Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753081Ab0KWLiS (ORCPT ); Tue, 23 Nov 2010 06:38:18 -0500 Received: from mail-gy0-f174.google.com ([209.85.160.174]:37172 "EHLO mail-gy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751083Ab0KWLiQ convert rfc822-to-8bit (ORCPT ); Tue, 23 Nov 2010 06:38:16 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:cc:content-type :content-transfer-encoding; b=uibH/ijahaHfuh3gIYlGFexwi6y0kmB0Q4Sa5765QLzZ8j0S4ROQLlLYMBo0FH7VhN pQjBG6ovEIxUd4YA2LOvNUhnN628AhLTy1KBOg3uHZmaFVQiGe0Sj8aKZIoJJILurAUq AeZKXgBisV3kmhxvbsaj7GQOd8u3qXlp7GoDE= MIME-Version: 1.0 In-Reply-To: <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> <20101122131010.GD31227@n2100.arm.linux.org.uk> Date: Tue, 23 Nov 2010 11:38:15 +0000 X-Google-Sender-Auth: -fPJhgXvCpJDNQHdc93j0_O1duU Message-ID: Subject: Re: [PATCH v2 08/20] ARM: LPAE: MMU setup for the 3-level page table format From: Catalin Marinas To: Russell King - ARM Linux Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5268 Lines: 129 On 22 November 2010 13:10, Russell King - ARM Linux wrote: > 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. [...] >> --- 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. It should actually be something PMD_ORDER because of the log2 value. >>  #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) ? SECTION_SHIFT - PMD_ORDER is (20 - 2) for classic page tables and (21 - 3) for LPAE. But we could change the 18 to some macros for clarification (the line would be long though). -- Catalin -- 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/