linux-kernel - [PATCH v4 RESEND 3/11] x86/asm: Add pud/pmd mask interfaces to handle large PAT bit

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Date:	Thu, 17 Sep 2015 12:24:16 -0600
From:	Toshi Kani <toshi.kani@....com>
To:	hpa@...or.com, tglx@...utronix.de, mingo@...hat.com
Cc:	akpm@...ux-foundation.org, bp@...en8.de, linux-mm@...ck.org,
	linux-kernel@...r.kernel.org, x86@...nel.org, jgross@...e.com,
	konrad.wilk@...cle.com, elliott@....com,
	Toshi Kani <toshi.kani@....com>
Subject: [PATCH v4 RESEND 3/11] x86/asm: Add pud/pmd mask interfaces to handle large PAT bit

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 used for masking pfn and flags for all levels.

Add pud/pmd mask interfaces to handle pfn and flags properly by using
P?D_PAGE_MASK when PUD/PMD mappings are used, i.e. PSE bit is set.

Suggested-by: Juergen Gross <jgross@...e.com>
Signed-off-by: Toshi Kani <toshi.kani@....com>
Cc: Juergen Gross <jgross@...e.com>
Cc: Konrad Wilk <konrad.wilk@...cle.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: H. Peter Anvin <hpa@...or.com>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: Borislav Petkov <bp@...en8.de>
---
 arch/x86/include/asm/pgtable_types.h |   36 ++++++++++++++++++++++++++++++++--
 1 file changed, 34 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h
index 13f310b..7c8f797 100644
--- a/arch/x86/include/asm/pgtable_types.h
+++ b/arch/x86/include/asm/pgtable_types.h
@@ -209,10 +209,10 @@ enum page_cache_mode {
 
 #include <linux/types.h>
 
-/* PTE_PFN_MASK extracts the PFN from a (pte|pmd|pud|pgd)val_t */
+/* Extracts the PFN from a (pte|pmd|pud|pgd)val_t of a 4KB page */
 #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)
 
 typedef struct pgprot { pgprotval_t pgprot; } pgprot_t;
@@ -276,11 +276,43 @@ static inline pmdval_t native_pmd_val(pmd_t pmd)
 }
 #endif
 
+static inline pudval_t pud_pfn_mask(pud_t pud)
+{
+	if (native_pud_val(pud) & _PAGE_PSE)
+		return PUD_PAGE_MASK & PHYSICAL_PAGE_MASK;
+	else
+		return PTE_PFN_MASK;
+}
+
+static inline pudval_t pud_flags_mask(pud_t pud)
+{
+	if (native_pud_val(pud) & _PAGE_PSE)
+		return ~(PUD_PAGE_MASK & (pudval_t)PHYSICAL_PAGE_MASK);
+	else
+		return ~PTE_PFN_MASK;
+}
+
 static inline pudval_t pud_flags(pud_t pud)
 {
 	return native_pud_val(pud) & PTE_FLAGS_MASK;
 }
 
+static inline pmdval_t pmd_pfn_mask(pmd_t pmd)
+{
+	if (native_pmd_val(pmd) & _PAGE_PSE)
+		return PMD_PAGE_MASK & PHYSICAL_PAGE_MASK;
+	else
+		return PTE_PFN_MASK;
+}
+
+static inline pmdval_t pmd_flags_mask(pmd_t pmd)
+{
+	if (native_pmd_val(pmd) & _PAGE_PSE)
+		return ~(PMD_PAGE_MASK & (pmdval_t)PHYSICAL_PAGE_MASK);
+	else
+		return ~PTE_PFN_MASK;
+}
+
 static inline pmdval_t pmd_flags(pmd_t pmd)
 {
 	return native_pmd_val(pmd) & PTE_FLAGS_MASK;
--
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