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authorMike Rapoport <rppt@linux.ibm.com>2020-06-08 21:32:38 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-06-09 09:39:13 -0700
commitca5999fde0a1761665a38e4c9a72dbcd7d190a81 (patch)
tree0ce961c9b4e7619753b858dd7997ffc0c1f087ef /include/linux/pgtable.h
parente31cf2f4ca422ac9b14ecc4a1295b8977a20f812 (diff)
downloadlinux-sh-ca5999fde0a1761665a38e4c9a72dbcd7d190a81.tar.gz
mm: introduce include/linux/pgtable.h
The include/linux/pgtable.h is going to be the home of generic page table manipulation functions. Start with moving asm-generic/pgtable.h to include/linux/pgtable.h and make the latter include asm/pgtable.h. Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Cain <bcain@codeaurora.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chris Zankel <chris@zankel.net> Cc: "David S. Miller" <davem@davemloft.net> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Greentime Hu <green.hu@gmail.com> Cc: Greg Ungerer <gerg@linux-m68k.org> Cc: Guan Xuetao <gxt@pku.edu.cn> Cc: Guo Ren <guoren@kernel.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Helge Deller <deller@gmx.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Ley Foon Tan <ley.foon.tan@intel.com> Cc: Mark Salter <msalter@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Matt Turner <mattst88@gmail.com> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Simek <monstr@monstr.eu> Cc: Nick Hu <nickhu@andestech.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Richard Weinberger <richard@nod.at> Cc: Rich Felker <dalias@libc.org> Cc: Russell King <linux@armlinux.org.uk> Cc: Stafford Horne <shorne@gmail.com> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Vincent Chen <deanbo422@gmail.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Will Deacon <will@kernel.org> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Link: http://lkml.kernel.org/r/20200514170327.31389-3-rppt@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/pgtable.h')
-rw-r--r--include/linux/pgtable.h1323
1 files changed, 1323 insertions, 0 deletions
diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
new file mode 100644
index 000000000000..6e274da637fd
--- /dev/null
+++ b/include/linux/pgtable.h
@@ -0,0 +1,1323 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_PGTABLE_H
+#define _LINUX_PGTABLE_H
+
+#include <linux/pfn.h>
+#include <asm/pgtable.h>
+
+#ifndef __ASSEMBLY__
+#ifdef CONFIG_MMU
+
+#include <linux/mm_types.h>
+#include <linux/bug.h>
+#include <linux/errno.h>
+#include <asm-generic/pgtable_uffd.h>
+
+#if 5 - defined(__PAGETABLE_P4D_FOLDED) - defined(__PAGETABLE_PUD_FOLDED) - \
+ defined(__PAGETABLE_PMD_FOLDED) != CONFIG_PGTABLE_LEVELS
+#error CONFIG_PGTABLE_LEVELS is not consistent with __PAGETABLE_{P4D,PUD,PMD}_FOLDED
+#endif
+
+/*
+ * On almost all architectures and configurations, 0 can be used as the
+ * upper ceiling to free_pgtables(): on many architectures it has the same
+ * effect as using TASK_SIZE. However, there is one configuration which
+ * must impose a more careful limit, to avoid freeing kernel pgtables.
+ */
+#ifndef USER_PGTABLES_CEILING
+#define USER_PGTABLES_CEILING 0UL
+#endif
+
+#ifndef __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
+extern int ptep_set_access_flags(struct vm_area_struct *vma,
+ unsigned long address, pte_t *ptep,
+ pte_t entry, int dirty);
+#endif
+
+#ifndef __HAVE_ARCH_PMDP_SET_ACCESS_FLAGS
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+extern int pmdp_set_access_flags(struct vm_area_struct *vma,
+ unsigned long address, pmd_t *pmdp,
+ pmd_t entry, int dirty);
+extern int pudp_set_access_flags(struct vm_area_struct *vma,
+ unsigned long address, pud_t *pudp,
+ pud_t entry, int dirty);
+#else
+static inline int pmdp_set_access_flags(struct vm_area_struct *vma,
+ unsigned long address, pmd_t *pmdp,
+ pmd_t entry, int dirty)
+{
+ BUILD_BUG();
+ return 0;
+}
+static inline int pudp_set_access_flags(struct vm_area_struct *vma,
+ unsigned long address, pud_t *pudp,
+ pud_t entry, int dirty)
+{
+ BUILD_BUG();
+ return 0;
+}
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
+#endif
+
+#ifndef __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
+static inline int ptep_test_and_clear_young(struct vm_area_struct *vma,
+ unsigned long address,
+ pte_t *ptep)
+{
+ pte_t pte = *ptep;
+ int r = 1;
+ if (!pte_young(pte))
+ r = 0;
+ else
+ set_pte_at(vma->vm_mm, address, ptep, pte_mkold(pte));
+ return r;
+}
+#endif
+
+#ifndef __HAVE_ARCH_PMDP_TEST_AND_CLEAR_YOUNG
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+static inline int pmdp_test_and_clear_young(struct vm_area_struct *vma,
+ unsigned long address,
+ pmd_t *pmdp)
+{
+ pmd_t pmd = *pmdp;
+ int r = 1;
+ if (!pmd_young(pmd))
+ r = 0;
+ else
+ set_pmd_at(vma->vm_mm, address, pmdp, pmd_mkold(pmd));
+ return r;
+}
+#else
+static inline int pmdp_test_and_clear_young(struct vm_area_struct *vma,
+ unsigned long address,
+ pmd_t *pmdp)
+{
+ BUILD_BUG();
+ return 0;
+}
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
+#endif
+
+#ifndef __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
+int ptep_clear_flush_young(struct vm_area_struct *vma,
+ unsigned long address, pte_t *ptep);
+#endif
+
+#ifndef __HAVE_ARCH_PMDP_CLEAR_YOUNG_FLUSH
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+extern int pmdp_clear_flush_young(struct vm_area_struct *vma,
+ unsigned long address, pmd_t *pmdp);
+#else
+/*
+ * Despite relevant to THP only, this API is called from generic rmap code
+ * under PageTransHuge(), hence needs a dummy implementation for !THP
+ */
+static inline int pmdp_clear_flush_young(struct vm_area_struct *vma,
+ unsigned long address, pmd_t *pmdp)
+{
+ BUILD_BUG();
+ return 0;
+}
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
+#endif
+
+#ifndef __HAVE_ARCH_PTEP_GET_AND_CLEAR
+static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
+ unsigned long address,
+ pte_t *ptep)
+{
+ pte_t pte = *ptep;
+ pte_clear(mm, address, ptep);
+ return pte;
+}
+#endif
+
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+#ifndef __HAVE_ARCH_PMDP_HUGE_GET_AND_CLEAR
+static inline pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm,
+ unsigned long address,
+ pmd_t *pmdp)
+{
+ pmd_t pmd = *pmdp;
+ pmd_clear(pmdp);
+ return pmd;
+}
+#endif /* __HAVE_ARCH_PMDP_HUGE_GET_AND_CLEAR */
+#ifndef __HAVE_ARCH_PUDP_HUGE_GET_AND_CLEAR
+static inline pud_t pudp_huge_get_and_clear(struct mm_struct *mm,
+ unsigned long address,
+ pud_t *pudp)
+{
+ pud_t pud = *pudp;
+
+ pud_clear(pudp);
+ return pud;
+}
+#endif /* __HAVE_ARCH_PUDP_HUGE_GET_AND_CLEAR */
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
+
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+#ifndef __HAVE_ARCH_PMDP_HUGE_GET_AND_CLEAR_FULL
+static inline pmd_t pmdp_huge_get_and_clear_full(struct vm_area_struct *vma,
+ unsigned long address, pmd_t *pmdp,
+ int full)
+{
+ return pmdp_huge_get_and_clear(vma->vm_mm, address, pmdp);
+}
+#endif
+
+#ifndef __HAVE_ARCH_PUDP_HUGE_GET_AND_CLEAR_FULL
+static inline pud_t pudp_huge_get_and_clear_full(struct mm_struct *mm,
+ unsigned long address, pud_t *pudp,
+ int full)
+{
+ return pudp_huge_get_and_clear(mm, address, pudp);
+}
+#endif
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
+
+#ifndef __HAVE_ARCH_PTEP_GET_AND_CLEAR_FULL
+static inline pte_t ptep_get_and_clear_full(struct mm_struct *mm,
+ unsigned long address, pte_t *ptep,
+ int full)
+{
+ pte_t pte;
+ pte = ptep_get_and_clear(mm, address, ptep);
+ return pte;
+}
+#endif
+
+
+/*
+ * If two threads concurrently fault at the same page, the thread that
+ * won the race updates the PTE and its local TLB/Cache. The other thread
+ * gives up, simply does nothing, and continues; on architectures where
+ * software can update TLB, local TLB can be updated here to avoid next page
+ * fault. This function updates TLB only, do nothing with cache or others.
+ * It is the difference with function update_mmu_cache.
+ */
+#ifndef __HAVE_ARCH_UPDATE_MMU_TLB
+static inline void update_mmu_tlb(struct vm_area_struct *vma,
+ unsigned long address, pte_t *ptep)
+{
+}
+#define __HAVE_ARCH_UPDATE_MMU_TLB
+#endif
+
+/*
+ * Some architectures may be able to avoid expensive synchronization
+ * primitives when modifications are made to PTE's which are already
+ * not present, or in the process of an address space destruction.
+ */
+#ifndef __HAVE_ARCH_PTE_CLEAR_NOT_PRESENT_FULL
+static inline void pte_clear_not_present_full(struct mm_struct *mm,
+ unsigned long address,
+ pte_t *ptep,
+ int full)
+{
+ pte_clear(mm, address, ptep);
+}
+#endif
+
+#ifndef __HAVE_ARCH_PTEP_CLEAR_FLUSH
+extern pte_t ptep_clear_flush(struct vm_area_struct *vma,
+ unsigned long address,
+ pte_t *ptep);
+#endif
+
+#ifndef __HAVE_ARCH_PMDP_HUGE_CLEAR_FLUSH
+extern pmd_t pmdp_huge_clear_flush(struct vm_area_struct *vma,
+ unsigned long address,
+ pmd_t *pmdp);
+extern pud_t pudp_huge_clear_flush(struct vm_area_struct *vma,
+ unsigned long address,
+ pud_t *pudp);
+#endif
+
+#ifndef __HAVE_ARCH_PTEP_SET_WRPROTECT
+struct mm_struct;
+static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long address, pte_t *ptep)
+{
+ pte_t old_pte = *ptep;
+ set_pte_at(mm, address, ptep, pte_wrprotect(old_pte));
+}
+#endif
+
+/*
+ * On some architectures hardware does not set page access bit when accessing
+ * memory page, it is responsibilty of software setting this bit. It brings
+ * out extra page fault penalty to track page access bit. For optimization page
+ * access bit can be set during all page fault flow on these arches.
+ * To be differentiate with macro pte_mkyoung, this macro is used on platforms
+ * where software maintains page access bit.
+ */
+#ifndef pte_sw_mkyoung
+static inline pte_t pte_sw_mkyoung(pte_t pte)
+{
+ return pte;
+}
+#define pte_sw_mkyoung pte_sw_mkyoung
+#endif
+
+#ifndef pte_savedwrite
+#define pte_savedwrite pte_write
+#endif
+
+#ifndef pte_mk_savedwrite
+#define pte_mk_savedwrite pte_mkwrite
+#endif
+
+#ifndef pte_clear_savedwrite
+#define pte_clear_savedwrite pte_wrprotect
+#endif
+
+#ifndef pmd_savedwrite
+#define pmd_savedwrite pmd_write
+#endif
+
+#ifndef pmd_mk_savedwrite
+#define pmd_mk_savedwrite pmd_mkwrite
+#endif
+
+#ifndef pmd_clear_savedwrite
+#define pmd_clear_savedwrite pmd_wrprotect
+#endif
+
+#ifndef __HAVE_ARCH_PMDP_SET_WRPROTECT
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+static inline void pmdp_set_wrprotect(struct mm_struct *mm,
+ unsigned long address, pmd_t *pmdp)
+{
+ pmd_t old_pmd = *pmdp;
+ set_pmd_at(mm, address, pmdp, pmd_wrprotect(old_pmd));
+}
+#else
+static inline void pmdp_set_wrprotect(struct mm_struct *mm,
+ unsigned long address, pmd_t *pmdp)
+{
+ BUILD_BUG();
+}
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
+#endif
+#ifndef __HAVE_ARCH_PUDP_SET_WRPROTECT
+#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
+static inline void pudp_set_wrprotect(struct mm_struct *mm,
+ unsigned long address, pud_t *pudp)
+{
+ pud_t old_pud = *pudp;
+
+ set_pud_at(mm, address, pudp, pud_wrprotect(old_pud));
+}
+#else
+static inline void pudp_set_wrprotect(struct mm_struct *mm,
+ unsigned long address, pud_t *pudp)
+{
+ BUILD_BUG();
+}
+#endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
+#endif
+
+#ifndef pmdp_collapse_flush
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+extern pmd_t pmdp_collapse_flush(struct vm_area_struct *vma,
+ unsigned long address, pmd_t *pmdp);
+#else
+static inline pmd_t pmdp_collapse_flush(struct vm_area_struct *vma,
+ unsigned long address,
+ pmd_t *pmdp)
+{
+ BUILD_BUG();
+ return *pmdp;
+}
+#define pmdp_collapse_flush pmdp_collapse_flush
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
+#endif
+
+#ifndef __HAVE_ARCH_PGTABLE_DEPOSIT
+extern void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
+ pgtable_t pgtable);
+#endif
+
+#ifndef __HAVE_ARCH_PGTABLE_WITHDRAW
+extern pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp);
+#endif
+
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+/*
+ * This is an implementation of pmdp_establish() that is only suitable for an
+ * architecture that doesn't have hardware dirty/accessed bits. In this case we
+ * can't race with CPU which sets these bits and non-atomic aproach is fine.
+ */
+static inline pmd_t generic_pmdp_establish(struct vm_area_struct *vma,
+ unsigned long address, pmd_t *pmdp, pmd_t pmd)
+{
+ pmd_t old_pmd = *pmdp;
+ set_pmd_at(vma->vm_mm, address, pmdp, pmd);
+ return old_pmd;
+}
+#endif
+
+#ifndef __HAVE_ARCH_PMDP_INVALIDATE
+extern pmd_t pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
+ pmd_t *pmdp);
+#endif
+
+#ifndef __HAVE_ARCH_PTE_SAME
+static inline int pte_same(pte_t pte_a, pte_t pte_b)
+{
+ return pte_val(pte_a) == pte_val(pte_b);
+}
+#endif
+
+#ifndef __HAVE_ARCH_PTE_UNUSED
+/*
+ * Some architectures provide facilities to virtualization guests
+ * so that they can flag allocated pages as unused. This allows the
+ * host to transparently reclaim unused pages. This function returns
+ * whether the pte's page is unused.
+ */
+static inline int pte_unused(pte_t pte)
+{
+ return 0;
+}
+#endif
+
+#ifndef pte_access_permitted
+#define pte_access_permitted(pte, write) \
+ (pte_present(pte) && (!(write) || pte_write(pte)))
+#endif
+
+#ifndef pmd_access_permitted
+#define pmd_access_permitted(pmd, write) \
+ (pmd_present(pmd) && (!(write) || pmd_write(pmd)))
+#endif
+
+#ifndef pud_access_permitted
+#define pud_access_permitted(pud, write) \
+ (pud_present(pud) && (!(write) || pud_write(pud)))
+#endif
+
+#ifndef p4d_access_permitted
+#define p4d_access_permitted(p4d, write) \
+ (p4d_present(p4d) && (!(write) || p4d_write(p4d)))
+#endif
+
+#ifndef pgd_access_permitted
+#define pgd_access_permitted(pgd, write) \
+ (pgd_present(pgd) && (!(write) || pgd_write(pgd)))
+#endif
+
+#ifndef __HAVE_ARCH_PMD_SAME
+static inline int pmd_same(pmd_t pmd_a, pmd_t pmd_b)
+{
+ return pmd_val(pmd_a) == pmd_val(pmd_b);
+}
+
+static inline int pud_same(pud_t pud_a, pud_t pud_b)
+{
+ return pud_val(pud_a) == pud_val(pud_b);
+}
+#endif
+
+#ifndef __HAVE_ARCH_P4D_SAME
+static inline int p4d_same(p4d_t p4d_a, p4d_t p4d_b)
+{
+ return p4d_val(p4d_a) == p4d_val(p4d_b);
+}
+#endif
+
+#ifndef __HAVE_ARCH_PGD_SAME
+static inline int pgd_same(pgd_t pgd_a, pgd_t pgd_b)
+{
+ return pgd_val(pgd_a) == pgd_val(pgd_b);
+}
+#endif
+
+/*
+ * Use set_p*_safe(), and elide TLB flushing, when confident that *no*
+ * TLB flush will be required as a result of the "set". For example, use
+ * in scenarios where it is known ahead of time that the routine is
+ * setting non-present entries, or re-setting an existing entry to the
+ * same value. Otherwise, use the typical "set" helpers and flush the
+ * TLB.
+ */
+#define set_pte_safe(ptep, pte) \
+({ \
+ WARN_ON_ONCE(pte_present(*ptep) && !pte_same(*ptep, pte)); \
+ set_pte(ptep, pte); \
+})
+
+#define set_pmd_safe(pmdp, pmd) \
+({ \
+ WARN_ON_ONCE(pmd_present(*pmdp) && !pmd_same(*pmdp, pmd)); \
+ set_pmd(pmdp, pmd); \
+})
+
+#define set_pud_safe(pudp, pud) \
+({ \
+ WARN_ON_ONCE(pud_present(*pudp) && !pud_same(*pudp, pud)); \
+ set_pud(pudp, pud); \
+})
+
+#define set_p4d_safe(p4dp, p4d) \
+({ \
+ WARN_ON_ONCE(p4d_present(*p4dp) && !p4d_same(*p4dp, p4d)); \
+ set_p4d(p4dp, p4d); \
+})
+
+#define set_pgd_safe(pgdp, pgd) \
+({ \
+ WARN_ON_ONCE(pgd_present(*pgdp) && !pgd_same(*pgdp, pgd)); \
+ set_pgd(pgdp, pgd); \
+})
+
+#ifndef __HAVE_ARCH_DO_SWAP_PAGE
+/*
+ * Some architectures support metadata associated with a page. When a
+ * page is being swapped out, this metadata must be saved so it can be
+ * restored when the page is swapped back in. SPARC M7 and newer
+ * processors support an ADI (Application Data Integrity) tag for the
+ * page as metadata for the page. arch_do_swap_page() can restore this
+ * metadata when a page is swapped back in.
+ */
+static inline void arch_do_swap_page(struct mm_struct *mm,
+ struct vm_area_struct *vma,
+ unsigned long addr,
+ pte_t pte, pte_t oldpte)
+{
+
+}
+#endif
+
+#ifndef __HAVE_ARCH_UNMAP_ONE
+/*
+ * Some architectures support metadata associated with a page. When a
+ * page is being swapped out, this metadata must be saved so it can be
+ * restored when the page is swapped back in. SPARC M7 and newer
+ * processors support an ADI (Application Data Integrity) tag for the
+ * page as metadata for the page. arch_unmap_one() can save this
+ * metadata on a swap-out of a page.
+ */
+static inline int arch_unmap_one(struct mm_struct *mm,
+ struct vm_area_struct *vma,
+ unsigned long addr,
+ pte_t orig_pte)
+{
+ return 0;
+}
+#endif
+
+#ifndef __HAVE_ARCH_PGD_OFFSET_GATE
+#define pgd_offset_gate(mm, addr) pgd_offset(mm, addr)
+#endif
+
+#ifndef __HAVE_ARCH_MOVE_PTE
+#define move_pte(pte, prot, old_addr, new_addr) (pte)
+#endif
+
+#ifndef pte_accessible
+# define pte_accessible(mm, pte) ((void)(pte), 1)
+#endif
+
+#ifndef flush_tlb_fix_spurious_fault
+#define flush_tlb_fix_spurious_fault(vma, address) flush_tlb_page(vma, address)
+#endif
+
+#ifndef pgprot_nx
+#define pgprot_nx(prot) (prot)
+#endif
+
+#ifndef pgprot_noncached
+#define pgprot_noncached(prot) (prot)
+#endif
+
+#ifndef pgprot_writecombine
+#define pgprot_writecombine pgprot_noncached
+#endif
+
+#ifndef pgprot_writethrough
+#define pgprot_writethrough pgprot_noncached
+#endif
+
+#ifndef pgprot_device
+#define pgprot_device pgprot_noncached
+#endif
+
+#ifndef pgprot_modify
+#define pgprot_modify pgprot_modify
+static inline pgprot_t pgprot_modify(pgprot_t oldprot, pgprot_t newprot)
+{
+ if (pgprot_val(oldprot) == pgprot_val(pgprot_noncached(oldprot)))
+ newprot = pgprot_noncached(newprot);
+ if (pgprot_val(oldprot) == pgprot_val(pgprot_writecombine(oldprot)))
+ newprot = pgprot_writecombine(newprot);
+ if (pgprot_val(oldprot) == pgprot_val(pgprot_device(oldprot)))
+ newprot = pgprot_device(newprot);
+ return newprot;
+}
+#endif
+
+/*
+ * When walking page tables, get the address of the next boundary,
+ * or the end address of the range if that comes earlier. Although no
+ * vma end wraps to 0, rounded up __boundary may wrap to 0 throughout.
+ */
+
+#define pgd_addr_end(addr, end) \
+({ unsigned long __boundary = ((addr) + PGDIR_SIZE) & PGDIR_MASK; \
+ (__boundary - 1 < (end) - 1)? __boundary: (end); \
+})
+
+#ifndef p4d_addr_end
+#define p4d_addr_end(addr, end) \
+({ unsigned long __boundary = ((addr) + P4D_SIZE) & P4D_MASK; \
+ (__boundary - 1 < (end) - 1)? __boundary: (end); \
+})
+#endif
+
+#ifndef pud_addr_end
+#define pud_addr_end(addr, end) \
+({ unsigned long __boundary = ((addr) + PUD_SIZE) & PUD_MASK; \
+ (__boundary - 1 < (end) - 1)? __boundary: (end); \
+})
+#endif
+
+#ifndef pmd_addr_end
+#define pmd_addr_end(addr, end) \
+({ unsigned long __boundary = ((addr) + PMD_SIZE) & PMD_MASK; \
+ (__boundary - 1 < (end) - 1)? __boundary: (end); \
+})
+#endif
+
+/*
+ * When walking page tables, we usually want to skip any p?d_none entries;
+ * and any p?d_bad entries - reporting the error before resetting to none.
+ * Do the tests inline, but report and clear the bad entry in mm/memory.c.
+ */
+void pgd_clear_bad(pgd_t *);
+
+#ifndef __PAGETABLE_P4D_FOLDED
+void p4d_clear_bad(p4d_t *);
+#else
+#define p4d_clear_bad(p4d) do { } while (0)
+#endif
+
+#ifndef __PAGETABLE_PUD_FOLDED
+void pud_clear_bad(pud_t *);
+#else
+#define pud_clear_bad(p4d) do { } while (0)
+#endif
+
+void pmd_clear_bad(pmd_t *);
+
+static inline int pgd_none_or_clear_bad(pgd_t *pgd)
+{
+ if (pgd_none(*pgd))
+ return 1;
+ if (unlikely(pgd_bad(*pgd))) {
+ pgd_clear_bad(pgd);
+ return 1;
+ }
+ return 0;
+}
+
+static inline int p4d_none_or_clear_bad(p4d_t *p4d)
+{
+ if (p4d_none(*p4d))
+ return 1;
+ if (unlikely(p4d_bad(*p4d))) {
+ p4d_clear_bad(p4d);
+ return 1;
+ }
+ return 0;
+}
+
+static inline int pud_none_or_clear_bad(pud_t *pud)
+{
+ if (pud_none(*pud))
+ return 1;
+ if (unlikely(pud_bad(*pud))) {
+ pud_clear_bad(pud);
+ return 1;
+ }
+ return 0;
+}
+
+static inline int pmd_none_or_clear_bad(pmd_t *pmd)
+{
+ if (pmd_none(*pmd))
+ return 1;
+ if (unlikely(pmd_bad(*pmd))) {
+ pmd_clear_bad(pmd);
+ return 1;
+ }
+ return 0;
+}
+
+static inline pte_t __ptep_modify_prot_start(struct vm_area_struct *vma,
+ unsigned long addr,
+ pte_t *ptep)
+{
+ /*
+ * Get the current pte state, but zero it out to make it
+ * non-present, preventing the hardware from asynchronously
+ * updating it.
+ */
+ return ptep_get_and_clear(vma->vm_mm, addr, ptep);
+}
+
+static inline void __ptep_modify_prot_commit(struct vm_area_struct *vma,
+ unsigned long addr,
+ pte_t *ptep, pte_t pte)
+{
+ /*
+ * The pte is non-present, so there's no hardware state to
+ * preserve.
+ */
+ set_pte_at(vma->vm_mm, addr, ptep, pte);
+}
+
+#ifndef __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION
+/*
+ * Start a pte protection read-modify-write transaction, which
+ * protects against asynchronous hardware modifications to the pte.
+ * The intention is not to prevent the hardware from making pte
+ * updates, but to prevent any updates it may make from being lost.
+ *
+ * This does not protect against other software modifications of the
+ * pte; the appropriate pte lock must be held over the transation.
+ *
+ * Note that this interface is intended to be batchable, meaning that
+ * ptep_modify_prot_commit may not actually update the pte, but merely
+ * queue the update to be done at some later time. The update must be
+ * actually committed before the pte lock is released, however.
+ */
+static inline pte_t ptep_modify_prot_start(struct vm_area_struct *vma,
+ unsigned long addr,
+ pte_t *ptep)
+{
+ return __ptep_modify_prot_start(vma, addr, ptep);
+}
+
+/*
+ * Commit an update to a pte, leaving any hardware-controlled bits in
+ * the PTE unmodified.
+ */
+static inline void ptep_modify_prot_commit(struct vm_area_struct *vma,
+ unsigned long addr,
+ pte_t *ptep, pte_t old_pte, pte_t pte)
+{
+ __ptep_modify_prot_commit(vma, addr, ptep, pte);
+}
+#endif /* __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION */
+#endif /* CONFIG_MMU */
+
+/*
+ * No-op macros that just return the current protection value. Defined here
+ * because these macros can be used used even if CONFIG_MMU is not defined.
+ */
+#ifndef pgprot_encrypted
+#define pgprot_encrypted(prot) (prot)
+#endif
+
+#ifndef pgprot_decrypted
+#define pgprot_decrypted(prot) (prot)
+#endif
+
+/*
+ * A facility to provide lazy MMU batching. This allows PTE updates and
+ * page invalidations to be delayed until a call to leave lazy MMU mode
+ * is issued. Some architectures may benefit from doing this, and it is
+ * beneficial for both shadow and direct mode hypervisors, which may batch
+ * the PTE updates which happen during this window. Note that using this
+ * interface requires that read hazards be removed from the code. A read
+ * hazard could result in the direct mode hypervisor case, since the actual
+ * write to the page tables may not yet have taken place, so reads though
+ * a raw PTE pointer after it has been modified are not guaranteed to be
+ * up to date. This mode can only be entered and left under the protection of
+ * the page table locks for all page tables which may be modified. In the UP
+ * case, this is required so that preemption is disabled, and in the SMP case,
+ * it must synchronize the delayed page table writes properly on other CPUs.
+ */
+#ifndef __HAVE_ARCH_ENTER_LAZY_MMU_MODE
+#define arch_enter_lazy_mmu_mode() do {} while (0)
+#define arch_leave_lazy_mmu_mode() do {} while (0)
+#define arch_flush_lazy_mmu_mode() do {} while (0)
+#endif
+
+/*
+ * A facility to provide batching of the reload of page tables and
+ * other process state with the actual context switch code for
+ * paravirtualized guests. By convention, only one of the batched
+ * update (lazy) modes (CPU, MMU) should be active at any given time,
+ * entry should never be nested, and entry and exits should always be
+ * paired. This is for sanity of maintaining and reasoning about the
+ * kernel code. In this case, the exit (end of the context switch) is
+ * in architecture-specific code, and so doesn't need a generic
+ * definition.
+ */
+#ifndef __HAVE_ARCH_START_CONTEXT_SWITCH
+#define arch_start_context_switch(prev) do {} while (0)
+#endif
+
+#ifdef CONFIG_HAVE_ARCH_SOFT_DIRTY
+#ifndef CONFIG_ARCH_ENABLE_THP_MIGRATION
+static inline pmd_t pmd_swp_mksoft_dirty(pmd_t pmd)
+{
+ return pmd;
+}
+
+static inline int pmd_swp_soft_dirty(pmd_t pmd)
+{
+ return 0;
+}
+
+static inline pmd_t pmd_swp_clear_soft_dirty(pmd_t pmd)
+{
+ return pmd;
+}
+#endif
+#else /* !CONFIG_HAVE_ARCH_SOFT_DIRTY */
+static inline int pte_soft_dirty(pte_t pte)
+{
+ return 0;
+}
+
+static inline int pmd_soft_dirty(pmd_t pmd)
+{
+ return 0;
+}
+
+static inline pte_t pte_mksoft_dirty(pte_t pte)
+{
+ return pte;
+}
+
+static inline pmd_t pmd_mksoft_dirty(pmd_t pmd)
+{
+ return pmd;
+}
+
+static inline pte_t pte_clear_soft_dirty(pte_t pte)
+{
+ return pte;
+}
+
+static inline pmd_t pmd_clear_soft_dirty(pmd_t pmd)
+{
+ return pmd;
+}
+
+static inline pte_t pte_swp_mksoft_dirty(pte_t pte)
+{
+ return pte;
+}
+
+static inline int pte_swp_soft_dirty(pte_t pte)
+{
+ return 0;
+}
+
+static inline pte_t pte_swp_clear_soft_dirty(pte_t pte)
+{
+ return pte;
+}
+
+static inline pmd_t pmd_swp_mksoft_dirty(pmd_t pmd)
+{
+ return pmd;
+}
+
+static inline int pmd_swp_soft_dirty(pmd_t pmd)
+{
+ return 0;
+}
+
+static inline pmd_t pmd_swp_clear_soft_dirty(pmd_t pmd)
+{
+ return pmd;
+}
+#endif
+
+#ifndef __HAVE_PFNMAP_TRACKING
+/*
+ * Interfaces that can be used by architecture code to keep track of
+ * memory type of pfn mappings specified by the remap_pfn_range,
+ * vmf_insert_pfn.
+ */
+
+/*
+ * track_pfn_remap is called when a _new_ pfn mapping is being established
+ * by remap_pfn_range() for physical range indicated by pfn and size.
+ */
+static inline int track_pfn_remap(struct vm_area_struct *vma, pgprot_t *prot,
+ unsigned long pfn, unsigned long addr,
+ unsigned long size)
+{
+ return 0;
+}
+
+/*
+ * track_pfn_insert is called when a _new_ single pfn is established
+ * by vmf_insert_pfn().
+ */
+static inline void track_pfn_insert(struct vm_area_struct *vma, pgprot_t *prot,
+ pfn_t pfn)
+{
+}
+
+/*
+ * track_pfn_copy is called when vma that is covering the pfnmap gets
+ * copied through copy_page_range().
+ */
+static inline int track_pfn_copy(struct vm_area_struct *vma)
+{
+ return 0;
+}
+
+/*
+ * untrack_pfn is called while unmapping a pfnmap for a region.
+ * untrack can be called for a specific region indicated by pfn and size or
+ * can be for the entire vma (in which case pfn, size are zero).
+ */
+static inline void untrack_pfn(struct vm_area_struct *vma,
+ unsigned long pfn, unsigned long size)
+{
+}
+
+/*
+ * untrack_pfn_moved is called while mremapping a pfnmap for a new region.
+ */
+static inline void untrack_pfn_moved(struct vm_area_struct *vma)
+{
+}
+#else
+extern int track_pfn_remap(struct vm_area_struct *vma, pgprot_t *prot,
+ unsigned long pfn, unsigned long addr,
+ unsigned long size);
+extern void track_pfn_insert(struct vm_area_struct *vma, pgprot_t *prot,
+ pfn_t pfn);
+extern int track_pfn_copy(struct vm_area_struct *vma);
+extern void untrack_pfn(struct vm_area_struct *vma, unsigned long pfn,
+ unsigned long size);
+extern void untrack_pfn_moved(struct vm_area_struct *vma);
+#endif
+
+#ifdef __HAVE_COLOR_ZERO_PAGE
+static inline int is_zero_pfn(unsigned long pfn)
+{
+ extern unsigned long zero_pfn;
+ unsigned long offset_from_zero_pfn = pfn - zero_pfn;
+ return offset_from_zero_pfn <= (zero_page_mask >> PAGE_SHIFT);
+}
+
+#define my_zero_pfn(addr) page_to_pfn(ZERO_PAGE(addr))
+
+#else
+static inline int is_zero_pfn(unsigned long pfn)
+{
+ extern unsigned long zero_pfn;
+ return pfn == zero_pfn;
+}
+
+static inline unsigned long my_zero_pfn(unsigned long addr)
+{
+ extern unsigned long zero_pfn;
+ return zero_pfn;
+}
+#endif
+
+#ifdef CONFIG_MMU
+
+#ifndef CONFIG_TRANSPARENT_HUGEPAGE
+static inline int pmd_trans_huge(pmd_t pmd)
+{
+ return 0;
+}
+#ifndef pmd_write
+static inline int pmd_write(pmd_t pmd)
+{
+ BUG();
+ return 0;
+}
+#endif /* pmd_write */
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
+
+#ifndef pud_write
+static inline int pud_write(pud_t pud)
+{
+ BUG();
+ return 0;
+}
+#endif /* pud_write */
+
+#if !defined(CONFIG_ARCH_HAS_PTE_DEVMAP) || !defined(CONFIG_TRANSPARENT_HUGEPAGE)
+static inline int pmd_devmap(pmd_t pmd)
+{
+ return 0;
+}
+static inline int pud_devmap(pud_t pud)
+{
+ return 0;
+}
+static inline int pgd_devmap(pgd_t pgd)
+{
+ return 0;
+}
+#endif
+
+#if !defined(CONFIG_TRANSPARENT_HUGEPAGE) || \
+ (defined(CONFIG_TRANSPARENT_HUGEPAGE) && \
+ !defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD))
+static inline int pud_trans_huge(pud_t pud)
+{
+ return 0;
+}
+#endif
+
+/* See pmd_none_or_trans_huge_or_clear_bad for discussion. */
+static inline int pud_none_or_trans_huge_or_dev_or_clear_bad(pud_t *pud)
+{
+ pud_t pudval = READ_ONCE(*pud);
+
+ if (pud_none(pudval) || pud_trans_huge(pudval) || pud_devmap(pudval))
+ return 1;
+ if (unlikely(pud_bad(pudval))) {
+ pud_clear_bad(pud);
+ return 1;
+ }
+ return 0;
+}
+
+/* See pmd_trans_unstable for discussion. */
+static inline int pud_trans_unstable(pud_t *pud)
+{
+#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && \
+ defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD)
+ return pud_none_or_trans_huge_or_dev_or_clear_bad(pud);
+#else
+ return 0;
+#endif
+}
+
+#ifndef pmd_read_atomic
+static inline pmd_t pmd_read_atomic(pmd_t *pmdp)
+{
+ /*
+ * Depend on compiler for an atomic pmd read. NOTE: this is
+ * only going to work, if the pmdval_t isn't larger than
+ * an unsigned long.
+ */
+ return *pmdp;
+}
+#endif
+
+#ifndef arch_needs_pgtable_deposit
+#define arch_needs_pgtable_deposit() (false)
+#endif
+/*
+ * This function is meant to be used by sites walking pagetables with
+ * the mmap_sem hold in read mode to protect against MADV_DONTNEED and
+ * transhuge page faults. MADV_DONTNEED can convert a transhuge pmd
+ * into a null pmd and the transhuge page fault can convert a null pmd
+ * into an hugepmd or into a regular pmd (if the hugepage allocation
+ * fails). While holding the mmap_sem in read mode the pmd becomes
+ * stable and stops changing under us only if it's not null and not a
+ * transhuge pmd. When those races occurs and this function makes a
+ * difference vs the standard pmd_none_or_clear_bad, the result is
+ * undefined so behaving like if the pmd was none is safe (because it
+ * can return none anyway). The compiler level barrier() is critically
+ * important to compute the two checks atomically on the same pmdval.
+ *
+ * For 32bit kernels with a 64bit large pmd_t this automatically takes
+ * care of reading the pmd atomically to avoid SMP race conditions
+ * against pmd_populate() when the mmap_sem is hold for reading by the
+ * caller (a special atomic read not done by "gcc" as in the generic
+ * version above, is also needed when THP is disabled because the page
+ * fault can populate the pmd from under us).
+ */
+static inline int pmd_none_or_trans_huge_or_clear_bad(pmd_t *pmd)
+{
+ pmd_t pmdval = pmd_read_atomic(pmd);
+ /*
+ * The barrier will stabilize the pmdval in a register or on
+ * the stack so that it will stop changing under the code.
+ *
+ * When CONFIG_TRANSPARENT_HUGEPAGE=y on x86 32bit PAE,
+ * pmd_read_atomic is allowed to return a not atomic pmdval
+ * (for example pointing to an hugepage that has never been
+ * mapped in the pmd). The below checks will only care about
+ * the low part of the pmd with 32bit PAE x86 anyway, with the
+ * exception of pmd_none(). So the important thing is that if
+ * the low part of the pmd is found null, the high part will
+ * be also null or the pmd_none() check below would be
+ * confused.
+ */
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+ barrier();
+#endif
+ /*
+ * !pmd_present() checks for pmd migration entries
+ *
+ * The complete check uses is_pmd_migration_entry() in linux/swapops.h
+ * But using that requires moving current function and pmd_trans_unstable()
+ * to linux/swapops.h to resovle dependency, which is too much code move.
+ *
+ * !pmd_present() is equivalent to is_pmd_migration_entry() currently,
+ * because !pmd_present() pages can only be under migration not swapped
+ * out.
+ *
+ * pmd_none() is preseved for future condition checks on pmd migration
+ * entries and not confusing with this function name, although it is
+ * redundant with !pmd_present().
+ */
+ if (pmd_none(pmdval) || pmd_trans_huge(pmdval) ||
+ (IS_ENABLED(CONFIG_ARCH_ENABLE_THP_MIGRATION) && !pmd_present(pmdval)))
+ return 1;
+ if (unlikely(pmd_bad(pmdval))) {
+ pmd_clear_bad(pmd);
+ return 1;
+ }
+ return 0;
+}
+
+/*
+ * This is a noop if Transparent Hugepage Support is not built into
+ * the kernel. Otherwise it is equivalent to
+ * pmd_none_or_trans_huge_or_clear_bad(), and shall only be called in
+ * places that already verified the pmd is not none and they want to
+ * walk ptes while holding the mmap sem in read mode (write mode don't
+ * need this). If THP is not enabled, the pmd can't go away under the
+ * code even if MADV_DONTNEED runs, but if THP is enabled we need to
+ * run a pmd_trans_unstable before walking the ptes after
+ * split_huge_pmd returns (because it may have run when the pmd become
+ * null, but then a page fault can map in a THP and not a regular page).
+ */
+static inline int pmd_trans_unstable(pmd_t *pmd)
+{
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+ return pmd_none_or_trans_huge_or_clear_bad(pmd);
+#else
+ return 0;
+#endif
+}
+
+#ifndef CONFIG_NUMA_BALANCING
+/*
+ * Technically a PTE can be PROTNONE even when not doing NUMA balancing but
+ * the only case the kernel cares is for NUMA balancing and is only ever set
+ * when the VMA is accessible. For PROT_NONE VMAs, the PTEs are not marked
+ * _PAGE_PROTNONE so by by default, implement the helper as "always no". It
+ * is the responsibility of the caller to distinguish between PROT_NONE
+ * protections and NUMA hinting fault protections.
+ */
+static inline int pte_protnone(pte_t pte)
+{
+ return 0;
+}
+
+static inline int pmd_protnone(pmd_t pmd)
+{
+ return 0;
+}
+#endif /* CONFIG_NUMA_BALANCING */
+
+#endif /* CONFIG_MMU */
+
+#ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
+
+#ifndef __PAGETABLE_P4D_FOLDED
+int p4d_set_huge(p4d_t *p4d, phys_addr_t addr, pgprot_t prot);
+int p4d_clear_huge(p4d_t *p4d);
+#else
+static inline int p4d_set_huge(p4d_t *p4d, phys_addr_t addr, pgprot_t prot)
+{
+ return 0;
+}
+static inline int p4d_clear_huge(p4d_t *p4d)
+{
+ return 0;
+}
+#endif /* !__PAGETABLE_P4D_FOLDED */
+
+int pud_set_huge(pud_t *pud, phys_addr_t addr, pgprot_t prot);
+int pmd_set_huge(pmd_t *pmd, phys_addr_t addr, pgprot_t prot);
+int pud_clear_huge(pud_t *pud);
+int pmd_clear_huge(pmd_t *pmd);
+int p4d_free_pud_page(p4d_t *p4d, unsigned long addr);
+int pud_free_pmd_page(pud_t *pud, unsigned long addr);
+int pmd_free_pte_page(pmd_t *pmd, unsigned long addr);
+#else /* !CONFIG_HAVE_ARCH_HUGE_VMAP */
+static inline int p4d_set_huge(p4d_t *p4d, phys_addr_t addr, pgprot_t prot)
+{
+ return 0;
+}
+static inline int pud_set_huge(pud_t *pud, phys_addr_t addr, pgprot_t prot)
+{
+ return 0;
+}
+static inline int pmd_set_huge(pmd_t *pmd, phys_addr_t addr, pgprot_t prot)
+{
+ return 0;
+}
+static inline int p4d_clear_huge(p4d_t *p4d)
+{
+ return 0;
+}
+static inline int pud_clear_huge(pud_t *pud)
+{
+ return 0;
+}
+static inline int pmd_clear_huge(pmd_t *pmd)
+{
+ return 0;
+}
+static inline int p4d_free_pud_page(p4d_t *p4d, unsigned long addr)
+{
+ return 0;
+}
+static inline int pud_free_pmd_page(pud_t *pud, unsigned long addr)
+{
+ return 0;
+}
+static inline int pmd_free_pte_page(pmd_t *pmd, unsigned long addr)
+{
+ return 0;
+}
+#endif /* CONFIG_HAVE_ARCH_HUGE_VMAP */
+
+#ifndef __HAVE_ARCH_FLUSH_PMD_TLB_RANGE
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+/*
+ * ARCHes with special requirements for evicting THP backing TLB entries can
+ * implement this. Otherwise also, it can help optimize normal TLB flush in
+ * THP regime. stock flush_tlb_range() typically has optimization to nuke the
+ * entire TLB TLB if flush span is greater than a threshold, which will
+ * likely be true for a single huge page. Thus a single thp flush will
+ * invalidate the entire TLB which is not desitable.
+ * e.g. see arch/arc: flush_pmd_tlb_range
+ */
+#define flush_pmd_tlb_range(vma, addr, end) flush_tlb_range(vma, addr, end)
+#define flush_pud_tlb_range(vma, addr, end) flush_tlb_range(vma, addr, end)
+#else
+#define flush_pmd_tlb_range(vma, addr, end) BUILD_BUG()
+#define flush_pud_tlb_range(vma, addr, end) BUILD_BUG()
+#endif
+#endif
+
+struct file;
+int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn,
+ unsigned long size, pgprot_t *vma_prot);
+
+#ifndef CONFIG_X86_ESPFIX64
+static inline void init_espfix_bsp(void) { }
+#endif
+
+extern void __init pgtable_cache_init(void);
+
+#ifndef __HAVE_ARCH_PFN_MODIFY_ALLOWED
+static inline bool pfn_modify_allowed(unsigned long pfn, pgprot_t prot)
+{
+ return true;
+}
+
+static inline bool arch_has_pfn_modify_check(void)
+{
+ return false;
+}
+#endif /* !_HAVE_ARCH_PFN_MODIFY_ALLOWED */
+
+/*
+ * Architecture PAGE_KERNEL_* fallbacks
+ *
+ * Some architectures don't define certain PAGE_KERNEL_* flags. This is either
+ * because they really don't support them, or the port needs to be updated to
+ * reflect the required functionality. Below are a set of relatively safe
+ * fallbacks, as best effort, which we can count on in lieu of the architectures
+ * not defining them on their own yet.
+ */
+
+#ifndef PAGE_KERNEL_RO
+# define PAGE_KERNEL_RO PAGE_KERNEL
+#endif
+
+#ifndef PAGE_KERNEL_EXEC
+# define PAGE_KERNEL_EXEC PAGE_KERNEL
+#endif
+
+/*
+ * Page Table Modification bits for pgtbl_mod_mask.
+ *
+ * These are used by the p?d_alloc_track*() set of functions an in the generic
+ * vmalloc/ioremap code to track at which page-table levels entries have been
+ * modified. Based on that the code can better decide when vmalloc and ioremap
+ * mapping changes need to be synchronized to other page-tables in the system.
+ */
+#define __PGTBL_PGD_MODIFIED 0
+#define __PGTBL_P4D_MODIFIED 1
+#define __PGTBL_PUD_MODIFIED 2
+#define __PGTBL_PMD_MODIFIED 3
+#define __PGTBL_PTE_MODIFIED 4
+
+#define PGTBL_PGD_MODIFIED BIT(__PGTBL_PGD_MODIFIED)
+#define PGTBL_P4D_MODIFIED BIT(__PGTBL_P4D_MODIFIED)
+#define PGTBL_PUD_MODIFIED BIT(__PGTBL_PUD_MODIFIED)
+#define PGTBL_PMD_MODIFIED BIT(__PGTBL_PMD_MODIFIED)
+#define PGTBL_PTE_MODIFIED BIT(__PGTBL_PTE_MODIFIED)
+
+/* Page-Table Modification Mask */
+typedef unsigned int pgtbl_mod_mask;
+
+#endif /* !__ASSEMBLY__ */
+
+#ifndef io_remap_pfn_range
+#define io_remap_pfn_range remap_pfn_range
+#endif
+
+#ifndef has_transparent_hugepage
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+#define has_transparent_hugepage() 1
+#else
+#define has_transparent_hugepage() 0
+#endif
+#endif
+
+/*
+ * On some architectures it depends on the mm if the p4d/pud or pmd
+ * layer of the page table hierarchy is folded or not.
+ */
+#ifndef mm_p4d_folded
+#define mm_p4d_folded(mm) __is_defined(__PAGETABLE_P4D_FOLDED)
+#endif
+
+#ifndef mm_pud_folded
+#define mm_pud_folded(mm) __is_defined(__PAGETABLE_PUD_FOLDED)
+#endif
+
+#ifndef mm_pmd_folded
+#define mm_pmd_folded(mm) __is_defined(__PAGETABLE_PMD_FOLDED)
+#endif
+
+/*
+ * p?d_leaf() - true if this entry is a final mapping to a physical address.
+ * This differs from p?d_huge() by the fact that they are always available (if
+ * the architecture supports large pages at the appropriate level) even
+ * if CONFIG_HUGETLB_PAGE is not defined.
+ * Only meaningful when called on a valid entry.
+ */
+#ifndef pgd_leaf
+#define pgd_leaf(x) 0
+#endif
+#ifndef p4d_leaf
+#define p4d_leaf(x) 0
+#endif
+#ifndef pud_leaf
+#define pud_leaf(x) 0
+#endif
+#ifndef pmd_leaf
+#define pmd_leaf(x) 0
+#endif
+
+#endif /* _LINUX_PGTABLE_H */