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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 5CAB0CD6E49 for ; Sat, 30 May 2026 16:19:52 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 348346B008A; Sat, 30 May 2026 12:19:51 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 2F8E16B0092; Sat, 30 May 2026 12:19:51 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 20EE26B0093; Sat, 30 May 2026 12:19:51 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 125056B008A for ; Sat, 30 May 2026 12:19:51 -0400 (EDT) Received: from smtpin06.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 4F1704038C for ; Sat, 30 May 2026 16:19:50 +0000 (UTC) X-FDA: 84824597340.06.6440812 Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf15.hostedemail.com (Postfix) with ESMTP id BC3ABA0009 for ; Sat, 30 May 2026 16:19:48 +0000 (UTC) Authentication-Results: imf15.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=WZl0+4I9; spf=pass (imf15.hostedemail.com: domain of rppt@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=rppt@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1780157988; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=WxYmQxwwBxgWs6asR9XSCI+irQfqn2faBEqKE1hn53E=; b=q/ITkzL3qZIkqEPT9flce7HPg+nc0dnK1EF8vJ9vgCQalcy+9dJ2V0l9z04yw0BKY2nuSY +2MtxLeZcjshN8+Uk20GtZnDJ++iEISarNI+3gSYG12y+aS0OYKfTmii0J4sLTUG8CmQ9e CrBRyomwgNGb++/geYP5e7nhua75YFg= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1780157988; a=rsa-sha256; cv=none; b=iEAE33cLwIzGnvaWuPx4C3ANjl54uSQ74qtas1NY9+cFldVmquvc24TelJi1VNTzbK0AmC aiZFBwmcQdUyk1VuGmL4gUTtCZv5FjeZ8Mt185XzjsBoePL2VKdn0lu7fbRftkZ0FUdxgq 9RvSRuHPBbEEbo86doc+8vRx25/PKBQ= ARC-Authentication-Results: i=1; imf15.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=WZl0+4I9; spf=pass (imf15.hostedemail.com: domain of rppt@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=rppt@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 18ACC600BB; Sat, 30 May 2026 16:19:48 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BD33E1F00893; Sat, 30 May 2026 16:19:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1780157987; bh=WxYmQxwwBxgWs6asR9XSCI+irQfqn2faBEqKE1hn53E=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=WZl0+4I9eq0OPPyxyDBdqCGRR+y0CoJpx7P9J1ZNHafWZGZX1fuK9HT7HOCSp1FVU 9ddWJ9lDITFjq9eKGfZ8XgcPI1Gceue8QxkZpOu0JwKjN75XEWJg4tA2a8UNAkWZvu d2ASsHkW3EY1IZ3rOpPzq31XPfEMQM756K5+/fSW612wkX78yv2eAZ66ejeZV4LlfY gAu+RNJYW42KKsssq+PHsl1z2ZSd/eOK+QZCgtAc5FgOD8sjUj3miMaJcP2gtaD17q 8U+HAlTtH77+9KCSbzDnS36KQEJCJesVoZVR5wfQkL3btqSLgCjvtjIMAmDS1I+rUb wf48OWQ3Lcqyg== Date: Sat, 30 May 2026 19:19:36 +0300 From: Mike Rapoport To: Ard Biesheuvel Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, will@kernel.org, catalin.marinas@arm.com, mark.rutland@arm.com, Ard Biesheuvel , Ryan Roberts , Anshuman Khandual , Kevin Brodsky , Liz Prucka , Seth Jenkins , Kees Cook , David Hildenbrand , Andrew Morton , Jann Horn , linux-mm@kvack.org, linux-hardening@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-sh@vger.kernel.org, Yoshinori Sato , Rich Felker , John Paul Adrian Glaubitz , Geert Uytterhoeven Subject: Re: [PATCH v7 12/15] sh: Drop cache flush of the zero page at boot Message-ID: References: <20260529150150.1670604-17-ardb+git@google.com> <20260529150150.1670604-29-ardb+git@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260529150150.1670604-29-ardb+git@google.com> X-Rspamd-Server: rspam11 X-Stat-Signature: hbocaoxt9xc8fgdxbt5agejm9cuyagdm X-Rspamd-Queue-Id: BC3ABA0009 X-Rspam-User: X-HE-Tag: 1780157988-532449 X-HE-Meta: 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 zLR3KpV1 nhqdsh/rbE6oJx/qs6XFA93dYhUlogVjC68+/5qor5RUPr96kKmSqw+SG0AZgbqVfbyTkQG+5YZnEsJaJFFgGbl8mRpAPenFr/R/yfXmUpaAkpR+rqsv0TelcyLaHtW9tEHoia2r2c/p9hoCXk5qk9VLEkswgS4oeu19aew9R1v5/nq5ZKivh7wJjrKmcaT05n/Z9WkLOyyoSGHKx2OtxWAM7jDb9rP4ahrfUgu+srS2EYSXsAjSqZGNN4xszI3RIy63IB+PGcyrr3fGIjT/6w+dqhjNHyp7brF93l6hOQuV/F0Sn1hzaU6gVsfvyIFwIzNM08PEn2iwcTlQiohgXm6cwGHd2gvr3SzjJzlfCM9Ef8F49ZM3blZiZ4IHaiM65L94BiMMM0kjoJ38B3Kcjh+5j69rNBufftNH1z2ZX+oTX/OA= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Fri, May 29, 2026 at 05:02:03PM +0200, Ard Biesheuvel wrote: > From: Ard Biesheuvel > > SuperH performs cache maintenance on the zero page during boot, > presumably because before commit > > 6215d9f4470f ("arch, mm: consolidate empty_zero_page") > > the zero page did double duty as a boot params region, and was cleared > separately, as it was not part of BSS. The memset() in question was > dropped by that commit, but the __flush_wback_region() call remained. > > As empty_zero_page[] has been moved to BSS, it can be treated as any > other BSS memory, and so the cache flush can be dropped. > > Cc: Yoshinori Sato > Cc: Rich Felker > Cc: John Paul Adrian Glaubitz > Cc: Mike Rapoport > Cc: Geert Uytterhoeven > Signed-off-by: Ard Biesheuvel Acked-by: Mike Rapoport (Microsoft) > --- > arch/sh/mm/init.c | 3 --- > 1 file changed, 3 deletions(-) -- Sincerely yours, Mike.