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>

diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 2c44c07..1441368 100644 (file)
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -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);