From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f71.google.com (mail-pg0-f71.google.com [74.125.83.71]) by kanga.kvack.org (Postfix) with ESMTP id C67D7440D52 for ; Sat, 11 Nov 2017 15:20:06 -0500 (EST) Received: by mail-pg0-f71.google.com with SMTP id 207so7727519pgc.21 for ; Sat, 11 Nov 2017 12:20:06 -0800 (PST) Received: from mga04.intel.com (mga04.intel.com. [192.55.52.120]) by mx.google.com with ESMTPS id m15si10960327pga.413.2017.11.11.12.20.05 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sat, 11 Nov 2017 12:20:05 -0800 (PST) Subject: [PATCH v2 3/4] mm: replace pmd_write with pmd_access_permitted in fault + gup paths From: Dan Williams Date: Sat, 11 Nov 2017 12:11:50 -0800 Message-ID: <151043111049.2842.15241454964150083466.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: <151043109403.2842.11607911965674122836.stgit@dwillia2-desk3.amr.corp.intel.com> References: <151043109403.2842.11607911965674122836.stgit@dwillia2-desk3.amr.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Sender: owner-linux-mm@kvack.org List-ID: To: akpm@linux-foundation.org Cc: linux-nvdimm@lists.01.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Dave Hansen , =?utf-8?b?SsOpcsO0bWU=?= Glisse , "Kirill A. Shutemov" The 'access_permitted' helper is used in the gup-fast path and goes beyond the simple _PAGE_RW check to also: * validate that the mapping is writable from a protection keys standpoint * validate that the pte has _PAGE_USER set since all fault paths where pmd_write is must be referencing user-memory. Cc: Dave Hansen Cc: Kirill A. Shutemov Cc: "JA(C)rA'me Glisse" Signed-off-by: Dan Williams --- arch/sparc/mm/gup.c | 2 +- fs/dax.c | 3 ++- mm/hmm.c | 4 ++-- mm/huge_memory.c | 4 ++-- mm/memory.c | 2 +- 5 files changed, 8 insertions(+), 7 deletions(-) diff --git a/arch/sparc/mm/gup.c b/arch/sparc/mm/gup.c index 5ae2d0a01a70..33c0f8bb0f33 100644 --- a/arch/sparc/mm/gup.c +++ b/arch/sparc/mm/gup.c @@ -75,7 +75,7 @@ static int gup_huge_pmd(pmd_t *pmdp, pmd_t pmd, unsigned long addr, if (!(pmd_val(pmd) & _PAGE_VALID)) return 0; - if (write && !pmd_write(pmd)) + if (!pmd_access_permitted(pmd, write)) return 0; refs = 0; diff --git a/fs/dax.c b/fs/dax.c index f001d8c72a06..3cc40eebbb9e 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -620,7 +620,8 @@ static void dax_mapping_entry_mkclean(struct address_space *mapping, if (pfn != pmd_pfn(*pmdp)) goto unlock_pmd; - if (!pmd_dirty(*pmdp) && !pmd_write(*pmdp)) + if (!pmd_dirty(*pmdp) + && !pmd_access_permitted(*pmdp, WRITE)) goto unlock_pmd; flush_cache_page(vma, address, pfn); diff --git a/mm/hmm.c b/mm/hmm.c index a88a847bccba..cbdd47bf6a48 100644 --- a/mm/hmm.c +++ b/mm/hmm.c @@ -391,11 +391,11 @@ static int hmm_vma_walk_pmd(pmd_t *pmdp, if (pmd_protnone(pmd)) return hmm_vma_walk_clear(start, end, walk); - if (write_fault && !pmd_write(pmd)) + if (!pmd_access_permitted(pmd, write_fault)) return hmm_vma_walk_clear(start, end, walk); pfn = pmd_pfn(pmd) + pte_index(addr); - flag |= pmd_write(pmd) ? HMM_PFN_WRITE : 0; + flag |= pmd_access_permitted(pmd, WRITE) ? HMM_PFN_WRITE : 0; for (; addr < end; addr += PAGE_SIZE, i++, pfn++) pfns[i] = hmm_pfn_t_from_pfn(pfn) | flag; return 0; diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 1e4e11275856..411ba3ba45f8 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -875,7 +875,7 @@ struct page *follow_devmap_pmd(struct vm_area_struct *vma, unsigned long addr, */ WARN_ONCE(flags & FOLL_COW, "mm: In follow_devmap_pmd with FOLL_COW set"); - if (flags & FOLL_WRITE && !pmd_write(*pmd)) + if (!pmd_access_permitted(*pmd, flags & FOLL_WRITE)) return NULL; if (pmd_present(*pmd) && pmd_devmap(*pmd)) @@ -1379,7 +1379,7 @@ int do_huge_pmd_wp_page(struct vm_fault *vmf, pmd_t orig_pmd) */ static inline bool can_follow_write_pmd(pmd_t pmd, unsigned int flags) { - return pmd_write(pmd) || + return pmd_access_permitted(pmd, WRITE) || ((flags & FOLL_FORCE) && (flags & FOLL_COW) && pmd_dirty(pmd)); } diff --git a/mm/memory.c b/mm/memory.c index 64f86beadcca..157fd4320bb3 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -4020,7 +4020,7 @@ static int __handle_mm_fault(struct vm_area_struct *vma, unsigned long address, if (pmd_protnone(orig_pmd) && vma_is_accessible(vma)) return do_huge_pmd_numa_page(&vmf, orig_pmd); - if (dirty && !pmd_write(orig_pmd)) { + if (dirty && !pmd_access_permitted(orig_pmd, WRITE)) { ret = wp_huge_pmd(&vmf, orig_pmd); if (!(ret & VM_FAULT_FALLBACK)) return ret; -- 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