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authorBenjamin Herrenschmidt <benh@kernel.crashing.org>2010-07-23 10:31:13 +1000
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2010-07-23 12:56:56 +1000
commit4b8692c022a4b149d0c2cc3f4f7a363453fde72a (patch)
tree11e71230effaa73f24d999ed7eeacb1125c8a047 /arch
parent171aa2caaad16ed32b655d33565e112a12cb3537 (diff)
downloadlinux-2.6.34-ux500-4b8692c022a4b149d0c2cc3f4f7a363453fde72a.tar.gz
powerpc/mm: Add some debug output when hash insertion fails
This adds some debug output to our MMU hash code to print out some useful debug data if the hypervisor refuses the insertion (which should normally never happen). Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> ---
Diffstat (limited to 'arch')
-rw-r--r--arch/powerpc/include/asm/mmu-hash64.h4
-rw-r--r--arch/powerpc/mm/hash_utils_64.c34
-rw-r--r--arch/powerpc/mm/hugetlbpage-hash64.c2
3 files changed, 34 insertions, 6 deletions
diff --git a/arch/powerpc/include/asm/mmu-hash64.h b/arch/powerpc/include/asm/mmu-hash64.h
index 2102b214a87..0e398cfee2c 100644
--- a/arch/powerpc/include/asm/mmu-hash64.h
+++ b/arch/powerpc/include/asm/mmu-hash64.h
@@ -250,7 +250,9 @@ extern int hash_page(unsigned long ea, unsigned long access, unsigned long trap)
int __hash_page_huge(unsigned long ea, unsigned long access, unsigned long vsid,
pte_t *ptep, unsigned long trap, int local, int ssize,
unsigned int shift, unsigned int mmu_psize);
-
+extern void hash_failure_debug(unsigned long ea, unsigned long access,
+ unsigned long vsid, unsigned long trap,
+ int ssize, int psize, unsigned long pte);
extern int htab_bolt_mapping(unsigned long vstart, unsigned long vend,
unsigned long pstart, unsigned long prot,
int psize, int ssize);
diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index 40847a9dd6d..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
@@ -1036,6 +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
@@ -1054,8 +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);
@@ -1101,11 +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);
}
diff --git a/arch/powerpc/mm/hugetlbpage-hash64.c b/arch/powerpc/mm/hugetlbpage-hash64.c
index faae9ec4cb0..cc5c273086c 100644
--- a/arch/powerpc/mm/hugetlbpage-hash64.c
+++ b/arch/powerpc/mm/hugetlbpage-hash64.c
@@ -127,6 +127,8 @@ repeat:
*/
if (unlikely(slot == -2)) {
*ptep = __pte(old_pte);
+ hash_failure_debug(ea, access, vsid, trap, ssize,
+ mmu_psize, old_pte);
return -1;
}