From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751162AbdCMFzH (ORCPT ); Mon, 13 Mar 2017 01:55:07 -0400 Received: from mga14.intel.com ([192.55.52.115]:11486 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750989AbdCMFv2 (ORCPT ); Mon, 13 Mar 2017 01:51:28 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.36,157,1486454400"; d="scan'208";a="943578237" From: "Kirill A. Shutemov" To: Linus Torvalds , Andrew Morton , x86@kernel.org, Thomas Gleixner , Ingo Molnar , Arnd Bergmann , "H. Peter Anvin" Cc: Andi Kleen , Dave Hansen , Andy Lutomirski , Michal Hocko , linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Kirill A. Shutemov" Subject: [PATCH 05/26] x86/mm: add support of p4d_t in vmalloc_fault() Date: Mon, 13 Mar 2017 08:49:59 +0300 Message-Id: <20170313055020.69655-6-kirill.shutemov@linux.intel.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20170313055020.69655-1-kirill.shutemov@linux.intel.com> References: <20170313055020.69655-1-kirill.shutemov@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org With 4-level paging copying happens on p4d level, as we have pgd_none() always false when p4d_t folded. Signed-off-by: Kirill A. Shutemov --- arch/x86/mm/fault.c | 27 ++++++++++++++++++++++++--- 1 file changed, 24 insertions(+), 3 deletions(-) diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index 605fd5e8e048..88040bb2b78a 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -435,6 +435,7 @@ void vmalloc_sync_all(void) static noinline int vmalloc_fault(unsigned long address) { pgd_t *pgd, *pgd_ref; + p4d_t *p4d, *p4d_ref; pud_t *pud, *pud_ref; pmd_t *pmd, *pmd_ref; pte_t *pte, *pte_ref; @@ -458,17 +459,37 @@ static noinline int vmalloc_fault(unsigned long address) if (pgd_none(*pgd)) { set_pgd(pgd, *pgd_ref); arch_flush_lazy_mmu_mode(); - } else { + } else if (CONFIG_PGTABLE_LEVELS > 4) { + /* + * With folded p4d, pgd_none() is always false. So pgd may + * point to empty page table entry and pgd_page_vaddr() + * will return garbage. + * + * We will do the correct sanity check on p4d level. + */ BUG_ON(pgd_page_vaddr(*pgd) != pgd_page_vaddr(*pgd_ref)); } + /* With 4-level paging copying happens on p4d level. */ + p4d = p4d_offset(pgd, address); + p4d_ref = p4d_offset(pgd_ref, address); + if (p4d_none(*p4d_ref)) + return -1; + + if (p4d_none(*p4d)) { + set_p4d(p4d, *p4d_ref); + arch_flush_lazy_mmu_mode(); + } else { + BUG_ON(p4d_pfn(*p4d) != p4d_pfn(*p4d_ref)); + } + /* * Below here mismatches are bugs because these lower tables * are shared: */ - pud = pud_offset(pgd, address); - pud_ref = pud_offset(pgd_ref, address); + pud = pud_offset(p4d, address); + pud_ref = pud_offset(p4d_ref, address); if (pud_none(*pud_ref)) return -1; -- 2.11.0 From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Kirill A. Shutemov" Subject: [PATCH 05/26] x86/mm: add support of p4d_t in vmalloc_fault() Date: Mon, 13 Mar 2017 08:49:59 +0300 Message-ID: <20170313055020.69655-6-kirill.shutemov@linux.intel.com> References: <20170313055020.69655-1-kirill.shutemov@linux.intel.com> Return-path: In-Reply-To: <20170313055020.69655-1-kirill.shutemov@linux.intel.com> Sender: owner-linux-mm@kvack.org To: Linus Torvalds , Andrew Morton , x86@kernel.org, Thomas Gleixner , Ingo Molnar , Arnd Bergmann , "H. Peter Anvin" Cc: Andi Kleen , Dave Hansen , Andy Lutomirski , Michal Hocko , linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Kirill A. Shutemov" List-Id: linux-arch.vger.kernel.org With 4-level paging copying happens on p4d level, as we have pgd_none() always false when p4d_t folded. Signed-off-by: Kirill A. Shutemov --- arch/x86/mm/fault.c | 27 ++++++++++++++++++++++++--- 1 file changed, 24 insertions(+), 3 deletions(-) diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index 605fd5e8e048..88040bb2b78a 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -435,6 +435,7 @@ void vmalloc_sync_all(void) static noinline int vmalloc_fault(unsigned long address) { pgd_t *pgd, *pgd_ref; + p4d_t *p4d, *p4d_ref; pud_t *pud, *pud_ref; pmd_t *pmd, *pmd_ref; pte_t *pte, *pte_ref; @@ -458,17 +459,37 @@ static noinline int vmalloc_fault(unsigned long address) if (pgd_none(*pgd)) { set_pgd(pgd, *pgd_ref); arch_flush_lazy_mmu_mode(); - } else { + } else if (CONFIG_PGTABLE_LEVELS > 4) { + /* + * With folded p4d, pgd_none() is always false. So pgd may + * point to empty page table entry and pgd_page_vaddr() + * will return garbage. + * + * We will do the correct sanity check on p4d level. + */ BUG_ON(pgd_page_vaddr(*pgd) != pgd_page_vaddr(*pgd_ref)); } + /* With 4-level paging copying happens on p4d level. */ + p4d = p4d_offset(pgd, address); + p4d_ref = p4d_offset(pgd_ref, address); + if (p4d_none(*p4d_ref)) + return -1; + + if (p4d_none(*p4d)) { + set_p4d(p4d, *p4d_ref); + arch_flush_lazy_mmu_mode(); + } else { + BUG_ON(p4d_pfn(*p4d) != p4d_pfn(*p4d_ref)); + } + /* * Below here mismatches are bugs because these lower tables * are shared: */ - pud = pud_offset(pgd, address); - pud_ref = pud_offset(pgd_ref, address); + pud = pud_offset(p4d, address); + pud_ref = pud_offset(p4d_ref, address); if (pud_none(*pud_ref)) return -1; -- 2.11.0 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org