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# HG changeset 265+266 patch
# User Keir Fraser <keir@xensource.com>
# Date 1192720728 -3600
# Node ID 7837d0ec57bce4578c17018ca1ef1ded64fe1dd3
# Parent 3116d92146522ae5989b40e1915d0baf6daa1008
Subject: Fix ptep_get_and_clear() on init_mm pte that is not mapped into
current address space.
Signed-off-by: Keir Fraser <keir@xensource.com>
Fix ptep_get_and_clear(): atomic operation required on user ptes to
get correct snapshot of A/D bits.
Signed-off-by: Keir Fraser <keir@xensource.com>
Acked-by: jbeulich@novell.com
Index: 10.3-2007-10-22/include/asm-i386/mach-xen/asm/pgtable-2level.h
===================================================================
--- 10.3-2007-10-22.orig/include/asm-i386/mach-xen/asm/pgtable-2level.h 2007-10-22 13:48:12.000000000 +0200
+++ 10.3-2007-10-22/include/asm-i386/mach-xen/asm/pgtable-2level.h 2007-10-22 13:52:04.000000000 +0200
@@ -42,10 +42,9 @@ static inline pte_t ptep_get_and_clear(s
{
pte_t pte = *ptep;
if (!pte_none(pte)) {
- if (mm != &init_mm)
+ if ((mm != &init_mm) ||
+ HYPERVISOR_update_va_mapping(addr, __pte(0), 0))
pte = __pte_ma(xchg(&ptep->pte_low, 0));
- else
- HYPERVISOR_update_va_mapping(addr, __pte(0), 0);
}
return pte;
}
Index: 10.3-2007-10-22/include/asm-i386/mach-xen/asm/pgtable-3level.h
===================================================================
--- 10.3-2007-10-22.orig/include/asm-i386/mach-xen/asm/pgtable-3level.h 2007-10-22 13:48:12.000000000 +0200
+++ 10.3-2007-10-22/include/asm-i386/mach-xen/asm/pgtable-3level.h 2007-10-22 13:52:04.000000000 +0200
@@ -125,7 +125,8 @@ static inline pte_t ptep_get_and_clear(s
{
pte_t pte = *ptep;
if (!pte_none(pte)) {
- if (mm != &init_mm) {
+ if ((mm != &init_mm) ||
+ HYPERVISOR_update_va_mapping(addr, __pte(0), 0)) {
uint64_t val = pte_val_ma(pte);
if (__cmpxchg64(ptep, val, 0) != val) {
/* xchg acts as a barrier before the setting of the high bits */
@@ -133,8 +134,7 @@ static inline pte_t ptep_get_and_clear(s
pte.pte_high = ptep->pte_high;
ptep->pte_high = 0;
}
- } else
- HYPERVISOR_update_va_mapping(addr, __pte(0), 0);
+ }
}
return pte;
}
Index: 10.3-2007-10-22/include/asm-x86_64/mach-xen/asm/pgtable.h
===================================================================
--- 10.3-2007-10-22.orig/include/asm-x86_64/mach-xen/asm/pgtable.h 2007-10-22 13:48:12.000000000 +0200
+++ 10.3-2007-10-22/include/asm-x86_64/mach-xen/asm/pgtable.h 2007-10-22 13:52:04.000000000 +0200
@@ -282,10 +282,9 @@ static inline pte_t ptep_get_and_clear(s
{
pte_t pte = *ptep;
if (!pte_none(pte)) {
- if (mm != &init_mm)
+ if ((mm != &init_mm) ||
+ HYPERVISOR_update_va_mapping(addr, __pte(0), 0))
pte = __pte_ma(xchg(&ptep->pte, 0));
- else
- HYPERVISOR_update_va_mapping(addr, __pte(0), 0);
}
return pte;
}
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