s390/boot: add dfltcc= kernel command line parameter

Add the new kernel command line parameter 'dfltcc=' to configure s390
zlib hardware support.

Format: { on | off | def_only | inf_only | always }
 on:       s390 zlib hardware support for compression on
           level 1 and decompression (default)
 off:      No s390 zlib hardware support
 def_only: s390 zlib hardware support for deflate
           only (compression on level 1)
 inf_only: s390 zlib hardware support for inflate
           only (decompression)
 always:   Same as 'on' but ignores the selected compression
           level always using hardware support (used for debugging)

Link: http://lkml.kernel.org/r/20200103223334.20669-5-zaslonko@linux.ibm.com
Signed-off-by: Mikhail Zaslonko <zaslonko@linux.ibm.com>
Cc: Chris Mason <clm@fb.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: David Sterba <dsterba@suse.com>
Cc: Eduard Shishkin <edward6@linux.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Ilya Leoshkevich <iii@linux.ibm.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/zlib_dfltcc/dfltcc_util.h

@@ -4,6 +4,7 @@
 
 #include <linux/zutil.h>
 #include <asm/facility.h>
+#include <asm/setup.h>
 
 /*
  * C wrapper for the DEFLATE CONVERSION CALL instruction.
@@ -102,7 +103,8 @@ static inline int dfltcc_are_params_ok(
 
 static inline int is_dfltcc_enabled(void)
 {
-    return test_facility(DFLTCC_FACILITY);
+    return (zlib_dfltcc_support != ZLIB_DFLTCC_DISABLED &&
+            test_facility(DFLTCC_FACILITY));
 }
 
 char *oesc_msg(char *buf, int oesc);