Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934995AbbEOUtk (ORCPT ); Fri, 15 May 2015 16:49:40 -0400 Received: from mail-ig0-f174.google.com ([209.85.213.174]:34249 "EHLO mail-ig0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934627AbbEOUtj (ORCPT ); Fri, 15 May 2015 16:49:39 -0400 Message-ID: <55565BDF.6050503@gmail.com> Date: Fri, 15 May 2015 13:49:35 -0700 From: David Daney User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130625 Thunderbird/17.0.7 MIME-Version: 1.0 To: Leonid Yegoshin CC: aleksey.makarov@auriga.com, james.hogan@imgtec.com, paul.burton@imgtec.com, david.daney@cavium.com, peterz@infradead.org, linux-mips@linux-mips.org, linux-kernel@vger.kernel.org, ralf@linux-mips.org, davidlohr@hp.com, kirill@shutemov.name, akpm@linux-foundation.org, mingo@kernel.org Subject: Re: [PATCH v2] MIPS64: Support of at least 48 bits of SEGBITS References: <20150515013351.7450.12130.stgit@ubuntu-yegoshin> In-Reply-To: <20150515013351.7450.12130.stgit@ubuntu-yegoshin> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4769 Lines: 140 On 05/14/2015 06:34 PM, Leonid Yegoshin wrote: > SEGBITS default is 40 bits or less, depending from CPU type. > This patch introduces 48bits of application virtual address (SEGBITS) support. > It is defined only for 16K and 64K pages and is optional (configurable). > > Penalty - a small number of additional pages for generic (small) applications. > But for 64K pages it adds 3rd level of PTE structure, which has a little > impact during software TLB refill. > > This patch is needed because MIPS I6XXX and P6XXX cores have 48 bit of > virtual address in each segment (SEGBITS). > Those processors don't require the patch. You wrote the patch to give a larger VA space at the request of kernel users. So perhaps say: The patch (optionally) increases the VA space available to userspace processes from N-bits to 48-bits > Signed-off-by: Leonid Yegoshin > --- > V2: Added correction for defintion of TASK_SIZE64 > --- > arch/mips/Kconfig | 11 +++++++++++ > arch/mips/include/asm/pgtable-64.h | 18 +++++++++++------- > arch/mips/include/asm/processor.h | 6 +++++- > 3 files changed, 27 insertions(+), 8 deletions(-) > > diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig > index 76efb02ae99f..3acff2f065e9 100644 > --- a/arch/mips/Kconfig > +++ b/arch/mips/Kconfig > @@ -2032,6 +2032,17 @@ config PAGE_SIZE_64KB > > endchoice > > +config 48VMBITS Should probabaly be called VABITS instead of VMBITS to match the terms used in the architecture reference manuals, as well as other ports (ARM64). Perhaps MIPS_VA_BITS_48 > + bool "48 bits virtual memory" > + depends on PAGE_SIZE_16KB || PAGE_SIZE_64KB > + depends on 64BIT > + help > + Define a maximum at least 48 bits of application virtual memory. > + Default is 40 bits or less, depending from CPU. > + In generic (small) application it is a small set of pages increase > + in page tables. > + If unsure, say N. > + > config FORCE_MAX_ZONEORDER > int "Maximum zone order" > range 14 64 if MIPS_HUGE_TLB_SUPPORT && PAGE_SIZE_64KB > diff --git a/arch/mips/include/asm/pgtable-64.h b/arch/mips/include/asm/pgtable-64.h > index cf661a2fb141..c6b5473440e6 100644 > --- a/arch/mips/include/asm/pgtable-64.h > +++ b/arch/mips/include/asm/pgtable-64.h > @@ -17,7 +17,7 @@ > #include > #include > > -#ifdef CONFIG_PAGE_SIZE_64KB > +#if defined(CONFIG_PAGE_SIZE_64KB) && !defined(CONFIG_48VMBITS) > #include > #else > #include > @@ -90,7 +90,11 @@ > #define PTE_ORDER 0 > #endif > #ifdef CONFIG_PAGE_SIZE_16KB > -#define PGD_ORDER 0 > +#ifdef CONFIG_48VMBITS > +#define PGD_ORDER 1 > +#else > +#define PGD_ORDER 0 > +#endif > #define PUD_ORDER aieeee_attempt_to_allocate_pud > #define PMD_ORDER 0 > #define PTE_ORDER 0 > @@ -104,7 +108,11 @@ > #ifdef CONFIG_PAGE_SIZE_64KB > #define PGD_ORDER 0 > #define PUD_ORDER aieeee_attempt_to_allocate_pud > +#ifdef CONFIG_48VMBITS > +#define PMD_ORDER 0 > +#else > #define PMD_ORDER aieeee_attempt_to_allocate_pmd > +#endif > #define PTE_ORDER 0 > #endif > > @@ -114,11 +122,7 @@ > #endif > #define PTRS_PER_PTE ((PAGE_SIZE << PTE_ORDER) / sizeof(pte_t)) > > -#if PGDIR_SIZE >= TASK_SIZE64 > -#define USER_PTRS_PER_PGD (1) > -#else > -#define USER_PTRS_PER_PGD (TASK_SIZE64 / PGDIR_SIZE) > -#endif > +#define USER_PTRS_PER_PGD ((TASK_SIZE64 / PGDIR_SIZE)?(TASK_SIZE64 / PGDIR_SIZE):1) > #define FIRST_USER_ADDRESS 0UL > > /* > diff --git a/arch/mips/include/asm/processor.h b/arch/mips/include/asm/processor.h > index 9b3b48e21c22..bd2030f32ea4 100644 > --- a/arch/mips/include/asm/processor.h > +++ b/arch/mips/include/asm/processor.h > @@ -69,7 +69,11 @@ extern unsigned int vced_count, vcei_count; > * 8192EB ... > */ > #define TASK_SIZE32 0x7fff8000UL > -#define TASK_SIZE64 0x10000000000UL > +#ifdef CONFIG_48VMBITS > +#define TASK_SIZE64 (0x1UL << ((cpu_data[0].vmbits>48)?48:cpu_data[0].vmbits)) > +#else > +#define TASK_SIZE64 (0x10000000000UL) > +#endif > #define TASK_SIZE (test_thread_flag(TIF_32BIT_ADDR) ? TASK_SIZE32 : TASK_SIZE64) > #define STACK_TOP_MAX TASK_SIZE64 > > > -- > 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/ > > -- 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/