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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>
52 lines
1.2 KiB
C
52 lines
1.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/* sun3_pgalloc.h --
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* reorganization around 2.3.39, routines moved from sun3_pgtable.h
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*
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*
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* 02/27/2002 -- Modified to support "highpte" implementation in 2.5.5 (Sam)
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*
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* moved 1/26/2000 Sam Creasey
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*/
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#ifndef _SUN3_PGALLOC_H
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#define _SUN3_PGALLOC_H
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#include <asm/tlb.h>
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#include <asm-generic/pgalloc.h>
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extern const char bad_pmd_string[];
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#define __pte_free_tlb(tlb, pte, addr) \
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do { \
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pagetable_dtor(page_ptdesc(pte)); \
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tlb_remove_page_ptdesc((tlb), page_ptdesc(pte)); \
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} while (0)
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static inline void pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd, pte_t *pte)
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{
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pmd_val(*pmd) = __pa((unsigned long)pte);
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}
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static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmd, pgtable_t page)
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{
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pmd_val(*pmd) = __pa((unsigned long)page_address(page));
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}
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/*
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* allocating and freeing a pmd is trivial: the 1-entry pmd is
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* inside the pgd, so has no extra memory associated with it.
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*/
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#define pmd_free(mm, x) do { } while (0)
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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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new_pgd = (pgd_t *)get_zeroed_page(GFP_KERNEL);
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memcpy(new_pgd, swapper_pg_dir, PAGE_SIZE);
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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 /* SUN3_PGALLOC_H */
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