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db6b435d73
The pagetable_p*_dtor() are exactly the same except for the handling of ptlock. If we make ptlock_free() handle the case where ptdesc->ptl is NULL and remove VM_BUG_ON_PAGE() from pmd_ptlock_free(), we can unify pagetable_p*_dtor() into one function. Let's introduce pagetable_dtor() to do this. Later, pagetable_dtor() will be moved to tlb_remove_ptdesc(), so that ptlock and page table pages can be freed together (regardless of whether RCU is used). This prevents the use-after-free problem where the ptlock is freed immediately but the page table pages is freed later via RCU. Link: https://lkml.kernel.org/r/47f44fff9dc68d9d9e9a0d6c036df275f820598a.1736317725.git.zhengqi.arch@bytedance.com Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com> Originally-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Kevin Brodsky <kevin.brodsky@arm.com> Acked-by: Alexander Gordeev <agordeev@linux.ibm.com> [s390] Cc: Alexandre Ghiti <alex@ghiti.fr> Cc: Alexandre Ghiti <alexghiti@rivosinc.com> Cc: Andreas Larsson <andreas@gaisler.com> Cc: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jann Horn <jannh@google.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Mike Rapoport (Microsoft) <rppt@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com> Cc: Will Deacon <will@kernel.org> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
95 lines
2.1 KiB
C
95 lines
2.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef M68K_MCF_PGALLOC_H
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#define M68K_MCF_PGALLOC_H
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#include <asm/tlb.h>
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#include <asm/tlbflush.h>
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static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
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{
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pagetable_free(virt_to_ptdesc(pte));
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}
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extern const char bad_pmd_string[];
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static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm)
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{
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struct ptdesc *ptdesc = pagetable_alloc((GFP_DMA | __GFP_ZERO) &
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~__GFP_HIGHMEM, 0);
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if (!ptdesc)
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return NULL;
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return ptdesc_address(ptdesc);
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}
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extern inline pmd_t *pmd_alloc_kernel(pgd_t *pgd, unsigned long address)
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{
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return (pmd_t *) pgd;
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}
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#define pmd_populate(mm, pmd, pte) (pmd_val(*pmd) = (unsigned long)(pte))
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#define pmd_populate_kernel pmd_populate
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static inline void __pte_free_tlb(struct mmu_gather *tlb, pgtable_t pgtable,
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unsigned long address)
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{
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struct ptdesc *ptdesc = virt_to_ptdesc(pgtable);
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pagetable_dtor(ptdesc);
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pagetable_free(ptdesc);
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}
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static inline pgtable_t pte_alloc_one(struct mm_struct *mm)
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{
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struct ptdesc *ptdesc = pagetable_alloc(GFP_DMA | __GFP_ZERO, 0);
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pte_t *pte;
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if (!ptdesc)
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return NULL;
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if (!pagetable_pte_ctor(ptdesc)) {
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pagetable_free(ptdesc);
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return NULL;
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}
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pte = ptdesc_address(ptdesc);
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return pte;
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}
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static inline void pte_free(struct mm_struct *mm, pgtable_t pgtable)
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{
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struct ptdesc *ptdesc = virt_to_ptdesc(pgtable);
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pagetable_dtor(ptdesc);
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pagetable_free(ptdesc);
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}
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/*
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* In our implementation, each pgd entry contains 1 pmd that is never allocated
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* or freed. pgd_present is always 1, so this should never be called. -NL
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*/
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#define pmd_free(mm, pmd) BUG()
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static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)
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{
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pagetable_free(virt_to_ptdesc(pgd));
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}
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static inline pgd_t *pgd_alloc(struct mm_struct *mm)
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{
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pgd_t *new_pgd;
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struct ptdesc *ptdesc = pagetable_alloc((GFP_DMA | __GFP_NOWARN) &
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~__GFP_HIGHMEM, 0);
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if (!ptdesc)
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return NULL;
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new_pgd = ptdesc_address(ptdesc);
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memcpy(new_pgd, swapper_pg_dir, PTRS_PER_PGD * sizeof(pgd_t));
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memset(new_pgd, 0, PAGE_OFFSET >> PGDIR_SHIFT);
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return new_pgd;
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}
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#endif /* M68K_MCF_PGALLOC_H */
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