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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 E0C79ECE564 for ; Tue, 18 Sep 2018 22:13:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 748312133F for ; Tue, 18 Sep 2018 22:13:41 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 748312133F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=zytor.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 S1728159AbeISDsT (ORCPT ); Tue, 18 Sep 2018 23:48:19 -0400 Received: from terminus.zytor.com ([198.137.202.136]:59251 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726995AbeISDsS (ORCPT ); Tue, 18 Sep 2018 23:48:18 -0400 Received: from terminus.zytor.com (localhost [127.0.0.1]) by terminus.zytor.com (8.15.2/8.15.2) with ESMTPS id w8IMD4Hb937144 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Tue, 18 Sep 2018 15:13:04 -0700 Received: (from tipbot@localhost) by terminus.zytor.com (8.15.2/8.15.2/Submit) id w8IMD42E937141; Tue, 18 Sep 2018 15:13:04 -0700 Date: Tue, 18 Sep 2018 15:13:04 -0700 X-Authentication-Warning: terminus.zytor.com: tipbot set sender to tipbot@zytor.com using -f From: tip-bot for Feng Tang Message-ID: Cc: dave.hansen@intel.com, peterz@infradead.org, tglx@linutronix.de, mingo@kernel.org, hpa@zytor.com, feng.tang@intel.com, mhocko@kernel.org, ak@linux.intel.com, hpa@linux.intel.com, linux-kernel@vger.kernel.org, yinghai@kernel.org Reply-To: dave.hansen@intel.com, mingo@kernel.org, tglx@linutronix.de, peterz@infradead.org, mhocko@kernel.org, ak@linux.intel.com, feng.tang@intel.com, hpa@zytor.com, yinghai@kernel.org, linux-kernel@vger.kernel.org, hpa@linux.intel.com In-Reply-To: <20180917091423.16069-1-feng.tang@intel.com> References: <20180917091423.16069-1-feng.tang@intel.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/urgent] x86/mm: Expand static page table for fixmap space Git-Commit-ID: 31217900acbaf66249b8befd06c975aa897b4deb X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 31217900acbaf66249b8befd06c975aa897b4deb Gitweb: https://git.kernel.org/tip/31217900acbaf66249b8befd06c975aa897b4deb Author: Feng Tang AuthorDate: Mon, 17 Sep 2018 17:14:23 +0800 Committer: Thomas Gleixner CommitDate: Wed, 19 Sep 2018 00:09:10 +0200 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 to ensure that the fixmap is covered by the intial static page tables. [ tglx: s/PTRS_PER_PMD/PTRS_PER_PTE/ and add the missing brackets ] Suggested-by: Thomas Gleixner Signed-off-by: Feng Tang Signed-off-by: Thomas Gleixner Reviewed-by: Juergen Gross (Xen parts) Cc: H Peter Anvin Cc: Peter Zijlstra Cc: Michal Hocko Cc: Yinghai Lu Cc: Dave Hansen Cc: Andi Kleen Link: https://lkml.kernel.org/r/20180917091423.16069-1-feng.tang@intel.com --- arch/x86/include/asm/fixmap.h | 8 ++++++++ arch/x86/include/asm/pgtable_64.h | 3 ++- arch/x86/kernel/head_64.S | 16 ++++++++++++---- arch/x86/mm/pgtable.c | 9 +++++++++ arch/x86/xen/mmu_pv.c | 8 ++++++-- 5 files changed, 37 insertions(+), 7 deletions(-) diff --git a/arch/x86/include/asm/fixmap.h b/arch/x86/include/asm/fixmap.h index e203169931c7..01e8da740293 100644 --- a/arch/x86/include/asm/fixmap.h +++ b/arch/x86/include/asm/fixmap.h @@ -14,6 +14,14 @@ #ifndef _ASM_X86_FIXMAP_H #define _ASM_X86_FIXMAP_H +/* + * Exposed to assembly code for setting up initial page tables. Cannot be + * calculated in assembly code (fixmap entries are an enum), but is sanity + * checked in the actual fixmap C code to make sure that the fixmap is + * covered fully. + */ +#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 ce2b59047cb8..9c85b54bf03c 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 15ebc2fc166e..a3618cf04cf6 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 +446,20 @@ 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 ae394552fb94..089e78c4effd 100644 --- a/arch/x86/mm/pgtable.c +++ b/arch/x86/mm/pgtable.c @@ -637,6 +637,15 @@ void __native_set_fixmap(enum fixed_addresses idx, pte_t pte) { unsigned long address = __fix_to_virt(idx); +#ifdef CONFIG_X86_64 + /* + * Ensure that the static initial page tables are covering the + * fixmap completely. + */ + BUILD_BUG_ON(__end_of_permanent_fixed_addresses > + (FIXMAP_PMD_NUM * PTRS_PER_PTE)); +#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 2fe5c9b1816b..dd461c0167ef 100644 --- a/arch/x86/xen/mmu_pv.c +++ b/arch/x86/xen/mmu_pv.c @@ -1907,7 +1907,7 @@ void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn) /* L3_k[511] -> level2_fixmap_pgt */ convert_pfn_mfn(level3_kernel_pgt); - /* L3_k[511][506] -> level1_fixmap_pgt */ + /* L3_k[511][508-FIXMAP_PMD_NUM ... 507] -> level1_fixmap_pgt */ convert_pfn_mfn(level2_fixmap_pgt); /* We get [511][511] and have Xen's version of level2_kernel_pgt */ @@ -1952,7 +1952,11 @@ 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 * PTRS_PER_PTE, + PAGE_KERNEL_RO); + } /* Pin down new L4 */ pin_pagetable_pfn(MMUEXT_PIN_L4_TABLE,