Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755486Ab0KVN2s (ORCPT ); Mon, 22 Nov 2010 08:28:48 -0500 Received: from caramon.arm.linux.org.uk ([78.32.30.218]:55916 "EHLO caramon.arm.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751885Ab0KVN2r (ORCPT ); Mon, 22 Nov 2010 08:28:47 -0500 Date: Mon, 22 Nov 2010 13:28:31 +0000 From: Russell King - ARM Linux To: Catalin Marinas Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 01/20] ARM: LPAE: Use PMD_(SHIFT|SIZE|MASK) instead of PGDIR_* Message-ID: <20101122132831.GH31227@n2100.arm.linux.org.uk> References: <1289584840-18097-1-git-send-email-catalin.marinas@arm.com> <1289584840-18097-2-git-send-email-catalin.marinas@arm.com> <20101122124353.GB31227@n2100.arm.linux.org.uk> <1290430810.29754.9.camel@e102109-lin.cambridge.arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1290430810.29754.9.camel@e102109-lin.cambridge.arm.com> User-Agent: Mutt/1.5.19 (2009-01-05) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2949 Lines: 61 On Mon, Nov 22, 2010 at 01:00:10PM +0000, Catalin Marinas wrote: > On Mon, 2010-11-22 at 12:43 +0000, Russell King - ARM Linux wrote: > > On Fri, Nov 12, 2010 at 06:00:21PM +0000, Catalin Marinas wrote: > > > diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c > > > index 8c19595..40b386c 100644 > > > --- a/arch/arm/kernel/smp.c > > > +++ b/arch/arm/kernel/smp.c > > > @@ -78,7 +78,7 @@ static inline void identity_mapping_add(pgd_t *pgd, unsigned long start, > > > if (cpu_architecture() <= CPU_ARCH_ARMv5TEJ && !cpu_is_xscale()) > > > prot |= PMD_BIT4; > > > > > > - for (addr = start & PGDIR_MASK; addr < end;) { > > > + for (addr = start & PMD_MASK; addr < end;) { > > > pmd = pmd_offset(pgd + pgd_index(addr), addr); > > > pmd[0] = __pmd(addr | prot); > > > addr += SECTION_SIZE; > > > @@ -95,7 +95,7 @@ static inline void identity_mapping_del(pgd_t *pgd, unsigned long start, > > > unsigned long addr; > > > pmd_t *pmd; > > > > > > - for (addr = start & PGDIR_MASK; addr < end; addr += PGDIR_SIZE) { > > > + for (addr = start & PMD_MASK; addr < end; addr += PMD_SIZE) { > > > pmd = pmd_offset(pgd + pgd_index(addr), addr); > > > pmd[0] = __pmd(0); > > > pmd[1] = __pmd(0); > > ... > > > @@ -1068,12 +1068,12 @@ void setup_mm_for_reboot(char mode) > > > base_pmdval |= PMD_BIT4; > > > > > > for (i = 0; i < FIRST_USER_PGD_NR + USER_PTRS_PER_PGD; i++, pgd++) { > > > - unsigned long pmdval = (i << PGDIR_SHIFT) | base_pmdval; > > > + unsigned long pmdval = (i << PMD_SHIFT) | base_pmdval; > > > pmd_t *pmd; > > > > > > - pmd = pmd_off(pgd, i << PGDIR_SHIFT); > > > + pmd = pmd_off(pgd, i << PMD_SHIFT); > > > pmd[0] = __pmd(pmdval); > > > - pmd[1] = __pmd(pmdval + (1 << (PGDIR_SHIFT - 1))); > > > + pmd[1] = __pmd(pmdval + (1 << (PMD_SHIFT - 1))); > > > flush_pmd_entry(pmd); > > > } > > > > > > > This lot really does need unifying - and in any case this last addition > > should be using 'SECTION SIZE' not something related to PMD shifts. > > On the classic page tables, the PMD_SHIFT is 21 while the SECTION_SHIFT > is 20. They have slightly different meaning. Correct, and if you look at the code again and analyze what it's doing, you'll see that it's using the wrong thing. The code pre-exists the SECTION_* macros, and was never fixed up when they were introduced. SECTION_SIZE is the right thing here - it's setting up sections. Just look at identity_mapping_add() to see how the code _should_ be. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/