[Xen-devel] [PATCH 2/2] x86: add pte_set_flags/clear_flags for pte flag manipulation

[Jeremy Fitzhardinge <jeremy@xxxxxxxx>]

It's not necessary to deconstruct and reconstruct a pte every time its
flags are being updated.  Introduce pte_set_flags and pte_clear_flags
to set and clear flags in a pte.  This allows the flag manipulation
code to be inlined, and avoids calls via paravirt-ops.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@xxxxxxxxxx>
---
arch/x86/include/asm/pgtable.h |   38 ++++++++++++++++++++++++++------------
1 file changed, 26 insertions(+), 12 deletions(-)

===================================================================
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -240,64 +240,78 @@
                (_PAGE_PSE | _PAGE_PRESENT);
}

+static inline pte_t pte_set_flags(pte_t pte, pteval_t set)
+{
+       pteval_t v = native_pte_val(pte);
+
+       return native_make_pte(v | set);
+}
+
+static inline pte_t pte_clear_flags(pte_t pte, pteval_t clear)
+{
+       pteval_t v = native_pte_val(pte);
+
+       return native_make_pte(v & ~clear);
+}
+
static inline pte_t pte_mkclean(pte_t pte)
{
-       return __pte(pte_val(pte) & ~_PAGE_DIRTY);
+       return pte_clear_flags(pte, _PAGE_DIRTY);
}

static inline pte_t pte_mkold(pte_t pte)
{
-       return __pte(pte_val(pte) & ~_PAGE_ACCESSED);
+       return pte_clear_flags(pte, _PAGE_ACCESSED);
}

static inline pte_t pte_wrprotect(pte_t pte)
{
-       return __pte(pte_val(pte) & ~_PAGE_RW);
+       return pte_clear_flags(pte, _PAGE_RW);
}

static inline pte_t pte_mkexec(pte_t pte)
{
-       return __pte(pte_val(pte) & ~_PAGE_NX);
+       return pte_clear_flags(pte, _PAGE_NX);
}

static inline pte_t pte_mkdirty(pte_t pte)
{
-       return __pte(pte_val(pte) | _PAGE_DIRTY);
+       return pte_set_flags(pte, _PAGE_DIRTY);
}

static inline pte_t pte_mkyoung(pte_t pte)
{
-       return __pte(pte_val(pte) | _PAGE_ACCESSED);
+       return pte_set_flags(pte, _PAGE_ACCESSED);
}

static inline pte_t pte_mkwrite(pte_t pte)
{
-       return __pte(pte_val(pte) | _PAGE_RW);
+       return pte_set_flags(pte, _PAGE_RW);
}

static inline pte_t pte_mkhuge(pte_t pte)
{
-       return __pte(pte_val(pte) | _PAGE_PSE);
+       return pte_set_flags(pte, _PAGE_PSE);
}

static inline pte_t pte_clrhuge(pte_t pte)
{
-       return __pte(pte_val(pte) & ~_PAGE_PSE);
+       return pte_clear_flags(pte, _PAGE_PSE);
}

static inline pte_t pte_mkglobal(pte_t pte)
{
-       return __pte(pte_val(pte) | _PAGE_GLOBAL);
+       return pte_set_flags(pte, _PAGE_GLOBAL);
}

static inline pte_t pte_clrglobal(pte_t pte)
{
-       return __pte(pte_val(pte) & ~_PAGE_GLOBAL);
+       return pte_clear_flags(pte, _PAGE_GLOBAL);
}

static inline pte_t pte_mkspecial(pte_t pte)
{
-       return __pte(pte_val(pte) | _PAGE_SPECIAL);
+       return pte_set_flags(pte, _PAGE_SPECIAL);
}

extern pteval_t __supported_pte_mask;



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