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Subject[PATCH 19/31] x86/mm/pae: Populate valid user PGD entries
Date
From: Joerg Roedel <jroedel@suse.de>

Generic page-table code populates all non-leaf entries with
_KERNPG_TABLE bits set. This is fine for all paging modes
except PAE.

In PAE mode only a subset of the bits is allowed to be set.
Make sure we only set allowed bits by masking out the
reserved bits.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
arch/x86/include/asm/pgtable_types.h | 26 ++++++++++++++++++++++++--
1 file changed, 24 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h
index 3696398..5027470 100644
--- a/arch/x86/include/asm/pgtable_types.h
+++ b/arch/x86/include/asm/pgtable_types.h
@@ -50,6 +50,7 @@
#define _PAGE_GLOBAL (_AT(pteval_t, 1) << _PAGE_BIT_GLOBAL)
#define _PAGE_SOFTW1 (_AT(pteval_t, 1) << _PAGE_BIT_SOFTW1)
#define _PAGE_SOFTW2 (_AT(pteval_t, 1) << _PAGE_BIT_SOFTW2)
+#define _PAGE_SOFTW3 (_AT(pteval_t, 1) << _PAGE_BIT_SOFTW3)
#define _PAGE_PAT (_AT(pteval_t, 1) << _PAGE_BIT_PAT)
#define _PAGE_PAT_LARGE (_AT(pteval_t, 1) << _PAGE_BIT_PAT_LARGE)
#define _PAGE_SPECIAL (_AT(pteval_t, 1) << _PAGE_BIT_SPECIAL)
@@ -267,14 +268,35 @@ typedef struct pgprot { pgprotval_t pgprot; } pgprot_t;

typedef struct { pgdval_t pgd; } pgd_t;

+#ifdef CONFIG_X86_PAE
+
+/*
+ * PHYSICAL_PAGE_MASK might be non-constant when SME is compiled in, so we can't
+ * use it here.
+ */
+#define PGD_PAE_PHYS_MASK (((1ULL << __PHYSICAL_MASK_SHIFT)-1) & PAGE_MASK)
+
+/*
+ * PAE allows Base Address, P, PWT, PCD and AVL bits to be set in PGD entries.
+ * All other bits are Reserved MBZ
+ */
+#define PGD_ALLOWED_BITS (PGD_PAE_PHYS_MASK | _PAGE_PRESENT | \
+ _PAGE_PWT | _PAGE_PCD | \
+ _PAGE_SOFTW1 | _PAGE_SOFTW2 | _PAGE_SOFTW3 )
+
+#else
+/* No need to mask any bits for !PAE */
+#define PGD_ALLOWED_BITS (~0ULL)
+#endif
+
static inline pgd_t native_make_pgd(pgdval_t val)
{
- return (pgd_t) { val };
+ return (pgd_t) { val & PGD_ALLOWED_BITS };
}

static inline pgdval_t native_pgd_val(pgd_t pgd)
{
- return pgd.pgd;
+ return pgd.pgd & PGD_ALLOWED_BITS;
}

static inline pgdval_t pgd_flags(pgd_t pgd)
--
2.7.4
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