From 7139bc1579901b53db7e898789e916ee2fb52d78 Mon Sep 17 00:00:00 2001 From: John David Anglin Date: Mon, 14 Jan 2013 19:45:00 -0500 Subject: [PARISC] Purge existing TLB entries in set_pte_at and ptep_set_wrprotect MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Cc: stable@vger.kernel.org Signed-off-by: James Bottomley --- arch/parisc/kernel/cache.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) (limited to 'arch/parisc/kernel') diff --git a/arch/parisc/kernel/cache.c b/arch/parisc/kernel/cache.c index 48e16dc20102..b89a85ab945e 100644 --- a/arch/parisc/kernel/cache.c +++ b/arch/parisc/kernel/cache.c @@ -419,6 +419,24 @@ void kunmap_parisc(void *addr) 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) { -- cgit v1.2.3