[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>

3 files changed, 19 insertions, 22 deletions

diff --git a/arch/s390/kernel/head64.S b/arch/s390/kernel/head64.S
index a87b1976d409..79dccd206a6e 100644
--- a/arch/s390/kernel/head64.S
+++ b/arch/s390/kernel/head64.S
@@ -157,7 +157,7 @@ startup_continue:
         .long   0xb2b10000              # store facility list
         tm      0xc8,0x08               # check bit for clearing-by-ASCE
         bno     0f-.LPG1(%r13)
-        lhi     %r1,2094
+        lhi     %r1,2048
         lhi     %r2,0
         .long   0xb98e2001
         oi      7(%r12),0x80            # set IDTE flag
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
diff --git a/include/asm-s390/tlbflush.h b/include/asm-s390/tlbflush.h
index a69bd2490d52..a5e876539ec6 100644
--- a/include/asm-s390/tlbflush.h
+++ b/include/asm-s390/tlbflush.h
@@ -42,11 +42,11 @@ static inline void __tlb_flush_global(void)
 /*
  * Flush all tlb entries of a page table on all cpus.
  */
-static inline void __tlb_flush_idte(pgd_t *pgd)
+static inline void __tlb_flush_idte(unsigned long asce)
 {
         asm volatile(
                 "       .insn   rrf,0xb98e0000,0,%0,%1,0"
-                : : "a" (2048), "a" (__pa(pgd) & PAGE_MASK) : "cc" );
+                : : "a" (2048), "a" (asce) : "cc" );
 }
 
 static inline void __tlb_flush_mm(struct mm_struct * mm)
@@ -61,11 +61,11 @@ static inline void __tlb_flush_mm(struct mm_struct * mm)
          * only ran on the local cpu.
          */
         if (MACHINE_HAS_IDTE) {
-                pgd_t *shadow_pgd = get_shadow_table(mm->pgd);
+                pgd_t *shadow = get_shadow_table(mm->pgd);
 
-                if (shadow_pgd)
-                        __tlb_flush_idte(shadow_pgd);
-                __tlb_flush_idte(mm->pgd);
+                if (shadow)
+                        __tlb_flush_idte((unsigned long) shadow | mm->context);
+                __tlb_flush_idte((unsigned long) mm->pgd | mm->context);
                 return;
         }
         preempt_disable();