From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933265AbcHNLAq (ORCPT ); Sun, 14 Aug 2016 07:00:46 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:51918 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933248AbcHNLAn (ORCPT ); Sun, 14 Aug 2016 07:00:43 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Martin Schwidefsky" , "Heiko Carstens" Date: Sat, 13 Aug 2016 18:42:51 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 065/305] s390/vmem: fix identity mapping In-Reply-To: X-SA-Exim-Connect-IP: 92.40.249.202 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.37-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Heiko Carstens commit c34a69059d7876e0793eb410deedfb08ccb22b02 upstream. The identity mapping is suboptimal for the last 2GB frame. The mapping will be established with a mix of 4KB and 1MB mappings instead of a single 2GB mapping. This happens because of a off-by-one bug introduced with commit 50be63450728 ("s390/mm: Convert bootmem to memblock"). Currently the identity mapping looks like this: 0x0000000080000000-0x0000000180000000 4G PUD RW 0x0000000180000000-0x00000001fff00000 2047M PMD RW 0x00000001fff00000-0x0000000200000000 1M PTE RW With the bug fixed it looks like this: 0x0000000080000000-0x0000000200000000 6G PUD RW Fixes: 50be63450728 ("s390/mm: Convert bootmem to memblock") Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky Signed-off-by: Ben Hutchings --- arch/s390/mm/vmem.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/arch/s390/mm/vmem.c +++ b/arch/s390/mm/vmem.c @@ -380,7 +380,7 @@ void __init vmem_map_init(void) ro_end = (unsigned long)&_eshared & PAGE_MASK; for_each_memblock(memory, reg) { start = reg->base; - end = reg->base + reg->size - 1; + end = reg->base + reg->size; if (start >= ro_end || end <= ro_start) vmem_add_mem(start, end - start, 0); else if (start >= ro_start && end <= ro_end)