[S390] Fix tlb flushing with idte.

The clear-by-asce operation of the idte instruction gets an asce
(address-space-control-element) as argument to specify which TLBs
need to get flushed. The current code passes a plain pointer to
the start of the pgd without the additional bits which would make
the pointer an asce. The current machines don't mind the difference
but a future model might want to use the designation type control
bits in the asce as a filter for the TLBs to flush.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 12 insertions, 15 deletions

diff --git a/include/asm-s390/mmu_context.h b/include/asm-s390/mmu_context.h
index 05b842126b99..a77d4ba3c8eb 100644
--- a/include/asm-s390/mmu_context.h
+++ b/include/asm-s390/mmu_context.h
@@ -12,10 +12,15 @@
 #include <asm/pgalloc.h>
 #include <asm-generic/mm_hooks.h>
 
-/*
- * get a new mmu context.. S390 don't know about contexts.
- */
-#define init_new_context(tsk,mm)        0
+static inline int init_new_context(struct task_struct *tsk,
+                                   struct mm_struct *mm)
+{
+        mm->context = _ASCE_TABLE_LENGTH | _ASCE_USER_BITS;
+#ifdef CONFIG_64BIT
+        mm->context |= _ASCE_TYPE_REGION3;
+#endif
+        return 0;
+}
 
 #define destroy_context(mm)             do { } while (0)
 
@@ -27,19 +32,11 @@
 
 static inline void update_mm(struct mm_struct *mm, struct task_struct *tsk)
 {
-        pgd_t *pgd = mm->pgd;
-        unsigned long asce_bits;
-
-        /* Calculate asce bits from the first pgd table entry. */
-        asce_bits = _ASCE_TABLE_LENGTH | _ASCE_USER_BITS;
-#ifdef CONFIG_64BIT
-        asce_bits |= _ASCE_TYPE_REGION3;
-#endif
-        S390_lowcore.user_asce = asce_bits | __pa(pgd);
+        S390_lowcore.user_asce = mm->context | __pa(mm->pgd);
         if (switch_amode) {
                 /* Load primary space page table origin. */
-                pgd_t *shadow_pgd = get_shadow_table(pgd) ? : pgd;
-                S390_lowcore.user_exec_asce = asce_bits | __pa(shadow_pgd);
+                pgd_t *shadow_pgd = get_shadow_table(mm->pgd) ? : mm->pgd;
+                S390_lowcore.user_exec_asce = mm->context | __pa(shadow_pgd);
                 asm volatile(LCTL_OPCODE" 1,1,%0\n"
                              : : "m" (S390_lowcore.user_exec_asce) );
         } else