[PARISC] Purge existing TLB entries in set_pte_at and ptep_set_wrprotect
This patch goes a long way toward fixing the minifail bug, and
it significantly improves the stability of SMP machines such as
the rp3440. When write protecting a page for COW, we need to
purge the existing translation. Otherwise, the COW break
doesn't occur as expected because the TLB may still have a stale entry
which allows writes.
[jejb: fix up checkpatch errors]
Signed-off-by: John David Anglin <dave.anglin@bell.net>
Cc: stable@vger.kernel.org
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
diff --git a/arch/parisc/kernel/cache.c b/arch/parisc/kernel/cache.c
index 48e16dc..b89a85a 100644
--- a/arch/parisc/kernel/cache.c
+++ b/arch/parisc/kernel/cache.c
@@ -419,6 +419,24 @@
EXPORT_SYMBOL(kunmap_parisc);
#endif
+void purge_tlb_entries(struct mm_struct *mm, unsigned long addr)
+{
+ unsigned long flags;
+
+ /* Note: purge_tlb_entries can be called at startup with
+ no context. */
+
+ /* Disable preemption while we play with %sr1. */
+ preempt_disable();
+ mtsp(mm->context, 1);
+ purge_tlb_start(flags);
+ pdtlb(addr);
+ pitlb(addr);
+ purge_tlb_end(flags);
+ preempt_enable();
+}
+EXPORT_SYMBOL(purge_tlb_entries);
+
void __flush_tlb_range(unsigned long sid, unsigned long start,
unsigned long end)
{