bitkeeper revision 1.1236.1.186 (424d5359kAhRjA4t3oq3aye_393FaQ)

Merge firebug.cl.cam.ac.uk:/auto/groups/xeno-xenod/BK/xen-unstable.bk
into firebug.cl.cam.ac.uk:/local/scratch/kaf24/xen-unstable.bk

linux-2.6.11-xen-sparse/arch/xen/i386/kernel/process.c

@@ -445,22 +445,7 @@ struct task_struct fastcall * __switch_to(struct task_struct *prev_p, struct tas
 	physdev_op_t iopl_op, iobmp_op;
 	multicall_entry_t _mcl[8], *mcl = _mcl;
 
-	/*
-	 * Save away %fs and %gs. No need to save %es and %ds, as
-	 * those are always kernel segments while inside the kernel.
-	 */
-	asm volatile("movl %%fs,%0":"=m" (*(int *)&prev->fs));
-	asm volatile("movl %%gs,%0":"=m" (*(int *)&prev->gs));
-
-	/*
-	 * We clobber FS and GS here so that we avoid a GPF when restoring
-	 * previous task's FS/GS values in Xen when the LDT is switched.
-	 */
-	__asm__ __volatile__ ( 
-		"xorl %%eax,%%eax; movl %%eax,%%fs; movl %%eax,%%gs" : : :
-		"eax" );
-
-	/* never put a printk in __switch_to... printk() calls wake_up*() indirectly */
+        /* XEN NOTE: FS/GS saved in switch_mm(), not here. */
 
 	/*
 	 * This is basically '__unlazy_fpu', except that we queue a

linux-2.6.11-xen-sparse/include/asm-xen/asm-i386/mmu_context.h

@@ -16,13 +16,31 @@ void destroy_context(struct mm_struct *mm);
 
 static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
 {
-#ifdef CONFIG_SMP
+#if 0 /* XEN */
 	unsigned cpu = smp_processor_id();
 	if (per_cpu(cpu_tlbstate, cpu).state == TLBSTATE_OK)
 		per_cpu(cpu_tlbstate, cpu).state = TLBSTATE_LAZY;
 #endif
 }
 
+#define prepare_arch_switch(rq,next)	__prepare_arch_switch()
+#define finish_arch_switch(rq, next)	spin_unlock_irq(&(rq)->lock)
+#define task_running(rq, p)		((rq)->curr == (p))
+
+static inline void __prepare_arch_switch(void)
+{
+	/*
+	 * Save away %fs and %gs. No need to save %es and %ds, as those
+	 * are always kernel segments while inside the kernel. Must
+	 * happen before reload of cr3/ldt (i.e., not in __switch_to).
+	 */
+	__asm__ __volatile__ ( "movl %%fs,%0 ; movl %%gs,%1"
+		: "=m" (*(int *)&current->thread.fs),
+		  "=m" (*(int *)&current->thread.gs));
+	__asm__ __volatile__ ( "movl %0,%%fs ; movl %0,%%gs"
+		: : "r" (0) );
+}
+
 static inline void switch_mm(struct mm_struct *prev,
 			     struct mm_struct *next,
 			     struct task_struct *tsk)
@@ -32,7 +50,7 @@ static inline void switch_mm(struct mm_struct *prev,
 	if (likely(prev != next)) {
 		/* stop flush ipis for the previous mm */
 		cpu_clear(cpu, prev->cpu_vm_mask);
-#ifdef CONFIG_SMP
+#if 0 /* XEN */
 		per_cpu(cpu_tlbstate, cpu).state = TLBSTATE_OK;
 		per_cpu(cpu_tlbstate, cpu).active_mm = next;
 #endif
@@ -47,7 +65,7 @@ static inline void switch_mm(struct mm_struct *prev,
 		if (unlikely(prev->context.ldt != next->context.ldt))
 			load_LDT_nolock(&next->context, cpu);
 	}
-#ifdef CONFIG_SMP
+#if 0 /* XEN */
 	else {
 		per_cpu(cpu_tlbstate, cpu).state = TLBSTATE_OK;
 		BUG_ON(per_cpu(cpu_tlbstate, cpu).active_mm != next);