bitkeeper revision 1.1159.62.1 (412f5ac2sXlMhMeRveH20BE_o6ZJVw)

Allow shadow p.t. code to do unsafe things with shadow locks held.

diff --git a/xen/arch/x86/shadow.c b/xen/arch/x86/shadow.c
index e1fac065d07a49bead6f310901ae00a4991b54a5..672f48ef9f08bfbe21837d623a253156517381c1 100644 (file)
--- a/xen/arch/x86/shadow.c
+++ b/xen/arch/x86/shadow.c
@@ -443,7 +443,7 @@ int shadow_mode_control(struct domain *d, dom0_shadow_control_t *sc)
     domain_pause(d);
     synchronise_pagetables(~0UL);
 
-    spin_lock(&d->mm.shadow_lock);
+    shadow_lock(&d->mm);
 
     if ( cmd == DOM0_SHADOW_CONTROL_OP_OFF )
     {
@@ -470,7 +470,7 @@ int shadow_mode_control(struct domain *d, dom0_shadow_control_t *sc)
         rc = -EINVAL;
     }
 
-    spin_unlock(&d->mm.shadow_lock);
+    shadow_unlock(&d->mm);
 
     domain_unpause(d);
 
@@ -620,19 +620,19 @@ int shadow_fault( unsigned long va, long error_code )
 
     // take the lock and reread gpte
 
-       spin_lock(&current->mm.shadow_lock);
+    shadow_lock(m);
        
     if ( unlikely(__get_user(gpte, (unsigned long*)&linear_pg_table[va>>PAGE_SHIFT])) )
     {
         SH_VVLOG("shadow_fault - EXIT: read gpte faulted" );
-        spin_unlock(&m->shadow_lock);
+        shadow_unlock(m);
         return 0;  // propagate to guest
     }
 
     if ( unlikely(!(gpte & _PAGE_PRESENT)) )
     {
         SH_VVLOG("shadow_fault - EXIT: gpte not present (%lx)",gpte );
-        spin_unlock(&m->shadow_lock);
+        shadow_unlock(m);
         return 0;  // we're not going to be able to help
     }
 
@@ -645,7 +645,7 @@ int shadow_fault( unsigned long va, long error_code )
         else
         {   // write fault on RO page
             SH_VVLOG("shadow_fault - EXIT: write fault on RO page (%lx)",gpte );
-            spin_unlock(&m->shadow_lock);
+            shadow_unlock(m);
             return 0; // propagate to guest
             // not clear whether we should set accessed bit here...
         }
@@ -737,7 +737,7 @@ int shadow_fault( unsigned long va, long error_code )
 
     check_pagetable( current, current->mm.pagetable, "post-sf" );
 
-    spin_unlock(&m->shadow_lock);
+    shadow_unlock(m);
 
     return 1; // let's try the faulting instruction again...
 

diff --git a/xen/common/kernel.c b/xen/common/kernel.c
index 6d70547321df9783de9a3bbf98e2e98a9d43938c..2c67cf7506b32c71f448f9ca0f75092d5890bc08 100644 (file)
--- a/xen/common/kernel.c
+++ b/xen/common/kernel.c
@@ -396,12 +396,20 @@ long do_ni_hypercall(void)
 
 #ifndef NDEBUG
 
-static int crit_count[NR_CPUS];
-static int crit_checking = 1;
+static int crit_count[NR_CPUS], crit_checking_disabled[NR_CPUS];
 
 void disable_criticalregion_checking(void)
 {
-    crit_checking = 0;
+    int cpu = smp_processor_id();
+    ASSERT(crit_checking_disabled[cpu] >= 0);
+    crit_checking_disabled[cpu]++;
+}
+
+void enable_criticalregion_checking(void)
+{
+    int cpu = smp_processor_id();
+    crit_checking_disabled[cpu]--;
+    ASSERT(crit_checking_disabled[cpu] >= 0);
 }
 
 void criticalregion_enter(void)
@@ -421,7 +429,7 @@ void criticalregion_exit(void)
 void ASSERT_no_criticalregion(void)
 {
     int cpu = smp_processor_id();
-    if ( (crit_count[cpu] == 0) || !crit_checking )
+    if ( (crit_count[cpu] == 0) || crit_checking_disabled[cpu] )
         return;
     disable_criticalregion_checking();
     ASSERT(crit_count[cpu] >= 0); /* -ve count is a special kind of bogus! */

diff --git a/xen/include/asm-x86/shadow.h b/xen/include/asm-x86/shadow.h
index f874b6be4a9df5f97c04583742aa60e6124509b6..5a1994cabbb4a720444bf667612862608bdadf79 100644 (file)
--- a/xen/include/asm-x86/shadow.h
+++ b/xen/include/asm-x86/shadow.h
@@ -26,6 +26,8 @@
 
 #define shadow_mode(_d)      ((_d)->mm.shadow_mode)
 #define shadow_lock_init(_d) spin_lock_init(&(_d)->mm.shadow_lock)
+#define shadow_lock(_m)      spin_lock_nochecking(&(_m)->shadow_lock)
+#define shadow_unlock(_m)    spin_unlock_nochecking(&(_m)->shadow_lock)
 
 extern void shadow_mode_init(void);
 extern int shadow_mode_control(struct domain *p, dom0_shadow_control_t *sc);
@@ -134,9 +136,9 @@ static inline int mark_dirty( struct mm_struct *m, unsigned int mfn )
     int rc;
     ASSERT(local_irq_is_enabled());
     //if(spin_is_locked(&m->shadow_lock)) printk("+");
-    spin_lock(&m->shadow_lock);
+    shadow_lock(m);
     rc = __mark_dirty( m, mfn );
-    spin_unlock(&m->shadow_lock);
+    shadow_unlock(m);
     return rc;
 }
 
@@ -388,20 +390,21 @@ static inline unsigned long get_shadow_status( struct mm_struct *m,
 
     ASSERT(local_irq_is_enabled());
     //if(spin_is_locked(&m->shadow_lock)) printk("*");
-    spin_lock(&m->shadow_lock);
+    shadow_lock(m);
 
     if( m->shadow_mode == SHM_logdirty )
         __mark_dirty( m, gpfn );
 
     res = __shadow_status( m, gpfn );
-    if (!res) spin_unlock(&m->shadow_lock);
+    if (!res) 
+        shadow_unlock(m);
     return res;
 }
 
 
 static inline void put_shadow_status( struct mm_struct *m )
 {
-    spin_unlock(&m->shadow_lock);
+    shadow_unlock(m);
 }
 
 
@@ -583,11 +586,9 @@ static inline void shadow_mk_pagetable( struct mm_struct *mm )
     if ( unlikely(mm->shadow_mode) )
     {
         ASSERT(local_irq_is_enabled());
-        spin_lock(&mm->shadow_lock);
-
-        __shadow_mk_pagetable( mm );
-
-        spin_unlock(&mm->shadow_lock);
+        shadow_lock(mm);
+        __shadow_mk_pagetable(mm);
+        shadow_unlock(mm);
     }
 
     SH_VVLOG("leaving shadow_mk_pagetable( gptbase=%08lx, mode=%d ) sh=%08lx",

diff --git a/xen/include/xen/spinlock.h b/xen/include/xen/spinlock.h
index 0b4503d999d6dffd3cf4c21392592283d5c8f904..fc2409f13d93448f30f855a9a255ba2369ffad18 100644 (file)
--- a/xen/include/xen/spinlock.h
+++ b/xen/include/xen/spinlock.h
@@ -78,6 +78,7 @@ extern void criticalregion_enter(void);
 extern void criticalregion_exit(void);
 extern void ASSERT_no_criticalregion(void);
 extern void disable_criticalregion_checking(void);
+extern void enable_criticalregion_checking(void);
 
 #define spin_lock(_lock) \
     do { criticalregion_enter(); _raw_spin_lock(_lock); } while (0)
@@ -111,6 +112,7 @@ static inline int spin_trylock(spinlock_t *lock)
 
 #define ASSERT_no_criticalregion()        ((void)0)
 #define disable_criticalregion_checking() ((void)0)
+#define enable_criticalregion_checking()  ((void)0)
 
 #define spin_lock(_lock)             _raw_spin_lock(_lock)
 #define spin_trylock(_lock)          _raw_spin_trylock(_lock)
@@ -124,4 +126,13 @@ static inline int spin_trylock(spinlock_t *lock)
 
 #endif
 
+/*
+ * Use these if you have taken special care to ensure that certain unsafe
+ * things can occur in your critical region (e.g., faults, user-space
+ * accesses). 
+ */
+#define spin_lock_nochecking(_lock)    _raw_spin_lock(_lock)
+#define spin_trylock_nochecking(_lock) _raw_spin_trylock(_lock)
+#define spin_unlock_nochecking(_lock)  _raw_spin_unlock(_lock)
+
 #endif /* __SPINLOCK_H__ */