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>

diff --git a/arch/s390/include/asm/page.h b/arch/s390/include/asm/page.h
index 75ce9b0..5d64fb7 100644 (file)
--- 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)