3.2-stable review patch. If anyone has any objections, please let me know.
------------------
From: John David Anglin <dave.ang...@bell.net>
commit 7139bc1579901b53db7e898789e916ee2fb52d78 upstream.
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.ang...@bell.net>
Signed-off-by: James Bottomley <jbottom...@parallels.com>
Signed-off-by: Ben Hutchings <b...@decadent.org.uk>
---
arch/parisc/include/asm/pgtable.h | 13 ++++++++++---
arch/parisc/kernel/cache.c | 18 ++++++++++++++++++
2 files changed, 28 insertions(+), 3 deletions(-)
--- a/arch/parisc/include/asm/pgtable.h
+++ b/arch/parisc/include/asm/pgtable.h
@@ -12,11 +12,10 @@
#include <linux/bitops.h>
#include <linux/spinlock.h>
+#include <linux/mm_types.h>
#include <asm/processor.h>
#include <asm/cache.h>
-struct vm_area_struct;
-
/*
* kern_addr_valid(ADDR) tests if ADDR is pointing to valid kernel
* memory. For the return value to be meaningful, ADDR must be >=
@@ -40,7 +39,14 @@ struct vm_area_struct;
do{ \
*(pteptr) = (pteval); \
} while(0)
-#define set_pte_at(mm,addr,ptep,pteval) set_pte(ptep,pteval)
+
+extern void purge_tlb_entries(struct mm_struct *, unsigned long);
+
+#define set_pte_at(mm, addr, ptep, pteval) \
+ do { \
+ set_pte(ptep, pteval); \
+ purge_tlb_entries(mm, addr); \
+ } while (0)
#endif /* !__ASSEMBLY__ */
@@ -464,6 +470,7 @@ static inline void ptep_set_wrprotect(st
old = pte_val(*ptep);
new = pte_val(pte_wrprotect(__pte (old)));
} while (cmpxchg((unsigned long *) ptep, old, new) != old);
+ purge_tlb_entries(mm, addr);
#else
pte_t old_pte = *ptep;
set_pte_at(mm, addr, ptep, pte_wrprotect(old_pte));
--- a/arch/parisc/kernel/cache.c
+++ b/arch/parisc/kernel/cache.c
@@ -421,6 +421,24 @@ 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)
{
--
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