Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752227AbdHIUJJ (ORCPT ); Wed, 9 Aug 2017 16:09:09 -0400 Received: from mail-io0-f178.google.com ([209.85.223.178]:38299 "EHLO mail-io0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752184AbdHIUJG (ORCPT ); Wed, 9 Aug 2017 16:09:06 -0400 From: Tycho Andersen To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, kernel-hardening@lists.openwall.com, Marco Benatto , Juerg Haefliger , Tycho Andersen Subject: [PATCH v5 09/10] mm: add a user_virt_to_phys symbol Date: Wed, 9 Aug 2017 14:07:54 -0600 Message-Id: <20170809200755.11234-10-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: 4186 Lines: 160 We need someting like this for testing XPFO. Since it's architecture specific, putting it in the test code is slightly awkward, so let's make it an arch-specific symbol and export it for use in LKDTM. Signed-off-by: Tycho Andersen Tested-by: Marco Benatto --- arch/arm64/mm/xpfo.c | 51 ++++++++++++++++++++++++++++++++++++++++++++++ arch/x86/mm/xpfo.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++++++++ include/linux/xpfo.h | 4 ++++ 3 files changed, 112 insertions(+) diff --git a/arch/arm64/mm/xpfo.c b/arch/arm64/mm/xpfo.c index c4deb2b720cf..a221799a9242 100644 --- a/arch/arm64/mm/xpfo.c +++ b/arch/arm64/mm/xpfo.c @@ -107,3 +107,54 @@ inline void xpfo_dma_map_unmap_area(bool map, const void *addr, size_t size, local_irq_restore(flags); } + +/* Convert a user space virtual address to a physical address. + * Shamelessly copied from slow_virt_to_phys() and lookup_address() in + * arch/x86/mm/pageattr.c + */ +phys_addr_t user_virt_to_phys(unsigned long addr) +{ + phys_addr_t phys_addr; + unsigned long offset; + pgd_t *pgd; + p4d_t *p4d; + pud_t *pud; + pmd_t *pmd; + pte_t *pte; + + pgd = pgd_offset(current->mm, addr); + if (pgd_none(*pgd)) + return 0; + + p4d = p4d_offset(pgd, addr); + if (p4d_none(*p4d)) + return 0; + + pud = pud_offset(p4d, addr); + if (pud_none(*pud)) + return 0; + + if (pud_sect(*pud) || !pud_present(*pud)) { + phys_addr = (unsigned long)pud_pfn(*pud) << PAGE_SHIFT; + offset = addr & ~PUD_MASK; + goto out; + } + + pmd = pmd_offset(pud, addr); + if (pmd_none(*pmd)) + return 0; + + if (pmd_sect(*pmd) || !pmd_present(*pmd)) { + phys_addr = (unsigned long)pmd_pfn(*pmd) << PAGE_SHIFT; + offset = addr & ~PMD_MASK; + goto out; + } + + pte = pte_offset_kernel(pmd, addr); + phys_addr = (phys_addr_t)pte_pfn(*pte) << PAGE_SHIFT; + offset = addr & ~PAGE_MASK; + +out: + return (phys_addr_t)(phys_addr | offset); +} +EXPORT_SYMBOL(user_virt_to_phys); diff --git a/arch/x86/mm/xpfo.c b/arch/x86/mm/xpfo.c index 3635b37f2fc5..a1344f27406c 100644 --- a/arch/x86/mm/xpfo.c +++ b/arch/x86/mm/xpfo.c @@ -94,3 +94,60 @@ inline void xpfo_flush_kernel_page(struct page *page, int order) flush_tlb_kernel_range(kaddr, kaddr + (1 << order) * size); } + +/* Convert a user space virtual address to a physical address. + * Shamelessly copied from slow_virt_to_phys() and lookup_address() in + * arch/x86/mm/pageattr.c + */ +phys_addr_t user_virt_to_phys(unsigned long addr) +{ + phys_addr_t phys_addr; + unsigned long offset; + pgd_t *pgd; + p4d_t *p4d; + pud_t *pud; + pmd_t *pmd; + pte_t *pte; + + pgd = pgd_offset(current->mm, addr); + if (pgd_none(*pgd)) + return 0; + + p4d = p4d_offset(pgd, addr); + if (p4d_none(*p4d)) + return 0; + + if (p4d_large(*p4d) || !p4d_present(*p4d)) { + phys_addr = (unsigned long)p4d_pfn(*p4d) << PAGE_SHIFT; + offset = addr & ~P4D_MASK; + goto out; + } + + pud = pud_offset(p4d, addr); + if (pud_none(*pud)) + return 0; + + if (pud_large(*pud) || !pud_present(*pud)) { + phys_addr = (unsigned long)pud_pfn(*pud) << PAGE_SHIFT; + offset = addr & ~PUD_MASK; + goto out; + } + + pmd = pmd_offset(pud, addr); + if (pmd_none(*pmd)) + return 0; + + if (pmd_large(*pmd) || !pmd_present(*pmd)) { + phys_addr = (unsigned long)pmd_pfn(*pmd) << PAGE_SHIFT; + offset = addr & ~PMD_MASK; + goto out; + } + + pte = pte_offset_kernel(pmd, addr); + phys_addr = (phys_addr_t)pte_pfn(*pte) << PAGE_SHIFT; + offset = addr & ~PAGE_MASK; + +out: + return (phys_addr_t)(phys_addr | offset); +} +EXPORT_SYMBOL(user_virt_to_phys); diff --git a/include/linux/xpfo.h b/include/linux/xpfo.h index 6b61f7b820f4..449cd8dbf064 100644 --- a/include/linux/xpfo.h +++ b/include/linux/xpfo.h @@ -16,6 +16,8 @@ #ifdef CONFIG_XPFO +#include + extern struct page_ext_operations page_xpfo_ops; void set_kpte(void *kaddr, struct page *page, pgprot_t prot); @@ -29,6 +31,8 @@ void xpfo_free_pages(struct page *page, int order); bool xpfo_page_is_unmapped(struct page *page); +extern phys_addr_t user_virt_to_phys(unsigned long addr); + #else /* !CONFIG_XPFO */ static inline void xpfo_kmap(void *kaddr, struct page *page) { } -- 2.11.0