s390: disable pfmf for clear page instruction

Wit the introduction of large pages Linux also used pfmf for page
clearing. The current implementation is not ideal, though:
- currently we set usage intent=0, but cleared pages are often used
directly after the clearing
- z/VM does not yet provide EDAT
- KVM does have to intercept PFMF even for resident pages

Lets just the mvcl loop in all cases until we have a well defined
pattern were pfmf is besser.

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

1 files changed, 8 insertions, 12 deletions

diff --git a/arch/s390/include/asm/page.h b/arch/s390/include/asm/page.h
index 75ce9b065f9f..5d64fb7619cc 100644
--- a/arch/s390/include/asm/page.h
+++ b/arch/s390/include/asm/page.h
@@ -32,7 +32,7 @@
 
 void storage_key_init_range(unsigned long start, unsigned long end);
 
-static unsigned long pfmf(unsigned long function, unsigned long address)
+static inline unsigned long pfmf(unsigned long function, unsigned long address)
 {
         asm volatile(
                 "       .insn   rre,0xb9af0000,%[function],%[address]"
@@ -44,17 +44,13 @@ static unsigned long pfmf(unsigned long function, unsigned long address)
 
 static inline void clear_page(void *page)
 {
-        if (MACHINE_HAS_PFMF) {
-                pfmf(0x10000, (unsigned long)page);
-        } else {
-                register unsigned long reg1 asm ("1") = 0;
-                register void *reg2 asm ("2") = page;
-                register unsigned long reg3 asm ("3") = 4096;
-                asm volatile(
-                        "       mvcl    2,0"
-                        : "+d" (reg2), "+d" (reg3) : "d" (reg1)
-                        : "memory", "cc");
-        }
+        register unsigned long reg1 asm ("1") = 0;
+        register void *reg2 asm ("2") = page;
+        register unsigned long reg3 asm ("3") = 4096;
+        asm volatile(
+                "       mvcl    2,0"
+                : "+d" (reg2), "+d" (reg3) : "d" (reg1)
+                : "memory", "cc");
 }
 
 static inline void copy_page(void *to, void *from)