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Groups > linux.kernel > #1593386

[PATCHv4 07/33] mm: introduce __p4d_alloc()

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For full 5-level paging we need a helper to allocate p4d page table.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
 mm/memory.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/mm/memory.c b/mm/memory.c
index 7f1c2163b3ce..235ba51b2fbf 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3906,6 +3906,29 @@ int handle_mm_fault(struct vm_area_struct *vma, unsigned long address,
 }
 EXPORT_SYMBOL_GPL(handle_mm_fault);
 
+#ifndef __PAGETABLE_P4D_FOLDED
+/*
+ * Allocate p4d page table.
+ * We've already handled the fast-path in-line.
+ */
+int __p4d_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
+{
+	p4d_t *new = p4d_alloc_one(mm, address);
+	if (!new)
+		return -ENOMEM;
+
+	smp_wmb(); /* See comment in __pte_alloc */
+
+	spin_lock(&mm->page_table_lock);
+	if (pgd_present(*pgd))		/* Another has populated it */
+		p4d_free(mm, new);
+	else
+		pgd_populate(mm, pgd, new);
+	spin_unlock(&mm->page_table_lock);
+	return 0;
+}
+#endif /* __PAGETABLE_P4D_FOLDED */
+
 #ifndef __PAGETABLE_PUD_FOLDED
 /*
  * Allocate page upper directory.
-- 
2.11.0

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[PATCHv4 00/33] 5-level paging "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-03-06 15:10 +0100
  [PATCHv4 01/33] x86/cpufeature: Add 5-level paging detection "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-03-06 15:10 +0100
  [PATCHv4 14/33] x86/kexec: support p4d_t "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-03-06 15:10 +0100
  [PATCHv4 18/33] x86/xen: convert __xen_pgd_walk() and xen_cleanmfnmap() to support p4d "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-03-06 15:10 +0100
    Re: [PATCHv4 18/33] x86/xen: convert __xen_pgd_walk() and  xen_cleanmfnmap() to support p4d Boris Ostrovsky <boris.ostrovsky@oracle.com> - 2017-03-06 21:50 +0100
      Re: [PATCHv4 18/33] x86/xen: convert __xen_pgd_walk() and  xen_cleanmfnmap() to support p4d "Kirill A. Shutemov" <kirill@shutemov.name> - 2017-03-07 14:10 +0100
        Re: [PATCHv4 18/33] x86/xen: convert __xen_pgd_walk() and  xen_cleanmfnmap() to support p4d Boris Ostrovsky <boris.ostrovsky@oracle.com> - 2017-03-07 19:20 +0100
          Re: [Xen-devel] [PATCHv4 18/33] x86/xen: convert __xen_pgd_walk() and  xen_cleanmfnmap() to support p4d Andrew Cooper <andrew.cooper3@citrix.com> - 2017-03-07 19:30 +0100
            Re: [Xen-devel] [PATCHv4 18/33] x86/xen: convert __xen_pgd_walk() and  xen_cleanmfnmap() to support p4d Boris Ostrovsky <boris.ostrovsky@oracle.com> - 2017-03-07 20:30 +0100
  [PATCHv4 30/33] x86/mm: make kernel_physical_mapping_init() support 5-level paging "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-03-06 15:10 +0100
  [PATCHv4 21/33] x86/asm: remove __VIRTUAL_MASK_SHIFT==47 assert "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-03-06 15:10 +0100
  [PATCHv4 08/33] x86: basic changes into headers for 5-level paging "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-03-06 15:10 +0100
  [PATCHv4 16/33] x86/mm/pat: handle additional page table "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-03-06 15:10 +0100
  [PATCHv4 05/33] asm-generic: introduce <asm-generic/pgtable-nop4d.h> "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-03-06 15:10 +0100
  [PATCHv4 15/33] x86/efi: handle p4d in EFI pagetables "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-03-06 15:10 +0100
  [PATCHv4 19/33] x86: convert the rest of the code to support p4d_t "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-03-06 15:10 +0100
  [PATCHv4 20/33] x86: detect 5-level paging support "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-03-06 15:10 +0100
  [PATCHv4 07/33] mm: introduce __p4d_alloc() "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-03-06 15:10 +0100
  [PATCHv4 27/33] x86/espfix: support 5-level paging "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-03-06 15:10 +0100
  [PATCHv4 13/33] x86/power: support p4d_t in hibernate code "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-03-06 15:10 +0100
  [PATCHv4 02/33] asm-generic: introduce 5level-fixup.h "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-03-06 15:20 +0100
  Re: [PATCHv4 00/33] 5-level paging Linus Torvalds <torvalds@linux-foundation.org> - 2017-03-06 19:40 +0100
    Re: [PATCHv4 00/33] 5-level paging Thomas Gleixner <tglx@linutronix.de> - 2017-03-06 19:50 +0100
      Re: [PATCHv4 00/33] 5-level paging Linus Torvalds <torvalds@linux-foundation.org> - 2017-03-06 20:10 +0100
        Re: [PATCHv4 00/33] 5-level paging "Kirill A. Shutemov" <kirill@shutemov.name> - 2017-03-06 20:10 +0100
          Re: [PATCHv4 00/33] 5-level paging Linus Torvalds <torvalds@linux-foundation.org> - 2017-03-06 20:50 +0100
      Re: [PATCHv4 00/33] 5-level paging Stephen Rothwell <sfr@canb.auug.org.au> - 2017-03-07 02:30 +0100
        Re: [PATCHv4 00/33] 5-level paging Thomas Gleixner <tglx@linutronix.de> - 2017-03-07 11:20 +0100

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