[S390] refactor page table functions for better pgste support

Rework the architecture page table functions to access the bits in the
page table extension array (pgste). There are a number of changes:
1) Fix missing pgste update if the attach_count for the mm is <= 1.
2) For every operation that affects the invalid bit in the pte or the
   rcp byte in the pgste the pcl lock needs to be acquired. The function
   pgste_get_lock gets the pcl lock and returns the current pgste value
   for a pte pointer. The function pgste_set_unlock stores the pgste
   and releases the lock. Between these two calls the bits in the pgste
   can be shuffled.
3) Define two software bits in the pte _PAGE_SWR and _PAGE_SWC to avoid
   calling SetPageDirty and SetPageReferenced from pgtable.h. If the
   host reference backup bit or the host change backup bit has been
   set the dirty/referenced state is transfered to the pte. The common
   code will pick up the state from the pte.
4) Add ptep_modify_prot_start and ptep_modify_prot_commit for mprotect.
5) Remove pgd_populate_kernel, pud_populate_kernel, pmd_populate_kernel
   pgd_clear_kernel, pud_clear_kernel, pmd_clear_kernel and ptep_invalidate.
6) Rename kvm_s390_test_and_clear_page_dirty to
   ptep_test_and_clear_user_dirty and add ptep_test_and_clear_user_young.
7) Define mm_exclusive() and mm_has_pgste() helper to improve readability.

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

3 files changed, 10 insertions, 9 deletions

diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
index bb409332a48..dfefc217169 100644
--- a/arch/s390/mm/init.c
+++ b/arch/s390/mm/init.c
@@ -175,7 +175,8 @@ void kernel_map_pages(struct page *page, int numpages, int enable)
                 pmd = pmd_offset(pud, address);
                 pte = pte_offset_kernel(pmd, address);
                 if (!enable) {
-                        ptep_invalidate(&init_mm, address, pte);
+                        __ptep_ipte(address, pte);
+                        pte_val(*pte) = _PAGE_TYPE_EMPTY;
                         continue;
                 }
                 *pte = mk_pte_phys(address, __pgprot(_PAGE_TYPE_RW));
diff --git a/arch/s390/mm/pageattr.c b/arch/s390/mm/pageattr.c
index f05edcc3bef..d013ed39743 100644
--- a/arch/s390/mm/pageattr.c
+++ b/arch/s390/mm/pageattr.c
@@ -28,7 +28,7 @@ static void change_page_attr(unsigned long addr, int numpages,
 
                 pte = *ptep;
                 pte = set(pte);
-                ptep_invalidate(&init_mm, addr, ptep);
+                __ptep_ipte(addr, ptep);
                 *ptep = pte;
                 addr += PAGE_SIZE;
         }
diff --git a/arch/s390/mm/vmem.c b/arch/s390/mm/vmem.c
index 34c43f23b28..8c1970d1dd9 100644
--- a/arch/s390/mm/vmem.c
+++ b/arch/s390/mm/vmem.c
@@ -95,7 +95,7 @@ static int vmem_add_mem(unsigned long start, unsigned long size, int ro)
                         pu_dir = vmem_pud_alloc();
                         if (!pu_dir)
                                 goto out;
-                        pgd_populate_kernel(&init_mm, pg_dir, pu_dir);
+                        pgd_populate(&init_mm, pg_dir, pu_dir);
                 }
 
                 pu_dir = pud_offset(pg_dir, address);
@@ -103,7 +103,7 @@ static int vmem_add_mem(unsigned long start, unsigned long size, int ro)
                         pm_dir = vmem_pmd_alloc();
                         if (!pm_dir)
                                 goto out;
-                        pud_populate_kernel(&init_mm, pu_dir, pm_dir);
+                        pud_populate(&init_mm, pu_dir, pm_dir);
                 }
 
                 pte = mk_pte_phys(address, __pgprot(ro ? _PAGE_RO : 0));
@@ -123,7 +123,7 @@ static int vmem_add_mem(unsigned long start, unsigned long size, int ro)
                         pt_dir = vmem_pte_alloc();
                         if (!pt_dir)
                                 goto out;
-                        pmd_populate_kernel(&init_mm, pm_dir, pt_dir);
+                        pmd_populate(&init_mm, pm_dir, pt_dir);
                 }
 
                 pt_dir = pte_offset_kernel(pm_dir, address);
@@ -159,7 +159,7 @@ static void vmem_remove_range(unsigned long start, unsigned long size)
                         continue;
 
                 if (pmd_huge(*pm_dir)) {
-                        pmd_clear_kernel(pm_dir);
+                        pmd_clear(pm_dir);
                         address += HPAGE_SIZE - PAGE_SIZE;
                         continue;
                 }
@@ -192,7 +192,7 @@ int __meminit vmemmap_populate(struct page *start, unsigned long nr, int node)
                         pu_dir = vmem_pud_alloc();
                         if (!pu_dir)
                                 goto out;
-                        pgd_populate_kernel(&init_mm, pg_dir, pu_dir);
+                        pgd_populate(&init_mm, pg_dir, pu_dir);
                 }
 
                 pu_dir = pud_offset(pg_dir, address);
@@ -200,7 +200,7 @@ int __meminit vmemmap_populate(struct page *start, unsigned long nr, int node)
                         pm_dir = vmem_pmd_alloc();
                         if (!pm_dir)
                                 goto out;
-                        pud_populate_kernel(&init_mm, pu_dir, pm_dir);
+                        pud_populate(&init_mm, pu_dir, pm_dir);
                 }
 
                 pm_dir = pmd_offset(pu_dir, address);
@@ -208,7 +208,7 @@ int __meminit vmemmap_populate(struct page *start, unsigned long nr, int node)
                         pt_dir = vmem_pte_alloc();
                         if (!pt_dir)
                                 goto out;
-                        pmd_populate_kernel(&init_mm, pm_dir, pt_dir);
+                        pmd_populate(&init_mm, pm_dir, pt_dir);
                 }
 
                 pt_dir = pte_offset_kernel(pm_dir, address);