Commit 34437e67 authored Sep 17, 2015 by Toshi Kani Committed by Thomas Gleixner Sep 22, 2015

x86/mm: Fix slow_virt_to_phys() to handle large PAT bit



slow_virt_to_phys() calls lookup_address() to obtain *pte and
its level.  It then calls pte_pfn() to obtain a physical address
for any level.  However, this physical address is not correct
when the large PAT bit is set because pte_pfn() does not mask
the large PAT bit properly for PUD/PMD.

Fix slow_virt_to_phys() to use pud_pfn() and pmd_pfn() for 1GB
and 2MB mapping levels.

Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Juergen Gross <jgross@suse.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Konrad Wilk <konrad.wilk@oracle.com>
Cc: Robert Elliot <elliott@hpe.com>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/1442514264-12475-8-git-send-email-toshi.kani@hpe.com


Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

parent da25e628

arch/x86/mm/pageattr.c

+17 −7

Original line number	Diff line number	Diff line
		@@ -414,18 +414,28 @@ pmd_t *lookup_pmd_address(unsigned long address)
		phys_addr_t slow_virt_to_phys(void *__virt_addr)
		{
		unsigned long virt_addr = (unsigned long)__virt_addr;
		phys_addr_t phys_addr;
		unsigned long offset;
		unsigned long phys_addr, offset;
		enum pg_level level;
		unsigned long pmask;
		pte_t *pte;

		pte = lookup_address(virt_addr, &level);
		BUG_ON(!pte);
		pmask = page_level_mask(level);
		offset = virt_addr & ~pmask;
		phys_addr = (phys_addr_t)pte_pfn(*pte) << PAGE_SHIFT;
		return (phys_addr \| offset);

		switch (level) {
		case PG_LEVEL_1G:
		phys_addr = pud_pfn((pud_t )pte) << PAGE_SHIFT;
		offset = virt_addr & ~PUD_PAGE_MASK;
		break;
		case PG_LEVEL_2M:
		phys_addr = pmd_pfn((pmd_t )pte) << PAGE_SHIFT;
		offset = virt_addr & ~PMD_PAGE_MASK;
		break;
		default:
		phys_addr = pte_pfn(*pte) << PAGE_SHIFT;
		offset = virt_addr & ~PAGE_MASK;
		}

		return (phys_addr_t)(phys_addr \| offset);
		}
		EXPORT_SYMBOL_GPL(slow_virt_to_phys);

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