Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752414AbdHIUKX (ORCPT ); Wed, 9 Aug 2017 16:10:23 -0400 Received: from mail-it0-f51.google.com ([209.85.214.51]:37258 "EHLO mail-it0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752064AbdHIUJA (ORCPT ); Wed, 9 Aug 2017 16:09:00 -0400 From: Tycho Andersen To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, kernel-hardening@lists.openwall.com, Marco Benatto , Juerg Haefliger , Juerg Haefliger Subject: [PATCH v5 05/10] arm64/mm: Add support for XPFO Date: Wed, 9 Aug 2017 14:07:50 -0600 Message-Id: <20170809200755.11234-6-tycho@docker.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20170809200755.11234-1-tycho@docker.com> References: <20170809200755.11234-1-tycho@docker.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2957 Lines: 110 From: Juerg Haefliger Enable support for eXclusive Page Frame Ownership (XPFO) for arm64 and provide a hook for updating a single kernel page table entry (which is required by the generic XPFO code). At the moment, only 64k page sizes are supported. Signed-off-by: Juerg Haefliger Tested-by: Tycho Andersen --- arch/arm64/Kconfig | 1 + arch/arm64/mm/Makefile | 2 ++ arch/arm64/mm/xpfo.c | 64 ++++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 67 insertions(+) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index dfd908630631..2ddae41e0793 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -121,6 +121,7 @@ config ARM64 select SPARSE_IRQ select SYSCTL_EXCEPTION_TRACE select THREAD_INFO_IN_TASK + select ARCH_SUPPORTS_XPFO if ARM64_64K_PAGES help ARM 64-bit (AArch64) Linux support. diff --git a/arch/arm64/mm/Makefile b/arch/arm64/mm/Makefile index 9b0ba191e48e..22e5cab543d8 100644 --- a/arch/arm64/mm/Makefile +++ b/arch/arm64/mm/Makefile @@ -11,3 +11,5 @@ KASAN_SANITIZE_physaddr.o += n obj-$(CONFIG_KASAN) += kasan_init.o KASAN_SANITIZE_kasan_init.o := n + +obj-$(CONFIG_XPFO) += xpfo.o diff --git a/arch/arm64/mm/xpfo.c b/arch/arm64/mm/xpfo.c new file mode 100644 index 000000000000..de03a652d48a --- /dev/null +++ b/arch/arm64/mm/xpfo.c @@ -0,0 +1,64 @@ +/* + * Copyright (C) 2017 Hewlett Packard Enterprise Development, L.P. + * Copyright (C) 2016 Brown University. All rights reserved. + * + * Authors: + * Juerg Haefliger + * Vasileios P. Kemerlis + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 as published by + * the Free Software Foundation. + */ + +#include +#include + +#include + +/* + * Lookup the page table entry for a virtual address and return a pointer to + * the entry. Based on x86 tree. + */ +static pte_t *lookup_address(unsigned long addr) +{ + pgd_t *pgd; + pud_t *pud; + pmd_t *pmd; + + pgd = pgd_offset_k(addr); + if (pgd_none(*pgd)) + return NULL; + + BUG_ON(pgd_bad(*pgd)); + + pud = pud_offset(pgd, addr); + if (pud_none(*pud)) + return NULL; + + BUG_ON(pud_bad(*pud)); + + pmd = pmd_offset(pud, addr); + if (pmd_none(*pmd)) + return NULL; + + BUG_ON(pmd_bad(*pmd)); + + return pte_offset_kernel(pmd, addr); +} + +/* Update a single kernel page table entry */ +inline void set_kpte(void *kaddr, struct page *page, pgprot_t prot) +{ + pte_t *pte = lookup_address((unsigned long)kaddr); + + set_pte(pte, pfn_pte(page_to_pfn(page), prot)); +} + +inline void xpfo_flush_kernel_page(struct page *page, int order) +{ + unsigned long kaddr = (unsigned long)page_address(page); + unsigned long size = PAGE_SIZE; + + flush_tlb_kernel_range(kaddr, kaddr + (1 << order) * size); +} -- 2.11.0