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Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Axel Rasmussen , Yuanchu Xie , Chunyan Zhang Subject: [PATCH V10 2/5] mm: uffd_wp: Add pte_uffd_wp_available() Date: Tue, 9 Sep 2025 17:56:08 +0800 Message-Id: <20250909095611.803898-3-zhangchunyan@iscas.ac.cn> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20250909095611.803898-1-zhangchunyan@iscas.ac.cn> References: <20250909095611.803898-1-zhangchunyan@iscas.ac.cn> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CM-TRANSID:qwCowADHHqHO+b9oWh7qAQ--.61766S4 X-Coremail-Antispam: 1UD129KBjvJXoWxtF1kWrWrJrWkWr15Kry5XFb_yoWxur4UpF 4xGw4Yqrn2vFykJa93AF4rA3s5Zw4xWFykWryF93W8Aa13t390vryFkr1FyF97Jr4kW34a qF17trZ5ur42vwUanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUmmb7Iv0xC_tr1lb4IE77IF4wAFF20E14v26rWj6s0DM7CY07I2 0VC2zVCF04k26cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28IrcIa0xkI8VA2jI 8067AKxVWUXwA2048vs2IY020Ec7CjxVAFwI0_Xr0E3s1l8cAvFVAK0II2c7xJM28CjxkF 64kEwVA0rcxSw2x7M28EF7xvwVC0I7IYx2IY67AKxVW8JVW5JwA2z4x0Y4vE2Ix0cI8IcV CY1x0267AKxVWxJVW8Jr1l84ACjcxK6I8E87Iv67AKxVWxJr0_GcWl84ACjcxK6I8E87Iv 6xkF7I0E14v26rxl6s0DM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI64kE6c 02F40Ex7xfMcIj6xIIjxv20xvE14v26r106r15McIj6I8E87Iv67AKxVW8JVWxJwAm72CE 4IkC6x0Yz7v_Jr0_Gr1lF7xvr2IYc2Ij64vIr41lFIxGxcIEc7CjxVA2Y2ka0xkIwI1lc7 CjxVAaw2AFwI0_GFv_Wrylc2xSY4AK67AK6r4fMxAIw28IcxkI7VAKI48JMxC20s026xCa FVCjc4AY6r1j6r4UMI8I3I0E5I8CrVAFwI0_Jr0_Jr4lx2IqxVCjr7xvwVAFwI0_JrI_Jr Wlx4CE17CEb7AF67AKxVW8ZVWrXwCIc40Y0x0EwIxGrwCI42IY6xIIjxv20xvE14v26r1j 6r1xMIIF0xvE2Ix0cI8IcVCY1x0267AKxVWxJVW8Jr1lIxAIcVCF04k26cxKx2IYs7xG6r 1j6r1xMIIF0xvEx4A2jsIE14v26r1j6r4UMIIF0xvEx4A2jsIEc7CjxVAFwI0_Gr0_Gr1U YxBIdaVFxhVjvjDU0xZFpf9x07jBXdUUUUUU= X-Originating-IP: [210.73.43.101] X-CM-SenderInfo: x2kd0wxfkx051dq6x2xfdvhtffof0/1tbiBwoAB2i-5-ZHLAAAsn X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 74683140008 X-Stat-Signature: eqosfqobwe84ou35h87yjcsh35fkumwm X-Rspam-User: X-HE-Tag: 1757411829-123827 X-HE-Meta: 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 ZcPEkE7L 1jbexKFp/gsPCHYoPjDTapQp9avxmvFqeVbQxz7uRm9gWmnAAOSEoWGs6bLU84IxEAPBSaDwJV4fElQTx/kUEzuGyEiVliPR9+jxn7NuRdWPQd6zsWFYOivXwRnkfGMp2CbRLcHDwL82SrMrcXmw80gExj5C3aS5L6M7trNgUGu6R6Fo4iM95vjmgppIwtzSUtvSI/Rmy+mcAALT5VPaEtrFgTzOU1ycjgoAUNeT8UIEJ8C/Dutj4UHQCbzapLUhrf7frieRZEZQZ0eOKCVp92Av/C3hGqlfdlkJyZwb5UZoM5vKX5YZY+dPBdbiOu13OmQjB 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: List-Subscribe: List-Unsubscribe: Some platforms can customize the PTE uffd_wp bit and make it unavailable even if the architecture allows providing the PTE resource. This patch adds a macro API which allows architectures to define their specific ones for checking if the PTE uffd_wp bit is available. Signed-off-by: Chunyan Zhang --- fs/userfaultfd.c | 25 +++++++++-------- include/asm-generic/pgtable_uffd.h | 12 ++++++++ include/linux/mm_inline.h | 7 +++++ include/linux/userfaultfd_k.h | 44 +++++++++++++++++++----------- mm/memory.c | 6 ++-- 5 files changed, 65 insertions(+), 29 deletions(-) diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c index 54c6cc7fe9c6..68e5006e5158 100644 --- a/fs/userfaultfd.c +++ b/fs/userfaultfd.c @@ -1270,9 +1270,10 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx, if (uffdio_register.mode & UFFDIO_REGISTER_MODE_MISSING) vm_flags |= VM_UFFD_MISSING; if (uffdio_register.mode & UFFDIO_REGISTER_MODE_WP) { -#ifndef CONFIG_HAVE_ARCH_USERFAULTFD_WP - goto out; -#endif + if (!IS_ENABLED(CONFIG_HAVE_ARCH_USERFAULTFD_WP) || + !pte_uffd_wp_available()) + goto out; + vm_flags |= VM_UFFD_WP; } if (uffdio_register.mode & UFFDIO_REGISTER_MODE_MINOR) { @@ -1980,14 +1981,16 @@ static int userfaultfd_api(struct userfaultfd_ctx *ctx, uffdio_api.features &= ~(UFFD_FEATURE_MINOR_HUGETLBFS | UFFD_FEATURE_MINOR_SHMEM); #endif -#ifndef CONFIG_HAVE_ARCH_USERFAULTFD_WP - uffdio_api.features &= ~UFFD_FEATURE_PAGEFAULT_FLAG_WP; -#endif -#ifndef CONFIG_PTE_MARKER_UFFD_WP - uffdio_api.features &= ~UFFD_FEATURE_WP_HUGETLBFS_SHMEM; - uffdio_api.features &= ~UFFD_FEATURE_WP_UNPOPULATED; - uffdio_api.features &= ~UFFD_FEATURE_WP_ASYNC; -#endif + if (!IS_ENABLED(CONFIG_HAVE_ARCH_USERFAULTFD_WP) || + !pte_uffd_wp_available()) + uffdio_api.features &= ~UFFD_FEATURE_PAGEFAULT_FLAG_WP; + + if (!IS_ENABLED(CONFIG_PTE_MARKER_UFFD_WP) || + !pte_uffd_wp_available()) { + uffdio_api.features &= ~UFFD_FEATURE_WP_HUGETLBFS_SHMEM; + uffdio_api.features &= ~UFFD_FEATURE_WP_UNPOPULATED; + uffdio_api.features &= ~UFFD_FEATURE_WP_ASYNC; + } ret = -EINVAL; if (features & ~uffdio_api.features) diff --git a/include/asm-generic/pgtable_uffd.h b/include/asm-generic/pgtable_uffd.h index 828966d4c281..abab46bd718b 100644 --- a/include/asm-generic/pgtable_uffd.h +++ b/include/asm-generic/pgtable_uffd.h @@ -61,6 +61,18 @@ static inline pmd_t pmd_swp_clear_uffd_wp(pmd_t pmd) { return pmd; } +#define pte_uffd_wp_available() (false) +#else +/* + * Some platforms can customize the PTE uffd_wp bit and make it unavailable + * even if the architecture allows providing the PTE resource. + * It allows architectures to define their APIs to check if the PTE + * uffd_wp bit is available on the specific devices. + */ +#ifndef pte_uffd_wp_available +#define pte_uffd_wp_available() (true) +#endif + #endif /* CONFIG_HAVE_ARCH_USERFAULTFD_WP */ #endif /* _ASM_GENERIC_PGTABLE_UFFD_H */ diff --git a/include/linux/mm_inline.h b/include/linux/mm_inline.h index 89b518ff097e..4e5a8a265642 100644 --- a/include/linux/mm_inline.h +++ b/include/linux/mm_inline.h @@ -571,6 +571,13 @@ pte_install_uffd_wp_if_needed(struct vm_area_struct *vma, unsigned long addr, pte_t *pte, pte_t pteval) { #ifdef CONFIG_PTE_MARKER_UFFD_WP + /* + * Some platforms can customize the PTE uffd_wp bit and make it unavailable + * even if the architecture allows providing the PTE resource. + */ + if (!pte_uffd_wp_available()) + return false; + bool arm_uffd_pte = false; /* The current status of the pte should be "cleared" before calling */ diff --git a/include/linux/userfaultfd_k.h b/include/linux/userfaultfd_k.h index c0e716aec26a..ec4a815286c8 100644 --- a/include/linux/userfaultfd_k.h +++ b/include/linux/userfaultfd_k.h @@ -228,15 +228,15 @@ static inline bool vma_can_userfault(struct vm_area_struct *vma, if (wp_async && (vm_flags == VM_UFFD_WP)) return true; -#ifndef CONFIG_PTE_MARKER_UFFD_WP /* * If user requested uffd-wp but not enabled pte markers for * uffd-wp, then shmem & hugetlbfs are not supported but only * anonymous. */ - if ((vm_flags & VM_UFFD_WP) && !vma_is_anonymous(vma)) + if ((!IS_ENABLED(CONFIG_PTE_MARKER_UFFD_WP) || + !pte_uffd_wp_available()) && + (vm_flags & VM_UFFD_WP) && !vma_is_anonymous(vma)) return false; -#endif /* By default, allow any of anon|shmem|hugetlb */ return vma_is_anonymous(vma) || is_vm_hugetlb_page(vma) || @@ -437,8 +437,11 @@ static inline bool userfaultfd_wp_use_markers(struct vm_area_struct *vma) static inline bool pte_marker_entry_uffd_wp(swp_entry_t entry) { #ifdef CONFIG_PTE_MARKER_UFFD_WP - return is_pte_marker_entry(entry) && - (pte_marker_get(entry) & PTE_MARKER_UFFD_WP); + if (pte_uffd_wp_available()) + return is_pte_marker_entry(entry) && + (pte_marker_get(entry) & PTE_MARKER_UFFD_WP); + else + return false; #else return false; #endif @@ -447,14 +450,19 @@ static inline bool pte_marker_entry_uffd_wp(swp_entry_t entry) static inline bool pte_marker_uffd_wp(pte_t pte) { #ifdef CONFIG_PTE_MARKER_UFFD_WP - swp_entry_t entry; + if (pte_uffd_wp_available()) { + swp_entry_t entry; - if (!is_swap_pte(pte)) - return false; + if (!is_swap_pte(pte)) + return false; - entry = pte_to_swp_entry(pte); + entry = pte_to_swp_entry(pte); + + return pte_marker_entry_uffd_wp(entry); + } else { + return false; + } - return pte_marker_entry_uffd_wp(entry); #else return false; #endif @@ -467,14 +475,18 @@ static inline bool pte_marker_uffd_wp(pte_t pte) static inline bool pte_swp_uffd_wp_any(pte_t pte) { #ifdef CONFIG_PTE_MARKER_UFFD_WP - if (!is_swap_pte(pte)) - return false; + if (pte_uffd_wp_available()) { + if (!is_swap_pte(pte)) + return false; - if (pte_swp_uffd_wp(pte)) - return true; + if (pte_swp_uffd_wp(pte)) + return true; - if (pte_marker_uffd_wp(pte)) - return true; + if (pte_marker_uffd_wp(pte)) + return true; + } else { + return false; + } #endif return false; } diff --git a/mm/memory.c b/mm/memory.c index 0ba4f6b71847..d6c874221433 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1465,7 +1465,9 @@ zap_install_uffd_wp_if_needed(struct vm_area_struct *vma, { bool was_installed = false; -#ifdef CONFIG_PTE_MARKER_UFFD_WP + if (!IS_ENABLED(CONFIG_PTE_MARKER_UFFD_WP) || !pte_uffd_wp_available()) + return false; + /* Zap on anonymous always means dropping everything */ if (vma_is_anonymous(vma)) return false; @@ -1482,7 +1484,7 @@ zap_install_uffd_wp_if_needed(struct vm_area_struct *vma, pte++; addr += PAGE_SIZE; } -#endif + return was_installed; } -- 2.34.1