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Diffstat (limited to 'arch/powerpc/mm/hash_utils_64.c')
-rw-r--r--arch/powerpc/mm/hash_utils_64.c53
1 files changed, 40 insertions, 13 deletions
diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index 98f262de558..09dffe6efa4 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -871,6 +871,18 @@ static inline int subpage_protection(struct mm_struct *mm, unsigned long ea)
}
#endif
+void hash_failure_debug(unsigned long ea, unsigned long access,
+ unsigned long vsid, unsigned long trap,
+ int ssize, int psize, unsigned long pte)
+{
+ if (!printk_ratelimit())
+ return;
+ pr_info("mm: Hashing failure ! EA=0x%lx access=0x%lx current=%s\n",
+ ea, access, current->comm);
+ pr_info(" trap=0x%lx vsid=0x%lx ssize=%d psize=%d pte=0x%lx\n",
+ trap, vsid, ssize, psize, pte);
+}
+
/* Result code is:
* 0 - handled
* 1 - normal page fault
@@ -955,6 +967,17 @@ int hash_page(unsigned long ea, unsigned long access, unsigned long trap)
return 1;
}
+ /* Add _PAGE_PRESENT to the required access perm */
+ access |= _PAGE_PRESENT;
+
+ /* Pre-check access permissions (will be re-checked atomically
+ * in __hash_page_XX but this pre-check is a fast path
+ */
+ if (access & ~pte_val(*ptep)) {
+ DBG_LOW(" no access !\n");
+ return 1;
+ }
+
#ifdef CONFIG_HUGETLB_PAGE
if (hugeshift)
return __hash_page_huge(ea, access, vsid, ptep, trap, local,
@@ -967,14 +990,6 @@ int hash_page(unsigned long ea, unsigned long access, unsigned long trap)
DBG_LOW(" i-pte: %016lx %016lx\n", pte_val(*ptep),
pte_val(*(ptep + PTRS_PER_PTE)));
#endif
- /* Pre-check access permissions (will be re-checked atomically
- * in __hash_page_XX but this pre-check is a fast path
- */
- if (access & ~pte_val(*ptep)) {
- DBG_LOW(" no access !\n");
- return 1;
- }
-
/* Do actual hashing */
#ifdef CONFIG_PPC_64K_PAGES
/* If _PAGE_4K_PFN is set, make sure this is a 4k segment */
@@ -1033,6 +1048,12 @@ int hash_page(unsigned long ea, unsigned long access, unsigned long trap)
local, ssize, spp);
}
+ /* Dump some info in case of hash insertion failure, they should
+ * never happen so it is really useful to know if/when they do
+ */
+ if (rc == -1)
+ hash_failure_debug(ea, access, vsid, trap, ssize, psize,
+ pte_val(*ptep));
#ifndef CONFIG_PPC_64K_PAGES
DBG_LOW(" o-pte: %016lx\n", pte_val(*ptep));
#else
@@ -1051,8 +1072,7 @@ void hash_preload(struct mm_struct *mm, unsigned long ea,
void *pgdir;
pte_t *ptep;
unsigned long flags;
- int local = 0;
- int ssize;
+ int rc, ssize, local = 0;
BUG_ON(REGION_ID(ea) != USER_REGION_ID);
@@ -1098,11 +1118,18 @@ void hash_preload(struct mm_struct *mm, unsigned long ea,
/* Hash it in */
#ifdef CONFIG_PPC_HAS_HASH_64K
if (mm->context.user_psize == MMU_PAGE_64K)
- __hash_page_64K(ea, access, vsid, ptep, trap, local, ssize);
+ rc = __hash_page_64K(ea, access, vsid, ptep, trap, local, ssize);
else
#endif /* CONFIG_PPC_HAS_HASH_64K */
- __hash_page_4K(ea, access, vsid, ptep, trap, local, ssize,
- subpage_protection(pgdir, ea));
+ rc = __hash_page_4K(ea, access, vsid, ptep, trap, local, ssize,
+ subpage_protection(pgdir, ea));
+
+ /* Dump some info in case of hash insertion failure, they should
+ * never happen so it is really useful to know if/when they do
+ */
+ if (rc == -1)
+ hash_failure_debug(ea, access, vsid, trap, ssize,
+ mm->context.user_psize, pte_val(*ptep));
local_irq_restore(flags);
}