linux/arch/nios2/include/asm/pgalloc.h
Qi Zheng db6b435d73 mm: pgtable: introduce pagetable_dtor()
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>
2025-01-25 20:22:22 -08:00

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/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 1994 - 2001, 2003 by Ralf Baechle
* Copyright (C) 1999, 2000, 2001 Silicon Graphics, Inc.
*/
#ifndef _ASM_NIOS2_PGALLOC_H
#define _ASM_NIOS2_PGALLOC_H
#include <linux/mm.h>
#include <asm-generic/pgalloc.h>
static inline void pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd,
pte_t *pte)
{
set_pmd(pmd, __pmd((unsigned long)pte));
}
static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmd,
pgtable_t pte)
{
set_pmd(pmd, __pmd((unsigned long)page_address(pte)));
}
extern pgd_t *pgd_alloc(struct mm_struct *mm);
#define __pte_free_tlb(tlb, pte, addr) \
do { \
pagetable_dtor(page_ptdesc(pte)); \
tlb_remove_page_ptdesc((tlb), (page_ptdesc(pte))); \
} while (0)
#endif /* _ASM_NIOS2_PGALLOC_H */