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(unknown [210.73.43.101]) by APP-03 (Coremail) with SMTP id rQCowABnsXvsLMpojtxAAw--.607S7; Wed, 17 Sep 2025 11:37:32 +0800 (CST) From: Chunyan Zhang To: linux-riscv@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti , Conor Dooley , Deepak Gupta , Ved Shanbhogue , Alexander Viro , Christian Brauner , Jan Kara , Andrew Morton , Peter Xu , Arnd Bergmann , David Hildenbrand , Lorenzo Stoakes , "Liam R . Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Axel Rasmussen , Yuanchu Xie , Chunyan Zhang Subject: [PATCH V13 5/6] riscv: mm: Add userfaultfd write-protect support Date: Wed, 17 Sep 2025 11:37:02 +0800 Message-Id: <20250917033703.1695933-6-zhangchunyan@iscas.ac.cn> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20250917033703.1695933-1-zhangchunyan@iscas.ac.cn> References: <20250917033703.1695933-1-zhangchunyan@iscas.ac.cn> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CM-TRANSID:rQCowABnsXvsLMpojtxAAw--.607S7 X-Coremail-Antispam: 1UD129KBjvJXoWxZF48ZF4kKF4xKFW5urWrAFb_yoWruw15pr s5GayrurWDJF97tayftr4YgrWrZw4fWa4DWr9xCa1kJFy7K3yDXr95Kry3try8JFWvv347 WFWrKr1rCw47JFDanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUQjb7Iv0xC_Zr1lb4IE77IF4wAFF20E14v26rWj6s0DM7CY07I2 0VC2zVCF04k26cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28IrcIa0xkI8VA2jI 8067AKxVWUAVCq3wA2048vs2IY020Ec7CjxVAFwI0_Xr0E3s1l8cAvFVAK0II2c7xJM28C jxkF64kEwVA0rcxSw2x7M28EF7xvwVC0I7IYx2IY67AKxVW8JVW5JwA2z4x0Y4vE2Ix0cI 8IcVCY1x0267AKxVW8Jr0_Cr1UM28EF7xvwVC2z280aVAFwI0_Cr1j6rxdM28EF7xvwVC2 z280aVCY1x0267AKxVW0oVCq3wAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0V AKzVAqx4xG6I80ewAv7VC0I7IYx2IY67AKxVWUGVWUXwAv7VC2z280aVAFwI0_Jr0_Gr1l Ox8S6xCaFVCjc4AY6r1j6r4UM4x0Y48IcxkI7VAKI48JM4IIrI8v6xkF7I0E8cxan2IY04 v7MxkF7I0En4kS14v26r4a6rW5MxkIecxEwVAFwVW8GwCF04k20xvY0x0EwIxGrwCFx2Iq xVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14v26r1j6r18MI8I3I0E7480Y4vE14v26r 106r1rMI8E67AF67kF1VAFwI0_GFv_WrylIxkGc2Ij64vIr41lIxAIcVC0I7IYx2IY67AK xVWUCVW8JwCI42IY6xIIjxv20xvEc7CjxVAFwI0_Gr1j6F4UJwCI42IY6xAIw20EY4v20x vaj40_Jr0_JF4lIxAIcVC2z280aVAFwI0_Jr0_Gr1lIxAIcVC2z280aVCY1x0267AKxVW8 Jr0_Cr1UYxBIdaVFxhVjvjDU0xZFpf9x07j9Z2-UUUUU= X-Originating-IP: [210.73.43.101] X-CM-SenderInfo: x2kd0wxfkx051dq6x2xfdvhtffof0/1tbiCQ4IB2jJ8TDyHQAAsH X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 05F4BC000C X-Stat-Signature: czoksokdmjg4crrq8jzpjf6n43fg78my X-Rspam-User: X-HE-Tag: 1758080264-389283 X-HE-Meta: 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 q55uOK0y iJOVu75liCFYzfpbY35zbKujPbx5v3k0B0oHi2SkN9yZVrG3+SFSVz2mJaNyErOW7TETbDgudwnXOYE++FRaCM6C4dVZxvLoUMPHrqamDl4VN6E2or86tGOfnWcGMPC6GJkkH7jTV8/K5PG5hs8GQ7d7gCDgRcku60eElADnUf7NGx1JnqlyS06iN2M4hHRqKMLHl+4MaDWDlyFc= 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: The Svrsw60t59b extension allows to free the PTE reserved bits 60 and 59 for software, this patch uses bit 60 for uffd-wp tracking Additionally for tracking the uffd-wp state as a PTE swap bit, we borrow bit 4 which is not involved into swap entry computation. Signed-off-by: Chunyan Zhang --- arch/riscv/Kconfig | 1 + arch/riscv/include/asm/pgtable-bits.h | 18 +++++++ arch/riscv/include/asm/pgtable.h | 68 +++++++++++++++++++++++++++ 3 files changed, 87 insertions(+) diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index 53b73e4bdf3f..f928768bb14a 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -147,6 +147,7 @@ config RISCV select HAVE_ARCH_TRANSPARENT_HUGEPAGE if 64BIT && MMU select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if 64BIT && MMU select HAVE_ARCH_USERFAULTFD_MINOR if 64BIT && USERFAULTFD + select HAVE_ARCH_USERFAULTFD_WP if 64BIT && MMU && USERFAULTFD && RISCV_ISA_SVRSW60T59B select HAVE_ARCH_VMAP_STACK if MMU && 64BIT select HAVE_ASM_MODVERSIONS select HAVE_CONTEXT_TRACKING_USER diff --git a/arch/riscv/include/asm/pgtable-bits.h b/arch/riscv/include/asm/pgtable-bits.h index f3bac2bbc157..b422d9691e60 100644 --- a/arch/riscv/include/asm/pgtable-bits.h +++ b/arch/riscv/include/asm/pgtable-bits.h @@ -38,6 +38,24 @@ #define _PAGE_SWP_SOFT_DIRTY 0 #endif /* CONFIG_MEM_SOFT_DIRTY */ +#ifdef CONFIG_HAVE_ARCH_USERFAULTFD_WP + +/* ext_svrsw60t59b: Bit(60) for uffd-wp tracking */ +#define _PAGE_UFFD_WP \ + ((riscv_has_extension_unlikely(RISCV_ISA_EXT_SVRSW60T59B)) ? \ + (1UL << 60) : 0) +/* + * Bit 4 is not involved into swap entry computation, so we + * can borrow it for swap page uffd-wp tracking. + */ +#define _PAGE_SWP_UFFD_WP \ + ((riscv_has_extension_unlikely(RISCV_ISA_EXT_SVRSW60T59B)) ? \ + _PAGE_USER : 0) +#else +#define _PAGE_UFFD_WP 0 +#define _PAGE_SWP_UFFD_WP 0 +#endif + #define _PAGE_TABLE _PAGE_PRESENT /* diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h index d7fe0f78107b..71e84c114dc4 100644 --- a/arch/riscv/include/asm/pgtable.h +++ b/arch/riscv/include/asm/pgtable.h @@ -416,6 +416,41 @@ static inline pte_t pte_wrprotect(pte_t pte) return __pte(pte_val(pte) & ~(_PAGE_WRITE)); } +#ifdef CONFIG_HAVE_ARCH_USERFAULTFD_WP +#define pgtable_supports_uffd_wp() \ + riscv_has_extension_unlikely(RISCV_ISA_EXT_SVRSW60T59B) + +static inline bool pte_uffd_wp(pte_t pte) +{ + return !!(pte_val(pte) & _PAGE_UFFD_WP); +} + +static inline pte_t pte_mkuffd_wp(pte_t pte) +{ + return pte_wrprotect(__pte(pte_val(pte) | _PAGE_UFFD_WP)); +} + +static inline pte_t pte_clear_uffd_wp(pte_t pte) +{ + return __pte(pte_val(pte) & ~(_PAGE_UFFD_WP)); +} + +static inline bool pte_swp_uffd_wp(pte_t pte) +{ + return !!(pte_val(pte) & _PAGE_SWP_UFFD_WP); +} + +static inline pte_t pte_swp_mkuffd_wp(pte_t pte) +{ + return __pte(pte_val(pte) | _PAGE_SWP_UFFD_WP); +} + +static inline pte_t pte_swp_clear_uffd_wp(pte_t pte) +{ + return __pte(pte_val(pte) & ~(_PAGE_SWP_UFFD_WP)); +} +#endif /* CONFIG_HAVE_ARCH_USERFAULTFD_WP */ + /* static inline pte_t pte_mkread(pte_t pte) */ static inline pte_t pte_mkwrite_novma(pte_t pte) @@ -838,6 +873,38 @@ static inline pud_t pud_mkspecial(pud_t pud) } #endif +#ifdef CONFIG_HAVE_ARCH_USERFAULTFD_WP +static inline bool pmd_uffd_wp(pmd_t pmd) +{ + return pte_uffd_wp(pmd_pte(pmd)); +} + +static inline pmd_t pmd_mkuffd_wp(pmd_t pmd) +{ + return pte_pmd(pte_mkuffd_wp(pmd_pte(pmd))); +} + +static inline pmd_t pmd_clear_uffd_wp(pmd_t pmd) +{ + return pte_pmd(pte_clear_uffd_wp(pmd_pte(pmd))); +} + +static inline bool pmd_swp_uffd_wp(pmd_t pmd) +{ + return pte_swp_uffd_wp(pmd_pte(pmd)); +} + +static inline pmd_t pmd_swp_mkuffd_wp(pmd_t pmd) +{ + return pte_pmd(pte_swp_mkuffd_wp(pmd_pte(pmd))); +} + +static inline pmd_t pmd_swp_clear_uffd_wp(pmd_t pmd) +{ + return pte_pmd(pte_swp_clear_uffd_wp(pmd_pte(pmd))); +} +#endif /* CONFIG_HAVE_ARCH_USERFAULTFD_WP */ + #ifdef CONFIG_HAVE_ARCH_SOFT_DIRTY static inline bool pmd_soft_dirty(pmd_t pmd) { @@ -1066,6 +1133,7 @@ static inline pud_t pud_modify(pud_t pud, pgprot_t newprot) * bit 0: _PAGE_PRESENT (zero) * bit 1 to 2: (zero) * bit 3: _PAGE_SWP_SOFT_DIRTY + * bit 4: _PAGE_SWP_UFFD_WP * bit 5: _PAGE_PROT_NONE (zero) * bit 6: exclusive marker * bits 7 to 11: swap type -- 2.34.1