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Commit 0318e5ab authored by Kirill A. Shutemov's avatar Kirill A. Shutemov Committed by Ingo Molnar
Browse files

x86/mm/gup: Add 5-level paging support 



Extend get_user_pages_fast() to handle an additional page table level.

Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arch@vger.kernel.org
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20170313143309.16020-4-kirill.shutemov@linux.intel.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent e0c4f675

arch/x86/mm/gup.c

+27 −6
Original line number Diff line number Diff line
@@ -76,9 +76,9 @@ static void undo_dev_pagemap(int *nr, int nr_start, struct page **pages) 
}



/*

 * 'pteval' can come from a pte, pmd or pud.  We only check

 * 'pteval' can come from a pte, pmd, pud or p4d.  We only check

 * _PAGE_PRESENT, _PAGE_USER, and _PAGE_RW in here which are the

 * same value on all 3 types.

 * same value on all 4 types.

 */

static inline int pte_allows_gup(unsigned long pteval, int write)

{
@@ -295,13 +295,13 @@ static noinline int gup_huge_pud(pud_t pud, unsigned long addr, 
	return 1;

}



static int gup_pud_range(pgd_t pgd, unsigned long addr, unsigned long end,

static int gup_pud_range(p4d_t p4d, unsigned long addr, unsigned long end,

			int write, struct page **pages, int *nr)

{

	unsigned long next;

	pud_t *pudp;



	pudp = pud_offset(&pgd, addr);

	pudp = pud_offset(&p4d, addr);

	do {

		pud_t pud = *pudp;
@@ -320,6 +320,27 @@ static int gup_pud_range(pgd_t pgd, unsigned long addr, unsigned long end, 
	return 1;

}



static int gup_p4d_range(pgd_t pgd, unsigned long addr, unsigned long end,

			int write, struct page **pages, int *nr)

{

	unsigned long next;

	p4d_t *p4dp;



	p4dp = p4d_offset(&pgd, addr);

	do {

		p4d_t p4d = *p4dp;



		next = p4d_addr_end(addr, end);

		if (p4d_none(p4d))

			return 0;

		BUILD_BUG_ON(p4d_large(p4d));

		if (!gup_pud_range(p4d, addr, next, write, pages, nr))

			return 0;

	} while (p4dp++, addr = next, addr != end);



	return 1;

}



/*

 * Like get_user_pages_fast() except its IRQ-safe in that it won't fall

 * back to the regular GUP.
@@ -368,7 +389,7 @@ int __get_user_pages_fast(unsigned long start, int nr_pages, int write, 
		next = pgd_addr_end(addr, end);

		if (pgd_none(pgd))

			break;

		if (!gup_pud_range(pgd, addr, next, write, pages, &nr))

		if (!gup_p4d_range(pgd, addr, next, write, pages, &nr))

			break;

	} while (pgdp++, addr = next, addr != end);

	local_irq_restore(flags);
@@ -440,7 +461,7 @@ int get_user_pages_fast(unsigned long start, int nr_pages, int write, 
		next = pgd_addr_end(addr, end);

		if (pgd_none(pgd))

			goto slow;

		if (!gup_pud_range(pgd, addr, next, write, pages, &nr))

		if (!gup_p4d_range(pgd, addr, next, write, pages, &nr))

			goto slow;

	} while (pgdp++, addr = next, addr != end);

	local_irq_enable();