arm64: hugetlb: add support for PTE contiguous bit
The arm64 MMU supports a Contiguous bit which is a hint that the TTE
is one of a set of contiguous entries which can be cached in a single
TLB entry. Supporting this bit adds new intermediate huge page sizes.
The set of huge page sizes available depends on the base page size.
Without using contiguous pages the huge page sizes are as follows.
4KB: 2MB 1GB
64KB: 512MB
With a 4KB granule, the contiguous bit groups together sets of 16 pages
and with a 64KB granule it groups sets of 32 pages. This enables two new
huge page sizes in each case, so that the full set of available sizes
is as follows.
4KB: 64KB 2MB 32MB 1GB
64KB: 2MB 512MB 16GB
If a 16KB granule is used then the contiguous bit groups 128 pages
at the PTE level and 32 pages at the PMD level.
If the base page size is set to 64KB then 2MB pages are enabled by
default. It is possible in the future to make 2MB the default huge
page size for both 4KB and 64KB granules.
Reviewed-by: Chris Metcalf <cmetcalf@ezchip.com>
Reviewed-by: Steve Capper <steve.capper@linaro.org>
Signed-off-by: David Woods <dwoods@ezchip.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 450b355..35a318c 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -227,7 +227,8 @@
static inline pte_t pte_mkcont(pte_t pte)
{
- return set_pte_bit(pte, __pgprot(PTE_CONT));
+ pte = set_pte_bit(pte, __pgprot(PTE_CONT));
+ return set_pte_bit(pte, __pgprot(PTE_TYPE_PAGE));
}
static inline pte_t pte_mknoncont(pte_t pte)
@@ -235,6 +236,11 @@
return clear_pte_bit(pte, __pgprot(PTE_CONT));
}
+static inline pmd_t pmd_mkcont(pmd_t pmd)
+{
+ return __pmd(pmd_val(pmd) | PMD_SECT_CONT);
+}
+
static inline void set_pte(pte_t *ptep, pte_t pte)
{
*ptep = pte;
@@ -304,7 +310,7 @@
/*
* Hugetlb definitions.
*/
-#define HUGE_MAX_HSTATE 2
+#define HUGE_MAX_HSTATE 4
#define HPAGE_SHIFT PMD_SHIFT
#define HPAGE_SIZE (_AC(1, UL) << HPAGE_SHIFT)
#define HPAGE_MASK (~(HPAGE_SIZE - 1))