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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>
75 lines
1.8 KiB
C
75 lines
1.8 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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* OpenRISC Linux
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*
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* Linux architectural port borrowing liberally from similar works of
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* others. All original copyrights apply as per the original source
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* declaration.
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*
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* OpenRISC implementation:
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* Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
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* Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
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* et al.
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*/
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#ifndef __ASM_OPENRISC_PGALLOC_H
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#define __ASM_OPENRISC_PGALLOC_H
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#include <asm/page.h>
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#include <linux/threads.h>
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#include <linux/mm.h>
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#include <linux/memblock.h>
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#define __HAVE_ARCH_PTE_ALLOC_ONE_KERNEL
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#include <asm-generic/pgalloc.h>
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extern int mem_init_done;
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#define pmd_populate_kernel(mm, pmd, pte) \
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set_pmd(pmd, __pmd(_KERNPG_TABLE + __pa(pte)))
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static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmd,
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struct page *pte)
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{
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set_pmd(pmd, __pmd(_KERNPG_TABLE +
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((unsigned long)page_to_pfn(pte) <<
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(unsigned long) PAGE_SHIFT)));
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}
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/*
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* Allocate and free page tables.
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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 *ret = (pgd_t *)__get_free_page(GFP_KERNEL);
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if (ret) {
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memset(ret, 0, USER_PTRS_PER_PGD * sizeof(pgd_t));
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memcpy(ret + USER_PTRS_PER_PGD,
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swapper_pg_dir + USER_PTRS_PER_PGD,
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(PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
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}
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return ret;
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}
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#if 0
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/* FIXME: This seems to be the preferred style, but we are using
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* current_pgd (from mm->pgd) to load kernel pages so we need it
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* initialized. This needs to be looked into.
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*/
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extern inline pgd_t *pgd_alloc(struct mm_struct *mm)
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{
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return (pgd_t *)get_zeroed_page(GFP_KERNEL);
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}
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#endif
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extern pte_t *pte_alloc_one_kernel(struct mm_struct *mm);
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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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#endif
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