From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: linuxppc-dev@ozlabs.org
Subject: [PATCH 4/5] powerpc/mm: Add some debug output when hash insertion fails
Date: Fri, 23 Jul 2010 10:41:43 +1000 [thread overview]
Message-ID: <1279845704-14848-4-git-send-email-benh@kernel.crashing.org> (raw)
In-Reply-To: <1279845704-14848-3-git-send-email-benh@kernel.crashing.org>
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>
---
---
arch/powerpc/include/asm/mmu-hash64.h | 4 ++-
arch/powerpc/mm/hash_utils_64.c | 34 ++++++++++++++++++++++++++++----
arch/powerpc/mm/hugetlbpage-hash64.c | 2 +
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 2102b21..0e398cf 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 40847a9..09dffe6 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 fd0a15e..db70c0d 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;
}
--
1.6.3.3
next prev parent reply other threads:[~2010-07-23 0:42 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-07-23 0:41 [PATCH 1/5] powerpc/mm: Handle hypervisor pte insert failure in __hash_page_huge Benjamin Herrenschmidt
2010-07-23 0:41 ` [PATCH 2/5] powerpc/mm: Move around testing of _PAGE_PRESENT in hash code Benjamin Herrenschmidt
2010-07-23 0:41 ` [PATCH 3/5] powerpc/mm: Fix bugs in huge page hashing Benjamin Herrenschmidt
2010-07-23 0:41 ` Benjamin Herrenschmidt [this message]
2010-07-23 0:41 ` [PATCH 5/5] powerpc: Fix erroneous lmb->memblock conversions Benjamin Herrenschmidt
2010-07-23 3:03 ` [PATCH 3/5] powerpc/mm: Fix bugs in huge page hashing Benjamin Herrenschmidt
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