.ksp : runtime stack top in __switch_to INIT_THREAD was setting up ksp to stack base which was not really needed - it would get overwritten with dynamic value on first call to __switch_to when init is switched out for the very first time. - [...] Content analysis details: (-5.4 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -5.0 RCVD_IN_DNSWL_HI RBL: Sender listed at https://www.dnswl.org/, high trust [139.178.84.217 listed in list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID_EF Message has a valid DKIM or DK signature from envelope-from domain -0.2 DKIMWL_WL_HIGH DKIMwl.org - High trust sender X-BeenThere: linux-snps-arc@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Linux on Synopsys ARC Processors List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-snps-arc" Errors-To: linux-snps-arc-bounces+incoming=patchwork.ozlabs.org@lists.infradead.org There are 2 pointers to kernel mode stack of a task - task_struct.stack: base address of stack page (max possible stack top) - thread_info.ksp : runtime stack top in __switch_to INIT_THREAD was setting up ksp to stack base which was not really needed - it would get overwritten with dynamic value on first call to __switch_to when init is switched out for the very first time. - generic code already does init_task.stack = init_stack and ARC code uses that to retrieve task's stack base. Signed-off-by: Vineet Gupta --- arch/arc/include/asm/processor.h | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/arch/arc/include/asm/processor.h b/arch/arc/include/asm/processor.h index fb844fce1ab6..82ddc929d6e7 100644 --- a/arch/arc/include/asm/processor.h +++ b/arch/arc/include/asm/processor.h @@ -33,9 +33,7 @@ struct thread_struct { #endif }; -#define INIT_THREAD { \ - .ksp = sizeof(init_stack) + (unsigned long) init_stack, \ -} +#define INIT_THREAD { } /* Forward declaration, a strange C thing */ struct task_struct;