patch-2.1.124 linux/include/asm-sparc64/mmu_context.h

• Lines: 114
• Date: Sun Oct 4 10:22:44 1998
• Orig file: v2.1.123/linux/include/asm-sparc64/mmu_context.h
• Orig date: Thu Aug 6 14:06:34 1998

diff -u --recursive --new-file v2.1.123/linux/include/asm-sparc64/mmu_context.h linux/include/asm-sparc64/mmu_context.h
@@ -1,4 +1,4 @@
-/* $Id: mmu_context.h,v 1.26 1998/07/31 10:42:38 jj Exp $ */
+/* $Id: mmu_context.h,v 1.31 1998/09/24 03:22:01 davem Exp $ */
 #ifndef __SPARC64_MMU_CONTEXT_H
 #define __SPARC64_MMU_CONTEXT_H
 
@@ -25,25 +25,47 @@
 /* Initialize/destroy the context related info for a new mm_struct
  * instance.
  */
-#define init_new_context(mm)	((mm)->context = NO_CONTEXT)
-#define destroy_context(mm)	do { 						\
-	if ((mm)->context != NO_CONTEXT) { 					\
+#define init_new_context(__mm)	((__mm)->context = NO_CONTEXT)
+
+/* Kernel threads like rpciod and nfsd drop their mm, and then use
+ * init_mm, when this happens we must make sure the tsk->tss.ctx is
+ * updated as well.  Otherwise we have disasters relating to
+ * set_fs/get_fs usage later on.
+ *
+ * Also we can only clear the mmu_context_bmap bit when this is
+ * the final reference to the address space.
+ */
+#define destroy_context(__mm)	do { 						\
+	if ((__mm)->context != NO_CONTEXT &&					\
+	    atomic_read(&(__mm)->count) == 1) { 				\
 		spin_lock(&scheduler_lock); 					\
-		if (!(((mm)->context ^ tlb_context_cache) & CTX_VERSION_MASK))	\
-			clear_bit((mm)->context & ~(CTX_VERSION_MASK),		\
+		if (!(((__mm)->context ^ tlb_context_cache) & CTX_VERSION_MASK))\
+			clear_bit((__mm)->context & ~(CTX_VERSION_MASK),	\
 				  mmu_context_bmap);				\
 		spin_unlock(&scheduler_lock); 					\
-		(mm)->context = NO_CONTEXT; 					\
+		(__mm)->context = NO_CONTEXT; 					\
+		if(current->mm == (__mm)) {					\
+			current->tss.ctx = 0;					\
+			spitfire_set_secondary_context(0);			\
+			__asm__ __volatile__("flush %g6");			\
+		}								\
 	} 									\
 } while (0)
 
-extern __inline__ void get_mmu_context(struct task_struct *tsk)
+/* This routine must called with interrupts off,
+ * this is necessary to guarentee that the current->tss.ctx
+ * to CPU secontary context register relationship is maintained
+ * when traps can happen.
+ *
+ * Also the caller must flush the current set of user windows
+ * to the stack (if necessary) before we get here.
+ */
+extern __inline__ void __get_mmu_context(struct task_struct *tsk)
 {
 	register unsigned long paddr asm("o5");
 	register unsigned long pgd_cache asm("o4");
 	struct mm_struct *mm = tsk->mm;
 
-	flushw_user();
 	if(!(tsk->tss.flags & SPARC_FLAG_KTHREAD)	&&
 	   !(tsk->flags & PF_EXITING)) {
 		unsigned long ctx = tlb_context_cache;
@@ -65,28 +87,43 @@
 	spitfire_set_secondary_context(tsk->tss.ctx);
 	__asm__ __volatile__("flush %g6");
 	paddr = __pa(mm->pgd);
-	if(tsk->tss.flags & SPARC_FLAG_32BIT)
+	if((tsk->tss.flags & (SPARC_FLAG_32BIT|SPARC_FLAG_KTHREAD)) ==
+	   (SPARC_FLAG_32BIT))
 		pgd_cache = (unsigned long) mm->pgd[0];
 	else
 		pgd_cache = 0;
 	__asm__ __volatile__("
-		rdpr		%%pstate, %%o3
-		wrpr		%%o3, %2, %%pstate
+		rdpr		%%pstate, %%o2
+		andn		%%o2, %2, %%o3
+		wrpr		%%o3, %5, %%pstate
 		mov		%4, %%g4
 		mov		%0, %%g7
 		stxa		%1, [%%g4] %3
-		wrpr		%%o3, 0x0, %%pstate
+		wrpr		%%o2, 0x0, %%pstate
 	" : /* no outputs */
-	  : "r" (paddr), "r" (pgd_cache), "i" (PSTATE_MG|PSTATE_IE),
-	    "i" (ASI_DMMU), "i" (TSB_REG)
-	  : "o3");
+	  : "r" (paddr), "r" (pgd_cache), "i" (PSTATE_IE),
+	    "i" (ASI_DMMU), "i" (TSB_REG), "i" (PSTATE_MG)
+	  : "o2", "o3");
 }
 
+/* Now we define this as a do nothing macro, because the only
+ * generic user right now is the scheduler, and we handle all
+ * the atomicity issues by having switch_to() call the above
+ * function itself.
+ */
+#define get_mmu_context(x)	do { } while(0)
+
 /*
  * After we have set current->mm to a new value, this activates
  * the context for the new mm so we see the new mappings.
  */
-#define activate_context(tsk)	get_mmu_context(tsk)
+#define activate_context(__tsk)		\
+do {	unsigned long __flags;		\
+	__save_and_cli(__flags);	\
+	flushw_user();			\
+	__get_mmu_context(__tsk);	\
+	__restore_flags(__flags);	\
+} while(0)
 
 #endif /* !(__ASSEMBLY__) */