From: "Aneesh Kumar K.V" <aneesh.ku...@linux.vnet.ibm.com>
We need to use smb_rmb when looking at hpte slot array. Otherwise we could
reorder the hpte_slot array load bfore even we marked the pmd trans huge.
Related smb_wmb()s is done in pgtable_trans_huge_deposit when we deposit
a pgtable.
Signed-off-by: Aneesh Kumar K.V <aneesh.ku...@linux.vnet.ibm.com>
---
arch/powerpc/include/asm/pgtable-ppc64.h | 15 +++++++++++++++
arch/powerpc/mm/hugepage-hash64.c | 6 +-----
arch/powerpc/mm/pgtable_64.c | 6 +-----
3 files changed, 17 insertions(+), 10 deletions(-)
diff --git a/arch/powerpc/include/asm/pgtable-ppc64.h
b/arch/powerpc/include/asm/pgtable-ppc64.h
index d046289..46db094 100644
--- a/arch/powerpc/include/asm/pgtable-ppc64.h
+++ b/arch/powerpc/include/asm/pgtable-ppc64.h
@@ -10,6 +10,7 @@
#else
#include <asm/pgtable-ppc64-4k.h>
#endif
+#include <asm/barrier.h>
#define FIRST_USER_ADDRESS 0
@@ -393,6 +394,20 @@ static inline void mark_hpte_slot_valid(unsigned char
*hpte_slot_array,
hpte_slot_array[index] = hidx << 4 | 0x1 << 3;
}
+static inline char *get_hpte_slot_array(pmd_t *pmdp)
+{
+ /*
+ * The hpte hindex is stored in the pgtable whose address is in the
+ * second half of the PMD
+ *
+ * Order this load with the test for pmd_trans_huge in the caller
+ */
+ smp_rmb();
+ return *(char **)(pmdp + PTRS_PER_PMD);
+
+
+}
+
extern void hpte_do_hugepage_flush(struct mm_struct *mm, unsigned long addr,
pmd_t *pmdp);
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
diff --git a/arch/powerpc/mm/hugepage-hash64.c
b/arch/powerpc/mm/hugepage-hash64.c
index e430766..c3ba3d5 100644
--- a/arch/powerpc/mm/hugepage-hash64.c
+++ b/arch/powerpc/mm/hugepage-hash64.c
@@ -84,11 +84,7 @@ int __hash_page_thp(unsigned long ea, unsigned long access,
unsigned long vsid,
vpn = hpt_vpn(ea, vsid, ssize);
hash = hpt_hash(vpn, shift, ssize);
- /*
- * The hpte hindex are stored in the pgtable whose address is in the
- * second half of the PMD
- */
- hpte_slot_array = *(char **)(pmdp + PTRS_PER_PMD);
+ hpte_slot_array = get_hpte_slot_array(pmdp);
valid = hpte_valid(hpte_slot_array, index);
if (valid) {
diff --git a/arch/powerpc/mm/pgtable_64.c b/arch/powerpc/mm/pgtable_64.c
index 8dd7c83..19d6734 100644
--- a/arch/powerpc/mm/pgtable_64.c
+++ b/arch/powerpc/mm/pgtable_64.c
@@ -701,11 +701,7 @@ void hpte_do_hugepage_flush(struct mm_struct *mm, unsigned
long addr,
* Flush all the hptes mapping this hugepage
*/
s_addr = addr & HPAGE_PMD_MASK;
- /*
- * The hpte hindex are stored in the pgtable whose address is in the
- * second half of the PMD
- */
- hpte_slot_array = *(char **)(pmdp + PTRS_PER_PMD);
+ hpte_slot_array = get_hpte_slot_array(pmdp);
/*
* IF we try to do a HUGE PTE update after a withdraw is done.
* we will find the below NULL. This happens when we do
--
1.8.1.2
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