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f1eb1bacfb
This patch is a cleanup to always wr-protect pte/pmd in mkuffd_wp paths.
The reasons I still think this patch is worthwhile, are:
(1) It is a cleanup already; diffstat tells.
(2) It just feels natural after I thought about this, if the pte is uffd
protected, let's remove the write bit no matter what it was.
(2) Since x86 is the only arch that supports uffd-wp, it also redefines
pte|pmd_mkuffd_wp() in that it should always contain removals of
write bits. It means any future arch that want to implement uffd-wp
should naturally follow this rule too. It's good to make it a
default, even if with vm_page_prot changes on VM_UFFD_WP.
(3) It covers more than vm_page_prot. So no chance of any potential
future "accident" (like pte_mkdirty() sparc64 or loongarch, even
though it just got its pte_mkdirty fixed <1 month ago). It'll be
fairly clear when reading the code too that we don't worry anything
before a pte_mkuffd_wp() on uncertainty of the write bit.
We may call pte_wrprotect() one more time in some paths (e.g. thp split),
but that should be fully local bitop instruction so the overhead should be
negligible.
Although this patch should logically also fix all the known issues on
uffd-wp too recently on page migration (not for numa hint recovery - that
may need another explcit pte_wrprotect), but this is not the plan for that
fix. So no fixes, and stable doesn't need this.
Link: https://lkml.kernel.org/r/20221214201533.1774616-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ives van Hoorne <ives@codesandbox.io>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
160 lines
3.5 KiB
C
160 lines
3.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_GENERIC_HUGETLB_H
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#define _ASM_GENERIC_HUGETLB_H
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#include <linux/swap.h>
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#include <linux/swapops.h>
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static inline pte_t mk_huge_pte(struct page *page, pgprot_t pgprot)
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{
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return mk_pte(page, pgprot);
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}
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static inline unsigned long huge_pte_write(pte_t pte)
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{
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return pte_write(pte);
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}
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static inline unsigned long huge_pte_dirty(pte_t pte)
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{
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return pte_dirty(pte);
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}
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static inline pte_t huge_pte_mkwrite(pte_t pte)
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{
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return pte_mkwrite(pte);
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}
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#ifndef __HAVE_ARCH_HUGE_PTE_WRPROTECT
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static inline pte_t huge_pte_wrprotect(pte_t pte)
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{
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return pte_wrprotect(pte);
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}
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#endif
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static inline pte_t huge_pte_mkdirty(pte_t pte)
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{
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return pte_mkdirty(pte);
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}
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static inline pte_t huge_pte_modify(pte_t pte, pgprot_t newprot)
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{
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return pte_modify(pte, newprot);
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}
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static inline pte_t huge_pte_mkuffd_wp(pte_t pte)
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{
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return huge_pte_wrprotect(pte_mkuffd_wp(pte));
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}
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static inline pte_t huge_pte_clear_uffd_wp(pte_t pte)
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{
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return pte_clear_uffd_wp(pte);
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}
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static inline int huge_pte_uffd_wp(pte_t pte)
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{
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return pte_uffd_wp(pte);
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}
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#ifndef __HAVE_ARCH_HUGE_PTE_CLEAR
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static inline void huge_pte_clear(struct mm_struct *mm, unsigned long addr,
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pte_t *ptep, unsigned long sz)
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{
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pte_clear(mm, addr, ptep);
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}
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#endif
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#ifndef __HAVE_ARCH_HUGETLB_FREE_PGD_RANGE
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static inline void hugetlb_free_pgd_range(struct mmu_gather *tlb,
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unsigned long addr, unsigned long end,
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unsigned long floor, unsigned long ceiling)
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{
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free_pgd_range(tlb, addr, end, floor, ceiling);
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}
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#endif
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#ifndef __HAVE_ARCH_HUGE_SET_HUGE_PTE_AT
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static inline void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
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pte_t *ptep, pte_t pte)
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{
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set_pte_at(mm, addr, ptep, pte);
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}
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#endif
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#ifndef __HAVE_ARCH_HUGE_PTEP_GET_AND_CLEAR
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static inline pte_t huge_ptep_get_and_clear(struct mm_struct *mm,
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unsigned long addr, pte_t *ptep)
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{
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return ptep_get_and_clear(mm, addr, ptep);
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}
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#endif
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#ifndef __HAVE_ARCH_HUGE_PTEP_CLEAR_FLUSH
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static inline pte_t huge_ptep_clear_flush(struct vm_area_struct *vma,
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unsigned long addr, pte_t *ptep)
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{
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return ptep_clear_flush(vma, addr, ptep);
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}
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#endif
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#ifndef __HAVE_ARCH_HUGE_PTE_NONE
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static inline int huge_pte_none(pte_t pte)
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{
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return pte_none(pte);
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}
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#endif
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/* Please refer to comments above pte_none_mostly() for the usage */
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static inline int huge_pte_none_mostly(pte_t pte)
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{
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return huge_pte_none(pte) || is_pte_marker(pte);
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}
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#ifndef __HAVE_ARCH_PREPARE_HUGEPAGE_RANGE
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static inline int prepare_hugepage_range(struct file *file,
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unsigned long addr, unsigned long len)
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{
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struct hstate *h = hstate_file(file);
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if (len & ~huge_page_mask(h))
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return -EINVAL;
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if (addr & ~huge_page_mask(h))
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return -EINVAL;
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return 0;
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}
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#endif
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#ifndef __HAVE_ARCH_HUGE_PTEP_SET_WRPROTECT
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static inline void huge_ptep_set_wrprotect(struct mm_struct *mm,
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unsigned long addr, pte_t *ptep)
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{
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ptep_set_wrprotect(mm, addr, ptep);
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}
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#endif
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#ifndef __HAVE_ARCH_HUGE_PTEP_SET_ACCESS_FLAGS
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static inline int huge_ptep_set_access_flags(struct vm_area_struct *vma,
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unsigned long addr, pte_t *ptep,
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pte_t pte, int dirty)
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{
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return ptep_set_access_flags(vma, addr, ptep, pte, dirty);
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}
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#endif
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#ifndef __HAVE_ARCH_HUGE_PTEP_GET
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static inline pte_t huge_ptep_get(pte_t *ptep)
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{
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return ptep_get(ptep);
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}
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#endif
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#ifndef __HAVE_ARCH_GIGANTIC_PAGE_RUNTIME_SUPPORTED
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static inline bool gigantic_page_runtime_supported(void)
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{
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return IS_ENABLED(CONFIG_ARCH_HAS_GIGANTIC_PAGE);
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}
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#endif /* __HAVE_ARCH_GIGANTIC_PAGE_RUNTIME_SUPPORTED */
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#endif /* _ASM_GENERIC_HUGETLB_H */
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