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(unknown [210.73.43.101]) by APP-01 (Coremail) with SMTP id qwCowABnwaNMvbpoocLNAA--.50311S4; Fri, 05 Sep 2025 18:37:02 +0800 (CST) From: Chunyan Zhang To: linux-riscv@lists.infradead.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti , Andrew Morton , Deepak Gupta , Ved Shanbhogue , Peter Xu , Alexander Viro , Christian Brauner , Arnd Bergmann , Jan Kara , Axel Rasmussen , Wei Xu , David Hildenbrand , Chunyan Zhang Subject: [PATCH v9 2/5] mm: uffd_wp: Add pte_uffd_wp_available() Date: Fri, 5 Sep 2025 18:36:48 +0800 Message-Id: <20250905103651.489197-3-zhangchunyan@iscas.ac.cn> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20250905103651.489197-1-zhangchunyan@iscas.ac.cn> References: <20250905103651.489197-1-zhangchunyan@iscas.ac.cn> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: qwCowABnwaNMvbpoocLNAA--.50311S4 X-Coremail-Antispam: 1UD129KBjvJXoWxtF1kWrWUtry5KFyrCFy3Jwb_yoW3GFW3pF 47Gw4Yqw1vvFykJa93JF4rA3s5Zw4xWFykWryF93W8Aa13t390vryFkr1FyF97Jr4kWa4a vF12qrZ5ur42vwUanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUPGb7Iv0xC_tr1lb4IE77IF4wAFF20E14v26rWj6s0DM7CY07I2 0VC2zVCF04k26cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28IrcIa0xkI8VA2jI 8067AKxVWUXwA2048vs2IY020Ec7CjxVAFwI0_Xr0E3s1l8cAvFVAK0II2c7xJM28CjxkF 64kEwVA0rcxSw2x7M28EF7xvwVC0I7IYx2IY67AKxVW8JVW5JwA2z4x0Y4vE2Ix0cI8IcV CY1x0267AKxVWxJVW8Jr1l84ACjcxK6I8E87Iv67AKxVW0oVCq3wA2z4x0Y4vEx4A2jsIE c7CjxVAFwI0_GcCE3s1le2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4xG64xvF2IEw4CE5I 8CrVC2j2WlYx0E2Ix0cI8IcVAFwI0_Jr0_Jr4lYx0Ex4A2jsIE14v26r4j6F4UMcvjeVCF s4IE7xkEbVWUJVW8JwACjcxG0xvY0x0EwIxGrwACI402YVCY1x02628vn2kIc2xKxwCY1x 0262kKe7AKxVW8ZVWrXwCF04k20xvY0x0EwIxGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC2 0s026c02F40E14v26r1j6r18MI8I3I0E7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI 0_GFv_WrylIxkGc2Ij64vIr41lIxAIcVC0I7IYx2IY67AKxVWUJVWUCwCI42IY6xIIjxv2 0xvEc7CjxVAFwI0_Cr0_Gr1UMIIF0xvE42xK8VAvwI8IcIk0rVWUJVWUCwCI42IY6I8E87 Iv67AKxVWUJVW8JwCI42IY6I8E87Iv6xkF7I0E14v26r4j6r4UJbIYCTnIWIevJa73UjIF yTuYvjxUaf-BDUUUU X-CM-SenderInfo: x2kd0wxfkx051dq6x2xfdvhtffof0/1tbiDAgQB2i6oeFs+gAAsX Content-Type: text/plain; charset="utf-8" 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 one 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 | 6 ++-- include/linux/pgtable.h | 1 + include/linux/userfaultfd_k.h | 44 +++++++++++++++++++----------- mm/memory.c | 6 ++-- 6 files changed, 63 insertions(+), 31 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_c= tx *ctx, if (uffdio_register.mode & UFFDIO_REGISTER_MODE_MISSING) vm_flags |=3D 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 |=3D 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 &=3D ~(UFFD_FEATURE_MINOR_HUGETLBFS | UFFD_FEATURE_MINOR_SHMEM); #endif -#ifndef CONFIG_HAVE_ARCH_USERFAULTFD_WP - uffdio_api.features &=3D ~UFFD_FEATURE_PAGEFAULT_FLAG_WP; -#endif -#ifndef CONFIG_PTE_MARKER_UFFD_WP - uffdio_api.features &=3D ~UFFD_FEATURE_WP_HUGETLBFS_SHMEM; - uffdio_api.features &=3D ~UFFD_FEATURE_WP_UNPOPULATED; - uffdio_api.features &=3D ~UFFD_FEATURE_WP_ASYNC; -#endif + if (!IS_ENABLED(CONFIG_HAVE_ARCH_USERFAULTFD_WP) || + !pte_uffd_wp_available()) + uffdio_api.features &=3D ~UFFD_FEATURE_PAGEFAULT_FLAG_WP; + + if (!IS_ENABLED(CONFIG_PTE_MARKER_UFFD_WP) || + !pte_uffd_wp_available()) { + uffdio_api.features &=3D ~UFFD_FEATURE_WP_HUGETLBFS_SHMEM; + uffdio_api.features &=3D ~UFFD_FEATURE_WP_UNPOPULATED; + uffdio_api.features &=3D ~UFFD_FEATURE_WP_ASYNC; + } =20 ret =3D -EINVAL; if (features & ~uffdio_api.features) diff --git a/include/asm-generic/pgtable_uffd.h b/include/asm-generic/pgtab= le_uffd.h index 828966d4c281..b86a5ff447da 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. + * This allows architectures to define their own API for checking if + * the PTE uffd_wp bit is available. + */ +#ifndef pte_uffd_wp_available +#define pte_uffd_wp_available() (true) +#endif + #endif /* CONFIG_HAVE_ARCH_USERFAULTFD_WP */ =20 #endif /* _ASM_GENERIC_PGTABLE_UFFD_H */ diff --git a/include/linux/mm_inline.h b/include/linux/mm_inline.h index 89b518ff097e..a81055bb3f87 100644 --- a/include/linux/mm_inline.h +++ b/include/linux/mm_inline.h @@ -570,7 +570,9 @@ static inline bool pte_install_uffd_wp_if_needed(struct vm_area_struct *vma, unsigned long ad= dr, pte_t *pte, pte_t pteval) { -#ifdef CONFIG_PTE_MARKER_UFFD_WP + if (!IS_ENABLED(CONFIG_PTE_MARKER_UFFD_WP) || !pte_uffd_wp_available()) + return false; + bool arm_uffd_pte =3D false; =20 /* The current status of the pte should be "cleared" before calling */ @@ -601,7 +603,7 @@ pte_install_uffd_wp_if_needed(struct vm_area_struct *vm= a, unsigned long addr, make_pte_marker(PTE_MARKER_UFFD_WP)); return true; } -#endif + return false; } =20 diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h index 2a489647ac96..51f5b610c5ec 100644 --- a/include/linux/pgtable.h +++ b/include/linux/pgtable.h @@ -1564,6 +1564,7 @@ static inline pmd_t pmd_swp_clear_soft_dirty(pmd_t pm= d) } #endif #else /* !CONFIG_HAVE_ARCH_SOFT_DIRTY */ +#define pte_soft_dirty_available() (false) static inline int pte_soft_dirty(pte_t pte) { return 0; 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_s= truct *vma, if (wp_async && (vm_flags =3D=3D VM_UFFD_WP)) return true; =20 -#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 =20 /* 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 v= m_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; =20 - if (!is_swap_pte(pte)) - return false; + if (!is_swap_pte(pte)) + return false; =20 - entry =3D pte_to_swp_entry(pte); + entry =3D pte_to_swp_entry(pte); + + return pte_marker_entry_uffd_wp(entry); + } else { + return false; + } =20 - 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; =20 - if (pte_swp_uffd_wp(pte)) - return true; + if (pte_swp_uffd_wp(pte)) + return true; =20 - 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..1c61b2d7bd4d 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 =3D false; =20 -#ifdef CONFIG_PTE_MARKER_UFFD_WP + if (!IS_ENABLED(CONFIG_PTE_MARKER_UFFD_WP) || !pte_uffd_wp_available()) + return was_installed; + /* 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 +=3D PAGE_SIZE; } -#endif + return was_installed; } =20 --=20 2.34.1