Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754695AbbEOKjP (ORCPT ); Fri, 15 May 2015 06:39:15 -0400 Received: from mail-la0-f51.google.com ([209.85.215.51]:33954 "EHLO mail-la0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752739AbbEOKjO (ORCPT ); Fri, 15 May 2015 06:39:14 -0400 Message-ID: <5555CCCE.6010006@cogentembedded.com> Date: Fri, 15 May 2015 13:39:10 +0300 From: Sergei Shtylyov User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:31.0) Gecko/20100101 Thunderbird/31.6.0 MIME-Version: 1.0 To: Leonid Yegoshin , 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: 3074 Lines: 95 Hello. On 5/15/2015 4:34 AM, 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). > 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 > + 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. s/from/on/. > + In generic (small) application it is a small set of pages increase > + in page tables. Can't parse that... [...] > 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 [...] > @@ -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) Could write this as '(TASK_SIZE64 / PGDIR_SIZE ?: 1)'. [...] > 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)) Perhaps '(0x1UL << (min(cpu_data[0].vmbits, 48))'? > +#else > +#define TASK_SIZE64 (0x10000000000UL) Parens not needed. [...] WBR, Sergei -- 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/