From 977870522af34359b461060597ee3a86f27450d6 Mon Sep 17 00:00:00 2001 From: Dave Hansen Date: Wed, 22 Oct 2025 16:26:29 +0800 Subject: mm: actually mark kernel page table pages Now that the API is in place, mark kernel page table pages just after they are allocated. Unmark them just before they are freed. Note: Unconditionally clearing the 'kernel' marking (via ptdesc_clear_kernel()) would be functionally identical to what is here. But having the if() makes it logically clear that this function can be used for kernel and non-kernel page tables. Link: https://lkml.kernel.org/r/20251022082635.2462433-4-baolu.lu@linux.intel.com Signed-off-by: Dave Hansen Signed-off-by: Lu Baolu Reviewed-by: Jason Gunthorpe Reviewed-by: Kevin Tian Acked-by: David Hildenbrand Acked-by: Mike Rapoport (Microsoft) Cc: Alistair Popple Cc: Andy Lutomirski Cc: Borislav Betkov Cc: Ingo Molnar Cc: Jann Horn Cc: Jean-Philippe Brucker Cc: Joerg Roedel Cc: Liam Howlett Cc: Lorenzo Stoakes Cc: Matthew Wilcox (Oracle) Cc: Michal Hocko Cc: Peter Zijlstra Cc: Robin Murohy Cc: Thomas Gleinxer Cc: "Uladzislau Rezki (Sony)" Cc: Vasant Hegde Cc: Vinicius Costa Gomes Cc: Vlastimil Babka Cc: Will Deacon Cc: Yi Lai Signed-off-by: Andrew Morton --- include/asm-generic/pgalloc.h | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) (limited to 'include/asm-generic/pgalloc.h') diff --git a/include/asm-generic/pgalloc.h b/include/asm-generic/pgalloc.h index 3c8ec3bfea44..b9d2a7c79b93 100644 --- a/include/asm-generic/pgalloc.h +++ b/include/asm-generic/pgalloc.h @@ -28,6 +28,8 @@ static inline pte_t *__pte_alloc_one_kernel_noprof(struct mm_struct *mm) return NULL; } + ptdesc_set_kernel(ptdesc); + return ptdesc_address(ptdesc); } #define __pte_alloc_one_kernel(...) alloc_hooks(__pte_alloc_one_kernel_noprof(__VA_ARGS__)) @@ -146,6 +148,10 @@ static inline pmd_t *pmd_alloc_one_noprof(struct mm_struct *mm, unsigned long ad pagetable_free(ptdesc); return NULL; } + + if (mm == &init_mm) + ptdesc_set_kernel(ptdesc); + return ptdesc_address(ptdesc); } #define pmd_alloc_one(...) alloc_hooks(pmd_alloc_one_noprof(__VA_ARGS__)) @@ -179,6 +185,10 @@ static inline pud_t *__pud_alloc_one_noprof(struct mm_struct *mm, unsigned long return NULL; pagetable_pud_ctor(ptdesc); + + if (mm == &init_mm) + ptdesc_set_kernel(ptdesc); + return ptdesc_address(ptdesc); } #define __pud_alloc_one(...) alloc_hooks(__pud_alloc_one_noprof(__VA_ARGS__)) @@ -233,6 +243,10 @@ static inline p4d_t *__p4d_alloc_one_noprof(struct mm_struct *mm, unsigned long return NULL; pagetable_p4d_ctor(ptdesc); + + if (mm == &init_mm) + ptdesc_set_kernel(ptdesc); + return ptdesc_address(ptdesc); } #define __p4d_alloc_one(...) alloc_hooks(__p4d_alloc_one_noprof(__VA_ARGS__)) @@ -277,6 +291,10 @@ static inline pgd_t *__pgd_alloc_noprof(struct mm_struct *mm, unsigned int order return NULL; pagetable_pgd_ctor(ptdesc); + + if (mm == &init_mm) + ptdesc_set_kernel(ptdesc); + return ptdesc_address(ptdesc); } #define __pgd_alloc(...) alloc_hooks(__pgd_alloc_noprof(__VA_ARGS__)) -- cgit v1.2.3 From 05be0287955970b043a0742e85b6c285dea4f286 Mon Sep 17 00:00:00 2001 From: Huacai Chen Date: Fri, 7 Nov 2025 17:55:36 +0800 Subject: mm: remove unnecessary __GFP_HIGHMEM in __p*d_alloc_one_*() __{pgd,p4d,pud,pmd,pte}_alloc_one_*() always allocate pages with GFP flag GFP_PGTABLE_KERNEL/GFP_PGTABLE_USER. These two macros are defined as follows: #define GFP_PGTABLE_KERNEL (GFP_KERNEL | __GFP_ZERO) #define GFP_PGTABLE_USER (GFP_PGTABLE_KERNEL | __GFP_ACCOUNT) There is no __GFP_HIGHMEM in them, so we needn't to clear __GFP_HIGHMEM explicitly. Link: https://lkml.kernel.org/r/20251109021817.346181-1-chenhuacai@loongson.cn Link: https://lkml.kernel.org/r/20251107095536.3101371-1-chenhuacai@loongson.cn Signed-off-by: Huacai Chen Acked-by: Mike Rapoport (Microsoft) Reviewed-by: Vishal Moola (Oracle) Reviewed-by: Anshuman Khandual Reviewed-by: Kevin Brodsky Cc: Arnd Bergmann Cc: Jan Kara Signed-off-by: Andrew Morton --- include/asm-generic/pgalloc.h | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) (limited to 'include/asm-generic/pgalloc.h') diff --git a/include/asm-generic/pgalloc.h b/include/asm-generic/pgalloc.h index b9d2a7c79b93..57137d3ac159 100644 --- a/include/asm-generic/pgalloc.h +++ b/include/asm-generic/pgalloc.h @@ -18,8 +18,7 @@ */ static inline pte_t *__pte_alloc_one_kernel_noprof(struct mm_struct *mm) { - struct ptdesc *ptdesc = pagetable_alloc_noprof(GFP_PGTABLE_KERNEL & - ~__GFP_HIGHMEM, 0); + struct ptdesc *ptdesc = pagetable_alloc_noprof(GFP_PGTABLE_KERNEL, 0); if (!ptdesc) return NULL; @@ -178,7 +177,6 @@ static inline pud_t *__pud_alloc_one_noprof(struct mm_struct *mm, unsigned long if (mm == &init_mm) gfp = GFP_PGTABLE_KERNEL; - gfp &= ~__GFP_HIGHMEM; ptdesc = pagetable_alloc_noprof(gfp, 0); if (!ptdesc) @@ -236,7 +234,6 @@ static inline p4d_t *__p4d_alloc_one_noprof(struct mm_struct *mm, unsigned long if (mm == &init_mm) gfp = GFP_PGTABLE_KERNEL; - gfp &= ~__GFP_HIGHMEM; ptdesc = pagetable_alloc_noprof(gfp, 0); if (!ptdesc) @@ -284,7 +281,6 @@ static inline pgd_t *__pgd_alloc_noprof(struct mm_struct *mm, unsigned int order if (mm == &init_mm) gfp = GFP_PGTABLE_KERNEL; - gfp &= ~__GFP_HIGHMEM; ptdesc = pagetable_alloc_noprof(gfp, order); if (!ptdesc) -- cgit v1.2.3