On 07/09/2015 07:03 PM, Toshi Kani wrote:
The PAT bit gets relocated to bit 12 when PUD and PMD mappings are
used. This bit 12, however, is not covered by PTE_FLAGS_MASK, which
is corrently used for masking the flag bits for all cases.
Fix pud_flags() and pmd_flags() to cover the PAT bit, _PAGE_PAT_LARGE,
when they are used to map a large page with _PAGE_PSE set.
Signed-off-by: Toshi Kani <toshi.kani@xxxxxx>
Cc: Juergen Gross <jgross@xxxxxxxx>
Cc: Konrad Wilk <konrad.wilk@xxxxxxxxxx>
Cc: Robert Elliott <elliott@xxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/x86/include/asm/pgtable_types.h | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)
diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h
index 13f310b..caaf45c 100644
--- a/arch/x86/include/asm/pgtable_types.h
+++ b/arch/x86/include/asm/pgtable_types.h
@@ -212,9 +212,13 @@ enum page_cache_mode {
/* PTE_PFN_MASK extracts the PFN from a (pte|pmd|pud|pgd)val_t */
#define PTE_PFN_MASK ((pteval_t)PHYSICAL_PAGE_MASK)
-/* PTE_FLAGS_MASK extracts the flags from a (pte|pmd|pud|pgd)val_t */
+/* Extracts the flags from a (pte|pmd|pud|pgd)val_t of a 4KB page */
#define PTE_FLAGS_MASK (~PTE_PFN_MASK)
+/* Extracts the flags from a (pmd|pud)val_t of a (1GB|2MB) page */
+#define PMD_FLAGS_MASK_LARGE ((~PTE_PFN_MASK) | _PAGE_PAT_LARGE)
+#define PUD_FLAGS_MASK_LARGE ((~PTE_PFN_MASK) | _PAGE_PAT_LARGE)
+
typedef struct pgprot { pgprotval_t pgprot; } pgprot_t;
typedef struct { pgdval_t pgd; } pgd_t;
@@ -278,12 +282,18 @@ static inline pmdval_t native_pmd_val(pmd_t pmd)
static inline pudval_t pud_flags(pud_t pud)
{
- return native_pud_val(pud) & PTE_FLAGS_MASK;
+ if (native_pud_val(pud) & _PAGE_PSE)
+ return native_pud_val(pud) & PUD_FLAGS_MASK_LARGE;
+ else
+ return native_pud_val(pud) & PTE_FLAGS_MASK;
}
static inline pmdval_t pmd_flags(pmd_t pmd)
{
- return native_pmd_val(pmd) & PTE_FLAGS_MASK;
+ if (native_pmd_val(pmd) & _PAGE_PSE)
+ return native_pmd_val(pmd) & PMD_FLAGS_MASK_LARGE;
+ else
+ return native_pmd_val(pmd) & PTE_FLAGS_MASK;
}
Hmm, I think this covers only half of the problem. pud_pfn() and
pmd_pfn() will return wrong results for large pages with PAT bit
set as well.
I'd rather use something like:
static inline unsigned long pmd_pfn_mask(pmd_t pmd)
{
if (pmd_large(pmd))
return PMD_PAGE_MASK & PHYSICAL_PAGE_MASK;
else
return PTE_PFN_MASK;
}
static inline unsigned long pmd_flags_mask(pmd_t pmd)
{
if (pmd_large(pmd))
return ~(PMD_PAGE_MASK & PHYSICAL_PAGE_MASK);
else
return ~PTE_PFN_MASK;
}
static inline unsigned long pmd_pfn(pmd_t pmd)
{
return (pmd_val(pmd) & pmd_pfn_mask(pmd)) >> PAGE_SHIFT;
}
static inline pmdval_t pmd_flags(pmd_t pmd)
{
return native_pmd_val(pmd) & ~pmd_flags_mask(pmd);
}
Juergen
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