From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751932AbcISOqf (ORCPT ); Mon, 19 Sep 2016 10:46:35 -0400 Received: from mail.southpole.se ([37.247.8.11]:36448 "EHLO mail.southpole.se" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751307AbcISOqd (ORCPT ); Mon, 19 Sep 2016 10:46:33 -0400 Subject: Re: [PATCH 2/7] openrisc: fix PTRS_PER_PGD define To: Stafford Horne , Stefan Kristiansson , Andrew Morton References: <1474036985-20981-1-git-send-email-shorne@gmail.com> <1474036985-20981-3-git-send-email-shorne@gmail.com> Cc: linux-kernel@vger.kernel.org From: Jonas Bonn Message-ID: <57DFF5BA.6090400@southpole.se> Date: Mon, 19 Sep 2016 16:27:06 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 MIME-Version: 1.0 In-Reply-To: <1474036985-20981-3-git-send-email-shorne@gmail.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-Assp-Version: 2.5.1(16177) on assp.southpole.se X-Assp-ID: assp.southpole.se 95226-01190 X-Assp-Session: 7F0FD1D28BD0 (mail 1) X-Assp-Client-SSL: yes X-Assp-Server-TLS: yes Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/16/2016 04:43 PM, Stafford Horne wrote: > From: Stefan Kristiansson > > On OpenRISC, with its 8k pages, PAGE_SHIFT is defined to be 13. > That makes the expression (1UL << (PAGE_SHIFT-2)) evaluate > to 2048. > The correct value for PTRS_PER_PGD should be 256. > > Correcting the PTRS_PER_PGD define unveiled a bug in map_ram(), > where PTRS_PER_PGD was used when the intent was to iterate > over a set of page table entries. > This patch corrects that issue as well. > > Signed-off-by: Stefan Kristiansson > Signed-off-by: Stafford Horne Acked-by: Jonas Bonn > --- > arch/openrisc/include/asm/pgtable.h | 2 +- > arch/openrisc/mm/init.c | 2 +- > 2 files changed, 2 insertions(+), 2 deletions(-) > > diff --git a/arch/openrisc/include/asm/pgtable.h b/arch/openrisc/include/asm/pgtable.h > index 69c7df0..3567aa7 100644 > --- a/arch/openrisc/include/asm/pgtable.h > +++ b/arch/openrisc/include/asm/pgtable.h > @@ -69,7 +69,7 @@ extern void paging_init(void); > */ > #define PTRS_PER_PTE (1UL << (PAGE_SHIFT-2)) > > -#define PTRS_PER_PGD (1UL << (PAGE_SHIFT-2)) > +#define PTRS_PER_PGD (1UL << (32-PGDIR_SHIFT)) > > /* calculate how many PGD entries a user-level program can use > * the first mappable virtual address is 0 > diff --git a/arch/openrisc/mm/init.c b/arch/openrisc/mm/init.c > index 7f94652..b782ce9 100644 > --- a/arch/openrisc/mm/init.c > +++ b/arch/openrisc/mm/init.c > @@ -110,7 +110,7 @@ static void __init map_ram(void) > set_pmd(pme, __pmd(_KERNPG_TABLE + __pa(pte))); > > /* Fill the newly allocated page with PTE'S */ > - for (j = 0; p < e && j < PTRS_PER_PGD; > + for (j = 0; p < e && j < PTRS_PER_PTE; > v += PAGE_SIZE, p += PAGE_SIZE, j++, pte++) { > if (v >= (u32) _e_kernel_ro || > v < (u32) _s_kernel_ro)