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authorMax Filippov <jcmvbkbc@gmail.com>2013-05-18 23:34:30 +0400
committerChris Zankel <chris@zankel.net>2013-05-20 11:48:23 -0700
commit51fc41a90603eaee7b6d03b6027be8f22fcf8ef9 (patch)
tree87f240d64051f5747027e07592f0ec50cbdd4e37 /arch/xtensa
parent7711ece9b31f0f3cf15ca16005dfd78988ea8f7e (diff)
downloadlinux-51fc41a90603eaee7b6d03b6027be8f22fcf8ef9.tar.gz
xtensa: fix fast_store_prohibited _PAGE_WRITABLE_BIT test
Before _PAGE_WRITABLE_BIT test fast_store_prohibited must make sure that PTE is present. Otherwise 'writable' bit is undefined and may be reused in the 'file offset' or 'swap type' PTE fields. Signed-off-by: Max Filippov <jcmvbkbc@gmail.com> Signed-off-by: Chris Zankel <chris@zankel.net>
Diffstat (limited to 'arch/xtensa')
-rw-r--r--arch/xtensa/kernel/entry.S7
1 files changed, 6 insertions, 1 deletions
diff --git a/arch/xtensa/kernel/entry.S b/arch/xtensa/kernel/entry.S
index 5082507d563..fa94512ff84 100644
--- a/arch/xtensa/kernel/entry.S
+++ b/arch/xtensa/kernel/entry.S
@@ -1792,10 +1792,15 @@ ENTRY(fast_store_prohibited)
l32i a0, a0, 0
beqz a0, 2f
- /* Note that we assume _PAGE_WRITABLE_BIT is only set if pte is valid.*/
+ /*
+ * Note that we test _PAGE_WRITABLE_BIT only if PTE is present
+ * and is not PAGE_NONE. See pgtable.h for possible PTE layouts.
+ */
_PTE_OFFSET(a0, a1, a4)
l32i a4, a0, 0 # read pteval
+ movi a1, _PAGE_CA_INVALID
+ ball a4, a1, 2f
bbci.l a4, _PAGE_WRITABLE_BIT, 2f
movi a1, _PAGE_ACCESSED | _PAGE_DIRTY | _PAGE_HW_WRITE