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bh=M7nWun3z+db3sBAe7iYaXrTLAK9O6JS/QNOYDD0lRw0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=uKHK81Vughycr2Fec3IOhaO6pqa5BpmtEOeHailq6wIswGpOLQ4C+aaS9XlvZ0xbi nEHkhqvkygf3VZQBfxA4v7HvSZi4GAEOBqlquC8V4znMgkmNArWBoC2zW38CKyjnwH /FUcGpSp76LzA+o93S4NTnGtMkhs3dE+dUq+rIrU= From: Dev Jain To: akpm@linux-foundation.org, david@kernel.org, ljs@kernel.org Cc: Dev Jain , liam@infradead.org, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, kasong@tencent.com, qi.zheng@linux.dev, shakeel.butt@linux.dev, baohua@kernel.org, axelrasmussen@google.com, yuanchu@google.com, weixugc@google.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, riel@surriel.com, harry@kernel.org, jannh@google.com, lance.yang@linux.dev, ryan.roberts@arm.com, anshuman.khandual@arm.com Subject: [PATCH 1/3] mm/memory: move pte_install_uffd_wp_if_needed() into memory.c Date: Wed, 15 Jul 2026 11:18:34 +0000 Message-ID: <20260715111839.1667914-2-dev.jain@arm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260715111839.1667914-1-dev.jain@arm.com> References: <20260715111839.1667914-1-dev.jain@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: CDB26A000F X-Stat-Signature: rxbid5jmgi37f9k3yzxm8hsz9kfbasnu X-Rspam-User: X-HE-Tag: 1784114339-49067 X-HE-Meta: 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 jJdiZDsT HnWGjKHM/9iDJX73MOoNfY/4MX4cL3wAcDzmffeDErZGs/U5dRiFyAkrWpHoLFlRl1Ta3EX4Bb2PC3lLh2IHVsjWF2PagTa9HLJEricCfk+IzwnGYuY1Ov7z1sJ7UYvfjfoj8B+3jgOakSMdj6CzYHy/v0c9Nm5pVxjcIHguc7hlxholm1o7S05OBX6DylVrUpIZsYBtxiWRGa51A62VIZMPWLecTxljdA1oxKSDvcUNIJEK8lccn0dVqpaJEq/H3WK4TDIWjsn/N6bXwbxJCN4cE+wBJfPZ7bDJygxyq9pNCSi8= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: pte_install_uffd_wp_if_needed() has grown too large for mm_inline.h. Move it to memory.c. While at it, convert the comment to kerneldoc and rename the local arguments from pte/pteval to ptep/pte so the pointer and pte value are easier to distinguish. Signed-off-by: Dev Jain --- include/linux/mm.h | 2 ++ include/linux/mm_inline.h | 53 ---------------------------------- mm/memory.c | 60 +++++++++++++++++++++++++++++++++++++++ 3 files changed, 62 insertions(+), 53 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 550fb92957d18..a71341c44655e 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -5406,4 +5406,6 @@ void map_anon_folio_pte_nopf(struct folio *folio, pte_t *pte, struct vm_area_struct *vma, unsigned long addr, bool uffd_wp); +bool pte_install_uffd_wp_if_needed(struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep, pte_t pte); #endif /* _LINUX_MM_H */ diff --git a/include/linux/mm_inline.h b/include/linux/mm_inline.h index b5c4dc0f3fe32..621c8653d8f7e 100644 --- a/include/linux/mm_inline.h +++ b/include/linux/mm_inline.h @@ -566,59 +566,6 @@ static inline pte_marker copy_pte_marker( return dstm; } -/* - * If this pte is wr-protected by uffd-wp in any form, arm the special pte to - * replace a none pte. NOTE! This should only be called when *pte is already - * cleared so we will never accidentally replace something valuable. Meanwhile - * none pte also means we are not demoting the pte so tlb flushed is not needed. - * E.g., when pte cleared the caller should have taken care of the tlb flush. - * - * Must be called with pgtable lock held so that no thread will see the none - * pte, and if they see it, they'll fault and serialize at the pgtable lock. - * - * Returns true if an uffd-wp pte was installed, false otherwise. - */ -static inline bool -pte_install_uffd_wp_if_needed(struct vm_area_struct *vma, unsigned long addr, - pte_t *pte, pte_t pteval) -{ - bool arm_uffd_pte = false; - - if (!uffd_supports_wp_marker()) - return false; - - /* The current status of the pte should be "cleared" before calling */ - WARN_ON_ONCE(!pte_none(ptep_get(pte))); - - /* - * NOTE: userfaultfd_wp_unpopulated() doesn't need this whole - * thing, because when zapping either it means it's dropping the - * page, or in TTU where the present pte will be quickly replaced - * with a swap pte. There's no way of leaking the bit. - */ - if (vma_is_anonymous(vma) || !userfaultfd_wp(vma)) - return false; - - /* A uffd-wp wr-protected normal pte */ - if (unlikely(pte_present(pteval) && pte_uffd(pteval))) - arm_uffd_pte = true; - - /* - * A uffd-wp wr-protected swap pte. Note: this should even cover an - * existing pte marker with uffd-wp bit set. - */ - if (unlikely(pte_swp_uffd_any(pteval))) - arm_uffd_pte = true; - - if (unlikely(arm_uffd_pte)) { - set_pte_at(vma->vm_mm, addr, pte, - make_pte_marker(PTE_MARKER_UFFD_WP)); - return true; - } - - return false; -} - static inline bool vma_has_recency(const struct vm_area_struct *vma) { if (vma->vm_flags & (VM_SEQ_READ | VM_RAND_READ)) diff --git a/mm/memory.c b/mm/memory.c index d5e87624f6920..98b3ace15cef2 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1675,6 +1675,66 @@ static inline bool zap_drop_markers(struct zap_details *details) return details->zap_flags & ZAP_FLAG_DROP_MARKER; } +/** + * pte_install_uffd_wp_if_needed - install uffd-wp marker after clearing a PTE + * @vma: The VMA the page is mapped into. + * @addr: Address the page is mapped at. + * @ptep: Page table pointer for this entry. + * @pte: Old value of the entry pointed to by @ptep. + * + * If the PTE was write-protected by uffd-wp in any form, arm a special PTE + * to replace a none PTE. NOTE! This should only be called when the PTE is + * already cleared so we will never accidentally replace something valuable. + * Meanwhile none PTEs also mean we are not demoting the PTE so a TLB flush is + * not needed. E.g., when the PTE was cleared, the caller should have taken care + * of the TLB flush. + * + * Must be called with the page table lock held so that no thread will see the + * none PTE, and if they see it, they'll fault and serialize at the page table + * lock. + * + * Returns true if an uffd-wp PTE was installed, false otherwise. + */ +bool pte_install_uffd_wp_if_needed(struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep, pte_t pte) +{ + bool arm_uffd_pte = false; + + if (!uffd_supports_wp_marker()) + return false; + + /* The current status of the pte should be "cleared" before calling */ + WARN_ON_ONCE(!pte_none(ptep_get(ptep))); + + /* + * NOTE: userfaultfd_wp_unpopulated() doesn't need this whole + * thing, because when zapping either it means it's dropping the + * page, or in TTU where the present pte will be quickly replaced + * with a swap pte. There's no way of leaking the bit. + */ + if (vma_is_anonymous(vma) || !userfaultfd_wp(vma)) + return false; + + /* A uffd-wp write-protected normal pte */ + if (unlikely(pte_present(pte) && pte_uffd(pte))) + arm_uffd_pte = true; + + /* + * A uffd-wp write-protected swap pte. Note: this should even cover an + * existing pte marker with uffd-wp bit set. + */ + if (unlikely(pte_swp_uffd_any(pte))) + arm_uffd_pte = true; + + if (unlikely(arm_uffd_pte)) { + set_pte_at(vma->vm_mm, addr, ptep, + make_pte_marker(PTE_MARKER_UFFD_WP)); + return true; + } + + return false; +} + /* * This function makes sure that we'll replace the none pte with an uffd-wp * swap special pte marker when necessary. Must be with the pgtable lock held. -- 2.43.0