s390/mm: make use of ipte range facility

Invalidate several pte entries at once if the ipte range facility
is available. Currently this works only for DEBUG_PAGE_ALLOC where
several up to 2 ^ MAX_ORDER may be invalidated at once.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/include/asm/pgtable.h

@@ -1053,6 +1053,22 @@ static inline void __ptep_ipte_local(unsigned long address, pte_t *ptep)
 		: "=m" (*ptep) : "m" (*ptep), "a" (pto), "a" (address));
 }
 
+static inline void __ptep_ipte_range(unsigned long address, int nr, pte_t *ptep)
+{
+	unsigned long pto = (unsigned long) ptep;
+
+#ifndef CONFIG_64BIT
+	/* pto in ESA mode must point to the start of the segment table */
+	pto &= 0x7ffffc00;
+#endif
+	/* Invalidate a range of ptes + global TLB flush of the ptes */
+	do {
+		asm volatile(
+			"	.insn rrf,0xb2210000,%2,%0,%1,0"
+			: "+a" (address), "+a" (nr) : "a" (pto) : "memory");
+	} while (nr != 255);
+}
+
 static inline void ptep_flush_direct(struct mm_struct *mm,
 				     unsigned long address, pte_t *ptep)
 {

arch/s390/mm/pageattr.c

@@ -6,6 +6,7 @@
 #include <linux/module.h>
 #include <linux/mm.h>
 #include <asm/cacheflush.h>
+#include <asm/facility.h>
 #include <asm/pgtable.h>
 #include <asm/page.h>
 
@@ -103,27 +104,50 @@ int set_memory_x(unsigned long addr, int numpages)
 }
 
 #ifdef CONFIG_DEBUG_PAGEALLOC
+
+static void ipte_range(pte_t *pte, unsigned long address, int nr)
+{
+	int i;
+
+	if (test_facility(13) && IS_ENABLED(CONFIG_64BIT)) {
+		__ptep_ipte_range(address, nr - 1, pte);
+		return;
+	}
+	for (i = 0; i < nr; i++) {
+		__ptep_ipte(address, pte);
+		address += PAGE_SIZE;
+		pte++;
+	}
+}
+
 void kernel_map_pages(struct page *page, int numpages, int enable)
 {
 	unsigned long address;
+	int nr, i, j;
 	pgd_t *pgd;
 	pud_t *pud;
 	pmd_t *pmd;
 	pte_t *pte;
-	int i;
 
-	for (i = 0; i < numpages; i++) {
+	for (i = 0; i < numpages;) {
 		address = page_to_phys(page + i);
 		pgd = pgd_offset_k(address);
 		pud = pud_offset(pgd, address);
 		pmd = pmd_offset(pud, address);
 		pte = pte_offset_kernel(pmd, address);
-		if (!enable) {
-			__ptep_ipte(address, pte);
-			pte_val(*pte) = _PAGE_INVALID;
-			continue;
+		nr = (unsigned long)pte >> ilog2(sizeof(long));
+		nr = PTRS_PER_PTE - (nr & (PTRS_PER_PTE - 1));
+		nr = min(numpages - i, nr);
+		if (enable) {
+			for (j = 0; j < nr; j++) {
+				pte_val(*pte) = __pa(address);
+				address += PAGE_SIZE;
+				pte++;
+			}
+		} else {
+			ipte_range(pte, address, nr);
 		}
-		pte_val(*pte) = __pa(address);
+		i += nr;
 	}
 }