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[192.55.52.93]) by mx.google.com with ESMTPS id 31-v6si17386340plz.217.2018.07.10.15.31.15 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 10 Jul 2018 15:31:15 -0700 (PDT) Received-SPF: pass (google.com: domain of yu-cheng.yu@intel.com designates 192.55.52.93 as permitted sender) client-ip=192.55.52.93; Authentication-Results: mx.google.com; spf=pass (google.com: domain of yu-cheng.yu@intel.com designates 192.55.52.93 as permitted sender) smtp.mailfrom=yu-cheng.yu@intel.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=intel.com X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga102.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 10 Jul 2018 15:31:14 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.51,335,1526367600"; d="scan'208";a="70305425" Received: from 2b52.sc.intel.com ([143.183.136.52]) by fmsmga004.fm.intel.com with ESMTP; 10 Jul 2018 15:31:14 -0700 From: Yu-cheng Yu To: x86@kernel.org, "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org, Arnd Bergmann , Andy Lutomirski , Balbir Singh , Cyrill Gorcunov , Dave Hansen , Florian Weimer , "H.J. Lu" , Jann Horn , Jonathan Corbet , Kees Cook , Mike Kravetz , Nadav Amit , Oleg Nesterov , Pavel Machek , Peter Zijlstra , "Ravi V. Shankar" , Vedvyas Shanbhogue Cc: Yu-cheng Yu Subject: [RFC PATCH v2 16/27] mm: Modify can_follow_write_pte/pmd for shadow stack Date: Tue, 10 Jul 2018 15:26:28 -0700 Message-Id: <20180710222639.8241-17-yu-cheng.yu@intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20180710222639.8241-1-yu-cheng.yu@intel.com> References: <20180710222639.8241-1-yu-cheng.yu@intel.com> X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: X-Virus-Scanned: ClamAV using ClamSMTP There are three possible shadow stack PTE settings: Normal SHSTK PTE: (R/O + DIRTY_HW) SHSTK PTE COW'ed: (R/O + DIRTY_HW) SHSTK PTE shared as R/O data: (R/O + DIRTY_SW) Update can_follow_write_pte/pmd for the shadow stack. Signed-off-by: Yu-cheng Yu --- mm/gup.c | 11 ++++++++--- mm/huge_memory.c | 10 +++++++--- 2 files changed, 15 insertions(+), 6 deletions(-) diff --git a/mm/gup.c b/mm/gup.c index b70d7ba7cc13..00171ee847af 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -64,10 +64,13 @@ static int follow_pfn_pte(struct vm_area_struct *vma, unsigned long address, * FOLL_FORCE can write to even unwritable pte's, but only * after we've gone through a COW cycle and they are dirty. */ -static inline bool can_follow_write_pte(pte_t pte, unsigned int flags) +static inline bool can_follow_write_pte(pte_t pte, unsigned int flags, + bool shstk) { + bool pte_cowed = shstk ? is_shstk_pte(pte):pte_dirty(pte); + return pte_write(pte) || - ((flags & FOLL_FORCE) && (flags & FOLL_COW) && pte_dirty(pte)); + ((flags & FOLL_FORCE) && (flags & FOLL_COW) && pte_cowed); } static struct page *follow_page_pte(struct vm_area_struct *vma, @@ -78,7 +81,9 @@ static struct page *follow_page_pte(struct vm_area_struct *vma, struct page *page; spinlock_t *ptl; pte_t *ptep, pte; + bool shstk; + shstk = is_shstk_mapping(vma->vm_flags); retry: if (unlikely(pmd_bad(*pmd))) return no_page_table(vma, flags); @@ -105,7 +110,7 @@ static struct page *follow_page_pte(struct vm_area_struct *vma, } if ((flags & FOLL_NUMA) && pte_protnone(pte)) goto no_page; - if ((flags & FOLL_WRITE) && !can_follow_write_pte(pte, flags)) { + if ((flags & FOLL_WRITE) && !can_follow_write_pte(pte, flags, shstk)) { pte_unmap_unlock(ptep, ptl); return NULL; } diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 7f3e11d3b64a..db4c689a960a 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1389,10 +1389,13 @@ int do_huge_pmd_wp_page(struct vm_fault *vmf, pmd_t orig_pmd) * FOLL_FORCE can write to even unwritable pmd's, but only * after we've gone through a COW cycle and they are dirty. */ -static inline bool can_follow_write_pmd(pmd_t pmd, unsigned int flags) +static inline bool can_follow_write_pmd(pmd_t pmd, unsigned int flags, + bool shstk) { + bool pmd_cowed = shstk ? is_shstk_pmd(pmd):pmd_dirty(pmd); + return pmd_write(pmd) || - ((flags & FOLL_FORCE) && (flags & FOLL_COW) && pmd_dirty(pmd)); + ((flags & FOLL_FORCE) && (flags & FOLL_COW) && pmd_cowed); } struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, @@ -1402,10 +1405,11 @@ struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, { struct mm_struct *mm = vma->vm_mm; struct page *page = NULL; + bool shstk = is_shstk_mapping(vma->vm_flags); assert_spin_locked(pmd_lockptr(mm, pmd)); - if (flags & FOLL_WRITE && !can_follow_write_pmd(*pmd, flags)) + if (flags & FOLL_WRITE && !can_follow_write_pmd(*pmd, flags, shstk)) goto out; /* Avoid dumping huge zero page */