summaryrefslogtreecommitdiff
path: root/arch/powerpc/include/asm/book3s/64/hash-64k.h
diff options
context:
space:
mode:
Diffstat (limited to 'arch/powerpc/include/asm/book3s/64/hash-64k.h')
-rw-r--r--arch/powerpc/include/asm/book3s/64/hash-64k.h73
1 files changed, 50 insertions, 23 deletions
diff --git a/arch/powerpc/include/asm/book3s/64/hash-64k.h b/arch/powerpc/include/asm/book3s/64/hash-64k.h
index 8d40cf03cb67..338b7da468ce 100644
--- a/arch/powerpc/include/asm/book3s/64/hash-64k.h
+++ b/arch/powerpc/include/asm/book3s/64/hash-64k.h
@@ -13,21 +13,17 @@
*/
#define H_PAGE_COMBO _RPAGE_RPN0 /* this is a combo 4k page */
#define H_PAGE_4K_PFN _RPAGE_RPN1 /* PFN is for a single 4k page */
+#define H_PAGE_BUSY _RPAGE_RPN44 /* software: PTE & hash are busy */
+#define H_PAGE_HASHPTE _RPAGE_RPN43 /* PTE has associated HPTE */
+
/*
* We need to differentiate between explicit huge page and THP huge
* page, since THP huge page also need to track real subpage details
*/
#define H_PAGE_THP_HUGE H_PAGE_4K_PFN
-/*
- * Used to track subpage group valid if H_PAGE_COMBO is set
- * This overloads H_PAGE_F_GIX and H_PAGE_F_SECOND
- */
-#define H_PAGE_COMBO_VALID (H_PAGE_F_GIX | H_PAGE_F_SECOND)
-
/* PTE flags to conserve for HPTE identification */
-#define _PAGE_HPTEFLAGS (H_PAGE_BUSY | H_PAGE_F_SECOND | \
- H_PAGE_F_GIX | H_PAGE_HASHPTE | H_PAGE_COMBO)
+#define _PAGE_HPTEFLAGS (H_PAGE_BUSY | H_PAGE_HASHPTE | H_PAGE_COMBO)
/*
* we support 16 fragments per PTE page of 64K size.
*/
@@ -55,24 +51,57 @@ static inline real_pte_t __real_pte(pte_t pte, pte_t *ptep)
unsigned long *hidxp;
rpte.pte = pte;
- rpte.hidx = 0;
- if (pte_val(pte) & H_PAGE_COMBO) {
- /*
- * Make sure we order the hidx load against the H_PAGE_COMBO
- * check. The store side ordering is done in __hash_page_4K
- */
- smp_rmb();
- hidxp = (unsigned long *)(ptep + PTRS_PER_PTE);
- rpte.hidx = *hidxp;
- }
+
+ /*
+ * Ensure that we do not read the hidx before we read the PTE. Because
+ * the writer side is expected to finish writing the hidx first followed
+ * by the PTE, by using smp_wmb(). pte_set_hash_slot() ensures that.
+ */
+ smp_rmb();
+
+ hidxp = (unsigned long *)(ptep + PTRS_PER_PTE);
+ rpte.hidx = *hidxp;
return rpte;
}
+/*
+ * shift the hidx representation by one-modulo-0xf; i.e hidx 0 is respresented
+ * as 1, 1 as 2,... , and 0xf as 0. This convention lets us represent a
+ * invalid hidx 0xf with a 0x0 bit value. PTEs are anyway zero'd when
+ * allocated. We dont have to zero them gain; thus save on the initialization.
+ */
+#define HIDX_UNSHIFT_BY_ONE(x) ((x + 0xfUL) & 0xfUL) /* shift backward by one */
+#define HIDX_SHIFT_BY_ONE(x) ((x + 0x1UL) & 0xfUL) /* shift forward by one */
+#define HIDX_BITS(x, index) (x << (index << 2))
+#define BITS_TO_HIDX(x, index) ((x >> (index << 2)) & 0xfUL)
+#define INVALID_RPTE_HIDX 0x0UL
+
static inline unsigned long __rpte_to_hidx(real_pte_t rpte, unsigned long index)
{
- if ((pte_val(rpte.pte) & H_PAGE_COMBO))
- return (rpte.hidx >> (index<<2)) & 0xf;
- return (pte_val(rpte.pte) >> H_PAGE_F_GIX_SHIFT) & 0xf;
+ return HIDX_UNSHIFT_BY_ONE(BITS_TO_HIDX(rpte.hidx, index));
+}
+
+/*
+ * Commit the hidx and return PTE bits that needs to be modified. The caller is
+ * expected to modify the PTE bits accordingly and commit the PTE to memory.
+ */
+static inline unsigned long pte_set_hidx(pte_t *ptep, real_pte_t rpte,
+ unsigned int subpg_index, unsigned long hidx)
+{
+ unsigned long *hidxp = (unsigned long *)(ptep + PTRS_PER_PTE);
+
+ rpte.hidx &= ~HIDX_BITS(0xfUL, subpg_index);
+ *hidxp = rpte.hidx | HIDX_BITS(HIDX_SHIFT_BY_ONE(hidx), subpg_index);
+
+ /*
+ * Anyone reading PTE must ensure hidx bits are read after reading the
+ * PTE by using the read-side barrier smp_rmb(). __real_pte() can be
+ * used for that.
+ */
+ smp_wmb();
+
+ /* No PTE bits to be modified, return 0x0UL */
+ return 0x0UL;
}
#define __rpte_to_pte(r) ((r).pte)
@@ -203,8 +232,6 @@ extern pmd_t hash__pmdp_collapse_flush(struct vm_area_struct *vma,
extern void hash__pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
pgtable_t pgtable);
extern pgtable_t hash__pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp);
-extern void hash__pmdp_huge_split_prepare(struct vm_area_struct *vma,
- unsigned long address, pmd_t *pmdp);
extern pmd_t hash__pmdp_huge_get_and_clear(struct mm_struct *mm,
unsigned long addr, pmd_t *pmdp);
extern int hash__has_transparent_hugepage(void);