[S390] dynamic page tables.
Add support for different number of page table levels dependent
on the highest address used for a process. This will cause a 31 bit
process to use a two level page table instead of the four level page
table that is the default after the pud has been introduced. Likewise
a normal 64 bit process will use three levels instead of four. Only
if a process runs out of the 4 tera bytes which can be addressed with
a three level page table the fourth level is dynamically added. Then
the process can use up to 8 peta byte.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/include/asm-s390/mmu_context.h b/include/asm-s390/mmu_context.h
index b3ea3e1..b5a34c6 100644
--- a/include/asm-s390/mmu_context.h
+++ b/include/asm-s390/mmu_context.h
@@ -18,9 +18,11 @@
{
mm->context.asce_bits = _ASCE_TABLE_LENGTH | _ASCE_USER_BITS;
#ifdef CONFIG_64BIT
- mm->context.asce_bits |= _ASCE_TYPE_REGION2;
+ mm->context.asce_bits |= _ASCE_TYPE_REGION3;
#endif
mm->context.noexec = s390_noexec;
+ mm->context.asce_limit = STACK_TOP_MAX;
+ crst_table_init((unsigned long *) mm->pgd, pgd_entry_type(mm));
return 0;
}
@@ -47,13 +49,12 @@
/* Load home space page table origin. */
asm volatile(LCTL_OPCODE" 13,13,%0"
: : "m" (S390_lowcore.user_asce) );
+ set_fs(current->thread.mm_segment);
}
static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
struct task_struct *tsk)
{
- if (unlikely(prev == next))
- return;
cpu_set(smp_processor_id(), next->cpu_vm_mask);
update_mm(next, tsk);
}
@@ -65,7 +66,6 @@
struct mm_struct *next)
{
switch_mm(prev, next, current);
- set_fs(current->thread.mm_segment);
}
#endif /* __S390_MMU_CONTEXT_H */