[S390] Cleanup page table definitions.

- De-confuse the defines for the address-space-control-elements
  and the segment/region table entries.
- Create out of line functions for page table allocation / freeing.
- Simplify get_shadow_xxx functions.

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

4 files changed, 114 insertions, 29 deletions

diff --git a/arch/s390/mm/Makefile b/arch/s390/mm/Makefile
index f95449b..6640193 100644
--- a/arch/s390/mm/Makefile
+++ b/arch/s390/mm/Makefile
@@ -2,6 +2,6 @@
 # Makefile for the linux s390-specific parts of the memory manager.
 #
 
-obj-y	 := init.o fault.o extmem.o mmap.o vmem.o
+obj-y	 := init.o fault.o extmem.o mmap.o vmem.o pgtable.o
 obj-$(CONFIG_CMM) += cmm.o
 
diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
index 3a25bbf..90ec058 100644
--- a/arch/s390/mm/init.c
+++ b/arch/s390/mm/init.c
@@ -103,32 +103,28 @@ static void __init setup_ro_region(void)
  */
 void __init paging_init(void)
 {
-	pgd_t *pg_dir;
-	int i;
-	unsigned long pgdir_k;
 	static const int ssm_mask = 0x04000000L;
 	unsigned long max_zone_pfns[MAX_NR_ZONES];
+	unsigned long pgd_type;
 
-	pg_dir = swapper_pg_dir;
-	
+	init_mm.pgd = swapper_pg_dir;
+	S390_lowcore.kernel_asce = __pa(init_mm.pgd) & PAGE_MASK;
 #ifdef CONFIG_64BIT
-	pgdir_k = (__pa(swapper_pg_dir) & PAGE_MASK) | _KERN_REGION_TABLE;
-	for (i = 0; i < PTRS_PER_PGD; i++)
-		pgd_clear_kernel(pg_dir + i);
+	S390_lowcore.kernel_asce |= _ASCE_TYPE_REGION3 | _ASCE_TABLE_LENGTH;
+	pgd_type = _REGION3_ENTRY_EMPTY;
 #else
-	pgdir_k = (__pa(swapper_pg_dir) & PAGE_MASK) | _KERNSEG_TABLE;
-	for (i = 0; i < PTRS_PER_PGD; i++)
-		pmd_clear_kernel((pmd_t *)(pg_dir + i));
+	S390_lowcore.kernel_asce |= _ASCE_TABLE_LENGTH;
+	pgd_type = _SEGMENT_ENTRY_EMPTY;
 #endif
+	clear_table((unsigned long *) init_mm.pgd, pgd_type,
+		    sizeof(unsigned long)*2048);
 	vmem_map_init();
 	setup_ro_region();
 
-	S390_lowcore.kernel_asce = pgdir_k;
-
         /* enable virtual mapping in kernel mode */
-	__ctl_load(pgdir_k, 1, 1);
-	__ctl_load(pgdir_k, 7, 7);
-	__ctl_load(pgdir_k, 13, 13);
+	__ctl_load(S390_lowcore.kernel_asce, 1, 1);
+	__ctl_load(S390_lowcore.kernel_asce, 7, 7);
+	__ctl_load(S390_lowcore.kernel_asce, 13, 13);
 	__raw_local_irq_ssm(ssm_mask);
 
 	memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c
new file mode 100644
index 0000000..e60e0ae
--- /dev/null
+++ b/arch/s390/mm/pgtable.c
@@ -0,0 +1,94 @@
+/*
+ *  arch/s390/mm/pgtable.c
+ *
+ *    Copyright IBM Corp. 2007
+ *    Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
+ */
+
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/mm.h>
+#include <linux/swap.h>
+#include <linux/smp.h>
+#include <linux/highmem.h>
+#include <linux/slab.h>
+#include <linux/pagemap.h>
+#include <linux/spinlock.h>
+#include <linux/module.h>
+#include <linux/quicklist.h>
+
+#include <asm/system.h>
+#include <asm/pgtable.h>
+#include <asm/pgalloc.h>
+#include <asm/tlb.h>
+#include <asm/tlbflush.h>
+
+#ifndef CONFIG_64BIT
+#define ALLOC_ORDER	1
+#else
+#define ALLOC_ORDER	2
+#endif
+
+unsigned long *crst_table_alloc(struct mm_struct *mm, int noexec)
+{
+	struct page *page = alloc_pages(GFP_KERNEL, ALLOC_ORDER);
+
+	if (!page)
+		return NULL;
+	page->index = 0;
+	if (noexec) {
+		struct page *shadow = alloc_pages(GFP_KERNEL, ALLOC_ORDER);
+		if (!shadow) {
+			__free_pages(page, ALLOC_ORDER);
+			return NULL;
+		}
+		page->index = page_to_phys(shadow);
+	}
+	return (unsigned long *) page_to_phys(page);
+}
+
+void crst_table_free(unsigned long *table)
+{
+	unsigned long *shadow = get_shadow_table(table);
+
+	if (shadow)
+		free_pages((unsigned long) shadow, ALLOC_ORDER);
+	free_pages((unsigned long) table, ALLOC_ORDER);
+}
+
+/*
+ * page table entry allocation/free routines.
+ */
+unsigned long *page_table_alloc(int noexec)
+{
+	struct page *page = alloc_page(GFP_KERNEL);
+	unsigned long *table;
+
+	if (!page)
+		return NULL;
+	page->index = 0;
+	if (noexec) {
+		struct page *shadow = alloc_page(GFP_KERNEL);
+		if (!shadow) {
+			__free_page(page);
+			return NULL;
+		}
+		table = (unsigned long *) page_to_phys(shadow);
+		clear_table(table, _PAGE_TYPE_EMPTY, PAGE_SIZE);
+		page->index = (addr_t) table;
+	}
+	table = (unsigned long *) page_to_phys(page);
+	clear_table(table, _PAGE_TYPE_EMPTY, PAGE_SIZE);
+	return table;
+}
+
+void page_table_free(unsigned long *table)
+{
+	unsigned long *shadow = get_shadow_pte(table);
+
+	if (shadow)
+		free_page((unsigned long) shadow);
+	free_page((unsigned long) table);
+
+}
diff --git a/arch/s390/mm/vmem.c b/arch/s390/mm/vmem.c
index fd594d5..1bd51d8 100644
--- a/arch/s390/mm/vmem.c
+++ b/arch/s390/mm/vmem.c
@@ -75,29 +75,24 @@ static void __init_refok *vmem_alloc_pages(unsigned int order)
 
 static inline pmd_t *vmem_pmd_alloc(void)
 {
-	pmd_t *pmd;
-	int i;
+	pmd_t *pmd = NULL;
 
-	pmd = vmem_alloc_pages(PMD_ALLOC_ORDER);
+#ifdef CONFIG_64BIT
+	pmd = vmem_alloc_pages(2);
 	if (!pmd)
 		return NULL;
-	for (i = 0; i < PTRS_PER_PMD; i++)
-		pmd_clear_kernel(pmd + i);
+	clear_table((unsigned long *) pmd, _SEGMENT_ENTRY_EMPTY, PAGE_SIZE*4);
+#endif
 	return pmd;
 }
 
 static inline pte_t *vmem_pte_alloc(void)
 {
-	pte_t *pte;
-	pte_t empty_pte;
-	int i;
+	pte_t *pte = vmem_alloc_pages(0);
 
-	pte = vmem_alloc_pages(PTE_ALLOC_ORDER);
 	if (!pte)
 		return NULL;
-	pte_val(empty_pte) = _PAGE_TYPE_EMPTY;
-	for (i = 0; i < PTRS_PER_PTE; i++)
-		pte[i] = empty_pte;
+	clear_table((unsigned long *) pte, _PAGE_TYPE_EMPTY, PAGE_SIZE);
 	return pte;
 }