Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753587Ab0KVNKa (ORCPT ); Mon, 22 Nov 2010 08:10:30 -0500 Received: from caramon.arm.linux.org.uk ([78.32.30.218]:46415 "EHLO caramon.arm.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751307Ab0KVNK3 (ORCPT ); Mon, 22 Nov 2010 08:10:29 -0500 Date: Mon, 22 Nov 2010 13:10:10 +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 08/20] ARM: LPAE: MMU setup for the 3-level page table format Message-ID: <20101122131010.GD31227@n2100.arm.linux.org.uk> References: <1289584840-18097-1-git-send-email-catalin.marinas@arm.com> <1289584840-18097-9-git-send-email-catalin.marinas@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1289584840-18097-9-git-send-email-catalin.marinas@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: 4489 Lines: 139 On Fri, Nov 12, 2010 at 06:00:28PM +0000, Catalin Marinas wrote: > This patch adds the MMU initialisation for the LPAE page table format. > The swapper_pg_dir size with LPAE is 5 rather than 4 pages. The > __v7_setup function configures the TTBRx split based on the PAGE_OFFSET > and sets the corresponding TTB control and MAIRx bits (similar to > PRRR/NMRR for TEX remapping). The 36-bit mappings (supersections) and > a few other memory types in mmu.c are conditionally compiled. > > Signed-off-by: Catalin Marinas > --- > arch/arm/kernel/head.S | 96 +++++++++++++++++++++++++++++++------------ > arch/arm/mm/mmu.c | 32 ++++++++++++++- > arch/arm/mm/proc-macros.S | 5 +- > arch/arm/mm/proc-v7.S | 99 ++++++++++++++++++++++++++++++++++++++++---- > 4 files changed, 193 insertions(+), 39 deletions(-) > > diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S > index dd6b369..fd8a29e 100644 > --- a/arch/arm/kernel/head.S > +++ b/arch/arm/kernel/head.S > @@ -21,6 +21,7 @@ > #include > #include > #include > +#include > > #ifdef CONFIG_DEBUG_LL > #include > @@ -45,11 +46,20 @@ > #error KERNEL_RAM_VADDR must start at 0xXXXX8000 > #endif > > +#ifdef CONFIG_ARM_LPAE > + /* LPAE requires an additional page for the PGD */ > +#define PG_DIR_SIZE 0x5000 > +#define PTE_WORDS 3 > +#else > +#define PG_DIR_SIZE 0x4000 > +#define PTE_WORDS 2 PTE is not the right prefix here - we don't deal with the lowest level of page tables, which in Linux is called PTE. I think you mean PMD_WORDS instead. > +#endif > + > .globl swapper_pg_dir > - .equ swapper_pg_dir, KERNEL_RAM_VADDR - 0x4000 > + .equ swapper_pg_dir, KERNEL_RAM_VADDR - PG_DIR_SIZE > > .macro pgtbl, rd > - ldr \rd, =(KERNEL_RAM_PADDR - 0x4000) > + ldr \rd, =(KERNEL_RAM_PADDR - PG_DIR_SIZE) > .endm > > #ifdef CONFIG_XIP_KERNEL > @@ -129,11 +139,11 @@ __create_page_tables: > pgtbl r4 @ page table address > > /* > - * Clear the 16K level 1 swapper page table > + * Clear the swapper page table > */ > mov r0, r4 > mov r3, #0 > - add r6, r0, #0x4000 > + add r6, r0, #PG_DIR_SIZE > 1: str r3, [r0], #4 > str r3, [r0], #4 > str r3, [r0], #4 > @@ -141,6 +151,23 @@ __create_page_tables: > teq r0, r6 > bne 1b > > +#ifdef CONFIG_ARM_LPAE > + /* > + * Build the PGD table (first level) to point to the PMD table. A PGD > + * entry is 64-bit wide and the top 32 bits are 0. > + */ > + mov r0, r4 > + add r3, r4, #0x1000 @ first PMD table address > + orr r3, r3, #3 @ PGD block type > + mov r6, #4 @ PTRS_PER_PGD > +1: str r3, [r0], #8 @ set PGD entry > + add r3, r3, #0x1000 @ next PMD table > + subs r6, r6, #1 > + bne 1b > + > + add r4, r4, #0x1000 @ point to the PMD tables > +#endif > + > ldr r7, [r10, #PROCINFO_MM_MMUFLAGS] @ mm_mmuflags > > /* > @@ -152,30 +179,30 @@ __create_page_tables: > sub r0, r0, r3 @ virt->phys offset > add r5, r5, r0 @ phys __enable_mmu > add r6, r6, r0 @ phys __enable_mmu_end > - mov r5, r5, lsr #20 > - mov r6, r6, lsr #20 > + mov r5, r5, lsr #SECTION_SHIFT > + mov r6, r6, lsr #SECTION_SHIFT > > -1: orr r3, r7, r5, lsl #20 @ flags + kernel base > - str r3, [r4, r5, lsl #2] @ identity mapping > - teq r5, r6 > - addne r5, r5, #1 @ next section > - bne 1b > +1: orr r3, r7, r5, lsl #SECTION_SHIFT @ flags + kernel base > + str r3, [r4, r5, lsl #PTE_WORDS] @ identity mapping > + cmp r5, r6 > + addlo r5, r5, #SECTION_SHIFT >> 20 @ next section > + blo 1b > > /* > * Now setup the pagetables for our kernel direct > * mapped region. > */ > mov r3, pc > - mov r3, r3, lsr #20 > - orr r3, r7, r3, lsl #20 > + mov r3, r3, lsr #SECTION_SHIFT > + orr r3, r7, r3, lsl #SECTION_SHIFT > add r0, r4, #(KERNEL_START & 0xff000000) >> 18 > - str r3, [r0, #(KERNEL_START & 0x00f00000) >> 18]! > + str r3, [r0, #(KERNEL_START & 0x00e00000) >> 18]! > ldr r6, =(KERNEL_END - 1) > - add r0, r0, #4 > + add r0, r0, #1 << PTE_WORDS > add r6, r4, r6, lsr #18 Are you sure these shifts by 18 places are correct? They're actually (val >> SECTION_SHIFT) << 2, so maybe they should be (SECTION_SHIFT - PMD_WORDS) ? -- 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/