From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DC3883093A6; Sat, 30 May 2026 16:19:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780157989; cv=none; b=Aicyo9OojNaheMpa3a2a7z12hRXIKQPagy0i4XoSdZkp6vaFHv6bRDAGUua/rQsz8Pxo1UepVycUKQIqOdAfOtBldAbAxdCKEJf8Jcf4XSs4NbOgYJN9gXgiZG71hND/+nvqr4m5lVuLrYZ0clsR3BtBjVS6E3h9ApPgLRWlk+s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780157989; c=relaxed/simple; bh=3ZBflBeNYm+c/oTiCGoL+2HSsJ8/5ZXdqbhea4+si1M=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=uW3vWjGffCE7W6DiQjT2zKRpaE70FjFViu9vAzB9b2QKblpLkU1fF/A45cQJQRizCHUcORP7EktO9eWwPIRcs1CcQYu4hN0ea8oSMmqtyqzzceAc2f3r4ZexCzEOl4dD7du9RfI4+KPSGJXtUpt8ZQ3V26ibPIbSP7sBgszMJYQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=WZl0+4I9; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="WZl0+4I9" 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> Precedence: bulk X-Mailing-List: linux-sh@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260529150150.1670604-29-ardb+git@google.com> 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.