From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eu-smtp-delivery-151.mimecast.com (eu-smtp-delivery-151.mimecast.com [185.58.85.151]) (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 AA86E3D96A for ; Sat, 14 Dec 2024 18:41:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.58.85.151 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734201673; cv=none; b=oAu3ZQNq8gjrhEbNMlp8tjUFNGCCds07fJYkjhADatpHSwYUv0VcIQV17TRfOw5WzUaUDmZMlqTyVem0UhJHb3U295V3YjqRMRByc67ynofirPg8sah9iCqdNe8sGYYyVC3FmUP7u+mY9l3Os55HAoRNDeOzT7AUF36H6vpd47o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734201673; c=relaxed/simple; bh=g7rTlp2Fy0rmh8iTu37cPNHXE5zBs2vgpiuv/ttvAcM=; h=From:To:CC:Subject:Date:Message-ID:References:In-Reply-To: MIME-Version:Content-Type; b=nVm5l4Is0qPTlRR7BJ5tM2Dc9J7y+tC7QahN7KCmcx0SOy3DZueXyGJHnykjQq/DzzNcuT1yhHAwp3iK+TqVUlOGK/TvfORcZEBi1UA2RZsql0wcqvrYtq1WOVU7vSrRy0Db+qLCa+9IZzKB5DkgNkotDoOoaly0g044qrNVodI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ACULAB.COM; spf=pass smtp.mailfrom=aculab.com; arc=none smtp.client-ip=185.58.85.151 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ACULAB.COM Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=aculab.com Received: from AcuMS.aculab.com (156.67.243.121 [156.67.243.121]) by relay.mimecast.com with ESMTP with both STARTTLS and AUTH (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id uk-mta-280-3Kd5c3ElMVu5EUN2SKtuRQ-1; Sat, 14 Dec 2024 18:41:08 +0000 X-MC-Unique: 3Kd5c3ElMVu5EUN2SKtuRQ-1 X-Mimecast-MFC-AGG-ID: 3Kd5c3ElMVu5EUN2SKtuRQ Received: from AcuMS.Aculab.com (10.202.163.4) by AcuMS.aculab.com (10.202.163.4) with Microsoft SMTP Server (TLS) id 15.0.1497.48; Sat, 14 Dec 2024 18:40:11 +0000 Received: from AcuMS.Aculab.com ([::1]) by AcuMS.aculab.com ([::1]) with mapi id 15.00.1497.048; Sat, 14 Dec 2024 18:40:11 +0000 From: David Laight To: 'Arnd Bergmann' , "linux-arm-kernel@lists.infradead.org" CC: "linux-kernel@vger.kernel.org" , "Arnd Bergmann" , "linux-mm@kvack.org" , "linux-rt-devel@lists.linux.dev" , "Ard Biesheuvel" , Clark Williams , "Jason Baron" , Josh Poimboeuf , "Linus Walleij" , Mark Rutland , Matthew Wilcox , Peter Zijlstra , Russell King , Sebastian Andrzej Siewior , Steven Rostedt Subject: RE: [PATCH 3/4] ARM: drop CONFIG_HIGHPTE support Thread-Topic: [PATCH 3/4] ARM: drop CONFIG_HIGHPTE support Thread-Index: AQHbSx10HM4hb1GiOk+xX2rPfGcyA7LmGAAw Date: Sat, 14 Dec 2024 18:40:11 +0000 Message-ID: References: <20241210160556.2341497-1-arnd@kernel.org> <20241210160556.2341497-4-arnd@kernel.org> In-Reply-To: <20241210160556.2341497-4-arnd@kernel.org> Accept-Language: en-GB, en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: griw3fBzfXZmiafbT2O0nxNZ3_0LigrR5nu9qFQykfg_1734201667 X-Mimecast-Originator: aculab.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable From: Arnd Bergmann > Sent: 10 December 2024 16:06 ... > Since Arm is the last architecture remaining that uses this, and almost > no 32-bit machines support more than 4GB of RAM, the cost of continuing > to maintain HIGHPTE seems unjustified, so remove it here to allow > simplifying the generic page table handling. 'Picking at nits' 'highmem' support was needed for systems with 4GB of RAM in order to use more than 3GB or 3.5GB (depending on the bios) because of the physical addresses that are reserved for PCI (and other MMIO). =09David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1= PT, UK Registration No: 1397386 (Wales)