linux-kernel - [PATCH 3.16 001/305] x86/asm: Add pud/pmd mask interfaces to handle large PAT bit

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Message-ID: <lsq.1549201508.606689081@decadent.org.uk>
Date:   Sun, 03 Feb 2019 14:45:08 +0100
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org, Denis Kirjanov <kda@...ux-powerpc.org>,
        "Konrad Wilk" <konrad.wilk@...cle.com>,
        "H. Peter Anvin" <hpa@...or.com>,
        "Robert Elliot" <elliott@....com>,
        "Wenkuan Wang" <Wenkuan.Wang@...driver.com>,
        "Thomas Gleixner" <tglx@...utronix.de>,
        "Borislav Petkov" <bp@...en8.de>,
        "Toshi Kani" <toshi.kani@....com>, linux-mm@...ck.org,
        "Ingo Molnar" <mingo@...hat.com>, "Juergen Gross" <jgross@...e.com>
Subject: [PATCH 3.16 001/305] x86/asm: Add pud/pmd mask interfaces to
 handle large  PAT bit

3.16.63-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Toshi Kani <toshi.kani@....com>

commit 4be4c1fb9a754b100466ebaec50f825be0b2050b upstream.

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: Andrew Morton <akpm@...ux-foundation.org>
Cc: Juergen Gross <jgross@...e.com>
Cc: H. Peter Anvin <hpa@...or.com>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Konrad Wilk <konrad.wilk@...cle.com>
Cc: Robert Elliot <elliott@....com>
Cc: linux-mm@...ck.org
Link: http://lkml.kernel.org/r/1442514264-12475-4-git-send-email-toshi.kani@hpe.com
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Signed-off-by: Wenkuan Wang <Wenkuan.Wang@...driver.com>
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 arch/x86/include/asm/pgtable_types.h | 36 ++++++++++++++++++++++++++++++++++--
 1 file changed, 34 insertions(+), 2 deletions(-)

--- a/arch/x86/include/asm/pgtable_types.h
+++ b/arch/x86/include/asm/pgtable_types.h
@@ -257,10 +257,10 @@
 
 #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;
@@ -329,11 +329,43 @@ static inline pmdval_t native_pmd_val(pm
 }
 #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;