From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_NEOMUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A3A21ECE562 for ; Mon, 17 Sep 2018 06:56:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 42AF5214D5 for ; Mon, 17 Sep 2018 06:56:40 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 42AF5214D5 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727782AbeIQMWk (ORCPT ); Mon, 17 Sep 2018 08:22:40 -0400 Received: from mga12.intel.com ([192.55.52.136]:61822 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726742AbeIQMWj (ORCPT ); Mon, 17 Sep 2018 08:22:39 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from orsmga006.jf.intel.com ([10.7.209.51]) by fmsmga106.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 16 Sep 2018 23:56:37 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.53,384,1531810800"; d="scan'208";a="74871284" Received: from shbuild888.sh.intel.com (HELO localhost) ([10.239.146.239]) by orsmga006.jf.intel.com with ESMTP; 16 Sep 2018 23:56:35 -0700 Date: Mon, 17 Sep 2018 15:01:35 +0800 From: Feng Tang To: Thomas Gleixner Cc: Michal Hocko , Peter Zijlstra , LKML , x86@kernel.org, Ingo Molnar , "H . Peter Anvin" , Yinghai Lu , Dave Hansen , Andi Kleen Subject: Re: [PATCH] x86, mm: Reserver some memory for bootmem allocator for NO_BOOTMEM Message-ID: <20180917070135.3ffqakrhfsjrn253@shbuild888> References: <20180910093938.ka732apzy3d3a5ip@shbuild888> <20180911061413.redy4oxia3hqifkh@shbuild888> <20180915164731.3zrdxijuwkgdi25p@shbuild888> <20180916143549.zmnlcviyn67fbxwh@shbuild888> <20180916150641.qvlfseyeue5vij4w@shbuild888> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180916150641.qvlfseyeue5vij4w@shbuild888> User-Agent: NeoMutt/20170609 (1.8.3) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Thomas, On Sun, Sep 16, 2018 at 11:06:41PM +0800, Feng Tang wrote: > Hi Thomas, > > On Sun, Sep 16, 2018 at 04:43:55PM +0200, Thomas Gleixner wrote: > > On Sun, 16 Sep 2018, Feng Tang wrote: > > > diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c > > > index e848a4811785..a927f5f39bee 100644 > > > --- a/arch/x86/mm/pgtable.c > > > +++ b/arch/x86/mm/pgtable.c > > > @@ -637,6 +637,16 @@ void __native_set_fixmap(enum fixed_addresses idx, pte_t pte) > > > { > > > unsigned long address = __fix_to_virt(idx); > > > > > > +#ifdef CONFIG_X86_64 > > > + /* > > > + * In arch/x86/kernel/head_64.S, the static page table has > > > + * been setup for fixmap. Add a sanity compiling check > > > + * whether fixmap space has exceeded the capacity. > > > + */ > > > + BUILD_BUG_ON((__end_of_permanent_fixed_addresses + 511)/512 > > > + > FIXMAP_PMD_NUM); > > > > There exist macros for rounding up and doing this in the header file is > > perfectly fine. > > I'll find the sample for the round up. > > And for the header file check, I initially put this check directly in > the fixmap.h like: > > #if ((__end_of_permanent_fixed_addresses + 511)/512 > FIXMAP_PMD_NUM) > #erro "some warning...." > #endif > > But failed to compile, I got the warning > warning: "__end_of_permanent_fixed_addresses" is not defined > > I guess the header file preprocessing can't handle it. Below is a patch against 4.19-rc4, verified with earlycon working fine, please review, thanks! - Feng --- >From 2710b48eb29a86c8ee568d00d5b04820c3fe1f3a Mon Sep 17 00:00:00 2001 From: Feng Tang Date: Mon, 17 Sep 2018 12:12:08 +0800 Subject: [PATCH] x86/mm: Expand static page table for fixmap space We met a kernel panic when enabling earlycon, which is due to the fixmap address of earlycon is not statically setup. Currently the static fixmap setup in head_64.S only covers 2M virtual address space, while it acutually could be in 4M space with different kernel configurations. So increase the static space to 4M for now by defining FIXMAP_PMD_NUM to 2, and add a build time check for future possible overflow so that the macro could be increased accordingly. Suggested-by: Thomas Gleixner Signed-off-by: Feng Tang --- arch/x86/include/asm/fixmap.h | 3 +++ arch/x86/include/asm/pgtable_64.h | 3 ++- arch/x86/kernel/head_64.S | 15 +++++++++++---- arch/x86/mm/pgtable.c | 10 ++++++++++ arch/x86/xen/mmu_pv.c | 4 +++- 5 files changed, 29 insertions(+), 6 deletions(-) diff --git a/arch/x86/include/asm/fixmap.h b/arch/x86/include/asm/fixmap.h index e203169..ffaa0fa 100644 --- a/arch/x86/include/asm/fixmap.h +++ b/arch/x86/include/asm/fixmap.h @@ -14,6 +14,9 @@ #ifndef _ASM_X86_FIXMAP_H #define _ASM_X86_FIXMAP_H +/* Put here to be accessble for assembly code like head_64.S */ +#define FIXMAP_PMD_NUM 2 + #ifndef __ASSEMBLY__ #include #include diff --git a/arch/x86/include/asm/pgtable_64.h b/arch/x86/include/asm/pgtable_64.h index ce2b590..9c85b54 100644 --- a/arch/x86/include/asm/pgtable_64.h +++ b/arch/x86/include/asm/pgtable_64.h @@ -14,6 +14,7 @@ #include #include #include +#include extern p4d_t level4_kernel_pgt[512]; extern p4d_t level4_ident_pgt[512]; @@ -22,7 +23,7 @@ extern pud_t level3_ident_pgt[512]; extern pmd_t level2_kernel_pgt[512]; extern pmd_t level2_fixmap_pgt[512]; extern pmd_t level2_ident_pgt[512]; -extern pte_t level1_fixmap_pgt[512]; +extern pte_t level1_fixmap_pgt[512 * FIXMAP_PMD_NUM]; extern pgd_t init_top_pgt[]; #define swapper_pg_dir init_top_pgt diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S index 15ebc2f..985eaff 100644 --- a/arch/x86/kernel/head_64.S +++ b/arch/x86/kernel/head_64.S @@ -24,6 +24,7 @@ #include "../entry/calling.h" #include #include +#include #ifdef CONFIG_PARAVIRT #include @@ -445,13 +446,19 @@ NEXT_PAGE(level2_kernel_pgt) KERNEL_IMAGE_SIZE/PMD_SIZE) NEXT_PAGE(level2_fixmap_pgt) - .fill 506,8,0 - .quad level1_fixmap_pgt - __START_KERNEL_map + _PAGE_TABLE_NOENC - /* 8MB reserved for vsyscalls + a 2MB hole = 4 + 1 entries */ - .fill 5,8,0 + .fill (512 - 4 - FIXMAP_PMD_NUM),8,0 + pgtno = 0 + .rept (FIXMAP_PMD_NUM) + .quad level1_fixmap_pgt + (pgtno << PAGE_SHIFT) - __START_KERNEL_map + _PAGE_TABLE_NOENC + pgtno = pgtno + 1 + .endr + /* 6 MB reserved space + a 2MB hole */ + .fill 4,8,0 NEXT_PAGE(level1_fixmap_pgt) + .rept (FIXMAP_PMD_NUM) .fill 512,8,0 + .endr #undef PMDS diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c index ae39455..c9d94d0 100644 --- a/arch/x86/mm/pgtable.c +++ b/arch/x86/mm/pgtable.c @@ -637,6 +637,16 @@ void __native_set_fixmap(enum fixed_addresses idx, pte_t pte) { unsigned long address = __fix_to_virt(idx); +#ifdef CONFIG_X86_64 + /* + * In arch/x86/kernel/head_64.S, the static page table has + * been setup for fixmap. Add a sanity compiling check + * whether fixmap space has exceeded the capacity. + */ + BUILD_BUG_ON(__end_of_permanent_fixed_addresses + > (FIXMAP_PMD_NUM * PTRS_PER_PMD)); +#endif + if (idx >= __end_of_fixed_addresses) { BUG(); return; diff --git a/arch/x86/xen/mmu_pv.c b/arch/x86/xen/mmu_pv.c index 2fe5c9b..19077f9 100644 --- a/arch/x86/xen/mmu_pv.c +++ b/arch/x86/xen/mmu_pv.c @@ -1952,7 +1952,9 @@ void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn) set_page_prot(level2_ident_pgt, PAGE_KERNEL_RO); set_page_prot(level2_kernel_pgt, PAGE_KERNEL_RO); set_page_prot(level2_fixmap_pgt, PAGE_KERNEL_RO); - set_page_prot(level1_fixmap_pgt, PAGE_KERNEL_RO); + + for (i = 0; i < FIXMAP_PMD_NUM; i++) + set_page_prot(level1_fixmap_pgt + i * 512, PAGE_KERNEL_RO); /* Pin down new L4 */ pin_pagetable_pfn(MMUEXT_PIN_L4_TABLE, -- 2.7.4