s390/mm: implement 5 level pages tables
Add the logic to upgrade the page table for a 64-bit process to
five levels. This increases the TASK_SIZE from 8PB to 16EB-4K.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/mm/pgalloc.c b/arch/s390/mm/pgalloc.c
index f502cbe..18918e3 100644
--- a/arch/s390/mm/pgalloc.c
+++ b/arch/s390/mm/pgalloc.c
@@ -76,29 +76,46 @@ static void __crst_table_upgrade(void *arg)
__tlb_flush_local();
}
-int crst_table_upgrade(struct mm_struct *mm)
+int crst_table_upgrade(struct mm_struct *mm, unsigned long end)
{
unsigned long *table, *pgd;
+ int rc, notify;
- /* upgrade should only happen from 3 to 4 levels */
- BUG_ON(mm->context.asce_limit != (1UL << 42));
-
- table = crst_table_alloc(mm);
- if (!table)
+ /* upgrade should only happen from 3 to 4, 3 to 5, or 4 to 5 levels */
+ BUG_ON(mm->context.asce_limit < (1UL << 42));
+ if (end >= TASK_SIZE_MAX)
return -ENOMEM;
-
- spin_lock_bh(&mm->page_table_lock);
- pgd = (unsigned long *) mm->pgd;
- crst_table_init(table, _REGION2_ENTRY_EMPTY);
- pgd_populate(mm, (pgd_t *) table, (pud_t *) pgd);
- mm->pgd = (pgd_t *) table;
- mm->context.asce_limit = 1UL << 53;
- mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
- _ASCE_USER_BITS | _ASCE_TYPE_REGION2;
- spin_unlock_bh(&mm->page_table_lock);
-
- on_each_cpu(__crst_table_upgrade, mm, 0);
- return 0;
+ rc = 0;
+ notify = 0;
+ while (mm->context.asce_limit < end) {
+ table = crst_table_alloc(mm);
+ if (!table) {
+ rc = -ENOMEM;
+ break;
+ }
+ spin_lock_bh(&mm->page_table_lock);
+ pgd = (unsigned long *) mm->pgd;
+ if (mm->context.asce_limit == (1UL << 42)) {
+ crst_table_init(table, _REGION2_ENTRY_EMPTY);
+ p4d_populate(mm, (p4d_t *) table, (pud_t *) pgd);
+ mm->pgd = (pgd_t *) table;
+ mm->context.asce_limit = 1UL << 53;
+ mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
+ _ASCE_USER_BITS | _ASCE_TYPE_REGION2;
+ } else {
+ crst_table_init(table, _REGION1_ENTRY_EMPTY);
+ pgd_populate(mm, (pgd_t *) table, (p4d_t *) pgd);
+ mm->pgd = (pgd_t *) table;
+ mm->context.asce_limit = -PAGE_SIZE;
+ mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
+ _ASCE_USER_BITS | _ASCE_TYPE_REGION1;
+ }
+ notify = 1;
+ spin_unlock_bh(&mm->page_table_lock);
+ }
+ if (notify)
+ on_each_cpu(__crst_table_upgrade, mm, 0);
+ return rc;
}
void crst_table_downgrade(struct mm_struct *mm)
@@ -274,7 +291,7 @@ static void __tlb_remove_table(void *_table)
struct page *page = pfn_to_page(__pa(table) >> PAGE_SHIFT);
switch (mask) {
- case 0: /* pmd or pud */
+ case 0: /* pmd, pud, or p4d */
free_pages((unsigned long) table, 2);
break;
case 1: /* lower 2K of a 4K page table */