* [PATCH 2/2] powerpc/mm/subpage: Fix subpage protection with 4K hpte config
2016-05-02 10:51 [PATCH 1/2] powerpc/mm/subpage: Init user psize correctly Aneesh Kumar K.V
@ 2016-05-02 10:51 ` Aneesh Kumar K.V
0 siblings, 0 replies; 2+ messages in thread
From: Aneesh Kumar K.V @ 2016-05-02 10:51 UTC (permalink / raw)
To: benh, paulus, mpe; +Cc: linuxppc-dev, Aneesh Kumar K.V
With Linux page size of 64K and hardware only supporting 4K hpte, if
we use subpage protection, we always fail for the subpage 0 as shown
below (using the selftest subpage_prot test).
520175565: (4520111850): Failed at 0x0x3fffad4b0000 (p=13,sp=0,w=0), want=fault, got=pass !
4520890210: (4520826495): Failed at 0x0x3fffad5b0000 (p=29,sp=0,w=0), want=fault, got=pass !
4521574251: (4521510536): Failed at 0x0x3fffad6b0000 (p=45,sp=0,w=0), want=fault, got=pass !
4522258324: (4522194609): Failed at 0x0x3fffad7b0000 (p=61,sp=0,w=0), want=fault, got=pass !
This is because hash preload wrongly insert the hpte entry for subpage 0
without looking at the subapge protection information. Don't do hash
page table entry preload if we have subpage protection configured for
that range.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
arch/powerpc/mm/hash_utils_64.c | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index 262082e51db1..b5a454415215 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -1329,15 +1329,26 @@ void hash_preload(struct mm_struct *mm, unsigned long ea,
unsigned long vsid;
pgd_t *pgdir;
pte_t *ptep;
+ int psize;
unsigned long flags;
int rc, ssize, update_flags = 0;
BUG_ON(REGION_ID(ea) != USER_REGION_ID);
#ifdef CONFIG_PPC_MM_SLICES
- /* We only prefault standard pages for now */
- if (unlikely(get_slice_psize(mm, ea) != mm->context.user_psize))
+ psize = get_slice_psize(mm, ea);
+ /*
+ * We only prefault standard pages
+ */
+ if (psize != mm->context.user_psize)
return;
+#ifdef CONFIG_PPC_64K_PAGES
+ /*
+ * Don't prefault is subpage protection is enabled for that ea
+ */
+ if ((psize == MMU_PAGE_4K) && subpage_protection(mm, ea))
+ return;
+#endif
#endif
DBG_LOW("hash_preload(mm=%p, mm->pgdir=%p, ea=%016lx, access=%lx,"
--
2.7.4
^ permalink raw reply related [flat|nested] 2+ messages in thread
* [PATCH 2/2] powerpc/mm/subpage: Fix subpage protection with 4K hpte config
@ 2016-05-02 10:56 Aneesh Kumar K.V
0 siblings, 0 replies; 2+ messages in thread
From: Aneesh Kumar K.V @ 2016-05-02 10:56 UTC (permalink / raw)
To: benh, paulus, mpe; +Cc: linuxppc-dev, Aneesh Kumar K.V
With Linux page size of 64K and hardware only supporting 4K hpte, if
we use subpage protection, we always fail for the subpage 0 as shown
below (using the selftest subpage_prot test).
520175565: (4520111850): Failed at 0x0x3fffad4b0000 (p=13,sp=0,w=0), want=fault, got=pass !
4520890210: (4520826495): Failed at 0x0x3fffad5b0000 (p=29,sp=0,w=0), want=fault, got=pass !
4521574251: (4521510536): Failed at 0x0x3fffad6b0000 (p=45,sp=0,w=0), want=fault, got=pass !
4522258324: (4522194609): Failed at 0x0x3fffad7b0000 (p=61,sp=0,w=0), want=fault, got=pass !
This is because hash preload wrongly insert the hpte entry for subpage 0
without looking at the subapge protection information. Don't do hash
page table entry preload if we have subpage protection configured for
that range.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
arch/powerpc/mm/hash_utils_64.c | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index 262082e51db1..b5a454415215 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -1329,15 +1329,26 @@ void hash_preload(struct mm_struct *mm, unsigned long ea,
unsigned long vsid;
pgd_t *pgdir;
pte_t *ptep;
+ int psize;
unsigned long flags;
int rc, ssize, update_flags = 0;
BUG_ON(REGION_ID(ea) != USER_REGION_ID);
#ifdef CONFIG_PPC_MM_SLICES
- /* We only prefault standard pages for now */
- if (unlikely(get_slice_psize(mm, ea) != mm->context.user_psize))
+ psize = get_slice_psize(mm, ea);
+ /*
+ * We only prefault standard pages
+ */
+ if (psize != mm->context.user_psize)
return;
+#ifdef CONFIG_PPC_64K_PAGES
+ /*
+ * Don't prefault is subpage protection is enabled for that ea
+ */
+ if ((psize == MMU_PAGE_4K) && subpage_protection(mm, ea))
+ return;
+#endif
#endif
DBG_LOW("hash_preload(mm=%p, mm->pgdir=%p, ea=%016lx, access=%lx,"
--
2.7.4
^ permalink raw reply related [flat|nested] 2+ messages in thread
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